Lab Reports

From McGill University Physics Department Technical Services Wiki

The Lab Reports follow a traditional format for reporting the results of an experimental program. The sample publication given as an example demonstrates the traditional format. We will discuss some of the component parts below, but a few general comments are in order.

The report is written in proper, consistent and grammatically correct English or French, including proper spelling. The report is concise and complete. The most effective communication of your ideas is usually done in the shortest possible space. The results and how they were obtained must be stated in an economical manner and all information required to repeat such an experiment must be included in the report.

Suggested Components of the Lab Report

Below gives the typical sections in a lab report, however there are not hard and fast rules. Although most reports have all the components listed below it may be that they appear in ways other than formal sections. The idea is not to follow a prescription but to be clear, complete and concise. For instance, if the apparatus is simple or very well known, it might only be necessary to add a sentence or paragraph to the introduction and not have a separate section called Experiment. Similarly, a report on an experimental apparatus may not need a theory section or even a data section as the information is interspersed through out the experiment section.

• Title - A short description of the experiment, physical measurement or result. This is one of the most important parts of the report since it must convey in very few words the idea that the experimenters feel is the key element of the work.

• Authors - This includes the name of each person who made a substantial contribution to the work. Persons who made minor contributions can be acknowledged at the end of the report.

• Abstract - One short paragraph which describes the purpose, method and results of the work.
• Introduction - This part of the report is intended to put the work described into a context. Their are many possible ways to do this; for example:
  • A discussion of why the measurement is of interest,
  • A short history of the importance of the physical idea or measurement,
  • A discussion of a new or novel technique for making a particular physical measurement,
  • A discussion of the theoretical implications of the measurement.

• Theory - In this section the notation and formalism used to describe the experimental data and results is introduced. Generally all the symbols used are defined here (all symbols must be defined before or with their first use). The theoretical relationships primary, measured quantities and the derived results are given. Theoretical results are not derived in this section, but references to the derivations are made. Equations are numbered for reference in the text and must be grammatically part of the text with proper punctuation.

• Experiment - This section contains the description of the apparatus and the background necessary to understand how the measurements were done and how accurately they were carried out. NOTE, that in the appended publication the apparatus is described in the introduction. This is not always appropriate, especially for more complex experiments. In this case it is better to describe the apparatus and the measurement procedure in a separate section. Whatever you decide, make sure that your report contains a (block-) diagram of the apparatus and a brief description of the set-up and the measurement procedure.

• Data - This section discusses the data and the analysis required to obtain the results. It is not necessary for this section to contain all the data that is presented in the report. Often calibration data and data describing how the equipment works it better presented in the experiment section. All of the raw data need not be presented, but it is essential to include at least one example of measured data from each distinctly different type of measurement done. Raw data is usually best presented in graphical form, but could in addition be in tabular form. Analyzed data can be presented in either tabular or graphical form. A discussion of any special circumstances on the data collection or analysis can be made in this section. Along with the results the sources of errors and their values should be given.

• Conclusions - This section is meant to convey the reader your opinion as to the nature and the significance of the results obtained. Often these comments will refer to the context discussed in the introduction.

• Acknowledgements - This section notes all persons whom the authors wish to name who made a direct but minor contribution to the work.

• References - All references to published material cited in the report are referred to by consecutive number and collected at the end of the report. The references are noted in the text by appropriate number as a superscript. The format for the references is indicated at the top of the first page of the enclosed article. Only references which are referred to explicitly in the report are included.

Figure, Graphs and Tables

Special attention needs to be paid to the use of Figures, Graphs and Tables. They are the most concise, convenient and effective ways for communicate ideas quickly. In some cases they may be the only part of the report that the reader examines in detail. Thus it is important to give careful consideration to their contents and presentation. Some guidelines are given below.

• All figures, graphs and tables are numbered for reference in the text and all include a caption which briefly describes the figure or table.

• All figures, graphs and tables must be referred in the text.

• Graphs must include labels and units on each axis. Data points include error bars if possible. If several sets of data are included on one graph, each must have its own unique symbol with an annotation. Any continuous curves drawn on the graph must be explained in the caption or text as to its origin, be it a fit to the data, a theoretical curve or a hand drawn curve to guide the eye.