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	<id>https://physwiki.apps01.yorku.ca//api.php?action=feedcontributions&amp;feedformat=atom&amp;user=Halatm</id>
	<title>Physics Wiki - User contributions [en]</title>
	<link rel="self" type="application/atom+xml" href="https://physwiki.apps01.yorku.ca//api.php?action=feedcontributions&amp;feedformat=atom&amp;user=Halatm"/>
	<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=Special:Contributions/Halatm"/>
	<updated>2026-04-14T20:17:14Z</updated>
	<subtitle>User contributions</subtitle>
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	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=Main_Page&amp;diff=61872</id>
		<title>Main Page</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=Main_Page&amp;diff=61872"/>
		<updated>2013-06-06T17:24:51Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&amp;lt;h1&amp;gt; Undergraduate Physics @ York University &amp;lt;/h1&amp;gt;&lt;br /&gt;
 {|&lt;br /&gt;
&lt;br /&gt;
|rowspan=&amp;quot;4&amp;quot;|[[File:Yorklogo.JPG|200px]]&lt;br /&gt;
|&amp;lt;b&amp;gt;Department of Physics and Astronomy&amp;lt;/b&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;b&amp;gt; Toronto, Ontario, Canada&amp;lt;/b&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;b&amp;gt;phas@yorku.ca&amp;lt;/b&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;b&amp;gt;416-736-5249&amp;lt;/b&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&amp;lt;h1&amp;gt;Courses&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[PHYS_1010, 1410 &amp;amp; 1420|PHYS 1010/1410/1420 -First Year Physics]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[Main Page/PHYS 3220|PHYS 3220  Experiments in Modern Physics]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt; [[Main Page/BPHS 4090|BPHS 4090  Biophysics II]]&amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt; [[Main Page/PHYS 4210|PHYS 4210/4211  Advanced Experimental Physics I/II]]&amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt; [[Main Page/PHYS 4061|PHYS 4061/5061  Experimental Techniques in Laser Physics]]&amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61871</id>
		<title>PHYS 1010, 1410 &amp; 1420</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61871"/>
		<updated>2013-06-05T17:37:29Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;[[File:BP.png|center|border]]&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;center&amp;gt;First year physics laboratories are located in '''102C''' and '''102D''' Bethune College and the classes are divided into Sections '''X''' and '''Y'''. &amp;lt;br /&amp;gt;&lt;br /&gt;
To find out which Section you are in, check the lists posted on the lab [http://google.ca website] or on the bulletin board located at the entrance to 102C Bethune College.&amp;lt;/center&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
=General Information=&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[LAB INFORMATION|LAB INFORMATION]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[MEASUREMENTS AND ERRORS|MEASUREMENTS AND ERRORS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[MEASURING LENGTH|MEASURING LENGTH]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[GRAPHS|GRAPHS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;br /&gt;
=Courses=&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1010 6.0 PHYSICS|SC/PHYS 1010 6.0 PHYSICS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1410 6.0 PHYSICAL SCIENCE|SC/PHYS 1410 6.0 PHYSICAL SCIENCE]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES|SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61870</id>
		<title>PHYS 1010, 1410 &amp; 1420</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61870"/>
		<updated>2013-06-05T17:32:32Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;[[File:BP.png|center]]&lt;br /&gt;
&amp;lt;center&amp;gt;First year physics laboratories are located in '''102C''' and '''102D''' Bethune College and the classes are divided into Sections '''X''' and '''Y'''. &lt;br /&gt;
To find out which Section you are in, check the lists posted on the lab [http://google.ca website] or on the bulletin board located at the entrance to 102C Bethune College.&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;h1&amp;gt;General Information&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[LAB INFORMATION|LAB INFORMATION]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[MEASUREMENTS AND ERRORS|MEASUREMENTS AND ERRORS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[MEASURING LENGTH|MEASURING LENGTH]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[GRAPHS|GRAPHS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;h1&amp;gt;Courses&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1010 6.0 PHYSICS|SC/PHYS 1010 6.0 PHYSICS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1410 6.0 PHYSICAL SCIENCE|SC/PHYS 1410 6.0 PHYSICAL SCIENCE]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES|SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61869</id>
		<title>PHYS 1010, 1410 &amp; 1420</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61869"/>
		<updated>2013-06-05T17:31:17Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;[[File:BP.png|center]]&lt;br /&gt;
&amp;lt;center&amp;gt;First year physics laboratories are located in '''102C''' and '''102D''' Bethune College. &lt;br /&gt;
Physics lab classes are divided into Sections '''X''' and '''Y'''. &lt;br /&gt;
To find out which Section you are in, check the lists posted on the lab [http://google.ca website] or on the bulletin board located at the entrance to 102C Bethune College.&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;h1&amp;gt;General Information&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[LAB INFORMATION|LAB INFORMATION]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[MEASUREMENTS AND ERRORS|MEASUREMENTS AND ERRORS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[MEASURING LENGTH|MEASURING LENGTH]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[GRAPHS|GRAPHS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;h1&amp;gt;Courses&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1010 6.0 PHYSICS|SC/PHYS 1010 6.0 PHYSICS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1410 6.0 PHYSICAL SCIENCE|SC/PHYS 1410 6.0 PHYSICAL SCIENCE]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES|SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61868</id>
		<title>PHYS 1010, 1410 &amp; 1420</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61868"/>
		<updated>2013-06-05T17:30:29Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;[[File:BP.png|center]]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&amp;lt;center&amp;gt;First year physics laboratories are located in '''102C''' and '''102D''' Bethune College. &lt;br /&gt;
Physics lab classes are divided into Sections '''X''' and '''Y'''. &lt;br /&gt;
To find out which Section you are in, check the lists posted on the lab [http://google.ca website] or on the bulletin board located at the entrance to 102C Bethune College.&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;h1&amp;gt;General Information&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[LAB INFORMATION|LAB INFORMATION]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[MEASUREMENTS AND ERRORS|MEASUREMENTS AND ERRORS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[MEASURING LENGTH|MEASURING LENGTH]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[GRAPHS|GRAPHS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;h1&amp;gt;Courses&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1010 6.0 PHYSICS|SC/PHYS 1010 6.0 PHYSICS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1410 6.0 PHYSICAL SCIENCE|SC/PHYS 1410 6.0 PHYSICAL SCIENCE]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES|SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61867</id>
		<title>PHYS 1010, 1410 &amp; 1420</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61867"/>
		<updated>2013-06-05T17:14:09Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;[[File:BP.png|center]]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
First year physics laboratories are located in '''102C''' and '''102D''' Bethune College. Physics lab classes are divided into Sections '''X''' and '''Y'''. &lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
To find out which Section you are in, check the lists posted on the lab [http://google.ca website] or on the bulletin board located at the entrance to 102C Bethune College.&lt;br /&gt;
&lt;br /&gt;
&amp;lt;h1&amp;gt;General Information&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[LAB INFORMATION|LAB INFORMATION]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[MEASUREMENTS AND ERRORS|MEASUREMENTS AND ERRORS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[MEASURING LENGTH|MEASURING LENGTH]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[GRAPHS|GRAPHS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;h1&amp;gt;Courses&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1010 6.0 PHYSICS|SC/PHYS 1010 6.0 PHYSICS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1410 6.0 PHYSICAL SCIENCE|SC/PHYS 1410 6.0 PHYSICAL SCIENCE]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES|SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=File:BP.png&amp;diff=61866</id>
		<title>File:BP.png</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=File:BP.png&amp;diff=61866"/>
		<updated>2013-06-05T17:13:10Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61865</id>
		<title>MEASUREMENTS AND ERRORS</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61865"/>
		<updated>2013-06-05T17:04:38Z</updated>

		<summary type="html">&lt;p&gt;Halatm: /* Relative and Percentage Errors */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;=MEASUREMENTS=&lt;br /&gt;
There are several requirements that must be met if a measurement is to be useful in a scientific experiment:&lt;br /&gt;
&lt;br /&gt;
==The Number of Determinations==&lt;br /&gt;
&lt;br /&gt;
It is a fundamental law of laboratory work that a single measurement is of little value because of the liability not only to gross mistakes but also to smaller random errors.&lt;br /&gt;
Accordingly, it is customary to repeat all measurements as many times as possible. The laws of statistics lead to the conclusion that the value having the highest possibility of being correct is the arithmetic mean or average, obtained by dividing the sum of the individual readings by the total number of observations.  Because of time limitations, we often suggest you do a minimal number of repetitive measurements but remember this reduces the reliability and respectability of your results.&lt;br /&gt;
&lt;br /&gt;
==Zero Reading==&lt;br /&gt;
&lt;br /&gt;
Every measurement is really a difference between two readings, although for convenience, most instruments are calibrated so that one of these readings will be zero. In many instruments, this zero is not exact for all time but may shift slightly due to wear or usage.  Thus it is essential that the zero be checked before every measurement where it is one of the two readings.  In some cases the zero can be reset manually, while in others it is necessary to record the exact zero reading and correct all subsequent readings accordingly.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
e.g.  When measuring the length AB, Fig. 1, a ruler could be placed (1) with 1.2 cm at A, then length AB = (4.0 - 1.2) cm = 2.8 cm.  The more usual ruler position (2) allows the length AB to be read as 2.8 cm directly, but remember this is still the difference between '''two''' readings: 2.8 cm and 0.0 cm.&lt;br /&gt;
[[File:Fzero.png|center|border|600px]]&lt;br /&gt;
&lt;br /&gt;
==Accuracy==&lt;br /&gt;
&lt;br /&gt;
Quantitative work requires that each measurement be made as accurately as possible.  The main units of a scale are usually divided, and the eye can easily subdivide a small a distance of 1 mm into five parts reasonably accurately.Thus, if a linear scale is divided into millimeters, e.g. on a high quality ruler, a reading could be expressed to 0.2 of a millimeter; e.g. 4.6 mm, 27.42 cm, where 3/5 and 1/5 of a mm are estimated by eye.  In cases where the reading falls exactly on a scale division, the estimated figure would be 0; e.g. 48.50 cm, indicating that you know the reading more accurately than 48.5 cm.  But it would not be possible to take a reading with greater accuracy then 0.2 mm with this equipment.  If the scale is not finely engraved, the lab meter sticks for example, it could probably only be read as 0.5 mm.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The accuracy desired from a measurement dictates the choice of instrument.  For example, a distance of 4 m should not be measured by a car's odometer, nor a distance of 2 km with a micrometer.  The student learns to decide which instrument is most appropriate for a certain measurement. Ideally, all measurements for any one experiment should have about the same percentage accuracy.&lt;br /&gt;
&lt;br /&gt;
==Significant Figures==&lt;br /&gt;
[[File:First_M_4.1.png|right|border]]&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
[[File:First_M_4.2.png|right|border]]&lt;br /&gt;
A significant figure is a digit which is reasonably trustworthy.  One and only one estimated or doubtful figure can be retained and regarded as significant in any measurement, or in any calculation involving physical measurements.  In the examples in (3) above, 4.6 mm has two significant figures, 27.42 cm has four significant figures.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The location of the decimal point has no relation to the number of significant figures.  The reading 6.54 cm could be written as 65.4 mm or as 0.0654 m without changing the number of significant figures - three in each case.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The presence of a zero is sometimes troublesome.  If it is used merely to indicate the location of the decimal point, it is not called a significant figure, as in 0.0654 m; if it is between two significant digits, as in a temperature reading of 20.5o, it is always significant.  A zero digit at the end of a number tends to be ambiguous.  In the absence of specific information we cannot tell whether it is there because it is the best estimate or merely to locate the decimal point.  In such cases the true situation should be expressed by writing the correct number of significant figures multiplied by the power of 10.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Thus a student measurement of the speed of light, 186,000 mi/s is best written as 1.86 x 105 mi/s to indicate that there are only three significant figures.  The latter form is called standard notation, and involves a number between 1 and 10 multiplied by the appropriate power of 10. It is equally important to include the zero at the end of a number if it is significant. If reading a meter-stick, one estimates to a fraction of a millimeter, then a reading of 20.00 cm is written quite correctly.  In such a case, valuable information would be thrown away if the reading were recorded as 20 cm.  The recorded number should always express the degree of accuracy of the reading.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
In computations involving measured quantities, carry only those digits which are significant.  Consider a rectangle whose sides are measured as 10.77 and 3.55 cm (the doubtful digits are underlined here). When these lengths are added to find the perimeter the last digit in the answer will also be doubtful.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
When the lengths are multiplied to obtain the area, any operation by a doubtful digit results in a doubtful digit.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
=ERRORS=&lt;br /&gt;
&lt;br /&gt;
A quantity measured or calculated by a scientists is only of value if he/she can attach to it quantitative limits within which he/she expects that it is accurate - that is, its uncertainty.  An uncertainty of 50% or even 100% is a vast improvement over no knowledge at all: an accuracy of ±10% is a great improvement over ±50% and so on. In fact much of science is directed toward reducing the uncertainties in specific quantities of scientific interest.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The uncertainty in a reading or calculated value is technically called on error.  The word has this precise meaning in science and carries no implication of mistake or sin.&lt;br /&gt;
&lt;br /&gt;
==Systematic Errors==&lt;br /&gt;
&lt;br /&gt;
*'''systematic error''' is one which always produces an error of the same sign.  Systematic errors may be sub-divided into three groups: instrumental, personal and external.  Corrections should be made for systematic errors when they are known to be present.&lt;br /&gt;
&lt;br /&gt;
*'''Instrumental Error''' is caused by faulty or inaccurate apparatus; for example an undetected zero error in a scale, an incorrectly adjusted watch.  If 0.2 mm has been worn off the end of this ruler, all readings will be 0.02 cm too high.&lt;br /&gt;
&lt;br /&gt;
*'''Personal Errors''' are due to some peculiarity or bias of the observer.  Probably the most common source of personal error is the tendency to assume that the first reading taken is correct.  A scientist must constantly be on guard against any bias of this nature and make each measurement as if it were completely isolated from all previous experience.  Other personal errors may be due to fatigue, the position of the eye relative to a scale, etc&lt;br /&gt;
&lt;br /&gt;
*'''External Errors''' are caused by external conditions (wind, temperature, humidity, vibration); examples are the expansion of a scale as the temperature rises or the swelling of a meter stick as humidity increases.&lt;br /&gt;
&lt;br /&gt;
==Random Errors==&lt;br /&gt;
&lt;br /&gt;
Random errors occur as variations which are due to a large number of factors.  Each factor adds its own contribution to the total error.  Resulting error is '''a matter of chance''' and, therefore, positive and negative errors are equally probable.  Because random errors are subject to the laws of chance, their effect in the experiment may be lessened by taking a large number of observations.  A simplified statistical treatment of random errors is described in Appendix A of this manual.&lt;br /&gt;
&lt;br /&gt;
==The Error Interval==&lt;br /&gt;
&lt;br /&gt;
If it is not practical or possible to repeat a measurement many times, the errors in measurement must be estimated differently.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Since the last digit recorded for a reading is only an estimation, there is some possibility of error in this digit due to the instrument itself and the judgement of the observer. Hence, the best that can be done is to assign some limits within which the observer believes the reading to be accurate.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
A reading of 6.540 cm might imply that it lay between 6.538 and 6.542 cm.  The reading would then be recorded as (6.540 ± 0.002 cm).  The scales on most instruments are as finely divided by the manufacturer as it is practical to read.  Hence, the error interval will probably be some fraction of the smallest readable division on the instrument; it might be 0.5 of a division, or perhaps 0.2 of a division. The error interval is a property of the instrument and the user, and will remain the same for all readings taken provided the scale is linear.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Remember that measurement of a quantity (such as length) also involves a zero reading, so the error in the quantity will be twice the reading error. '''Note that it is essential to quote an error with every set of measurements.'''&lt;br /&gt;
&lt;br /&gt;
==Absolute Errors==&lt;br /&gt;
&lt;br /&gt;
The estimation of an error interval gives what is called an &amp;quot;absolute&amp;quot; error.  It has the same units as the measurement itself; e.g. (2.56 &amp;amp;#8723; 0.03) cm.&lt;br /&gt;
&lt;br /&gt;
==Relative and Percentage Errors==&lt;br /&gt;
[[File:First_M_4.3.png|center]]&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=File:First_M_4.3.png&amp;diff=61864</id>
		<title>File:First M 4.3.png</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=File:First_M_4.3.png&amp;diff=61864"/>
		<updated>2013-06-05T17:03:59Z</updated>

