Every lab report requires a conclusion.  Writing the conclusion is important. This is the spot where you briefly describe the overall result of the lab in a few sentences.

The word conclusion written in chalk.

What is in the Conclusion?

The conclusion briefly restates what you did in the lab…

We dropped several masses and measured their positions as a function of time using a ticker-tape timer.  This data was used to determine the acceleration due to gravity by fitting the position data with a second order polynomial equation.

The conclusion restates your results and compares them to known or other experimental data.  This can be done in a single sentence like…

We found the experimental value of the acceleration due to gravity to be 9.35 m/s² which is within 4.59% of the accepted value.

If your lab had multiple parts, you can add similar statements about what you did and what your findings were.

Finally, the conclusion should mention where these results could be useful.

The acceleration due to gravity is useful for calculating falling times or time of flight for projectiles.

What is not in the Conclusion?

The conclusion should not contain statements about how you felt about the lab.  At the college level, this shouldn’t really be included anywhere in the lab report.  If you found something to be interesting, you can say that in the results and discussion section.

How Long is the Conclusion?

The conclusion should only contain a sentence or two about the experimental method and data analysis. It should contain a single sentence for each numerical result. You should also include a sentence or two about the applications of the research.

This means that for a lab with a single experiment, you should only have four or five sentences.  If your experiment contains multiple sections, each section should have its own four or five sentences.  For multipart labs, you could include a sentence or two linking each section.

Isn’t This Just Repetition?

Many students seem to think that restating the results in the conclusion is needless repetition.  However, the format of lab reports requires you to include these repetitions.

When a scientist reads a journal article, we often read the article out of order.  We first read through the abstract.  Next we skim through the paper looking at graphs, pictures, and diagrams. We read the conclusion.  After this quick overview of the paper, we then read through the entire paper.

The results are repeated at least three times.  First in the abstract, next in the results section, and once again in the conclusion.

Take time when writing the conclusion of your lab report. The conclusion doesn’t need to be more than a few sentences, but it is important that you include the necessary information.