Physics 3802L:
Lab report format

Before a report can be written, the student must take a set of measurements. For this purpose the students are required to keep a laboratory notebook (not loose leaf type) in which the observations are recorded. This should include the date, time of day, the temperature and any pertinent information that may prove useful in explaining your data later. Discarded data should be lightly crossed out so that it is still readable. This may be useful later in tracing any source of disturbances. The type of equipment used should be identified (by make and model) and recorded. The notebook may be checked by the instructor(s) from time to time and is to be turned in with the last report.

The format of a report is that required for publication in a scientific journal. The Physical Review is a good example. The Journal contains articles in all areas of physics and there are some papers which you can read with reasonable ease.

The report needs to be written in sufficient detail so that a person on the same level as you can read the report and perform the same experiment. It should be written in good English and must not be in note form. Normally the report is divided into sections. Below is a guide that will aid you in your preparation of a report.

1. The title page should be on a separate page and contain the title, your name, the name of your laboratory partner, the course number, the date the report was turned in, and the number of grace days used.

2. Next is the abstract which must be on a separate page. The abstract is a synopsis of the laboratory report and should not be more than one page long. It should provide a concise, but self-contained description of the basic idea of the experiment and quote the main results and conclusions; it must not refer to the main text. The idea is to convey the main points of the experiment to a casual reader without having him read the whole report.

3. The Table of Contents should list the major and minor sections, and the page number.

4. The first part of the text should be the introduction and be about three paragraphs long. The introduction varies with the style of the author and experiments performed. However, it should have information that is relevant to the experiment. Normally it would contain (i) any background information, (ii) the motivation of the experiment, and (iii) an outline of the following sections.

The main body of the report consists of five areas (i) the theoretical background, (ii) the experimental techniques, (iii) data in tabular and graphic form, (iv) the analysis of the data, including determination of uncertianties, and (v) discussion and conclusion. Each section should be part of the whole.

5. Theoretical background. A complete derivation of the theory for the experiment is expected as part of the report. Mathematical equations would normally be required to give a comprehensive description of the theory. Number the equations used. Any physical interpretation of the equations is to be included.

6. Experimental techniques. A description of the experiment consisting of text and diagrams. Each diagram needs to be labeled and should have a caption which explains what is seen in the figure so that a reader need not have to refer to the text to find out what they represent. The text must be sufficiently detailed, including the type of apparatus used. This part should include properties and specifications, as well as settings of equipment (e.g. range, sensitivity, amplification,..)

7. Data. Tabulate your data, and where appropriate, present your results in figures. The table should be in neat columns and have headings describing the columns. Any units and uncertainties must be included in the table. The figures are to be plotted in such a way that they would allow extraction of numbers from them. Each figure and table should be accompanied by a caption which explains what is represented in the table or figure, and defines symbols, abbreviations and terms used. Plot each measurement with error bars. Comparison with theory on the same figure as the experimental results is strongly encouraged.


Fig. 1: Thermal conductivity (in W cm-1K-1) vs temperature (in K). The dots are experimental measurements, the curve is a theoretical prediction according to the theory of  ABC.

Example of a table with the required heading:

 
Table I. Lorenz number L, (thermal to electrical conductivity ratio) at two temperatures. 
Each entry is the result of a complete experiment.
 L x 108 W Ω /(oC)2
Metal 0oC  100oC 
Ag 2.31±0.01 2.37±0.02
Au 2.35±0.02 2.40±0.01
Cd 2.42±0.01 2.43±0.02

8. Analysis. A sample calculation for any quantity and its uncertainty is to be presented in detail. Uncertainties must be discussed in detail, and random and systematic contributions identified. If you had to make assumptions about uncertainties due to equipment and/or procedure, you should clearly state these assumptions. The accuracy of the measured quantity should be discussed. Note that in "real life", e.g. in fields of active research, as well is in routine laboratory work in industry, the "correct" value of a measured quantity is in general not known. When performing a measurement, it is important to understand how close the measured value is expected to be to the unknown "true" value. If you compare the result of a measurement with a theoretical prediction or with the result of somebody else's measurement, it is essential to understand whether possible disagreements are significant.

9. Discussion. Compare your result with the accepted value. (Accepted values can often be found in the CRC handbook or in other reference books.) Is your result in agreement with the accepted value within uncertainties? Discuss and try to explain discrepancies. Can you give suggestions about how to improve the experimental method so as to reduce uncertainties? The discussion section should include a physical interpretation of the results.   Understanding the physics is why you do experiments.

10. Conclusion. Generally the conclusion consists of a brief summary of your main results together with their uncertainties. You may want to include suggestions on how to improve the experiment given more time and money.

11. Appendix. This is an optional section. Any derivation that does not properly fit in the theory section can be presented here, as well as any other additional information that you want to present.

12. References. Any textbooks or articles referred to in the text is to be listed under this section. The article (or book) must be listed by author, title, journal name (or publisher), volume number, page, year of publication. For example:

1. C. Kittel, Introduction to Solid State Physics, 5th Edition, Wiley (1976) p.166.

2. P.W. Anderson, Science, 235, 1196 (1987).