		<summary type="html">&lt;p&gt;Halatm: uploaded a new version of &amp;amp;quot;File:First M 4.3.png&amp;amp;quot;&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61863</id>
		<title>MEASUREMENTS AND ERRORS</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61863"/>
		<updated>2013-06-05T17:01:56Z</updated>

		<summary type="html">&lt;p&gt;Halatm: /* Relative and Percentage Errors */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;=MEASUREMENTS=&lt;br /&gt;
There are several requirements that must be met if a measurement is to be useful in a scientific experiment:&lt;br /&gt;
&lt;br /&gt;
==The Number of Determinations==&lt;br /&gt;
&lt;br /&gt;
It is a fundamental law of laboratory work that a single measurement is of little value because of the liability not only to gross mistakes but also to smaller random errors.&lt;br /&gt;
Accordingly, it is customary to repeat all measurements as many times as possible. The laws of statistics lead to the conclusion that the value having the highest possibility of being correct is the arithmetic mean or average, obtained by dividing the sum of the individual readings by the total number of observations.  Because of time limitations, we often suggest you do a minimal number of repetitive measurements but remember this reduces the reliability and respectability of your results.&lt;br /&gt;
&lt;br /&gt;
==Zero Reading==&lt;br /&gt;
&lt;br /&gt;
Every measurement is really a difference between two readings, although for convenience, most instruments are calibrated so that one of these readings will be zero. In many instruments, this zero is not exact for all time but may shift slightly due to wear or usage.  Thus it is essential that the zero be checked before every measurement where it is one of the two readings.  In some cases the zero can be reset manually, while in others it is necessary to record the exact zero reading and correct all subsequent readings accordingly.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
e.g.  When measuring the length AB, Fig. 1, a ruler could be placed (1) with 1.2 cm at A, then length AB = (4.0 - 1.2) cm = 2.8 cm.  The more usual ruler position (2) allows the length AB to be read as 2.8 cm directly, but remember this is still the difference between '''two''' readings: 2.8 cm and 0.0 cm.&lt;br /&gt;
[[File:Fzero.png|center|border|600px]]&lt;br /&gt;
&lt;br /&gt;
==Accuracy==&lt;br /&gt;
&lt;br /&gt;
Quantitative work requires that each measurement be made as accurately as possible.  The main units of a scale are usually divided, and the eye can easily subdivide a small a distance of 1 mm into five parts reasonably accurately.Thus, if a linear scale is divided into millimeters, e.g. on a high quality ruler, a reading could be expressed to 0.2 of a millimeter; e.g. 4.6 mm, 27.42 cm, where 3/5 and 1/5 of a mm are estimated by eye.  In cases where the reading falls exactly on a scale division, the estimated figure would be 0; e.g. 48.50 cm, indicating that you know the reading more accurately than 48.5 cm.  But it would not be possible to take a reading with greater accuracy then 0.2 mm with this equipment.  If the scale is not finely engraved, the lab meter sticks for example, it could probably only be read as 0.5 mm.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The accuracy desired from a measurement dictates the choice of instrument.  For example, a distance of 4 m should not be measured by a car's odometer, nor a distance of 2 km with a micrometer.  The student learns to decide which instrument is most appropriate for a certain measurement. Ideally, all measurements for any one experiment should have about the same percentage accuracy.&lt;br /&gt;
&lt;br /&gt;
==Significant Figures==&lt;br /&gt;
[[File:First_M_4.1.png|right|border]]&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
[[File:First_M_4.2.png|right|border]]&lt;br /&gt;
A significant figure is a digit which is reasonably trustworthy.  One and only one estimated or doubtful figure can be retained and regarded as significant in any measurement, or in any calculation involving physical measurements.  In the examples in (3) above, 4.6 mm has two significant figures, 27.42 cm has four significant figures.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The location of the decimal point has no relation to the number of significant figures.  The reading 6.54 cm could be written as 65.4 mm or as 0.0654 m without changing the number of significant figures - three in each case.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The presence of a zero is sometimes troublesome.  If it is used merely to indicate the location of the decimal point, it is not called a significant figure, as in 0.0654 m; if it is between two significant digits, as in a temperature reading of 20.5o, it is always significant.  A zero digit at the end of a number tends to be ambiguous.  In the absence of specific information we cannot tell whether it is there because it is the best estimate or merely to locate the decimal point.  In such cases the true situation should be expressed by writing the correct number of significant figures multiplied by the power of 10.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Thus a student measurement of the speed of light, 186,000 mi/s is best written as 1.86 x 105 mi/s to indicate that there are only three significant figures.  The latter form is called standard notation, and involves a number between 1 and 10 multiplied by the appropriate power of 10. It is equally important to include the zero at the end of a number if it is significant. If reading a meter-stick, one estimates to a fraction of a millimeter, then a reading of 20.00 cm is written quite correctly.  In such a case, valuable information would be thrown away if the reading were recorded as 20 cm.  The recorded number should always express the degree of accuracy of the reading.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
In computations involving measured quantities, carry only those digits which are significant.  Consider a rectangle whose sides are measured as 10.77 and 3.55 cm (the doubtful digits are underlined here). When these lengths are added to find the perimeter the last digit in the answer will also be doubtful.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
When the lengths are multiplied to obtain the area, any operation by a doubtful digit results in a doubtful digit.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
=ERRORS=&lt;br /&gt;
&lt;br /&gt;
A quantity measured or calculated by a scientists is only of value if he/she can attach to it quantitative limits within which he/she expects that it is accurate - that is, its uncertainty.  An uncertainty of 50% or even 100% is a vast improvement over no knowledge at all: an accuracy of ±10% is a great improvement over ±50% and so on. In fact much of science is directed toward reducing the uncertainties in specific quantities of scientific interest.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The uncertainty in a reading or calculated value is technically called on error.  The word has this precise meaning in science and carries no implication of mistake or sin.&lt;br /&gt;
&lt;br /&gt;
==Systematic Errors==&lt;br /&gt;
&lt;br /&gt;
*'''systematic error''' is one which always produces an error of the same sign.  Systematic errors may be sub-divided into three groups: instrumental, personal and external.  Corrections should be made for systematic errors when they are known to be present.&lt;br /&gt;
&lt;br /&gt;
*'''Instrumental Error''' is caused by faulty or inaccurate apparatus; for example an undetected zero error in a scale, an incorrectly adjusted watch.  If 0.2 mm has been worn off the end of this ruler, all readings will be 0.02 cm too high.&lt;br /&gt;
&lt;br /&gt;
*'''Personal Errors''' are due to some peculiarity or bias of the observer.  Probably the most common source of personal error is the tendency to assume that the first reading taken is correct.  A scientist must constantly be on guard against any bias of this nature and make each measurement as if it were completely isolated from all previous experience.  Other personal errors may be due to fatigue, the position of the eye relative to a scale, etc&lt;br /&gt;
&lt;br /&gt;
*'''External Errors''' are caused by external conditions (wind, temperature, humidity, vibration); examples are the expansion of a scale as the temperature rises or the swelling of a meter stick as humidity increases.&lt;br /&gt;
&lt;br /&gt;
==Random Errors==&lt;br /&gt;
&lt;br /&gt;
Random errors occur as variations which are due to a large number of factors.  Each factor adds its own contribution to the total error.  Resulting error is '''a matter of chance''' and, therefore, positive and negative errors are equally probable.  Because random errors are subject to the laws of chance, their effect in the experiment may be lessened by taking a large number of observations.  A simplified statistical treatment of random errors is described in Appendix A of this manual.&lt;br /&gt;
&lt;br /&gt;
==The Error Interval==&lt;br /&gt;
&lt;br /&gt;
If it is not practical or possible to repeat a measurement many times, the errors in measurement must be estimated differently.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Since the last digit recorded for a reading is only an estimation, there is some possibility of error in this digit due to the instrument itself and the judgement of the observer. Hence, the best that can be done is to assign some limits within which the observer believes the reading to be accurate.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
A reading of 6.540 cm might imply that it lay between 6.538 and 6.542 cm.  The reading would then be recorded as (6.540 ± 0.002 cm).  The scales on most instruments are as finely divided by the manufacturer as it is practical to read.  Hence, the error interval will probably be some fraction of the smallest readable division on the instrument; it might be 0.5 of a division, or perhaps 0.2 of a division. The error interval is a property of the instrument and the user, and will remain the same for all readings taken provided the scale is linear.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Remember that measurement of a quantity (such as length) also involves a zero reading, so the error in the quantity will be twice the reading error. '''Note that it is essential to quote an error with every set of measurements.'''&lt;br /&gt;
&lt;br /&gt;
==Absolute Errors==&lt;br /&gt;
&lt;br /&gt;
The estimation of an error interval gives what is called an &amp;quot;absolute&amp;quot; error.  It has the same units as the measurement itself; e.g. (2.56 &amp;amp;#8723; 0.03) cm.&lt;br /&gt;
&lt;br /&gt;
==Relative and Percentage Errors==&lt;br /&gt;
[[File:First_M_4.3.png]]&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=File:First_M_4.3.png&amp;diff=61862</id>
		<title>File:First M 4.3.png</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=File:First_M_4.3.png&amp;diff=61862"/>
		<updated>2013-06-05T17:00:54Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61861</id>
		<title>MEASUREMENTS AND ERRORS</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61861"/>
		<updated>2013-06-04T22:39:57Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;=MEASUREMENTS=&lt;br /&gt;
There are several requirements that must be met if a measurement is to be useful in a scientific experiment:&lt;br /&gt;
&lt;br /&gt;
==The Number of Determinations==&lt;br /&gt;
&lt;br /&gt;
It is a fundamental law of laboratory work that a single measurement is of little value because of the liability not only to gross mistakes but also to smaller random errors.&lt;br /&gt;
Accordingly, it is customary to repeat all measurements as many times as possible. The laws of statistics lead to the conclusion that the value having the highest possibility of being correct is the arithmetic mean or average, obtained by dividing the sum of the individual readings by the total number of observations.  Because of time limitations, we often suggest you do a minimal number of repetitive measurements but remember this reduces the reliability and respectability of your results.&lt;br /&gt;
&lt;br /&gt;
==Zero Reading==&lt;br /&gt;
&lt;br /&gt;
Every measurement is really a difference between two readings, although for convenience, most instruments are calibrated so that one of these readings will be zero. In many instruments, this zero is not exact for all time but may shift slightly due to wear or usage.  Thus it is essential that the zero be checked before every measurement where it is one of the two readings.  In some cases the zero can be reset manually, while in others it is necessary to record the exact zero reading and correct all subsequent readings accordingly.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
e.g.  When measuring the length AB, Fig. 1, a ruler could be placed (1) with 1.2 cm at A, then length AB = (4.0 - 1.2) cm = 2.8 cm.  The more usual ruler position (2) allows the length AB to be read as 2.8 cm directly, but remember this is still the difference between '''two''' readings: 2.8 cm and 0.0 cm.&lt;br /&gt;
[[File:Fzero.png|center|border|600px]]&lt;br /&gt;
&lt;br /&gt;
==Accuracy==&lt;br /&gt;
&lt;br /&gt;
Quantitative work requires that each measurement be made as accurately as possible.  The main units of a scale are usually divided, and the eye can easily subdivide a small a distance of 1 mm into five parts reasonably accurately.Thus, if a linear scale is divided into millimeters, e.g. on a high quality ruler, a reading could be expressed to 0.2 of a millimeter; e.g. 4.6 mm, 27.42 cm, where 3/5 and 1/5 of a mm are estimated by eye.  In cases where the reading falls exactly on a scale division, the estimated figure would be 0; e.g. 48.50 cm, indicating that you know the reading more accurately than 48.5 cm.  But it would not be possible to take a reading with greater accuracy then 0.2 mm with this equipment.  If the scale is not finely engraved, the lab meter sticks for example, it could probably only be read as 0.5 mm.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The accuracy desired from a measurement dictates the choice of instrument.  For example, a distance of 4 m should not be measured by a car's odometer, nor a distance of 2 km with a micrometer.  The student learns to decide which instrument is most appropriate for a certain measurement. Ideally, all measurements for any one experiment should have about the same percentage accuracy.&lt;br /&gt;
&lt;br /&gt;
==Significant Figures==&lt;br /&gt;
[[File:First_M_4.1.png|right|border]]&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
[[File:First_M_4.2.png|right|border]]&lt;br /&gt;
A significant figure is a digit which is reasonably trustworthy.  One and only one estimated or doubtful figure can be retained and regarded as significant in any measurement, or in any calculation involving physical measurements.  In the examples in (3) above, 4.6 mm has two significant figures, 27.42 cm has four significant figures.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The location of the decimal point has no relation to the number of significant figures.  The reading 6.54 cm could be written as 65.4 mm or as 0.0654 m without changing the number of significant figures - three in each case.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The presence of a zero is sometimes troublesome.  If it is used merely to indicate the location of the decimal point, it is not called a significant figure, as in 0.0654 m; if it is between two significant digits, as in a temperature reading of 20.5o, it is always significant.  A zero digit at the end of a number tends to be ambiguous.  In the absence of specific information we cannot tell whether it is there because it is the best estimate or merely to locate the decimal point.  In such cases the true situation should be expressed by writing the correct number of significant figures multiplied by the power of 10.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Thus a student measurement of the speed of light, 186,000 mi/s is best written as 1.86 x 105 mi/s to indicate that there are only three significant figures.  The latter form is called standard notation, and involves a number between 1 and 10 multiplied by the appropriate power of 10. It is equally important to include the zero at the end of a number if it is significant. If reading a meter-stick, one estimates to a fraction of a millimeter, then a reading of 20.00 cm is written quite correctly.  In such a case, valuable information would be thrown away if the reading were recorded as 20 cm.  The recorded number should always express the degree of accuracy of the reading.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
In computations involving measured quantities, carry only those digits which are significant.  Consider a rectangle whose sides are measured as 10.77 and 3.55 cm (the doubtful digits are underlined here). When these lengths are added to find the perimeter the last digit in the answer will also be doubtful.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
When the lengths are multiplied to obtain the area, any operation by a doubtful digit results in a doubtful digit.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
=ERRORS=&lt;br /&gt;
&lt;br /&gt;
A quantity measured or calculated by a scientists is only of value if he/she can attach to it quantitative limits within which he/she expects that it is accurate - that is, its uncertainty.  An uncertainty of 50% or even 100% is a vast improvement over no knowledge at all: an accuracy of ±10% is a great improvement over ±50% and so on. In fact much of science is directed toward reducing the uncertainties in specific quantities of scientific interest.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The uncertainty in a reading or calculated value is technically called on error.  The word has this precise meaning in science and carries no implication of mistake or sin.&lt;br /&gt;
&lt;br /&gt;
==Systematic Errors==&lt;br /&gt;
&lt;br /&gt;
*'''systematic error''' is one which always produces an error of the same sign.  Systematic errors may be sub-divided into three groups: instrumental, personal and external.  Corrections should be made for systematic errors when they are known to be present.&lt;br /&gt;
&lt;br /&gt;
*'''Instrumental Error''' is caused by faulty or inaccurate apparatus; for example an undetected zero error in a scale, an incorrectly adjusted watch.  If 0.2 mm has been worn off the end of this ruler, all readings will be 0.02 cm too high.&lt;br /&gt;
&lt;br /&gt;
*'''Personal Errors''' are due to some peculiarity or bias of the observer.  Probably the most common source of personal error is the tendency to assume that the first reading taken is correct.  A scientist must constantly be on guard against any bias of this nature and make each measurement as if it were completely isolated from all previous experience.  Other personal errors may be due to fatigue, the position of the eye relative to a scale, etc&lt;br /&gt;
&lt;br /&gt;
*'''External Errors''' are caused by external conditions (wind, temperature, humidity, vibration); examples are the expansion of a scale as the temperature rises or the swelling of a meter stick as humidity increases.&lt;br /&gt;
&lt;br /&gt;
==Random Errors==&lt;br /&gt;
&lt;br /&gt;
Random errors occur as variations which are due to a large number of factors.  Each factor adds its own contribution to the total error.  Resulting error is '''a matter of chance''' and, therefore, positive and negative errors are equally probable.  Because random errors are subject to the laws of chance, their effect in the experiment may be lessened by taking a large number of observations.  A simplified statistical treatment of random errors is described in Appendix A of this manual.&lt;br /&gt;
&lt;br /&gt;
==The Error Interval==&lt;br /&gt;
&lt;br /&gt;
If it is not practical or possible to repeat a measurement many times, the errors in measurement must be estimated differently.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Since the last digit recorded for a reading is only an estimation, there is some possibility of error in this digit due to the instrument itself and the judgement of the observer. Hence, the best that can be done is to assign some limits within which the observer believes the reading to be accurate.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
A reading of 6.540 cm might imply that it lay between 6.538 and 6.542 cm.  The reading would then be recorded as (6.540 ± 0.002 cm).  The scales on most instruments are as finely divided by the manufacturer as it is practical to read.  Hence, the error interval will probably be some fraction of the smallest readable division on the instrument; it might be 0.5 of a division, or perhaps 0.2 of a division. The error interval is a property of the instrument and the user, and will remain the same for all readings taken provided the scale is linear.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Remember that measurement of a quantity (such as length) also involves a zero reading, so the error in the quantity will be twice the reading error. '''Note that it is essential to quote an error with every set of measurements.'''&lt;br /&gt;
&lt;br /&gt;
==Absolute Errors==&lt;br /&gt;
&lt;br /&gt;
The estimation of an error interval gives what is called an &amp;quot;absolute&amp;quot; error.  It has the same units as the measurement itself; e.g. (2.56 &amp;amp;#8723; 0.03) cm.&lt;br /&gt;
&lt;br /&gt;
==Relative and Percentage Errors==&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61860</id>
		<title>MEASUREMENTS AND ERRORS</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61860"/>
		<updated>2013-06-04T22:36:07Z</updated>

