Writing a good lab report starts with taking smart steps when you conduct the lab. You should take notes about your methods, keep careful track of your data, and think critically during the lab about what could have been improved or done differently. If you are allowed to, taking pictures of your experimental setup is a good idea to make sure you are accurate in your descriptions when you write your lab report for your AP® Biology class. If photos are not allowed, consider making sketches in your lab notebook of any complicated setups. Don’t wait too long after you perform the lab to write the lab report, so that the information is still fresh in your mind.
Individual teachers vary in their specific requirements for AP Biology lab report formats, so make sure you pay attention to the instructions your teacher gives you. If you have any questions or if there is something you don’t understand, ask your teacher! They are there to help you. After you write your lab report, it is important to read over it and check for spelling or grammatical errors, which are not acceptable in scientific writing. Note that, with the exception of the title and materials list, you should always use complete sentences in your lab report.
Below are some general guidelines on how to write an AP Biology lab report. With this goal in mind, a great lab report is both concise and descriptive and contains the following sections:
The title of your lab report should be as specific as possible (i.e., “Lab 1” is not a specific title). Oftentimes, you can follow the model of “The Effect of X on Y.” For example, in an experiment where you tested different types of fertilizer and how well they made potato plants grow, a good title would be “The Effect of Fertilizer Type on Growth in Potato Plants.”
You don’t need to go into too much detail in the title; that’s what the other sections are for. As an example, “The Effect of Organic and Synthetic Fertilizers on Growth in Eighteen Potato Plants” is too much information. You should be as concise as possible while still giving your reader a good idea of what type of experiment you performed and what they should expect from the overall report.
Although not all teachers will require an abstract, this section is good practice for reading and writing real scientific articles. This section should give a brief summary (typically less than 100 words) of the entire experiment and analysis. You should cover what is being studied, your hypothesis, and a summary of the results. You should also include a concluding statement of the big takeaways from the experiment.
This section of your lab report should provide your reader with any background information they will need to understand your experiment. You should introduce the purpose of the experiment in this section of the lab report so that it is clear why the lab experiment was performed.
In this portion of your lab report, you will state your hypothesis, or testable statement. Your hypothesis is generally written in an “If…, then…” format (eg, “If organic fertilizer is better for plant growth than synthetic fertilizer, then potato plants will grow taller when exposed to organic fertilizer than when exposed to synthetic fertilizer”). You should include any reasoning that went into the formation of your hypothesis.
For example, if you hypothesize that organic fertilizer will result in better potato plant growth than synthetic fertilizer, why do you think that? Generally, you need to provide a brief definition of key terms you use in this section when they are introduced.
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In this portion of your lab report, you will go into detail about the materials you used in your experiment and what steps you performed. Typically, this section involves a bulleted list of all materials used and their quantities. However, different teachers may have different preferences for how the materials you used are communicated in your lab report. Remember to include all materials you used; for example, don’t forget items such as soil and water in a plant growth experiment.
In addition to the materials list, you will detail each step you took to complete your experiment. The goal of writing this section in any scientific field is to make your results reproducible by other scientists, which would make your experiment accurate and valid in the eyes of the scientific community.
Employing meticulousness in writing this section is preparing you for what to expect in the real world of science. With this in mind, make sure you mention all the variables that were controlled, along with the independent and dependent variables. In addition, you should use the past tense when writing this section, as your materials and methods are a description of an experiment that you have already performed. For example, you would write, “the height of each potato plant was measured daily”, not “measure the height of each potato plant daily.”
The results you obtained during your experiment are displayed in this section of your lab report. Usually, this will be in the form of table(s) and/or graph(s), depending on your experiment. Think about your experiment and results, and how you can best depict them visually.
When creating tables and graphs, make sure each one is clear and easy to follow and that they each have a descriptive title. Consider whether you should include averages for experiments in which multiple trials were performed. When you display numerical figures, units should always be included. If your lab report contains a graph, make sure to label both the X and Y axes appropriately and to include a key or legend if necessary. In some labs, you will perform statistical analyses; make sure to include this here if it was part of your experiment.
The statistical analyses, graphing tasks, and tabular data production required for your AP Biology lab report are directly tied to the science practices you will be tested on during the AP Biology exam, as shown in our AP Biology Study Guide and Materials article. So make sure you put your best effort into learning and mastering the skill set of representing scientific data in a visual manner and using statistics-based reasoning.
Often, results that do not support your hypothesis are just as valuable as results that do. Results that do not support your hypothesis do not mean that your experiment has “failed” or that you should make up false results. So, for this section of the lab report, it is extremely important that you always represent the actual data you obtained in the experiment.
