Lab Write-up

Go Directly to "Lab Report" section

During the course of the AP Biology class you will be performing a series of labs. You have been provided a lab notebook to write up pre-lab information and to record data during the lab. I will randomly call for these lab books to assure that YOU are doing the work and not just relying upon the CHOSEN student in your group. I may also randomly choose one person's lab book per group and have that be the lab book for the group's experiment...BE PREPARED!!! Your notebook should be prepared in such a way that you can perform the lab without any further reference to the lab handouts. DO NOT cut out and glue the lab handout into your notebook. That does not help you understand what is going on.

In order to participate in labs you must have a signed copy of the "Safety Contract" on file with me. This must be signed by both you and your parents/guardian even if you are over 18.

The following information was adapted from

Download a copy of what follows here: "Lab Procedures"

Pre-Lab Work

For the pre-lab work and write-up you should do/include the following in your lab notebooks and MUST be completed prior to starting the lab. You should not rely upon the lab handouts to perform the lab.

  1. READ ALL MATERIAL: Make sure to read and understand all lab material associated with the lab. The material will contain background information concerning the subject of study, as well as the procedures that you will be performing.
  2. Answer the following questions about the lab in your lab notebook. These questions will be used to create the introduction section of your lab write-up.
    1. What scientific concept is being studied in this lab? DO NOT just write a one word or one sentence general description of the subject. Your answer should include as much information about the concept as will help you in the lab. You should consult the text, lab handouts, lectures, etc.
    2. What are the objectives of the lab? These may or may not be listed directly in the lab. What are you ultimately measuring, recording, or analyzing?
    3. What is the purpose of this lab? How do your answers to question #2 link to your answers to question #1?
    4. What is your hypothesis? In order to write your hypothesis you will need to identify your variables, both independent and dependent (make sure to explicitly state these). Your hypothesis can be a 1-2 sentence explanation, a paragraph, or even a graph of what you expect to see.
    5. Why are you hypothesizing what you are? What evidence or scientific concepts appear to support your hypothesis. Explain your rationale for your hypothesis. Why do you think what you think will happen will happen? (HA! Think about that for a second!)
  3. Make a list of needed materials. Make sure to note any special considerations in the handling, disposal, or use of chemicals if any are noted in the lab.
  4. Make a list of procedures and steps in the lab. This can be a written list, or it can be diagrams showing what is happening in each step. Make sure to highlight, bold, underline, or otherwise bring attention to important parts/steps of the experiment.
  5. Explain the type of data that you will be collecting. Is the data quantitative or qualitative? At what intervals will it be collected? What are the units of measure? Decide how the data will be recorded and ultimately represented. If a graph is required, what type of graph will best match the type of data collected?

Lab Work (Recorded in Lab Notebook)

During the lab you should make careful notes as to what occurred during the lab. Not only are you recording collected data, you should note:

  1. any problems that occurred during the lab.
  2. any variations to the listed procedures.
  3. any errors that occurred during the lab that may have impacted the outcome.
  4. any substitutions made to the list of needed materials.
  5. anything that could impact the reproducibility of the results.

During the lab work you should begin to note trends in the results you are observing. Make sure to record the data in a legible and understandable way. Create a data table using your identified independent and dependent variables, making sure to include units of measure for both.

At the end of the lab you should summarize the results of the lab in a way that helps you understand the studied lab. Now would also be a good time to compare results with other students and discuss reasons why the results may have varied between groups. ALWAYS compare results and note the similarities and differences in your lab book.

Lab Report (Not in lab notebook)

The following explanation will reference the image to the right. Click on the image to view it larger.

The lab write-up must be typed in size 12 font (including 'Title') using either 'Helvetica', 'Times', or 'Times New Roman' font. Smaller fonts should only be used on charts or image captions. Spacing can be single or double spaced. Any deviations from these specifications will result in the report being returned so that it can be properly formatted and a loss of points.


The title should be specific and descriptive. "pH Lab" would not be an acceptable title. The title should describe the importance of the lab, the concept being studied, the independent variables, or the procedures employed. For example, "A study of the osmotic potential of various solutions using dialysis tubing as the semi-permeable membrane" would be an acceptable title for the AP lab on osmosis and diffusion.


The abstract is a summary of each section of the report. The abstract will contain a 1-2 sentence summary on each of the sections of the write-up (more than 2 if a section is particularly complex). The abstract should include a summary of results as well. Your abstract should be complete enough so that a reader can determine if the results and procedures justify a further in depth reading of the report. Notice that the abstract has a different left and right margin than the other sections.


In section #2 of the pre-Lab section of these lab procedures you answered a series of 5 questions. You will use the answers to those questions to compose your introduction. The first 1-2 paragraphs will be your answer to question 1. The next paragraph will be your answers to questions 2 & 3. And the final paragraph would be your answer to questions 4 & 5. Make sure to connect the paragraphs in a legible and readable form. It should not sound like you are answering questions. Make sure to note any citations used so that you can include them in your references.


In the methods section you will write out in paragraph form the steps used in conducting your experiment. There should be enough detail about the methods and materials that a reader could repeat the experiment.


In this section of the report you will explain the results of your experiment. This is the section in which you will include your collected data. Make sure that any graphs or data tables are properly labeled and formatted. You will begin this section with a 1 to 2 sentence description of the results of your experiment. In the next several paragraphs you will explain your supporting visuals.


In the first paragraph you will discuss whether the results of the experiment supported, did not support, or supported-with-limitations your hypothesis (i.e. it somewhat supported your hypothesis, but with limitations). In following paragraphs you will present and discuss the specific data that you used to support or reject your hypothesis. If your hypothesis was not fully supported by the data, discuss what was learned during this lab that helped expand your current understanding of the subject studied. In the final paragraph you will discuss: (1) any errors or discrepancies in your procedures that may have resulted in erroneous or unexpected results and how you could prevent them if you were to rerun the lab; (2) how your findings compared to other students' results (if you compared data) and what may have caused these discrepancies; and (3) ways that you could improve the lab and your results.Conclusions In the conclusion you will explain how your understanding on the subject grew as a result of this experiment. When applicable, support your explanations with data from the lab. If you learned anything not directly associated with the subject of study, such as methods of data collection and analysis, include those in a 2nd paragraph.References If you used any citations than you will need to provide a reference to them in APA format. Use the "Purdue Online Writing Lab" for help in formatting you references.Summary of these Lab Procedures So once again, the pre-lab and lab work information is included in your lab notebook. Pre-lab work MUST be completed prior to beginning of the lab. All students should record the data and results in their own lab notebook. If you ever forget your notebook you should record the information on a separate sheet of paper and transfer into your lab notebook. The final lab report will be turned in separately and must be typed using the formatting indicated above and include ALL sections indicated.