		<summary type="html">&lt;p&gt;Halatm: /* The Error Interval */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;=MEASUREMENTS=&lt;br /&gt;
There are several requirements that must be met if a measurement is to be useful in a scientific experiment:&lt;br /&gt;
&lt;br /&gt;
==The Number of Determinations==&lt;br /&gt;
&lt;br /&gt;
It is a fundamental law of laboratory work that a single measurement is of little value because of the liability not only to gross mistakes but also to smaller random errors.&lt;br /&gt;
Accordingly, it is customary to repeat all measurements as many times as possible. The laws of statistics lead to the conclusion that the value having the highest possibility of being correct is the arithmetic mean or average, obtained by dividing the sum of the individual readings by the total number of observations.  Because of time limitations, we often suggest you do a minimal number of repetitive measurements but remember this reduces the reliability and respectability of your results.&lt;br /&gt;
&lt;br /&gt;
==Zero Reading==&lt;br /&gt;
&lt;br /&gt;
Every measurement is really a difference between two readings, although for convenience, most instruments are calibrated so that one of these readings will be zero. In many instruments, this zero is not exact for all time but may shift slightly due to wear or usage.  Thus it is essential that the zero be checked before every measurement where it is one of the two readings.  In some cases the zero can be reset manually, while in others it is necessary to record the exact zero reading and correct all subsequent readings accordingly.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
e.g.  When measuring the length AB, Fig. 1, a ruler could be placed (1) with 1.2 cm at A, then length AB = (4.0 - 1.2) cm = 2.8 cm.  The more usual ruler position (2) allows the length AB to be read as 2.8 cm directly, but remember this is still the difference between '''two''' readings: 2.8 cm and 0.0 cm.&lt;br /&gt;
[[File:Fzero.png|center|border|600px]]&lt;br /&gt;
&lt;br /&gt;
==Accuracy==&lt;br /&gt;
&lt;br /&gt;
Quantitative work requires that each measurement be made as accurately as possible.  The main units of a scale are usually divided, and the eye can easily subdivide a small a distance of 1 mm into five parts reasonably accurately.Thus, if a linear scale is divided into millimeters, e.g. on a high quality ruler, a reading could be expressed to 0.2 of a millimeter; e.g. 4.6 mm, 27.42 cm, where 3/5 and 1/5 of a mm are estimated by eye.  In cases where the reading falls exactly on a scale division, the estimated figure would be 0; e.g. 48.50 cm, indicating that you know the reading more accurately than 48.5 cm.  But it would not be possible to take a reading with greater accuracy then 0.2 mm with this equipment.  If the scale is not finely engraved, the lab meter sticks for example, it could probably only be read as 0.5 mm.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The accuracy desired from a measurement dictates the choice of instrument.  For example, a distance of 4 m should not be measured by a car's odometer, nor a distance of 2 km with a micrometer.  The student learns to decide which instrument is most appropriate for a certain measurement. Ideally, all measurements for any one experiment should have about the same percentage accuracy.&lt;br /&gt;
&lt;br /&gt;
==Significant Figures==&lt;br /&gt;
[[File:First_M_4.1.png|right|border]]&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
[[File:First_M_4.2.png|right|border]]&lt;br /&gt;
A significant figure is a digit which is reasonably trustworthy.  One and only one estimated or doubtful figure can be retained and regarded as significant in any measurement, or in any calculation involving physical measurements.  In the examples in (3) above, 4.6 mm has two significant figures, 27.42 cm has four significant figures.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The location of the decimal point has no relation to the number of significant figures.  The reading 6.54 cm could be written as 65.4 mm or as 0.0654 m without changing the number of significant figures - three in each case.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The presence of a zero is sometimes troublesome.  If it is used merely to indicate the location of the decimal point, it is not called a significant figure, as in 0.0654 m; if it is between two significant digits, as in a temperature reading of 20.5o, it is always significant.  A zero digit at the end of a number tends to be ambiguous.  In the absence of specific information we cannot tell whether it is there because it is the best estimate or merely to locate the decimal point.  In such cases the true situation should be expressed by writing the correct number of significant figures multiplied by the power of 10.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Thus a student measurement of the speed of light, 186,000 mi/s is best written as 1.86 x 105 mi/s to indicate that there are only three significant figures.  The latter form is called standard notation, and involves a number between 1 and 10 multiplied by the appropriate power of 10. It is equally important to include the zero at the end of a number if it is significant. If reading a meter-stick, one estimates to a fraction of a millimeter, then a reading of 20.00 cm is written quite correctly.  In such a case, valuable information would be thrown away if the reading were recorded as 20 cm.  The recorded number should always express the degree of accuracy of the reading.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
In computations involving measured quantities, carry only those digits which are significant.  Consider a rectangle whose sides are measured as 10.77 and 3.55 cm (the doubtful digits are underlined here). When these lengths are added to find the perimeter the last digit in the answer will also be doubtful.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
When the lengths are multiplied to obtain the area, any operation by a doubtful digit results in a doubtful digit.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
=ERRORS=&lt;br /&gt;
&lt;br /&gt;
A quantity measured or calculated by a scientists is only of value if he/she can attach to it quantitative limits within which he/she expects that it is accurate - that is, its uncertainty.  An uncertainty of 50% or even 100% is a vast improvement over no knowledge at all: an accuracy of ±10% is a great improvement over ±50% and so on. In fact much of science is directed toward reducing the uncertainties in specific quantities of scientific interest.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The uncertainty in a reading or calculated value is technically called on error.  The word has this precise meaning in science and carries no implication of mistake or sin.&lt;br /&gt;
&lt;br /&gt;
==Systematic Errors==&lt;br /&gt;
&lt;br /&gt;
*'''systematic error''' is one which always produces an error of the same sign.  Systematic errors may be sub-divided into three groups: instrumental, personal and external.  Corrections should be made for systematic errors when they are known to be present.&lt;br /&gt;
&lt;br /&gt;
*'''Instrumental Error''' is caused by faulty or inaccurate apparatus; for example an undetected zero error in a scale, an incorrectly adjusted watch.  If 0.2 mm has been worn off the end of this ruler, all readings will be 0.02 cm too high.&lt;br /&gt;
&lt;br /&gt;
*'''Personal Errors''' are due to some peculiarity or bias of the observer.  Probably the most common source of personal error is the tendency to assume that the first reading taken is correct.  A scientist must constantly be on guard against any bias of this nature and make each measurement as if it were completely isolated from all previous experience.  Other personal errors may be due to fatigue, the position of the eye relative to a scale, etc&lt;br /&gt;
&lt;br /&gt;
*'''External Errors''' are caused by external conditions (wind, temperature, humidity, vibration); examples are the expansion of a scale as the temperature rises or the swelling of a meter stick as humidity increases.&lt;br /&gt;
&lt;br /&gt;
==Random Errors==&lt;br /&gt;
&lt;br /&gt;
Random errors occur as variations which are due to a large number of factors.  Each factor adds its own contribution to the total error.  Resulting error is '''a matter of chance''' and, therefore, positive and negative errors are equally probable.  Because random errors are subject to the laws of chance, their effect in the experiment may be lessened by taking a large number of observations.  A simplified statistical treatment of random errors is described in Appendix A of this manual.&lt;br /&gt;
&lt;br /&gt;
==The Error Interval==&lt;br /&gt;
&lt;br /&gt;
If it is not practical or possible to repeat a measurement many times, the errors in measurement must be estimated differently.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Since the last digit recorded for a reading is only an estimation, there is some possibility of error in this digit due to the instrument itself and the judgement of the observer. Hence, the best that can be done is to assign some limits within which the observer believes the reading to be accurate.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
A reading of 6.540 cm might imply that it lay between 6.538 and 6.542 cm.  The reading would then be recorded as (6.540 ± 0.002 cm).  The scales on most instruments are as finely divided by the manufacturer as it is practical to read.  Hence, the error interval will probably be some fraction of the smallest readable division on the instrument; it might be 0.5 of a division, or perhaps 0.2 of a division. The error interval is a property of the instrument and the user, and will remain the same for all readings taken provided the scale is linear.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Remember that measurement of a quantity (such as length) also involves a zero reading, so the error in the quantity will be twice the reading error. '''Note that it is essential to quote an error with every set of measurements.'''&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61859</id>
		<title>MEASUREMENTS AND ERRORS</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61859"/>
		<updated>2013-06-04T22:35:46Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;=MEASUREMENTS=&lt;br /&gt;
There are several requirements that must be met if a measurement is to be useful in a scientific experiment:&lt;br /&gt;
&lt;br /&gt;
==The Number of Determinations==&lt;br /&gt;
&lt;br /&gt;
It is a fundamental law of laboratory work that a single measurement is of little value because of the liability not only to gross mistakes but also to smaller random errors.&lt;br /&gt;
Accordingly, it is customary to repeat all measurements as many times as possible. The laws of statistics lead to the conclusion that the value having the highest possibility of being correct is the arithmetic mean or average, obtained by dividing the sum of the individual readings by the total number of observations.  Because of time limitations, we often suggest you do a minimal number of repetitive measurements but remember this reduces the reliability and respectability of your results.&lt;br /&gt;
&lt;br /&gt;
==Zero Reading==&lt;br /&gt;
&lt;br /&gt;
Every measurement is really a difference between two readings, although for convenience, most instruments are calibrated so that one of these readings will be zero. In many instruments, this zero is not exact for all time but may shift slightly due to wear or usage.  Thus it is essential that the zero be checked before every measurement where it is one of the two readings.  In some cases the zero can be reset manually, while in others it is necessary to record the exact zero reading and correct all subsequent readings accordingly.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
e.g.  When measuring the length AB, Fig. 1, a ruler could be placed (1) with 1.2 cm at A, then length AB = (4.0 - 1.2) cm = 2.8 cm.  The more usual ruler position (2) allows the length AB to be read as 2.8 cm directly, but remember this is still the difference between '''two''' readings: 2.8 cm and 0.0 cm.&lt;br /&gt;
[[File:Fzero.png|center|border|600px]]&lt;br /&gt;
&lt;br /&gt;
==Accuracy==&lt;br /&gt;
&lt;br /&gt;
Quantitative work requires that each measurement be made as accurately as possible.  The main units of a scale are usually divided, and the eye can easily subdivide a small a distance of 1 mm into five parts reasonably accurately.Thus, if a linear scale is divided into millimeters, e.g. on a high quality ruler, a reading could be expressed to 0.2 of a millimeter; e.g. 4.6 mm, 27.42 cm, where 3/5 and 1/5 of a mm are estimated by eye.  In cases where the reading falls exactly on a scale division, the estimated figure would be 0; e.g. 48.50 cm, indicating that you know the reading more accurately than 48.5 cm.  But it would not be possible to take a reading with greater accuracy then 0.2 mm with this equipment.  If the scale is not finely engraved, the lab meter sticks for example, it could probably only be read as 0.5 mm.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The accuracy desired from a measurement dictates the choice of instrument.  For example, a distance of 4 m should not be measured by a car's odometer, nor a distance of 2 km with a micrometer.  The student learns to decide which instrument is most appropriate for a certain measurement. Ideally, all measurements for any one experiment should have about the same percentage accuracy.&lt;br /&gt;
&lt;br /&gt;
==Significant Figures==&lt;br /&gt;
[[File:First_M_4.1.png|right|border]]&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
[[File:First_M_4.2.png|right|border]]&lt;br /&gt;
A significant figure is a digit which is reasonably trustworthy.  One and only one estimated or doubtful figure can be retained and regarded as significant in any measurement, or in any calculation involving physical measurements.  In the examples in (3) above, 4.6 mm has two significant figures, 27.42 cm has four significant figures.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The location of the decimal point has no relation to the number of significant figures.  The reading 6.54 cm could be written as 65.4 mm or as 0.0654 m without changing the number of significant figures - three in each case.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The presence of a zero is sometimes troublesome.  If it is used merely to indicate the location of the decimal point, it is not called a significant figure, as in 0.0654 m; if it is between two significant digits, as in a temperature reading of 20.5o, it is always significant.  A zero digit at the end of a number tends to be ambiguous.  In the absence of specific information we cannot tell whether it is there because it is the best estimate or merely to locate the decimal point.  In such cases the true situation should be expressed by writing the correct number of significant figures multiplied by the power of 10.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Thus a student measurement of the speed of light, 186,000 mi/s is best written as 1.86 x 105 mi/s to indicate that there are only three significant figures.  The latter form is called standard notation, and involves a number between 1 and 10 multiplied by the appropriate power of 10. It is equally important to include the zero at the end of a number if it is significant. If reading a meter-stick, one estimates to a fraction of a millimeter, then a reading of 20.00 cm is written quite correctly.  In such a case, valuable information would be thrown away if the reading were recorded as 20 cm.  The recorded number should always express the degree of accuracy of the reading.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
In computations involving measured quantities, carry only those digits which are significant.  Consider a rectangle whose sides are measured as 10.77 and 3.55 cm (the doubtful digits are underlined here). When these lengths are added to find the perimeter the last digit in the answer will also be doubtful.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
When the lengths are multiplied to obtain the area, any operation by a doubtful digit results in a doubtful digit.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
=ERRORS=&lt;br /&gt;
&lt;br /&gt;
A quantity measured or calculated by a scientists is only of value if he/she can attach to it quantitative limits within which he/she expects that it is accurate - that is, its uncertainty.  An uncertainty of 50% or even 100% is a vast improvement over no knowledge at all: an accuracy of ±10% is a great improvement over ±50% and so on. In fact much of science is directed toward reducing the uncertainties in specific quantities of scientific interest.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The uncertainty in a reading or calculated value is technically called on error.  The word has this precise meaning in science and carries no implication of mistake or sin.&lt;br /&gt;
&lt;br /&gt;
==Systematic Errors==&lt;br /&gt;
&lt;br /&gt;
*'''systematic error''' is one which always produces an error of the same sign.  Systematic errors may be sub-divided into three groups: instrumental, personal and external.  Corrections should be made for systematic errors when they are known to be present.&lt;br /&gt;
&lt;br /&gt;
*'''Instrumental Error''' is caused by faulty or inaccurate apparatus; for example an undetected zero error in a scale, an incorrectly adjusted watch.  If 0.2 mm has been worn off the end of this ruler, all readings will be 0.02 cm too high.&lt;br /&gt;
&lt;br /&gt;
*'''Personal Errors''' are due to some peculiarity or bias of the observer.  Probably the most common source of personal error is the tendency to assume that the first reading taken is correct.  A scientist must constantly be on guard against any bias of this nature and make each measurement as if it were completely isolated from all previous experience.  Other personal errors may be due to fatigue, the position of the eye relative to a scale, etc&lt;br /&gt;
&lt;br /&gt;
*'''External Errors''' are caused by external conditions (wind, temperature, humidity, vibration); examples are the expansion of a scale as the temperature rises or the swelling of a meter stick as humidity increases.&lt;br /&gt;
&lt;br /&gt;
==Random Errors==&lt;br /&gt;
&lt;br /&gt;
Random errors occur as variations which are due to a large number of factors.  Each factor adds its own contribution to the total error.  Resulting error is '''a matter of chance''' and, therefore, positive and negative errors are equally probable.  Because random errors are subject to the laws of chance, their effect in the experiment may be lessened by taking a large number of observations.  A simplified statistical treatment of random errors is described in Appendix A of this manual.&lt;br /&gt;
&lt;br /&gt;
==The Error Interval==&lt;br /&gt;
&lt;br /&gt;
If it is not practical or possible to repeat a measurement many times, the errors in measurement must be estimated differently.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Since the last digit recorded for a reading is only an estimation, there is some possibility of error in this digit due to the instrument itself and the judgement of the observer. Hence, the best that can be done is to assign some limits within which the observer believes the reading to be accurate.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
A reading of 6.540 cm might imply that it lay between 6.538 and 6.542 cm.  The reading would then be recorded as (6.540 ± 0.002 cm).  The scales on most instruments are as finely divided by the manufacturer as it is practical to read.  Hence, the error interval will probably be some fraction of the smallest readable division on the instrument; it might be 0.5 of a division, or perhaps 0.2 of a division. The error interval is a property of the instrument and the user, and will remain the same for all readings taken provided the scale is linear.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Remember that measurement of a quantity (such as length) also involves a zero reading, so the error in the quantity will be twice the reading error. '''Note that it is essential to quote an error with every set of measurements.'''&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=File:First_M_4.2.png&amp;diff=61858</id>
		<title>File:First M 4.2.png</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=File:First_M_4.2.png&amp;diff=61858"/>
		<updated>2013-06-04T22:23:15Z</updated>

