How to structure an experiment report

At the top of an experiment report, there should be experiment theme, your name, affiliation, and student number, and submission date. The most basic structure is aims ⇨ theory ⇨ method ⇨ results ⇨ discussion ⇨ conclusion ⇨ references (⇨ impressions). However, if specific instructions are given in the class, you should follow those.

• ‘Aims’ should be what will be clarified by the experiment. Writing it in your own words, rather than copying the textbook, will help you understand the contents better. If you chose the theme and method of experiment by yourself, make sure to include insights from and the limitations of previous studies as well as explain the significance of your research theme and what makes your selected method suitable. The title of this section can be ‘aims and background’ or something similar.
• ‘Theory’ should be an outline of the theories and principles that form the basis of the experiment. Do not copy from your textbook, but summarize the contents as you understand it. Depending on the discipline and the theme of experiment, it might be better to include this part in ‘aims’ or ‘method.’
• ‘Method’ should be written accurately and in the past tense, concretely describing what and how you did. It is necessary to write in this manner so that others can replicate the experiment just by reading your report.
• ‘Results’ and ‘discussion’ can be written separately or they can be written as one section. ‘Results’ gives the actual data measured or phenomena observed in the experiment. In most cases, you can show these with graphs, tables, or photos. Take care not to include conjectures, judgments, or opinions. ‘Discussion’ is where you verify whether you accomplished the aims of the experiment. You should write logically about the meaning of the results obtained with referring to existing theory, etc. Do not include impressions or personal opinions.
• ‘Conclusion’ should correspond to ‘aims’ given at the beginning.
• ‘References’ should be written if you refer to or cite something from literature other than the experiment texts. You also need to insert citation in the main text when citing something.

There are different opinions about whether an ‘impressions’ section should be included, but it is a good opportunity for students to look back at their own learning experiences and it also provides valuable information for instructors when they plan classes. Clearly differentiate from the facts described in ‘results and discussion’, and write down what you felt, unresolved tasks, and proposals for improving the student experiment in this section.

Obtaining accurate data

It is necessary to conduct the experiment/observation carefully to avoid mistakes; to accurately record the conditions of and data obtained from the experiment/observation; and to express this with SI (International System of Units). It will help you later if you write what happened in a chronological order.

Make sure to save a record of your results even if they differ from the theoretical values. Take note that accurate data does not necessarily mean that they agree with the theoretical values. Thinking about why they differ and then retrying to the experiment/observation in an improved manner are important aspects of student experiment courses.

Repeat the experiment several times to increase the precision of the results. An experiment that can only be conducted once requires all the more care and attention. Record even small events that happen during the experiment. They will help you when you discuss the accuracy and precision of the results.

The basic approach to your writing should be to use quantitative expressions and write objectively. For example, do not simply write ‘I slowly added some A’, but express it as ‘200 mg of A was slowly added to liquid B over 10 seconds’ instead. The same goes for when you describe observed phenomena. Anything that is difficult to quantify should be depicted in detail using figures or photos.

Knowing the basics of making figures and tables

Figures and tables should be numbered and titled. This is generally done beneath the figure and above the table, respectively.

Both the x- and y-axes of a graph should be labelled with quantities and units. Observational drawings and imaging data should always come with a scale. You should also include other information for understanding the graphs, such as experiment conditions and what the colors represent. When adding leader lines to figures for explanatory texts, take care not to take too much attention away from the figure itself and to make it clear what part they explain.

Try to make the figures and tables simple. For tables, this includes deleting the outer frame or using the horizontal lines only. For figures, making sure that each figure only shows one thing and that you only use colors meaningfully will help the reader see what contents are important.

When making figures and tables, keep in mind to use conventional formats, as using your own style could potentially confuse the readers. For example, if you want to use colors in the graph to show different temperatures, use red for high temperatures and blue for low temperatures. When making a flowchart showing the experimental process, go from up to down, from left to right, and clock-wise. Equipment images should normally be cross sections with partial external views so that the readers can image the equipment in its entirety.

Discussing scientifically from multiple angles

Think about how well your results fit in with existing theories, etc. You should compare your results with theoretical and reference values as well as discuss the accuracy of the experiment and measurement errors (uncertainty). Put in ideas for improvement, such as how to increase the experiment’s accuracy or how to obtain similar results in easier ways.

Make sure that all descriptions are objective. For example, you can write ‘it became clear that the results of this experiment agree with XX theory, which indicates […]’ or ‘the methodology of this experiment has the limitations as follows: […], but it was demonstrated that it could tell us […] with sufficient accuracy’. A discussion is not complete with a mere ‘the experiment went well,’ and ‘it was interesting’ is an impression that does not form part of the discussion.

One aspect of student experiments is that they nurture the skills and attitudes that form the foundation for more sophisticated research activities in the future. Although it is unlikely that a student experiment will result in a scientific-breakthrough, it is very meaningful and important to acquire an attitude of stimulating as much discussion as possible from the results obtained.

The final fixes

First make sure that everything is written objectively and logically. Check also that there is not too much or too little in terms of figures and tables.

Check that the report is easy to read and understand. You should of course check that there are no typos, that you have used a consistent writing style, and that there is subject–verb agreement. It is also important to use the paragraph-writing style (each paragraph should have a clear main message and start with a topic sentence).

It is a good idea to check your report together with your classmates or ask your TA for advice. You can also consult library books concerning student experiments.