Keeping a well organized and in depth lab notebook is essential to progressing through any research endeavor, especially a long term project such as a graduate thesis. Experimentalists and theorists alike rely on their notes taken at the time of the investigation to later describe their observations for public review. The following notes and suggestions may be helpful to those who are beginning to write lab notes for the first time.

While teaching a laboratory course, I developed the following four areas in which the students' lab notebooks were graded. The section on requirements needs some individual application. The requirements are valid for the laboratory class, though it is possible that not all of them apply to other lab environments. These four areas summarize the different aspects of a good notebook:

• Are your notes legible?
  Everything written in your notebook must be readable by another person. You may write in cursive so long as your handwriting is easily understood.
• Does the notebook conform to the requirements?
  The requirements listed below are the bare minimum for maintaining a proper research notebook.
• Can the work be repeated using your notebook as a guide?
  Results are useless if they cannot be observed through a standard procedure. In a professional research setting a thorough lab notebook can be used to demonstrate legal claim to a patent.
• Are the results clearly indicated?
  In addition to being able to reproduce the work, any other person familiar with the physics should be able to determine whether they have successfully repeated your results. This requires detailed notes on quantitative observations. Include units on all numbers and provide error values.

Requirements
In a classroom setting, the following items are required for the grading of notebooks.

• All notes should be written in pen. Ink lasts longer than pencil lead and is easier to read over time.
• Never erase or completely strike anything from the notebook. Errors should have a single strikethrough line so that they are still capable of being read.
• Do not use slang or include unnecessary opinions. This makes it very difficult for another person to use your notes to repeat the work.
• Save space for a table of contents in the front of the book.

Fig. 1: Sample Table of Contents

Table of Contents
A lab notebook is important for maintaining a collection of notes on procedures and equipment that is not used every day. It is entirely likely that one may use a piece of equipment for a week, and then not need to use it again for over a year. A content listing will allow readers, including yourself, to quickly find information they seek.

The table of contents should be placed in the front of your notebook. This means that the first two to four pages of the notebook must be left blank. These pages will be filled in with a content listing as the book is filled with notes. The level of detail placed in the table of contents is nearly arbitrary, with only a minimum but no strict maximum. Figure 1 shows a table of contents in which lab sessions are subdivided to indicate the specific tasks encountered during that time. In this example, the designation "Vacuum System" is going to be useful when a future reader has a question about this system. If the label were to be only "Session 1," then there is no way to immediately know where the vacuum information may be found and the table of contents is considerably less useful.

Fig. 2: Example Circuit Diagram

Images and Diagrams
Photographs and drawings add detail to a notebook with little effort. An experimental setup may be difficult to explain with words. In such cases it is necessary to draw diagrams in which all the different parts of the apparatus are indicated.

This is true for mechanical systems and it also holds for electrical circuits. Figure 2 is an example of a circuit diagram used to explain an electron beam circuit. There is a title directly above the drawing to clarify what it is supposed to represent. The various components are labeled, and there are a few system specific notes below the drawing. Reviewing this diagram, it is seen that a large amount of lab information may be collected. The vacuum chamber is connected to the anode. This means that the electrons emitted by the cathode close a current path through the chamber (for those not immediately striking the anode). Since the chamber is a part of the circuit, additional exercises could be setup using this as a ground (biasing a conducting grid negatively with respect to the chamber allows for experiments in which the electron beam is reflected at various angles). It is generally possible for a diagram to help explain nuances and properties of a system that the experimentalist may not have considered while doing the work. Again, notebooks are primarily used long after the work is done because during the experiment one is probably keeping track of everything in one's mind.

Bad Example

The image below illustrates a poorly maintained notebook. The black ink is the original content of this notebook entry; the green ink represents additional comments that I added at a later time. If the notebook has been used correctly, then it should rarely be necessary to add new material at a later date. The red circled numbers are used to mark the items that are discussed here.

This page is taken from my lab notebook. The notes pertain to an experimental run that took place on June 17, 2005.

1. The "ABORTED" note signifies that there was an error and the data run had to be stopped before completion. This is a poor note, however, because it leaves room for interpretation. The run definitely did not complete, but it is still possible that a majority of the data was collected. I should have written about how much of the run was successful (e.g. 75% complete) and the cause of the error that stopped it prematurely. A simple note like this results in my having to look through the data file during analysis because I do not already know whether there is anything useful in it.

2. There are notes about the probe position file (6k) and the data acquisition settings file (sis), but there is nothing written about the purpose of this data run. What were the independent variables in this run? Was this run setup to add to a previous run, or is it the beginning of a completely new investigation?

3. There are notes about "digital filtering" that are not necessary in the lab notebook. Digital filtering is applied during data analysis and can be calculated at any time. Everything on this page should relate directly to the work being done during this run. It is reasonable to start a second notebook for theory and data analysis in order to keep experimental run-time notes separate from processing and publication notes. Keeping all of this in one notebook has its merits (easier to carry one book than two) and in such a case one must be sure to label the analysis notes separately from those taken at run-time.

4. All the green writing represents notes that should have been made during the experiment run. In this example the green notes indicate which data acquisition channels represent which measurements. Such information is vital. The lesson was learned during the time it took for me to read the data files and process it in a variety of ways to determine which parameters it could possibly represent.

Example page of a poorly written notebook.

Good Example

The image below represents a well written notebook entry. The first thing to notice is that there is no green writing. Nothing has been added to these notes since they were originally taken. The date appears on the previous page and is not seen in the image (October 26, 2005). As with the bad example, the circled red numbers label the points that are discussed here.

1. A hand drawn trace of typical data is helpful in multiple ways. While performing analysis it will be obvious whether the correct file is being read. If the raw data plots look nothing like this hand drawn plot, then I will know that there is an error in my file reading routine. When it is time to set new run parameters I can review this plot to predict the type of result they will produce.

2. This is a run-time note suggesting the explanation for the data drawn previously. It is not actual analysis, rather, it is a suggestion to myself based upon an initial impression from the lab. Such a reminder proves useful as an indication of behavior that may be particularly interesting or that may need to be explained in order to account for analysis results.

3. A clear distinction is made between different data runs. The solid horizontal line indicates that any notes above it pertain to that parameter set. This data might be reviewed multiple times over the course of a three to five year thesis effort. It would be very depressing to find exciting results but not know which machine settings had been applied. A well organized notebook saves time and ensures that there is no confusion when analysis time arrives.

Example page of a well written notebook.

Tags: lab notebooks, scientific notebooks