		<summary type="html">&lt;p&gt;Halatm: uploaded a new version of &amp;amp;quot;File:First M 4.2.png&amp;amp;quot;&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=File:First_M_4.2.png&amp;diff=61857</id>
		<title>File:First M 4.2.png</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=File:First_M_4.2.png&amp;diff=61857"/>
		<updated>2013-06-04T22:22:11Z</updated>

		<summary type="html">&lt;p&gt;Halatm: uploaded a new version of &amp;amp;quot;File:First M 4.2.png&amp;amp;quot;&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61856</id>
		<title>MEASUREMENTS AND ERRORS</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61856"/>
		<updated>2013-06-04T22:21:10Z</updated>

		<summary type="html">&lt;p&gt;Halatm: /* 4. Significant Figures */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;=MEASUREMENTS=&lt;br /&gt;
There are several requirements that must be met if a measurement is to be useful in a scientific experiment:&lt;br /&gt;
&lt;br /&gt;
==1. The Number of Determinations==&lt;br /&gt;
&lt;br /&gt;
It is a fundamental law of laboratory work that a single measurement is of little value because of the liability not only to gross mistakes but also to smaller random errors.&lt;br /&gt;
Accordingly, it is customary to repeat all measurements as many times as possible. The laws of statistics lead to the conclusion that the value having the highest possibility of being correct is the arithmetic mean or average, obtained by dividing the sum of the individual readings by the total number of observations.  Because of time limitations, we often suggest you do a minimal number of repetitive measurements but remember this reduces the reliability and respectability of your results.&lt;br /&gt;
&lt;br /&gt;
==2. Zero Reading==&lt;br /&gt;
&lt;br /&gt;
Every measurement is really a difference between two readings, although for convenience, most instruments are calibrated so that one of these readings will be zero. In many instruments, this zero is not exact for all time but may shift slightly due to wear or usage.  Thus it is essential that the zero be checked before every measurement where it is one of the two readings.  In some cases the zero can be reset manually, while in others it is necessary to record the exact zero reading and correct all subsequent readings accordingly.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
e.g.  When measuring the length AB, Fig. 1, a ruler could be placed (1) with 1.2 cm at A, then length AB = (4.0 - 1.2) cm = 2.8 cm.  The more usual ruler position (2) allows the length AB to be read as 2.8 cm directly, but remember this is still the difference between '''two''' readings: 2.8 cm and 0.0 cm.&lt;br /&gt;
[[File:Fzero.png|center|frame|600px]]&lt;br /&gt;
&lt;br /&gt;
==3. Accuracy==&lt;br /&gt;
&lt;br /&gt;
Quantitative work requires that each measurement be made as accurately as possible.  The main units of a scale are usually divided, and the eye can easily subdivide a small a distance of 1 mm into five parts reasonably accurately.Thus, if a linear scale is divided into millimeters, e.g. on a high quality ruler, a reading could be expressed to 0.2 of a millimeter; e.g. 4.6 mm, 27.42 cm, where 3/5 and 1/5 of a mm are estimated by eye.  In cases where the reading falls exactly on a scale division, the estimated figure would be 0; e.g. 48.50 cm, indicating that you know the reading more accurately than 48.5 cm.  But it would not be possible to take a reading with greater accuracy then 0.2 mm with this equipment.  If the scale is not finely engraved, the lab meter sticks for example, it could probably only be read as 0.5 mm.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The accuracy desired from a measurement dictates the choice of instrument.  For example, a distance of 4 m should not be measured by a car's odometer, nor a distance of 2 km with a micrometer.  The student learns to decide which instrument is most appropriate for a certain measurement. Ideally, all measurements for any one experiment should have about the same percentage accuracy.&lt;br /&gt;
&lt;br /&gt;
==4. Significant Figures==&lt;br /&gt;
[[File:First_M_4.1.png|right|frame]]&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
[[File:First_M_4.2.png|right|frame]]&lt;br /&gt;
A significant figure is a digit which is reasonably trustworthy.  One and only one estimated or doubtful figure can be retained and regarded as significant in any measurement, or in any calculation involving physical measurements.  In the examples in (3) above, 4.6 mm has two significant figures, 27.42 cm has four significant figures.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The location of the decimal point has no relation to the number of significant figures.  The reading 6.54 cm could be written as 65.4 mm or as 0.0654 m without changing the number of significant figures - three in each case.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The presence of a zero is sometimes troublesome.  If it is used merely to indicate the location of the decimal point, it is not called a significant figure, as in 0.0654 m; if it is between two significant digits, as in a temperature reading of 20.5o, it is always significant.  A zero digit at the end of a number tends to be ambiguous.  In the absence of specific information we cannot tell whether it is there because it is the best estimate or merely to locate the decimal point.  In such cases the true situation should be expressed by writing the correct number of significant figures multiplied by the power of 10.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Thus a student measurement of the speed of light, 186,000 mi/s is best written as 1.86 x 105 mi/s to indicate that there are only three significant figures.  The latter form is called standard notation, and involves a number between 1 and 10 multiplied by the appropriate power of 10. It is equally important to include the zero at the end of a number if it is significant. If reading a meter-stick, one estimates to a fraction of a millimeter, then a reading of 20.00 cm is written quite correctly.  In such a case, valuable information would be thrown away if the reading were recorded as 20 cm.  The recorded number should always express the degree of accuracy of the reading.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
In computations involving measured quantities, carry only those digits which are significant.  Consider a rectangle whose sides are measured as 10.77 and 3.55 cm (the doubtful digits are underlined here). When these lengths are added to find the perimeter the last digit in the answer will also be doubtful.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
When the lengths are multiplied to obtain the area, any operation by a doubtful digit results in a doubtful digit.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61855</id>
		<title>MEASUREMENTS AND ERRORS</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61855"/>
		<updated>2013-06-04T22:18:50Z</updated>

