Keeping a Laboratory Notebook

Introduction

While preparing for and doing an experiment, you will keep a lab notebook. The notebook is a running record of your goals, procedures, observations, measurements, calculations, results, and conclusions. Keeping a good notebook requires a great deal of patience and discipline. It is difficult to stop in the middle of your work and write down comments in your notebook. Keeping an accurate record is essential if you wish to use the scientific method to learn anything from your experiment.

Page Header

In order to easily find things in your notebook put the title of the project, the date, and a page number at the top of every page.

Project Write-up

Fundamentally, a notebook is just a running account of what you do as you prepare for and carry out your experiment and analysis. The main sections of a good write-up are listed below, but these are just guidelines. Use common sense. Strive to include enough information so that you or a fellow student could repeat the experiment at a later date using only your notebook.

Project Title - Provide a descriptive title for the project.

Goals or Purpose - Begin with a brief statement of the goals of the project. This information will help guide you through the experiment. One common mistake is to start the project without having a clear idea of exactly what you are trying to do. A project with many small parts should have a goal for each part. In most cases this section will be quite short.

Equipment - If necessary, describe the equipment used. It is usually useful to include a clear sketch or block diagram. However, you need only include information relevant to your project.

Preliminary Information - This section contains information you gathered and calculations you might have done in preparation for doing the lab. It should also include a plan of action. Information from books or other sources must be referenced properly, including the page number, in case you have to refer to it again.

You should have a good idea of what you will need and what you will be doing when you go into the lab. Record a tentative procedure or experimental plan in this section.

This section should be done before you start the experiment.

Experimental Procedure and Tabulation of Data - In this section record what you actually do in the lab. Start with the procedure outlined in the Preliminary Information section as a guide, but don't be afraid to improvise. This section is also where you will record the data you take. This is often recorded in a table. Be sure to include column headings that include units. Record uncertainties when appropriate (almost always).

Data Reduction - This is where your record the procedure you use to reduce the data. Often the data reduction is more work than the experiment. It is good to outline the reduction procedure before you begin. This is where you would include sample calculations. If you use a computer for your reduction, don't forget to record the names of the programs used and the algorithm they use to do the calculation. If a program isn't too long you can print it out and include it in your notebook. (Don't forget to check your program with a sample calculation. Record the calculation in your notebook.) Record the results from major intermediate steps. Quote all results with estimated uncertainties. You may want to include graphs. If you draw them by hand, use a straight edge and do it neatly. Be sure to label the axes and include units. If you generate a graph by computer, print it out and put in a notebook.

Interpretation of Results and Summary - In this section, summarize your major results. Include a discussion of the source, effect and possible methods for reducing uncertainty. When appropriate, interpret your result (this is the fun part) and try to determine what your result implies about the phenomenon in question. The interpretation leads naturally to new questions, so you might discuss future work that might be done to better understand the subject.

General Guidelines for Making Entries in the Notebook:

• Don't use scratch paper. Record everything in your notebook. Don't write things on slips of paper to be transcribed later. If you wish, reserve the left-hand pages of the notebook for scratch work.
• Don't erase anything. Neatly draw a line through an incorrect entry and write the correct value nearby. Leave extra space in tables, etc., in case corrections are needed.
• Title all tables and graphs. Record units in the table headings and put them on graphs. Include the uncertainties in your table and error bars on your graphs when this is appropriate.
• Define all symbols used in diagrams, graphs, and equations.
• Take care in drawing graphs. Graph data whenever you can. A graph often allows you to estimate the quality of the data just by looking at it.
• Estimate the uncertainties in your data and results (if possible) as you go. These uncertainly estimates are often used to determine the number of measurements needed.
• Record qualitative observations as well as data.
• Try to be neat. Remember you (and I) will have to read the notebook. Sloppiness and carelessness can make the best data impossible to decipher.
• Number and date each page of the notebook at the top of each page. If you add something or make a correction on that page later, then box and date the new entry.
• Your notebook is a success if you or a colleague can use it a year later as a guide in repeating or expanding on your work or in writing up a scientific paper.

Scientific Integrity

No one learns in a vacuum. Don't hesitate to consult texts, the instructor, or your lab partners for help. However, it is essential that you give credit where credit is due. When you work in a lab group, be sure to list the members of your group. You may share data but you must not transcribe another student's work without that students permission and without giving him or her proper credit.