Human Chromosomes (SEM)

AP Biology

Framingham High School- Dr. Langdon (email)

The Laboratory Notebook

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The laboratory notebook is an essential part of scientific research.  It is a complete record of the experiment being conducted.  For successful experiments, it allows other scientists to repeat and confirm your findings.  For unsuccessful experiments (by far the vast majority), it allows for a post-mortem evaluation, identifying mistakes by the researcher, inadequacies in the equipment, or incompleteness in the protocol.  In industrial and commercial labs, it also serves as a record of when discoveries are made, which is very important in patent applications.

You will be using a college-style bound lab notebook.  While your lab notebook will follow traditional conventions, you will have some flexibility to develop your own style of data recoding.  You must ensure your notebook is organized, clear, and able to be followed by other trained scientists.  A guide to completing the notebook follows, including a sample notebook page.

Some general notes—

Read the lab completely before you even touch your notebook.  Pay attention to the purpose of the lab (what you must experimentally determine), the technique you will use to do the lab, and what data you will amass.  You should plan any data tables you will need.

Always use pen when writing in your lab notebook. Make sure the ink is not water soluble, or spills could eradicate your data. 

The entries do not have to follow a set form.  Some researchers use complete sentences, others only phrases.  Some write in paragraphs, others in bulleted or numbered lists.  Choose whatever form is most comfortable for you.

Below is information on preparing particular parts of the notebook entry:

Page Heading

The first page should include the name, date, and title of the experiment or experiment part.  Some of the AP Biology labs are actually a number of unrelated experiments.  It is often easier to enter these separately in your notebook.

Additional pages should include your name, date and a brief running title of the experiment.


At the start of each lab or section of a lab, write a brief purpose.  It should be very explicit:  most experiments are designed to determine only one outcome.  For example, you may be placing a number of potato cores into many different beakers of varying concentrations of sucrose and measuring the change in mass of the potatoes, but your goal is to determine the water potential of a potato cell. 

Procedure and Data

Since you will be repeating experiments done before and not designing your own protocols, you should always start this section with a reference to the procedure you will be following.  Often this is as simple as saying “Performed experiment according to the protocol from AP Biology lab 12.”  In addition, briefly describe the steps you follow as you do them.  A numbered list or bullet list works well here. 

Record all measurements and data in your notebook after the step you obtained them or in a prepared data table if you think that more appropriate.  Individual measurements are best recorded in line with the procedure in your notebook.  Recurring measurements are best recorded in a data table.  Always include the units, and pay attention to significant figures.  Always record the entire measurement from a device, even trailing zeros (e.g., 2.30 grams, not 2.3 grams).

If you perform a calculation in any of the steps, record it—even if it seems trivial.  Include the substituted formula and the answer you derived.  Many scientists discover that their experiment failed because of a simple mathematical error like using the wrong molecular mass for a chemical when calculating a molarity.

If something accidental or unexpected happens, enter it in your notebook.  If you accidentally expose your chloroplast samples to light or if the solution that started out clear suddenly becomes cloudy or colored, record it.  The change observation or procedure mistake may offer an explanation if your experimental results differ from the norm. 

Do all work, including graphing, directly in the lab notebook.  If you have a printout from a piece of equipment, tape this into the notebook. 


At the end of each lab or lab section, explicitly state your conclusion.  This is often just a few sentences long.  Include numerical data to support your results.  Though unfortunate, sometimes you must state that you are unable to draw a conclusion at this time due to a catastrophic failure in the experiment.

Click the Thumbnail below to see a sample notebook page.

 Sample AP Biology lab notebook page