		<summary type="html">&lt;p&gt;Halatm: /* 4. Significant Figures */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;=MEASUREMENTS=&lt;br /&gt;
There are several requirements that must be met if a measurement is to be useful in a scientific experiment:&lt;br /&gt;
&lt;br /&gt;
==1. The Number of Determinations==&lt;br /&gt;
&lt;br /&gt;
It is a fundamental law of laboratory work that a single measurement is of little value because of the liability not only to gross mistakes but also to smaller random errors.&lt;br /&gt;
Accordingly, it is customary to repeat all measurements as many times as possible. The laws of statistics lead to the conclusion that the value having the highest possibility of being correct is the arithmetic mean or average, obtained by dividing the sum of the individual readings by the total number of observations.  Because of time limitations, we often suggest you do a minimal number of repetitive measurements but remember this reduces the reliability and respectability of your results.&lt;br /&gt;
&lt;br /&gt;
==2. Zero Reading==&lt;br /&gt;
&lt;br /&gt;
Every measurement is really a difference between two readings, although for convenience, most instruments are calibrated so that one of these readings will be zero. In many instruments, this zero is not exact for all time but may shift slightly due to wear or usage.  Thus it is essential that the zero be checked before every measurement where it is one of the two readings.  In some cases the zero can be reset manually, while in others it is necessary to record the exact zero reading and correct all subsequent readings accordingly.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
e.g.  When measuring the length AB, Fig. 1, a ruler could be placed (1) with 1.2 cm at A, then length AB = (4.0 - 1.2) cm = 2.8 cm.  The more usual ruler position (2) allows the length AB to be read as 2.8 cm directly, but remember this is still the difference between '''two''' readings: 2.8 cm and 0.0 cm.&lt;br /&gt;
[[File:Fzero.png|center|frame|600px]]&lt;br /&gt;
&lt;br /&gt;
==3. Accuracy==&lt;br /&gt;
&lt;br /&gt;
Quantitative work requires that each measurement be made as accurately as possible.  The main units of a scale are usually divided, and the eye can easily subdivide a small a distance of 1 mm into five parts reasonably accurately.Thus, if a linear scale is divided into millimeters, e.g. on a high quality ruler, a reading could be expressed to 0.2 of a millimeter; e.g. 4.6 mm, 27.42 cm, where 3/5 and 1/5 of a mm are estimated by eye.  In cases where the reading falls exactly on a scale division, the estimated figure would be 0; e.g. 48.50 cm, indicating that you know the reading more accurately than 48.5 cm.  But it would not be possible to take a reading with greater accuracy then 0.2 mm with this equipment.  If the scale is not finely engraved, the lab meter sticks for example, it could probably only be read as 0.5 mm.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The accuracy desired from a measurement dictates the choice of instrument.  For example, a distance of 4 m should not be measured by a car's odometer, nor a distance of 2 km with a micrometer.  The student learns to decide which instrument is most appropriate for a certain measurement. Ideally, all measurements for any one experiment should have about the same percentage accuracy.&lt;br /&gt;
&lt;br /&gt;
==4. Significant Figures==&lt;br /&gt;
&lt;br /&gt;
A significant figure is a digit which is reasonably trustworthy.  One and only one estimated or doubtful figure can be retained and regarded as significant in any measurement, or in any calculation involving physical measurements.  In the examples in (3) above, 4.6 mm has two significant figures, 27.42 cm has four significant figures.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The location of the decimal point has no relation to the number of significant figures.  The reading 6.54 cm could be written as 65.4 mm or as 0.0654 m without changing the number of significant figures - three in each case.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The presence of a zero is sometimes troublesome.  If it is used merely to indicate the location of the decimal point, it is not called a significant figure, as in 0.0654 m; if it is between two significant digits, as in a temperature reading of 20.5o, it is always significant.  A zero digit at the end of a number tends to be ambiguous.  In the absence of specific information we cannot tell whether it is there because it is the best estimate or merely to locate the decimal point.  In such cases the true situation should be expressed by writing the correct number of significant figures multiplied by the power of 10.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Thus a student measurement of the speed of light, 186,000 mi/s is best written as 1.86 x 105 mi/s to indicate that there are only three significant figures.  The latter form is called standard notation, and involves a number between 1 and 10 multiplied by the appropriate power of 10. It is equally important to include the zero at the end of a number if it is significant. If reading a meter-stick, one estimates to a fraction of a millimeter, then a reading of 20.00 cm is written quite correctly.  In such a case, valuable information would be thrown away if the reading were recorded as 20 cm.  The recorded number should always express the degree of accuracy of the reading.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
In computations involving measured quantities, carry only those digits which are significant.  Consider a rectangle whose sides are measured as 10.77 and 3.55 cm (the doubtful digits are underlined here). When these lengths are added to find the perimeter the last digit in the answer will also be doubtful.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
[[File:First_M_4.1.png|center|frame]]&lt;br /&gt;
When the lengths are multiplied to obtain the area, any operation by a doubtful digit results in a doubtful digit.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
[[File:First_M_4.2.png|center|frame]]&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=File:First_M_4.2.png&amp;diff=61854</id>
		<title>File:First M 4.2.png</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=File:First_M_4.2.png&amp;diff=61854"/>
		<updated>2013-06-04T22:17:45Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61853</id>
		<title>MEASUREMENTS AND ERRORS</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61853"/>
		<updated>2013-06-04T22:17:01Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;=MEASUREMENTS=&lt;br /&gt;
There are several requirements that must be met if a measurement is to be useful in a scientific experiment:&lt;br /&gt;
&lt;br /&gt;
==1. The Number of Determinations==&lt;br /&gt;
&lt;br /&gt;
It is a fundamental law of laboratory work that a single measurement is of little value because of the liability not only to gross mistakes but also to smaller random errors.&lt;br /&gt;
Accordingly, it is customary to repeat all measurements as many times as possible. The laws of statistics lead to the conclusion that the value having the highest possibility of being correct is the arithmetic mean or average, obtained by dividing the sum of the individual readings by the total number of observations.  Because of time limitations, we often suggest you do a minimal number of repetitive measurements but remember this reduces the reliability and respectability of your results.&lt;br /&gt;
&lt;br /&gt;
==2. Zero Reading==&lt;br /&gt;
&lt;br /&gt;
Every measurement is really a difference between two readings, although for convenience, most instruments are calibrated so that one of these readings will be zero. In many instruments, this zero is not exact for all time but may shift slightly due to wear or usage.  Thus it is essential that the zero be checked before every measurement where it is one of the two readings.  In some cases the zero can be reset manually, while in others it is necessary to record the exact zero reading and correct all subsequent readings accordingly.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
e.g.  When measuring the length AB, Fig. 1, a ruler could be placed (1) with 1.2 cm at A, then length AB = (4.0 - 1.2) cm = 2.8 cm.  The more usual ruler position (2) allows the length AB to be read as 2.8 cm directly, but remember this is still the difference between '''two''' readings: 2.8 cm and 0.0 cm.&lt;br /&gt;
[[File:Fzero.png|center|frame|600px]]&lt;br /&gt;
&lt;br /&gt;
==3. Accuracy==&lt;br /&gt;
&lt;br /&gt;
Quantitative work requires that each measurement be made as accurately as possible.  The main units of a scale are usually divided, and the eye can easily subdivide a small a distance of 1 mm into five parts reasonably accurately.Thus, if a linear scale is divided into millimeters, e.g. on a high quality ruler, a reading could be expressed to 0.2 of a millimeter; e.g. 4.6 mm, 27.42 cm, where 3/5 and 1/5 of a mm are estimated by eye.  In cases where the reading falls exactly on a scale division, the estimated figure would be 0; e.g. 48.50 cm, indicating that you know the reading more accurately than 48.5 cm.  But it would not be possible to take a reading with greater accuracy then 0.2 mm with this equipment.  If the scale is not finely engraved, the lab meter sticks for example, it could probably only be read as 0.5 mm.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The accuracy desired from a measurement dictates the choice of instrument.  For example, a distance of 4 m should not be measured by a car's odometer, nor a distance of 2 km with a micrometer.  The student learns to decide which instrument is most appropriate for a certain measurement. Ideally, all measurements for any one experiment should have about the same percentage accuracy.&lt;br /&gt;
&lt;br /&gt;
==4. Significant Figures==&lt;br /&gt;
&lt;br /&gt;
A significant figure is a digit which is reasonably trustworthy.  One and only one estimated or doubtful figure can be retained and regarded as significant in any measurement, or in any calculation involving physical measurements.  In the examples in (3) above, 4.6 mm has two significant figures, 27.42 cm has four significant figures.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The location of the decimal point has no relation to the number of significant figures.  The reading 6.54 cm could be written as 65.4 mm or as 0.0654 m without changing the number of significant figures - three in each case.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The presence of a zero is sometimes troublesome.  If it is used merely to indicate the location of the decimal point, it is not called a significant figure, as in 0.0654 m; if it is between two significant digits, as in a temperature reading of 20.5o, it is always significant.  A zero digit at the end of a number tends to be ambiguous.  In the absence of specific information we cannot tell whether it is there because it is the best estimate or merely to locate the decimal point.  In such cases the true situation should be expressed by writing the correct number of significant figures multiplied by the power of 10.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Thus a student measurement of the speed of light, 186,000 mi/s is best written as 1.86 x 105 mi/s to indicate that there are only three significant figures.  The latter form is called standard notation, and involves a number between 1 and 10 multiplied by the appropriate power of 10. It is equally important to include the zero at the end of a number if it is significant. If reading a meter-stick, one estimates to a fraction of a millimeter, then a reading of 20.00 cm is written quite correctly.  In such a case, valuable information would be thrown away if the reading were recorded as 20 cm.  The recorded number should always express the degree of accuracy of the reading.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
In computations involving measured quantities, carry only those digits which are significant.  Consider a rectangle whose sides are measured as 10.77 and 3.55 cm (the doubtful digits are underlined here). When these lengths are added to find the perimeter the last digit in the answer will also be doubtful.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
[[File:First_M_4.1.png|center|frame]]&lt;br /&gt;
When the lengths are multiplied to obtain the area, any operation by a doubtful digit results in a doubtful digit.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=File:First_M_4.1.png&amp;diff=61852</id>
		<title>File:First M 4.1.png</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=File:First_M_4.1.png&amp;diff=61852"/>
		<updated>2013-06-04T22:14:29Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61851</id>
		<title>MEASUREMENTS AND ERRORS</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61851"/>
		<updated>2013-06-04T22:12:16Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;=MEASUREMENTS=&lt;br /&gt;
There are several requirements that must be met if a measurement is to be useful in a scientific experiment:&lt;br /&gt;
&lt;br /&gt;
==1. The Number of Determinations==&lt;br /&gt;
&lt;br /&gt;
It is a fundamental law of laboratory work that a single measurement is of little value because of the liability not only to gross mistakes but also to smaller random errors.&lt;br /&gt;
Accordingly, it is customary to repeat all measurements as many times as possible. The laws of statistics lead to the conclusion that the value having the highest possibility of being correct is the arithmetic mean or average, obtained by dividing the sum of the individual readings by the total number of observations.  Because of time limitations, we often suggest you do a minimal number of repetitive measurements but remember this reduces the reliability and respectability of your results.&lt;br /&gt;
&lt;br /&gt;
==2. Zero Reading==&lt;br /&gt;
&lt;br /&gt;
Every measurement is really a difference between two readings, although for convenience, most instruments are calibrated so that one of these readings will be zero. In many instruments, this zero is not exact for all time but may shift slightly due to wear or usage.  Thus it is essential that the zero be checked before every measurement where it is one of the two readings.  In some cases the zero can be reset manually, while in others it is necessary to record the exact zero reading and correct all subsequent readings accordingly.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
e.g.  When measuring the length AB, Fig. 1, a ruler could be placed (1) with 1.2 cm at A, then length AB = (4.0 - 1.2) cm = 2.8 cm.  The more usual ruler position (2) allows the length AB to be read as 2.8 cm directly, but remember this is still the difference between '''two''' readings: 2.8 cm and 0.0 cm.&lt;br /&gt;
[[File:Fzero.png|center|frame|600px]]&lt;br /&gt;
&lt;br /&gt;
==3. Accuracy==&lt;br /&gt;
&lt;br /&gt;
Quantitative work requires that each measurement be made as accurately as possible.  The main units of a scale are usually divided, and the eye can easily subdivide a small a distance of 1 mm into five parts reasonably accurately.Thus, if a linear scale is divided into millimeters, e.g. on a high quality ruler, a reading could be expressed to 0.2 of a millimeter; e.g. 4.6 mm, 27.42 cm, where 3/5 and 1/5 of a mm are estimated by eye.  In cases where the reading falls exactly on a scale division, the estimated figure would be 0; e.g. 48.50 cm, indicating that you know the reading more accurately than 48.5 cm.  But it would not be possible to take a reading with greater accuracy then 0.2 mm with this equipment.  If the scale is not finely engraved, the lab meter sticks for example, it could probably only be read as 0.5 mm.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The accuracy desired from a measurement dictates the choice of instrument.  For example, a distance of 4 m should not be measured by a car's odometer, nor a distance of 2 km with a micrometer.  The student learns to decide which instrument is most appropriate for a certain measurement. Ideally, all measurements for any one experiment should have about the same percentage accuracy.&lt;br /&gt;
&lt;br /&gt;
==4. Significant Figures==&lt;br /&gt;
&lt;br /&gt;
A significant figure is a digit which is reasonably trustworthy.  One and only one estimated or doubtful figure can be retained and regarded as significant in any measurement, or in any calculation involving physical measurements.  In the examples in (3) above, 4.6 mm has two significant figures, 27.42 cm has four significant figures.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The location of the decimal point has no relation to the number of significant figures.  The reading 6.54 cm could be written as 65.4 mm or as 0.0654 m without changing the number of significant figures - three in each case.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The presence of a zero is sometimes troublesome.  If it is used merely to indicate the location of the decimal point, it is not called a significant figure, as in 0.0654 m; if it is between two significant digits, as in a temperature reading of 20.5o, it is always significant.  A zero digit at the end of a number tends to be ambiguous.  In the absence of specific information we cannot tell whether it is there because it is the best estimate or merely to locate the decimal point.  In such cases the true situation should be expressed by writing the correct number of significant figures multiplied by the power of 10.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Thus a student measurement of the speed of light, 186,000 mi/s is best written as 1.86 x 105 mi/s to indicate that there are only three significant figures.  The latter form is called standard notation, and involves a number between 1 and 10 multiplied by the appropriate power of 10. It is equally important to include the zero at the end of a number if it is significant. If reading a meter-stick, one estimates to a fraction of a millimeter, then a reading of 20.00 cm is written quite correctly.  In such a case, valuable information would be thrown away if the reading were recorded as 20 cm.  The recorded number should always express the degree of accuracy of the reading.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
In computations involving measured quantities, carry only those digits which are significant.  Consider a rectangle whose sides are measured as 10.77 and 3.55 cm (the doubtful digits are underlined here). When these lengths are added to find the perimeter the last digit in the answer will also be doubtful.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
When the lengths are multiplied to obtain the area, any operation by a doubtful digit results in a doubtful digit.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61850</id>
		<title>MEASUREMENTS AND ERRORS</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=MEASUREMENTS_AND_ERRORS&amp;diff=61850"/>
		<updated>2013-06-04T22:02:06Z</updated>

		<summary type="html">&lt;p&gt;Halatm: Created page with &amp;quot;=MEASUREMENTS= There are several requirements that must be met if a measurement is to be useful in a scientific experiment:  ==1. The Number of Determinations==  It is a fundamen...&amp;quot;&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;=MEASUREMENTS=&lt;br /&gt;
There are several requirements that must be met if a measurement is to be useful in a scientific experiment:&lt;br /&gt;
&lt;br /&gt;
==1. The Number of Determinations==&lt;br /&gt;
&lt;br /&gt;
It is a fundamental law of laboratory work that a single measurement is of little value because of the liability not only to gross mistakes but also to smaller random errors.&lt;br /&gt;
Accordingly, it is customary to repeat all measurements as many times as possible. The laws of statistics lead to the conclusion that the value having the highest possibility of being correct is the arithmetic mean or average, obtained by dividing the sum of the individual readings by the total number of observations.  Because of time limitations, we often suggest you do a minimal number of repetitive measurements but remember this reduces the reliability and respectability of your results.&lt;br /&gt;
&lt;br /&gt;
==2. Zero Reading==&lt;br /&gt;
&lt;br /&gt;
Every measurement is really a difference between two readings, although for convenience, most instruments are calibrated so that one of these readings will be zero. In many instruments, this zero is not exact for all time but may shift slightly due to wear or usage.  Thus it is essential that the zero be checked before every measurement where it is one of the two readings.  In some cases the zero can be reset manually, while in others it is necessary to record the exact zero reading and correct all subsequent readings accordingly.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
e.g.  When measuring the length AB, Fig. 1, a ruler could be placed (1) with 1.2 cm at A, then length AB = (4.0 - 1.2) cm = 2.8 cm.  The more usual ruler position (2) allows the length AB to be read as 2.8 cm directly, but remember this is still the difference between '''two''' readings: 2.8 cm and 0.0 cm.&lt;br /&gt;
&lt;br /&gt;
==3. Accuracy==&lt;br /&gt;
&lt;br /&gt;
Quantitative work requires that each measurement be made as accurately as possible.  The main units of a scale are usually divided, and the eye can easily subdivide a small a distance of 1 mm into five parts reasonably accurately.Thus, if a linear scale is divided into millimeters, e.g. on a high quality ruler, a reading could be expressed to 0.2 of a millimeter; e.g. 4.6 mm, 27.42 cm, where 3/5 and 1/5 of a mm are estimated by eye.  In cases where the reading falls exactly on a scale division, the estimated figure would be 0; e.g. 48.50 cm, indicating that you know the reading more accurately than 48.5 cm.  But it would not be possible to take a reading with greater accuracy then 0.2 mm with this equipment.  If the scale is not finely engraved, the lab meter sticks for example, it could probably only be read as 0.5 mm.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The accuracy desired from a measurement dictates the choice of instrument.  For example, a distance of 4 m should not be measured by a car's odometer, nor a distance of 2 km with a micrometer.  The student learns to decide which instrument is most appropriate for a certain measurement. Ideally, all measurements for any one experiment should have about the same percentage accuracy.&lt;br /&gt;
&lt;br /&gt;
==4. Significant Figures==&lt;br /&gt;
&lt;br /&gt;
A significant figure is a digit which is reasonably trustworthy.  One and only one estimated or doubtful figure can be retained and regarded as significant in any measurement, or in any calculation involving physical measurements.  In the examples in (3) above, 4.6 mm has two significant figures, 27.42 cm has four significant figures.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The location of the decimal point has no relation to the number of significant figures.  The reading 6.54 cm could be written as 65.4 mm or as 0.0654 m without changing the number of significant figures - three in each case.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The presence of a zero is sometimes troublesome.  If it is used merely to indicate the location of the decimal point, it is not called a significant figure, as in 0.0654 m; if it is between two significant digits, as in a temperature reading of 20.5o, it is always significant.  A zero digit at the end of a number tends to be ambiguous.  In the absence of specific information we cannot tell whether it is there because it is the best estimate or merely to locate the decimal point.  In such cases the true situation should be expressed by writing the correct number of significant figures multiplied by the power of 10.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Thus a student measurement of the speed of light, 186,000 mi/s is best written as 1.86 x 105 mi/s to indicate that there are only three significant figures.  The latter form is called standard notation, and involves a number between 1 and 10 multiplied by the appropriate power of 10. It is equally important to include the zero at the end of a number if it is significant. If reading a meter-stick, one estimates to a fraction of a millimeter, then a reading of 20.00 cm is written quite correctly.  In such a case, valuable information would be thrown away if the reading were recorded as 20 cm.  The recorded number should always express the degree of accuracy of the reading.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
In computations involving measured quantities, carry only those digits which are significant.  Consider a rectangle whose sides are measured as 10.77 and 3.55 cm (the doubtful digits are underlined here). When these lengths are added to find the perimeter the last digit in the answer will also be doubtful.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
When the lengths are multiplied to obtain the area, any operation by a doubtful digit results in a doubtful digit.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=File:Fzero.png&amp;diff=61849</id>
		<title>File:Fzero.png</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=File:Fzero.png&amp;diff=61849"/>
		<updated>2013-06-04T22:01:33Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61848</id>
		<title>PHYS 1010, 1410 &amp; 1420</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61848"/>
		<updated>2013-06-04T21:30:54Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;First year physics laboratories are located in '''102C''' and '''102D''' Bethune College. Physics lab classes are divided into Sections '''X''' and '''Y'''. &lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
To find out which Section you are in, check the lists posted on the lab [http://google.ca website] or on the bulletin board located at the entrance to 102C Bethune College.&lt;br /&gt;
&lt;br /&gt;
&amp;lt;h1&amp;gt;General Information&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[LAB INFORMATION|LAB INFORMATION]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[MEASUREMENTS AND ERRORS|MEASUREMENTS AND ERRORS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[MEASURING LENGTH|MEASURING LENGTH]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[GRAPHS|GRAPHS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;h1&amp;gt;Courses&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1010 6.0 PHYSICS|SC/PHYS 1010 6.0 PHYSICS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1410 6.0 PHYSICAL SCIENCE|SC/PHYS 1410 6.0 PHYSICAL SCIENCE]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES|SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61847</id>
		<title>PHYS 1010, 1410 &amp; 1420</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61847"/>
		<updated>2013-06-04T21:30:21Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;First year physics laboratories are located in '''102C''' and '''102D''' Bethune College. Physics lab classes are divided into Sections '''X''' and '''Y'''. &lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
To find out which Section you are in, check the lists posted on the lab website (www.yorku.ca/jerzak/lab) or on the bulletin board located at the entrance to 102C Bethune College.&lt;br /&gt;
&lt;br /&gt;
&amp;lt;h1&amp;gt;General Information&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[LAB INFORMATION|LAB INFORMATION]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[MEASUREMENTS AND ERRORS|MEASUREMENTS AND ERRORS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[MEASURING LENGTH|MEASURING LENGTH]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[GRAPHS|GRAPHS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;h1&amp;gt;Courses&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1010 6.0 PHYSICS|SC/PHYS 1010 6.0 PHYSICS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1410 6.0 PHYSICAL SCIENCE|SC/PHYS 1410 6.0 PHYSICAL SCIENCE]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES|SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=LAB_INFORMATION&amp;diff=61846</id>
		<title>LAB INFORMATION</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=LAB_INFORMATION&amp;diff=61846"/>
		<updated>2013-06-04T21:28:31Z</updated>

