How to Write a Scientific Laboratory Report

While training to be a scientist, it is important to know how to write a lab procedure and to be able to write effectively so that the details of your experiment can be explained clearly and explicitly.  Throughout your time at Marywood, you’ll be asked to prepare laboratory reports for several of your laboratory classes.  Below are the guidelines for writing a scientific laboratory report.  Additionally, laboratory reports are written in past tense and in third person.  And always remember that grammar and spelling are important!

Name:  Name of experimenter
Lab Partner(s): List first & last names
Title: The title of the experiment
Date:  Date experiment performed

Purpose: A brief description of why the experiment is being performed. Include details about the experiment, such as the methods used, a specific chemical reaction(s), and/or anticipated product.

Hypothesis: Provide a statement or two about the anticipated outcome of the experiment.

Experimental Procedure: A step-by-step description of the experiment including the chemicals, equipment, and/or methods used. Complete sentences must be used for the description. DO NOT simply copy the procedure from a lab manual or a handout. Condense the given procedure into steps so that you can understand and follow them.

Laboratory Safety: Give a complete, descriptive listing of the safety precautions, hazards, or other safety procedures that are needed for this experiment.

Experimental Data: Record all data resulting from the experiment in your laboratory notebook.  The experimental data should be recorded in tabular form. Do not record your experimental data in your laboratory manual.

Observations: This section is used to record any qualitative observations and notes on the changes to the experimental procedure. Sudden bursts of scientific insight or other information during the experiment that may aid in the interpretation of the data generated are to be entered in this section. No points will be awarded when the observations are recorded outside of the laboratory.  It is also important that you record your unknown number in this section of your notebook.

Calculations: Present outcome/summary of data analysis using tables, Excel graphs, and/or figures. List separately all pertinent mathematical equations followed by a sample calculation for each. Use the recorded data from the experiment when performing the calculations.

Results/Discussion: Questions that should be addressed in this section may include: Did the experiment work, and if not, why not? Were the results obtained in the experiment those expected based on the laboratory procedure? If the experiment was to be repeated, what improvements would be made? What types of errors occurred and how could they be corrected?  How did the observations play a role in the outcome of the experiment? When applicable, you should compare your experimental value(s) to that of a published, literature value(s), commenting on the accuracy of your technique.  

Conclusion: Summarize the findings of the experiment, which must include the final results of the experiment, e.g., the percent yield of a reaction, the identity of an unknown, etc. Look back at the purpose and hypothesis of your experiment and assess whether or not you met your goal in performing the experiment.

References: Include all pertinent information such as, your laboratory manual, textbooks, web sites, and any other library resources used in the preparation of your laboratory report.