Main Page/PHYS 3220/How to Write Reports

Here we provide some guidelines for writing laboratory reports. Keep in mind that the report should summarize the experiment as you understood and encountered it, so that, for example, a fellow student could obtain a good idea about the physics behind the experiment, as well as how your data were obtained. You will learn valuable writing and communication skills in this course that should prove very useful beyond your university studies. You will exercise a variety of data analysis and error analysis techniques.

Reports have to be structured properly. The laboratory manuals conform to a similar structure except that they do not report and discuss results. Do not copy sections from the lab manuals; use your own words to introduce the physics and to describe the experiment. The structure of your report should be as follows (apart from the title page):

As an indication of the completeness expected in these reports you should realize that in refereed articles independent, anonymous readers review your submission. If they can not understand exactly what you have done or the written submission does not indicate that a careful experiment is done with appropriate attention given to detail and uncertainties it will not be published.

1. Abstract. State briefly your method and the main results, with comparison to published values. (Typically paragraph, ~10 sentences).

   Example:

   The results of a measurement of the gravitational constant using the Cavendish method are presented. Experiments were carried out and data taken over a period of … Results from the 2 data sets (result 1, result 2) were consistent within uncertainties with a combined result for this fundamental constant, G , of (6.4 ± 0.8) x 10^-11 N m² kg^-2… The dominant uncertainty came from … The measured value is in agreement with the accepted value of (6.67384+/- 0.00080) x 10^-11 N m² kg^-2 (Ref. NIST Codata 2010) which was determined using ….

   Note that the quotation of the estimated uncertainty of the experiment and the accepted value are listed in the abstract using the appropriate significant figures. This permits the reader to make a general assessment of your experiments relevance after reading only the abstract. In refereed journals this is like the “Hook” in which you convince the reader that the experiment is reliable and they should read the following article. This briefly describes the technique used so the reader can be reminded of other reports on similar experiments. This is where the reader/marker will get a first impression of your experiment and if it is worth the read.

2. Introduction. A concise review of the physics relevant to this experiment fits well here. Equations are labeled throughout so you can refer to them later. Long derivations should be placed into an appendix with a suitable reference in order to facilitate reading. Figures (even if photocopied from the lab manual) are labeled and referred to in the text.
3. Method. This is not a step-by-step set of instructions! You describe how you carried out the experiment. A thorough description of the apparatus used with diagrams (with labels and captions) to which you refer in the text. Describe what you think were important details when carrying out the experiment. Don’t get bogged down in trivia. Remember to refer to your lab note book for specific details.

4. Results (INCLUDING ERROR ANALYSIS). Experimental data are summarized in tables (with label and caption). If the tables are very long, they can also be placed in an appendix. In this situation you would still provide an exemplary result in the text, say 10 measurements from the table, and place the bulk into an appendix.

   Provide explanations about where your numbers (particularly uncertainties) are coming from. Carry out an error propagation analysis with an explicitly calculated example. An error analysis includes an examination of the relative contributions of each error toward the final result (including statistical and systematic) so that one can pinpoint the dominant uncertainty.

5. Discussion (Conclusion). Summarize your experiment and compare your results to the accepted value(s). Is the deviation within the estimated error bounds? Provide comments discussing the agreement or disagreement. Answer questions that were asked in the lab manual (if this hasn't been covered before in the report). Conclude with remarks concerning how you think the experiment could be improved if you were to redo the experiment.
6. References. Bibliography. Compiled using the resources introduced in the Thursday library classes. Each of the later 3 reports (2, 3, and 4) should include a Refworks bibliography.
7. Appendices. Appendices contain details that would otherwise inhibit reading your report. How much material should be deferred to appendices is a judgment call. Label them properly.