		<summary type="html">&lt;p&gt;Halatm: /* GENERAL INFORMATION */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;=General Info=&lt;br /&gt;
You will have been assigned to a particular 3-hour laboratory time at registration.  '''This may only be changed by arrangement with Lab Coordinator'''.  On the lab [http://google.ca website] and on the bulletin board outside 102C Bethune College you will find your name on a student list with your particular group section (A, B, C).  A schedule will be posted on the lab website and on the board showing which experiment each group will be doing week by week. This schedule is also included at the front of the manual.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
In most cases, experiments of the schedule are arranged in twos, one-half of the class will be doing each of these experiments in any one week.  The same experiments will run for three weeks, by which time every student will have completed both, though not in the same order.  Students are required to attend all laboratory sessions to which they are assigned.  Please be certain to sign the demonstrator's mark list as proof of attendance.  Absence due to illness or other legitimate cause should be reported to Lab Coordinator, 233 PSE, as soon as possible so that credit may be obtained or an alternate lab assigned.&lt;br /&gt;
__TOC__&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
;Why do Laboratory Work?&lt;br /&gt;
#all science is based on a foundation of experimental data and your experiments will exemplify and illuminate many of the principles studied in the lectures.  &lt;br /&gt;
#the laboratory will be a medium for teaching some new material which will not be covered in the lecture course.&lt;br /&gt;
#it gives you an opportunity to train your brain, eyes and hands in good experimental techniques, while familiarizing yourself with some of the instruments used in experimental science.&lt;br /&gt;
#Obtaining good results is important, particularly if you intend to go on to more difficult labs.  But do not get so involved in the mechanics of &amp;quot;doing&amp;quot; that you lose sight of the goal of the experiment, the theory behind it, and its wider applications.&lt;br /&gt;
&lt;br /&gt;
We try to timetable experiments as near as possible to the related material in the lecture schedule.  However, details in the operation of the laboratories prevent us from achieving a perfect match and we ask you to be tolerant in this regard.&lt;br /&gt;
&lt;br /&gt;
;You will need&lt;br /&gt;
*this manual&lt;br /&gt;
*the usual writing materials (graph paper is provided)&lt;br /&gt;
*an electronic calculator&lt;br /&gt;
&lt;br /&gt;
==Lab Schedules and Attendance==&lt;br /&gt;
Laboratory classes are held at the following times:&lt;br /&gt;
::;Fall/Winter session&lt;br /&gt;
:::Tuesday and Thursday,	9:30 a.m. - 12:30 p.m.&lt;br /&gt;
:::Monday to Friday,		2:30 p.m. -  5:30 p.m.&lt;br /&gt;
:::Tuesday and Thursday	7:00 p.m. - 10:00 p.m.&lt;br /&gt;
::;Summer session&lt;br /&gt;
:::Tuesday and Thursday,	2:30 a.m. -  5:30 p.m.&lt;br /&gt;
:::Wednesday,		           9:30 a.m. - 12:30 p.m. and 1:30 a.m. -  4:30 p.m.&lt;br /&gt;
&lt;br /&gt;
:::The laboratories are located in '''120C''' and '''102D''' Bethune College.&lt;br /&gt;
&lt;br /&gt;
==Prelab Preparation==&lt;br /&gt;
You will know from the posted schedule which experiment you will be doing.  Before coming to do the experiment, you are expected to read the appropriate section of this manual.  Be sure you understand the theory involved, consult your textbook, and plan your practical work.  Most of the lab outlines contain prelab exercises which must be completed on a separate sheet of paper before you come to the lab.  This preparation is most important.  It is unlikely that you will be able to finish the experiment satisfactorily or learn from them if you do not prepare beforehand.  There may be short, unannounced quizzes on the experiment during some labs.&lt;br /&gt;
&lt;br /&gt;
==Reports==&lt;br /&gt;
&lt;br /&gt;
A sample lab report is included in the manual (appendix F).&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
We do not require you to write an elaborate report for each experiment.  The report should include name, name of partner, title and date.  The experimental data, whenever possible, should be summarized in the form of a table, with title, column headings, units and experimental errors. Graphs should have titles, axes labelled and units included. Errors of all measured quantities should be indicated on graphs in the form of error bars.  Calculations should be shown and organized in a logical way, with short comments and explanations.  Just formulas with substituted data are not acceptable.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Calculations of errors is an important part of the lab report (next section in the manual provides more information regarding error calculations and rounding of final result and its error).&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
You are encouraged to record in your report for future reference any comments regarding the theory or method or apparatus which enhance your understanding.  Your report should resemble a research scientist's day-to-day experimental log rather than a polished scientific paper.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
It is preferred that you write laboratory reports in notebooks, which encourage better organization and neatness.  Do not tear pages out of the books, if a mistake is made, simply cross out the mistake neatly.  Two books will be required to be used alternately throughout the year.  Light weight coil notebooks are suitable.  Put your name and lab time clearly on the outside.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The three-hour session should be sufficient for the taking of measurements and for calculations and conclusions, etc.  Be punctual - latecomers will find it difficult to complete the assignment. ''' All lab reports, finished or unfinished, must be handed in to your demonstrator by the end of the three-hour lab session.'''&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Your report will be marked by the demonstrator whose name appears on the top of the attendance list which you sign.  It will be your responsibility to collect your report from this demonstrator during your next laboratory session.  At this time you should discuss with your demonstrator any matters concerning the report(s).&lt;br /&gt;
&lt;br /&gt;
==Lab Marks==&lt;br /&gt;
&lt;br /&gt;
The final lab mark will contribute approximately 10-20% (depending on the course) to the final grade.  It will take into consideration prelab questions and quizzes, the weekly lab reports and the lab test which is written at the end of the session.  Students should keep their lab reports for reference and as a record of marks.  All your Fall Term lab marks will be posted in the lab in January for you to check.&lt;br /&gt;
&lt;br /&gt;
==Lab Partners==&lt;br /&gt;
&lt;br /&gt;
Some students claim that they learn more while working with a lab partner; others prefer to work alone.  For certain experiments where basic techniques, etc. are explored, you will be required to work individually - this will be stated in the lab outline for those particular experiments.  For the other experiments we will try to provide sufficient apparatus so that you may work with another student who has been assigned the same experiment or alone, as you prefer.  For a few of the experiments the mechanical work is so difficult that one person cannot perform the experiment satisfactorily.  If two students work together, '''each should take a turn at reading all the instruments and although both will have the same data, each student must submit an independent report, with independent calculations.  No more than two students working together as lab partners is allowed.'''&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Lab partners are '''randomly assigned'''.  This facilitates meeting many friends, promotes social skills as well as reduces the probability of dishonesty when doing lab work.  The details of how lab partners are assigned will be explained in the first lab.&lt;br /&gt;
&lt;br /&gt;
==Cleanliness and Care of Equipment==&lt;br /&gt;
&lt;br /&gt;
We do not charge you for accidental breakages, but please report them to the demonstrator or lab technologist immediately, so that equipment can be replaced or repaired.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Students must leave their place of work in the lab neat with all the apparatus complete.  Each experimental set-up will be used by approximately forty students before it is retired for the year, so leave it for the next student in the state in which you would like to find it.&lt;br /&gt;
&lt;br /&gt;
'''When a student hands in a report, the demonstrator will check their place of work to see that it is left in satisfactory condition. When satisfied, the demonstrator will accept the report.'''&lt;br /&gt;
&lt;br /&gt;
==Lab Safety==&lt;br /&gt;
&lt;br /&gt;
Scientists very commonly live to a grand old age in spite of their daily encounters with many hazards.  The main reason for this is that a scientist doing an experiment is paying very close attention to everything that happens, is expecting the unknown and can react quickly to it.  Your best protection against accidents in the lab is a constant thoughtful alertness which never permits your actions to become &amp;quot;mechanical&amp;quot; and &amp;quot;reflex&amp;quot;.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Specific hazards which exist in particular experiments will be stressed in the respective lab outline.  Please pay very careful attention to these warnings and act accordingly.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Notify the demonstrator or lab technician of any accident or injury no matter how insignificant it may seem.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
In the case of a fire, at the sound of the fire alarm in the building, the university stipulates that everyone must leave the building.  In the case of a fire in the lab, the demonstrator is responsible for taking the appropriate action to curb it, but the students must leave the building immediately.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
----&lt;br /&gt;
&amp;lt;h5&amp;gt;&amp;lt;center&amp;gt;&lt;br /&gt;
'''A 24-hour Emergency Services Telephone Centre operates on York Campus and can be alerted by calling 33333 on all campus telephones or 736-2100 Ext. 33333 on public telephones.'''&lt;br /&gt;
&lt;br /&gt;
'''Health services are located in York Lanes.'''&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;/center&amp;gt;&amp;lt;/h5&amp;gt;&lt;br /&gt;
----&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
==Academic Dishonesty==&lt;br /&gt;
&lt;br /&gt;
Students will certainly discuss and talk about their studies with their friends and this can be very useful; but any work that you hand in must have been done by yourself.  This is the only way to test your own competence and to prepare yourself for positions of responsibility after graduation.  If scientists are dishonest, they are useless.&lt;br /&gt;
&lt;br /&gt;
'''THE UNIVERSITY CONSIDERS ALL FORMS OF COPYING AND CHEATING TO BE SERIOUS OFFENCES.'''  Read the policy statement in the Undergraduate Calendar.&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=LAB_INFORMATION&amp;diff=61845</id>
		<title>LAB INFORMATION</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=LAB_INFORMATION&amp;diff=61845"/>
		<updated>2013-06-04T21:27:31Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;=GENERAL INFORMATION=&lt;br /&gt;
You will have been assigned to a particular 3-hour laboratory time at registration.  '''This may only be changed by arrangement with Lab Coordinator'''.  On the lab [http://google.ca website] and on the bulletin board outside 102C Bethune College you will find your name on a student list with your particular group section (A, B, C).  A schedule will be posted on the lab website and on the board showing which experiment each group will be doing week by week. This schedule is also included at the front of the manual.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
In most cases, experiments of the schedule are arranged in twos, one-half of the class will be doing each of these experiments in any one week.  The same experiments will run for three weeks, by which time every student will have completed both, though not in the same order.  Students are required to attend all laboratory sessions to which they are assigned.  Please be certain to sign the demonstrator's mark list as proof of attendance.  Absence due to illness or other legitimate cause should be reported to Lab Coordinator, 233 PSE, as soon as possible so that credit may be obtained or an alternate lab assigned.&lt;br /&gt;
__TOC__&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
;Why do Laboratory Work?&lt;br /&gt;
#all science is based on a foundation of experimental data and your experiments will exemplify and illuminate many of the principles studied in the lectures.  &lt;br /&gt;
#the laboratory will be a medium for teaching some new material which will not be covered in the lecture course.&lt;br /&gt;
#it gives you an opportunity to train your brain, eyes and hands in good experimental techniques, while familiarizing yourself with some of the instruments used in experimental science.&lt;br /&gt;
#Obtaining good results is important, particularly if you intend to go on to more difficult labs.  But do not get so involved in the mechanics of &amp;quot;doing&amp;quot; that you lose sight of the goal of the experiment, the theory behind it, and its wider applications.&lt;br /&gt;
&lt;br /&gt;
We try to timetable experiments as near as possible to the related material in the lecture schedule.  However, details in the operation of the laboratories prevent us from achieving a perfect match and we ask you to be tolerant in this regard.&lt;br /&gt;
&lt;br /&gt;
;You will need&lt;br /&gt;
*this manual&lt;br /&gt;
*the usual writing materials (graph paper is provided)&lt;br /&gt;
*an electronic calculator&lt;br /&gt;
&lt;br /&gt;
==Lab Schedules and Attendance==&lt;br /&gt;
Laboratory classes are held at the following times:&lt;br /&gt;
::;Fall/Winter session&lt;br /&gt;
:::Tuesday and Thursday,	9:30 a.m. - 12:30 p.m.&lt;br /&gt;
:::Monday to Friday,		2:30 p.m. -  5:30 p.m.&lt;br /&gt;
:::Tuesday and Thursday	7:00 p.m. - 10:00 p.m.&lt;br /&gt;
::;Summer session&lt;br /&gt;
:::Tuesday and Thursday,	2:30 a.m. -  5:30 p.m.&lt;br /&gt;
:::Wednesday,		           9:30 a.m. - 12:30 p.m. and 1:30 a.m. -  4:30 p.m.&lt;br /&gt;
&lt;br /&gt;
:::The laboratories are located in '''120C''' and '''102D''' Bethune College.&lt;br /&gt;
&lt;br /&gt;
==Prelab Preparation==&lt;br /&gt;
You will know from the posted schedule which experiment you will be doing.  Before coming to do the experiment, you are expected to read the appropriate section of this manual.  Be sure you understand the theory involved, consult your textbook, and plan your practical work.  Most of the lab outlines contain prelab exercises which must be completed on a separate sheet of paper before you come to the lab.  This preparation is most important.  It is unlikely that you will be able to finish the experiment satisfactorily or learn from them if you do not prepare beforehand.  There may be short, unannounced quizzes on the experiment during some labs.&lt;br /&gt;
&lt;br /&gt;
==Reports==&lt;br /&gt;
&lt;br /&gt;
A sample lab report is included in the manual (appendix F).&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
We do not require you to write an elaborate report for each experiment.  The report should include name, name of partner, title and date.  The experimental data, whenever possible, should be summarized in the form of a table, with title, column headings, units and experimental errors. Graphs should have titles, axes labelled and units included. Errors of all measured quantities should be indicated on graphs in the form of error bars.  Calculations should be shown and organized in a logical way, with short comments and explanations.  Just formulas with substituted data are not acceptable.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Calculations of errors is an important part of the lab report (next section in the manual provides more information regarding error calculations and rounding of final result and its error).&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
You are encouraged to record in your report for future reference any comments regarding the theory or method or apparatus which enhance your understanding.  Your report should resemble a research scientist's day-to-day experimental log rather than a polished scientific paper.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
It is preferred that you write laboratory reports in notebooks, which encourage better organization and neatness.  Do not tear pages out of the books, if a mistake is made, simply cross out the mistake neatly.  Two books will be required to be used alternately throughout the year.  Light weight coil notebooks are suitable.  Put your name and lab time clearly on the outside.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The three-hour session should be sufficient for the taking of measurements and for calculations and conclusions, etc.  Be punctual - latecomers will find it difficult to complete the assignment. ''' All lab reports, finished or unfinished, must be handed in to your demonstrator by the end of the three-hour lab session.'''&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Your report will be marked by the demonstrator whose name appears on the top of the attendance list which you sign.  It will be your responsibility to collect your report from this demonstrator during your next laboratory session.  At this time you should discuss with your demonstrator any matters concerning the report(s).&lt;br /&gt;
&lt;br /&gt;
==Lab Marks==&lt;br /&gt;
&lt;br /&gt;
The final lab mark will contribute approximately 10-20% (depending on the course) to the final grade.  It will take into consideration prelab questions and quizzes, the weekly lab reports and the lab test which is written at the end of the session.  Students should keep their lab reports for reference and as a record of marks.  All your Fall Term lab marks will be posted in the lab in January for you to check.&lt;br /&gt;
&lt;br /&gt;
==Lab Partners==&lt;br /&gt;
&lt;br /&gt;
Some students claim that they learn more while working with a lab partner; others prefer to work alone.  For certain experiments where basic techniques, etc. are explored, you will be required to work individually - this will be stated in the lab outline for those particular experiments.  For the other experiments we will try to provide sufficient apparatus so that you may work with another student who has been assigned the same experiment or alone, as you prefer.  For a few of the experiments the mechanical work is so difficult that one person cannot perform the experiment satisfactorily.  If two students work together, '''each should take a turn at reading all the instruments and although both will have the same data, each student must submit an independent report, with independent calculations.  No more than two students working together as lab partners is allowed.'''&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Lab partners are '''randomly assigned'''.  This facilitates meeting many friends, promotes social skills as well as reduces the probability of dishonesty when doing lab work.  The details of how lab partners are assigned will be explained in the first lab.&lt;br /&gt;
&lt;br /&gt;
==Cleanliness and Care of Equipment==&lt;br /&gt;
&lt;br /&gt;
We do not charge you for accidental breakages, but please report them to the demonstrator or lab technologist immediately, so that equipment can be replaced or repaired.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Students must leave their place of work in the lab neat with all the apparatus complete.  Each experimental set-up will be used by approximately forty students before it is retired for the year, so leave it for the next student in the state in which you would like to find it.&lt;br /&gt;
&lt;br /&gt;
'''When a student hands in a report, the demonstrator will check their place of work to see that it is left in satisfactory condition. When satisfied, the demonstrator will accept the report.'''&lt;br /&gt;
&lt;br /&gt;
==Lab Safety==&lt;br /&gt;
&lt;br /&gt;
Scientists very commonly live to a grand old age in spite of their daily encounters with many hazards.  The main reason for this is that a scientist doing an experiment is paying very close attention to everything that happens, is expecting the unknown and can react quickly to it.  Your best protection against accidents in the lab is a constant thoughtful alertness which never permits your actions to become &amp;quot;mechanical&amp;quot; and &amp;quot;reflex&amp;quot;.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Specific hazards which exist in particular experiments will be stressed in the respective lab outline.  Please pay very careful attention to these warnings and act accordingly.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Notify the demonstrator or lab technician of any accident or injury no matter how insignificant it may seem.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
In the case of a fire, at the sound of the fire alarm in the building, the university stipulates that everyone must leave the building.  In the case of a fire in the lab, the demonstrator is responsible for taking the appropriate action to curb it, but the students must leave the building immediately.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
----&lt;br /&gt;
&amp;lt;h5&amp;gt;&amp;lt;center&amp;gt;&lt;br /&gt;
'''A 24-hour Emergency Services Telephone Centre operates on York Campus and can be alerted by calling 33333 on all campus telephones or 736-2100 Ext. 33333 on public telephones.'''&lt;br /&gt;
&lt;br /&gt;
'''Health services are located in York Lanes.'''&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;/center&amp;gt;&amp;lt;/h5&amp;gt;&lt;br /&gt;
----&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
==Academic Dishonesty==&lt;br /&gt;
&lt;br /&gt;
Students will certainly discuss and talk about their studies with their friends and this can be very useful; but any work that you hand in must have been done by yourself.  This is the only way to test your own competence and to prepare yourself for positions of responsibility after graduation.  If scientists are dishonest, they are useless.&lt;br /&gt;
&lt;br /&gt;
'''THE UNIVERSITY CONSIDERS ALL FORMS OF COPYING AND CHEATING TO BE SERIOUS OFFENCES.'''  Read the policy statement in the Undergraduate Calendar.&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=LAB_INFORMATION&amp;diff=61844</id>
		<title>LAB INFORMATION</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=LAB_INFORMATION&amp;diff=61844"/>
		<updated>2013-06-04T21:23:01Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;=GENERAL INFORMATION=&lt;br /&gt;
You will have been assigned to a particular 3-hour laboratory time at registration.  '''This may only be changed by arrangement with Lab Coordinator'''.  On the lab [http://google.ca website] and on the bulletin board outside 102C Bethune College you will find your name on a student list with your particular group section (A, B, C).  A schedule will be posted on the lab website and on the board showing which experiment each group will be doing week by week. This schedule is also included at the front of the manual.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
In most cases, experiments of the schedule are arranged in twos, one-half of the class will be doing each of these experiments in any one week.  The same experiments will run for three weeks, by which time every student will have completed both, though not in the same order.  Students are required to attend all laboratory sessions to which they are assigned.  Please be certain to sign the demonstrator's mark list as proof of attendance.  Absence due to illness or other legitimate cause should be reported to Lab Coordinator, 233 PSE, as soon as possible so that credit may be obtained or an alternate lab assigned.&lt;br /&gt;
&lt;br /&gt;
;Why do Laboratory Work?&lt;br /&gt;
#all science is based on a foundation of experimental data and your experiments will exemplify and illuminate many of the principles studied in the lectures.  &lt;br /&gt;
#the laboratory will be a medium for teaching some new material which will not be covered in the lecture course.&lt;br /&gt;
#it gives you an opportunity to train your brain, eyes and hands in good experimental techniques, while familiarizing yourself with some of the instruments used in experimental science.&lt;br /&gt;
#Obtaining good results is important, particularly if you intend to go on to more difficult labs.  But do not get so involved in the mechanics of &amp;quot;doing&amp;quot; that you lose sight of the goal of the experiment, the theory behind it, and its wider applications.&lt;br /&gt;
&lt;br /&gt;
We try to timetable experiments as near as possible to the related material in the lecture schedule.  However, details in the operation of the laboratories prevent us from achieving a perfect match and we ask you to be tolerant in this regard.&lt;br /&gt;
&lt;br /&gt;
;You will need&lt;br /&gt;
*this manual&lt;br /&gt;
*the usual writing materials (graph paper is provided)&lt;br /&gt;
*an electronic calculator&lt;br /&gt;
&lt;br /&gt;
==Lab Schedules and Attendance==&lt;br /&gt;
Laboratory classes are held at the following times:&lt;br /&gt;
::;Fall/Winter session&lt;br /&gt;
:::Tuesday and Thursday,	9:30 a.m. - 12:30 p.m.&lt;br /&gt;
:::Monday to Friday,		2:30 p.m. -  5:30 p.m.&lt;br /&gt;
:::Tuesday and Thursday	7:00 p.m. - 10:00 p.m.&lt;br /&gt;
::;Summer session&lt;br /&gt;
:::Tuesday and Thursday,	2:30 a.m. -  5:30 p.m.&lt;br /&gt;
:::Wednesday,		           9:30 a.m. - 12:30 p.m. and 1:30 a.m. -  4:30 p.m.&lt;br /&gt;
&lt;br /&gt;
:::The laboratories are located in '''120C''' and '''102D''' Bethune College.&lt;br /&gt;
&lt;br /&gt;
==Prelab Preparation==&lt;br /&gt;
You will know from the posted schedule which experiment you will be doing.  Before coming to do the experiment, you are expected to read the appropriate section of this manual.  Be sure you understand the theory involved, consult your textbook, and plan your practical work.  Most of the lab outlines contain prelab exercises which must be completed on a separate sheet of paper before you come to the lab.  This preparation is most important.  It is unlikely that you will be able to finish the experiment satisfactorily or learn from them if you do not prepare beforehand.  There may be short, unannounced quizzes on the experiment during some labs.&lt;br /&gt;
&lt;br /&gt;
==Reports==&lt;br /&gt;
&lt;br /&gt;
A sample lab report is included in the manual (appendix F).&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
We do not require you to write an elaborate report for each experiment.  The report should include name, name of partner, title and date.  The experimental data, whenever possible, should be summarized in the form of a table, with title, column headings, units and experimental errors. Graphs should have titles, axes labelled and units included. Errors of all measured quantities should be indicated on graphs in the form of error bars.  Calculations should be shown and organized in a logical way, with short comments and explanations.  Just formulas with substituted data are not acceptable.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Calculations of errors is an important part of the lab report (next section in the manual provides more information regarding error calculations and rounding of final result and its error).&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
You are encouraged to record in your report for future reference any comments regarding the theory or method or apparatus which enhance your understanding.  Your report should resemble a research scientist's day-to-day experimental log rather than a polished scientific paper.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
It is preferred that you write laboratory reports in notebooks, which encourage better organization and neatness.  Do not tear pages out of the books, if a mistake is made, simply cross out the mistake neatly.  Two books will be required to be used alternately throughout the year.  Light weight coil notebooks are suitable.  Put your name and lab time clearly on the outside.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
The three-hour session should be sufficient for the taking of measurements and for calculations and conclusions, etc.  Be punctual - latecomers will find it difficult to complete the assignment. ''' All lab reports, finished or unfinished, must be handed in to your demonstrator by the end of the three-hour lab session.'''&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Your report will be marked by the demonstrator whose name appears on the top of the attendance list which you sign.  It will be your responsibility to collect your report from this demonstrator during your next laboratory session.  At this time you should discuss with your demonstrator any matters concerning the report(s).&lt;br /&gt;
&lt;br /&gt;
==Lab Marks==&lt;br /&gt;
&lt;br /&gt;
The final lab mark will contribute approximately 10-20% (depending on the course) to the final grade.  It will take into consideration prelab questions and quizzes, the weekly lab reports and the lab test which is written at the end of the session.  Students should keep their lab reports for reference and as a record of marks.  All your Fall Term lab marks will be posted in the lab in January for you to check.&lt;br /&gt;
&lt;br /&gt;
==Lab Partners==&lt;br /&gt;
&lt;br /&gt;
Some students claim that they learn more while working with a lab partner; others prefer to work alone.  For certain experiments where basic techniques, etc. are explored, you will be required to work individually - this will be stated in the lab outline for those particular experiments.  For the other experiments we will try to provide sufficient apparatus so that you may work with another student who has been assigned the same experiment or alone, as you prefer.  For a few of the experiments the mechanical work is so difficult that one person cannot perform the experiment satisfactorily.  If two students work together, '''each should take a turn at reading all the instruments and although both will have the same data, each student must submit an independent report, with independent calculations.  No more than two students working together as lab partners is allowed.'''&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Lab partners are '''randomly assigned'''.  This facilitates meeting many friends, promotes social skills as well as reduces the probability of dishonesty when doing lab work.  The details of how lab partners are assigned will be explained in the first lab.&lt;br /&gt;
&lt;br /&gt;
==Cleanliness and Care of Equipment==&lt;br /&gt;
&lt;br /&gt;
We do not charge you for accidental breakages, but please report them to the demonstrator or lab technologist immediately, so that equipment can be replaced or repaired.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Students must leave their place of work in the lab neat with all the apparatus complete.  Each experimental set-up will be used by approximately forty students before it is retired for the year, so leave it for the next student in the state in which you would like to find it.&lt;br /&gt;
&lt;br /&gt;
'''When a student hands in a report, the demonstrator will check their place of work to see that it is left in satisfactory condition. When satisfied, the demonstrator will accept the report.'''&lt;br /&gt;
&lt;br /&gt;
==Lab Safety==&lt;br /&gt;
&lt;br /&gt;
Scientists very commonly live to a grand old age in spite of their daily encounters with many hazards.  The main reason for this is that a scientist doing an experiment is paying very close attention to everything that happens, is expecting the unknown and can react quickly to it.  Your best protection against accidents in the lab is a constant thoughtful alertness which never permits your actions to become &amp;quot;mechanical&amp;quot; and &amp;quot;reflex&amp;quot;.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Specific hazards which exist in particular experiments will be stressed in the respective lab outline.  Please pay very careful attention to these warnings and act accordingly.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
Notify the demonstrator or lab technician of any accident or injury no matter how insignificant it may seem.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
In the case of a fire, at the sound of the fire alarm in the building, the university stipulates that everyone must leave the building.  In the case of a fire in the lab, the demonstrator is responsible for taking the appropriate action to curb it, but the students must leave the building immediately.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
----&lt;br /&gt;
&amp;lt;h5&amp;gt;&amp;lt;center&amp;gt;&lt;br /&gt;
'''A 24-hour Emergency Services Telephone Centre operates on York Campus and can be alerted by calling 33333 on all campus telephones or 736-2100 Ext. 33333 on public telephones.'''&lt;br /&gt;
&lt;br /&gt;
'''Health services are located in York Lanes.'''&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
&amp;lt;/center&amp;gt;&amp;lt;/h5&amp;gt;&lt;br /&gt;
----&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
==Academic Dishonesty==&lt;br /&gt;
&lt;br /&gt;
Students will certainly discuss and talk about their studies with their friends and this can be very useful; but any work that you hand in must have been done by yourself.  This is the only way to test your own competence and to prepare yourself for positions of responsibility after graduation.  If scientists are dishonest, they are useless.&lt;br /&gt;
&lt;br /&gt;
'''THE UNIVERSITY CONSIDERS ALL FORMS OF COPYING AND CHEATING TO BE SERIOUS OFFENCES.'''  Read the policy statement in the Undergraduate Calendar.&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=LAB_INFORMATION&amp;diff=61843</id>
		<title>LAB INFORMATION</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=LAB_INFORMATION&amp;diff=61843"/>
		<updated>2013-06-04T20:39:33Z</updated>

