Lab Reports

Lab reports may have varied criteria. Each experiment (and teacher) may require different sections to be included. Regardless of variations, however, the goal of lab reports remains the same: document your findings and communicate their significance.

A good lab report does more than present data; it demonstrates the writer’s comprehension of the concepts behind the data. Merely recording the expected and observed results is not sufficient; you should also identify how and why differences occurred, explain how they affected your experiment, and show your understanding of the principles the experiment was designed to examine.

Style, Format and Mechanics

• Read the criteria carefully!
• Laboratory reports are typed or written in ink.
• Each section is clearly indicated with a heading.
• Check for spelling and grammatical errors.
• The laboratory report should reflect the objective qualities of the scientific process. Avoid using the more personal first person singular (“I”) or plural (“we”). The past perfect tense is preferred.

For example:
Preferred –  The results indicated that solution A had a higher concentration than solution B
Avoid – In this lab I learned that solution A had a higher concentration than solution B

Introduction (Purpose, Background, Hypothesis)
Review the criteria to determine is a full introduction is needed. Some reports only require purpose or hypothesis.

• Purpose: The objective of the lab or experiment. A purpose should clearly state what the experiment is designed to test or demonstrate. The purpose is expressed clearly in only one or two sentences, including the main methods used to accomplish the purpose.
• Background Information: The background section should include research that needed to do in order to understand the experiment. Students may want to use outside resources such as notes, textbooks, reference books, scientific publications, and other high-quality sources. The background information should be as straightforward, clear, and concise as possible.
• Hypothesis: A hypothesis is an educated prediction about what is expected to happen in the experiment based on background information. The hypothesis should be able to be written in a format with the words: “If…then…because…” and it should include the independent and dependent variables. More about writing a hypothesis

Materials

Write a complete and accurate list of equipment and chemicals. Indicate how much of each material will be used in the experiment. Sketches or photographs of complex setups may also be included.

Procedure

• The procedure section includes the process of the experiment exactly as it was done in the laboratory.
• The procedure is written out step-wise in the form of a numbered list.
• It should include cleaning equipment, setting up equipment, taking measurements, and even cleaning up.
• A good rule of thumb for writing complete but concise
  experimental procedures is to include enough information so that others who read the report would be able to duplicate the experiment at a later date.
•  In some cases, you can simply direct the reader to a lab manual or standard procedure.

Results/Observations/Data

• This section should include observations from the experiment.
• Use tables, charts, and graphs whenever possible.
• Photographs or drawings from your experiment may be added to supplement your data.
• Organize narrative observations (information written using sentences) in a neat and orderly form.
• Include observations such as color, shape, mass (weight), length, volume, temperature, and smell.
• Data and results should be labeled clearly and include units.
• You may be asked to show sample calculations in this section.

Conclusion/Discussion

This section summarizes your purpose, explains the reasoning of your procedure and  provides a scientific explanation of your results. It requires thinking critically about the findings and examining the relationship of the results to other experiments.   Parts of the conclusion repeat other elements of your report.  This is OK.  A reader should be able to understand the entire experiment by reading only the conclusion.

• Make a claim about the overall pattern or trend that answers the purpose of the lab.
• Support the claim using appropriate vocabulary to demonstrate your understanding of the principles demonstrated in the lab
• Include relevant background information to further support your claim.
• Describe sources of error that may have affected your results. 
• Provide possible extensions to your experimental design that could lend greater support to your claim or extend the application of the principles demonstrated. 

References

University of Toronto Lab Report Guide

How to write a lab report

Lab Report Guidelines