		<summary type="html">&lt;p&gt;Halatm: Created page with &amp;quot;=GENERAL INFORMATION= &amp;amp;nbsp; *;Why do Laboratory Work? #all science is based on a foundation of experimental data and your experiments will exemplify and illuminate many of the p...&amp;quot;&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;=GENERAL INFORMATION=&lt;br /&gt;
&amp;amp;nbsp;&lt;br /&gt;
*;Why do Laboratory Work?&lt;br /&gt;
#all science is based on a foundation of experimental data and your experiments will exemplify and illuminate many of the principles studied in the lectures.  &lt;br /&gt;
#the laboratory will be a medium for teaching some new material which will not be covered in the lecture course.&lt;br /&gt;
#it gives you an opportunity to train your brain, eyes and hands in good experimental techniques, while familiarizing yourself with some of the instruments used in experimental science.&lt;br /&gt;
#Obtaining good results is important, particularly if you intend to go on to more difficult labs.  But do not get so involved in the mechanics of &amp;quot;doing&amp;quot; that you lose sight of the goal of the experiment, the theory behind it, and its wider applications.&lt;br /&gt;
*;We try to timetable experiments as near as possible to the related material in the lecture schedule.  However, details in the operation of the laboratories prevent us from achieving a perfect match and we ask you to be tolerant in this regard.&lt;br /&gt;
&lt;br /&gt;
*;You will need&lt;br /&gt;
**this manual&lt;br /&gt;
**the usual writing materials (graph paper is provided)&lt;br /&gt;
**an electronic calculator&lt;br /&gt;
&lt;br /&gt;
*;Lab Schedules and Attendance&lt;br /&gt;
:Laboratory classes are held at the following times:&lt;br /&gt;
:::;Fall/Winter session&lt;br /&gt;
::::Tuesday and Thursday,	9:30 a.m. - 12:30 p.m.&lt;br /&gt;
::::Monday to Friday,		2:30 p.m. -  5:30 p.m.&lt;br /&gt;
::::Tuesday and Thursday	7:00 p.m. - 10:00 p.m.&lt;br /&gt;
:::;Summer session&lt;br /&gt;
::::Tuesday and Thursday,	2:30 a.m. -  5:30 p.m.&lt;br /&gt;
::::Wednesday,		           9:30 a.m. - 12:30 p.m. and 1:30 a.m. -  4:30 p.m.&lt;br /&gt;
&lt;br /&gt;
:::;The laboratories are located in 120C and 102D Bethune College.&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61842</id>
		<title>PHYS 1010, 1410 &amp; 1420</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61842"/>
		<updated>2013-06-04T19:15:56Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;First year physics laboratories are located in 102C and 102D Bethune College. Physics lab classes are divided into Sections X and Y. To find out which Section you are in, check the lists posted on the lab website (www.yorku.ca/jerzak/lab) or on the bulletin board located at the entrance to 102C Bethune College.&lt;br /&gt;
&lt;br /&gt;
&amp;lt;h1&amp;gt;General Information&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[LAB INFORMATION|LAB INFORMATION]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[MEASUREMENTS AND ERRORS|MEASUREMENTS AND ERRORS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[MEASURING LENGTH|MEASURING LENGTH]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[GRAPHS|GRAPHS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;h1&amp;gt;Courses&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1010 6.0 PHYSICS|SC/PHYS 1010 6.0 PHYSICS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1410 6.0 PHYSICAL SCIENCE|SC/PHYS 1410 6.0 PHYSICAL SCIENCE]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES|SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=MediaWiki:Sidebar&amp;diff=61841</id>
		<title>MediaWiki:Sidebar</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=MediaWiki:Sidebar&amp;diff=61841"/>
		<updated>2013-06-04T19:05:16Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;* navigation&lt;br /&gt;
** mainpage|mainpage-description&lt;br /&gt;
**PHYS 1010, 1410 &amp;amp; 1420|first year physics&lt;br /&gt;
** Main_Page/PHYS_3220|PHYS 3220&lt;br /&gt;
** Main_Page/BPHS_4090|BPHS 4090&lt;br /&gt;
** Main_Page/PHYS_4210|PHYS 4210&lt;br /&gt;
** Main_Page/PHYS_4061|PHYS 4061&lt;br /&gt;
* SEARCH&lt;br /&gt;
* TOOLBOX&lt;br /&gt;
* LANGUAGES&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=MediaWiki:Sidebar&amp;diff=61840</id>
		<title>MediaWiki:Sidebar</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=MediaWiki:Sidebar&amp;diff=61840"/>
		<updated>2013-06-04T19:04:29Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;* navigation&lt;br /&gt;
** mainpage|mainpage-description&lt;br /&gt;
**first year physics|first year physics&lt;br /&gt;
** Main_Page/PHYS_3220|PHYS 3220&lt;br /&gt;
** Main_Page/BPHS_4090|BPHS 4090&lt;br /&gt;
** Main_Page/PHYS_4210|PHYS 4210&lt;br /&gt;
** Main_Page/PHYS_4061|PHYS 4061&lt;br /&gt;
* SEARCH&lt;br /&gt;
* TOOLBOX&lt;br /&gt;
* LANGUAGES&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=MediaWiki:Sidebar&amp;diff=61839</id>
		<title>MediaWiki:Sidebar</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=MediaWiki:Sidebar&amp;diff=61839"/>
		<updated>2013-06-04T19:03:37Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;* navigation&lt;br /&gt;
** mainpage|mainpage-description&lt;br /&gt;
**1ST YEAR PHYS|1ST YEAR PHYS&lt;br /&gt;
** Main_Page/PHYS_3220|PHYS 3220&lt;br /&gt;
** Main_Page/BPHS_4090|BPHS 4090&lt;br /&gt;
** Main_Page/PHYS_4210|PHYS 4210&lt;br /&gt;
** Main_Page/PHYS_4061|PHYS 4061&lt;br /&gt;
* SEARCH&lt;br /&gt;
* TOOLBOX&lt;br /&gt;
* LANGUAGES&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61838</id>
		<title>PHYS 1010, 1410 &amp; 1420</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61838"/>
		<updated>2013-06-04T19:01:22Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&amp;lt;h1&amp;gt;Courses&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1010 6.0 PHYSICS|SC/PHYS 1010 6.0 PHYSICS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1410 6.0 PHYSICAL SCIENCE|SC/PHYS 1410 6.0 PHYSICAL SCIENCE]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES|SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61837</id>
		<title>PHYS 1010, 1410 &amp; 1420</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61837"/>
		<updated>2013-06-04T19:00:35Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;SC/PHYS 1010 6.0 PHYSICS&lt;br /&gt;
SC/PHYS 1410 6.0 PHYSICAL SCIENCE&lt;br /&gt;
SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES&lt;br /&gt;
&lt;br /&gt;
&amp;lt;h1&amp;gt;Courses&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1010 6.0 PHYSICS|SC/PHYS 1010 6.0 PHYSICS]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1410 6.0 PHYSICAL SCIENCE|SC/PHYS 1410 6.0 PHYSICAL SCIENCE]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES|SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61836</id>
		<title>PHYS 1010, 1410 &amp; 1420</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61836"/>
		<updated>2013-06-04T18:58:25Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;SC/PHYS 1010 6.0 PHYSICS&lt;br /&gt;
SC/PHYS 1410 6.0 PHYSICAL SCIENCE&lt;br /&gt;
SC/PHYS 1420 6.0 PHYSICS WITH APPLICATION TO THE LIFE SCIENCES&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61835</id>
		<title>PHYS 1010, 1410 &amp; 1420</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=PHYS_1010,_1410_%26_1420&amp;diff=61835"/>
		<updated>2013-06-04T18:57:40Z</updated>

		<summary type="html">&lt;p&gt;Halatm: Created page with &amp;quot;hi&amp;quot;&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;hi&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=Main_Page&amp;diff=61834</id>
		<title>Main Page</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=Main_Page&amp;diff=61834"/>
		<updated>2013-06-04T18:57:30Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&amp;lt;h1&amp;gt; Undergraduate Physics @ York University &amp;lt;/h1&amp;gt;&lt;br /&gt;
 {|&lt;br /&gt;
&lt;br /&gt;
|rowspan=&amp;quot;4&amp;quot;|[[File:Yorklogo.JPG|200px]]&lt;br /&gt;
|&amp;lt;b&amp;gt;Department of Physics and Astronomy&amp;lt;/b&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;b&amp;gt; Toronto, Ontario, Canada&amp;lt;/b&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;b&amp;gt;phas@yorku.ca&amp;lt;/b&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;b&amp;gt;416-736-5249&amp;lt;/b&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&amp;lt;h1&amp;gt;Courses&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[PHYS_1010, 1410 &amp;amp; 1420|first year physics]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[Main Page/PHYS 3220|PHYS 3220  Experiments in Modern Physics]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt; [[Main Page/BPHS 4090|BPHS 4090  Biophysics II]]&amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt; [[Main Page/PHYS 4210|PHYS 4210/4211  Advanced Experimental Physics I/II]]&amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt; [[Main Page/PHYS 4061|PHYS 4061/5061  Experimental Techniques in Laser Physics]]&amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=MediaWiki:Sidebar&amp;diff=61833</id>
		<title>MediaWiki:Sidebar</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=MediaWiki:Sidebar&amp;diff=61833"/>
		<updated>2013-06-04T18:54:16Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;* navigation&lt;br /&gt;
** mainpage|mainpage-description&lt;br /&gt;
**PHYS_1010, 1410 &amp;amp; 1420|first year physics&lt;br /&gt;
** Main_Page/PHYS_3220|PHYS 3220&lt;br /&gt;
** Main_Page/BPHS_4090|BPHS 4090&lt;br /&gt;
** Main_Page/PHYS_4210|PHYS 4210&lt;br /&gt;
** Main_Page/PHYS_4061|PHYS 4061&lt;br /&gt;
* SEARCH&lt;br /&gt;
* TOOLBOX&lt;br /&gt;
* LANGUAGES&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=MediaWiki:Sidebar&amp;diff=61832</id>
		<title>MediaWiki:Sidebar</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=MediaWiki:Sidebar&amp;diff=61832"/>
		<updated>2013-06-04T18:52:32Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;* navigation&lt;br /&gt;
** mainpage|mainpage-description&lt;br /&gt;
**PHYS_1010|PHYS 1010&lt;br /&gt;
** PHYS_1410|PHYS 1410&lt;br /&gt;
** PHYS_1420|PHYS 1420&lt;br /&gt;
** Main_Page/PHYS_3220|PHYS 3220&lt;br /&gt;
** Main_Page/BPHS_4090|BPHS 4090&lt;br /&gt;
** Main_Page/PHYS_4210|PHYS 4210&lt;br /&gt;
** Main_Page/PHYS_4061|PHYS 4061&lt;br /&gt;
* SEARCH&lt;br /&gt;
* TOOLBOX&lt;br /&gt;
* LANGUAGES&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=MediaWiki:Sidebar&amp;diff=61831</id>
		<title>MediaWiki:Sidebar</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=MediaWiki:Sidebar&amp;diff=61831"/>
		<updated>2013-06-04T18:50:14Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;* navigation&lt;br /&gt;
** mainpage|mainpage-description&lt;br /&gt;
**Main_page/PHYS_1010|PHYS 1010&lt;br /&gt;
** Main_Page/PHYS_1410|PHYS 1410&lt;br /&gt;
** Main_Page/PHYS_1420|PHYS 1420&lt;br /&gt;
** Main_Page/PHYS_3220|PHYS 3220&lt;br /&gt;
** Main_Page/BPHS_4090|BPHS 4090&lt;br /&gt;
** Main_Page/PHYS_4210|PHYS 4210&lt;br /&gt;
** Main_Page/PHYS_4061|PHYS 4061&lt;br /&gt;
* SEARCH&lt;br /&gt;
* TOOLBOX&lt;br /&gt;
* LANGUAGES&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=Main_Page/PHYS_1420&amp;diff=61830</id>
		<title>Main Page/PHYS 1420</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=Main_Page/PHYS_1420&amp;diff=61830"/>
		<updated>2013-06-04T18:36:31Z</updated>

		<summary type="html">&lt;p&gt;Halatm: Blanked the page&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=Main_Page/PHYS_1420&amp;diff=61829</id>
		<title>Main Page/PHYS 1420</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=Main_Page/PHYS_1420&amp;diff=61829"/>
		<updated>2013-05-28T19:01:54Z</updated>

		<summary type="html">&lt;p&gt;Halatm: /* CSS Priority scheme (highest to lowest) */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;===CSS Priority scheme (highest to lowest)===&lt;br /&gt;
{| class=&amp;quot;wikitable&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
! table !! titles etc&lt;br /&gt;
|-&lt;br /&gt;
| 1 || this is an example || answer&lt;br /&gt;
|-&lt;br /&gt;
| 2 || Inline || HTML&lt;br /&gt;
|}&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=Main_Page/PHYS_1420&amp;diff=61828</id>
		<title>Main Page/PHYS 1420</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=Main_Page/PHYS_1420&amp;diff=61828"/>
		<updated>2013-05-28T19:01:30Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;===CSS Priority scheme (highest to lowest)===&lt;br /&gt;
{| class=&amp;quot;wikitable&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
! table !! titles !! etc&lt;br /&gt;
|-&lt;br /&gt;
| 1 || this is an example || answer&lt;br /&gt;
|-&lt;br /&gt;
| 2 || Inline || HTML&lt;br /&gt;
|}&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=Main_Page/PHYS_1420&amp;diff=61827</id>
		<title>Main Page/PHYS 1420</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=Main_Page/PHYS_1420&amp;diff=61827"/>
		<updated>2013-05-28T19:00:14Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;===CSS Priority scheme (highest to lowest)===&lt;br /&gt;
{| class=&amp;quot;wikitable&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
! High Priority !! CSS Source Type !! Description&lt;br /&gt;
|-&lt;br /&gt;
| 1 || User defined || Most browsers have the accessibility feature: a user defined CSS&lt;br /&gt;
|-&lt;br /&gt;
| 2 || Inline || A style applied to an HTML element via HTML ‘style’ property &lt;br /&gt;
|-&lt;br /&gt;
| 3 || Media Type || A property definition applies to all media types, unless a media specific CSS defined&lt;br /&gt;
|-&lt;br /&gt;
| 4 || Importance || The ‘!important’ value overwrites the previous priority types&lt;br /&gt;
|-&lt;br /&gt;
| 5 || Selector specificity || A specific contextual selector (#heading p) overwrites generic definition&lt;br /&gt;
|-&lt;br /&gt;
| 6 || Rule order || Last rule declaration has a higher priority&lt;br /&gt;
|-&lt;br /&gt;
| 7 || Parent inheritance || If a property is not specified, it will be inherited from a parent element&lt;br /&gt;
|-&lt;br /&gt;
| 8 || CSS property definition in HTML document || CSS rule or CSS inline style overwrites a default browser value&lt;br /&gt;
|-&lt;br /&gt;
| 9 || Browser default || The lowest priority: browser default value is determined by W3C initial value specifications&lt;br /&gt;
|}&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=Main_Page&amp;diff=61826</id>
		<title>Main Page</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=Main_Page&amp;diff=61826"/>
		<updated>2013-05-28T18:57:43Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&amp;lt;h1&amp;gt; Undergraduate Physics @ York University &amp;lt;/h1&amp;gt;&lt;br /&gt;
 {|&lt;br /&gt;
&lt;br /&gt;
|rowspan=&amp;quot;4&amp;quot;|[[File:Yorklogo.JPG|200px]]&lt;br /&gt;
|&amp;lt;b&amp;gt;Department of Physics and Astronomy&amp;lt;/b&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;b&amp;gt; Toronto, Ontario, Canada&amp;lt;/b&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;b&amp;gt;phas@yorku.ca&amp;lt;/b&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;b&amp;gt;416-736-5249&amp;lt;/b&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&amp;lt;h1&amp;gt;Courses&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[Main Page/PHYS 1420|PHYS 1420 First Years Physics]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[Main Page/PHYS 3220|PHYS 3220  Experiments in Modern Physics]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt; [[Main Page/BPHS 4090|BPHS 4090  Biophysics II]]&amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt; [[Main Page/PHYS 4210|PHYS 4210/4211  Advanced Experimental Physics I/II]]&amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt; [[Main Page/PHYS 4061|PHYS 4061/5061  Experimental Techniques in Laser Physics]]&amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=Main_Page&amp;diff=61825</id>
		<title>Main Page</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=Main_Page&amp;diff=61825"/>
		<updated>2013-05-28T18:57:29Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&amp;lt;h1&amp;gt; Undergraduate Physics @ York University &amp;lt;/h1&amp;gt;&lt;br /&gt;
 {|&lt;br /&gt;
&lt;br /&gt;
|rowspan=&amp;quot;4&amp;quot;|[[File:Yorklogo.JPG|200px]]&lt;br /&gt;
|&amp;lt;b&amp;gt;Department of Physics and Astronomy&amp;lt;/b&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;b&amp;gt; Toronto, Ontario, Canada&amp;lt;/b&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;b&amp;gt;phas@yorku.ca&amp;lt;/b&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;b&amp;gt;416-736-5249&amp;lt;/b&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&amp;lt;h1&amp;gt;Courses&amp;lt;/h1&amp;gt;&lt;br /&gt;
&amp;lt;ul&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[Main Page/PHYS 1420|PHYS 1420 First Years Physics]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt;[[Main Page/PHYS 3220|PHYS 3220  Experiments in Modern Physics]] &amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt; [[Main Page/BPHS 4090|BPHS 4090  Biophysics II]]&amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt; [[Main Page/PHYS 4210|PHYS 4210/4211  Advanced Experimental Physics I/II]]&amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;li&amp;gt; [[Main Page/PHYS 4061|PHYS 4061/5061  Experimental Techniques in Laser Physics]]&amp;lt;/li&amp;gt;&lt;br /&gt;
&amp;lt;/ul&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;style type=&amp;quot;text/css&amp;quot;&amp;gt;&lt;br /&gt;
	body {&lt;br /&gt;
		color: green;&lt;br /&gt;
		background-color: blue;&lt;br /&gt;
		font-size: 80%;&lt;br /&gt;
	}&lt;br /&gt;
	p {&lt;br /&gt;
		line-height: 1.5em;&lt;br /&gt;
	}&lt;br /&gt;
&amp;lt;/style&amp;gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=Main_Page/PHYS_1420&amp;diff=61824</id>
		<title>Main Page/PHYS 1420</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=Main_Page/PHYS_1420&amp;diff=61824"/>
		<updated>2013-05-28T18:57:17Z</updated>

		<summary type="html">&lt;p&gt;Halatm: Blanked the page&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
	<entry>
		<id>https://physwiki.apps01.yorku.ca//index.php?title=Main_Page/PHYS_1420&amp;diff=61823</id>
		<title>Main Page/PHYS 1420</title>
		<link rel="alternate" type="text/html" href="https://physwiki.apps01.yorku.ca//index.php?title=Main_Page/PHYS_1420&amp;diff=61823"/>
		<updated>2013-05-28T18:57:07Z</updated>

		<summary type="html">&lt;p&gt;Halatm: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;&amp;lt;style type=&amp;quot;text/css&amp;quot;&amp;gt;&lt;br /&gt;
	body {&lt;br /&gt;
		color: green;&lt;br /&gt;
		background-color: blue;&lt;br /&gt;
		font-size: 80%;&lt;br /&gt;
	}&lt;br /&gt;
	p {&lt;br /&gt;
		line-height: 1.5em;&lt;br /&gt;
	}&lt;br /&gt;
&amp;lt;/style&amp;gt;&lt;/div&gt;</summary>
		<author><name>Halatm</name></author>
		
	</entry>
</feed>