ELEC 241 Lab

Chapter 2

Your Lab Notebook

A lab notebook serves several functions. In industry it serves as a legal document to establish priority of invention in patent disputes. While we don't expect many patentable discoveries to come out of 241 Lab, you should develop good notebook habits in case you should go to work for a company that does have such expectations.

In scientific research, it provides a record that allows you to duplicate your work if you succeed at your endeavor (or if you achieve some unexpected but significant result). It's also useful in identifying what might have gone wrong if you achieve neither your desired result nor the discovery of a replacement for aniline.

In an educational environment, we have some additional goals. Since we don't have weekly lab reports, the lab notebook provides a mechanism for evaluating your performance.

With this background, let's see what your lab notebook should look like.

The Book Itself

Each lab group will keep a single notebook. The lab notebook must be a bound book (i.e. sewn-in pages, not spiral or loose leaf) with consecutively numbered pages. If the pages are not numbered when you buy the notebook, number them (every page) before using it. Composition books having quadrille ruled sheets make good lab notebooks; they allow tables, graphs, and circuit diagrams to be laid out neatly. Notebooks with duplicate pages and carbon paper are impressive, but rather messy and not really necessary.

Format

Reserve the first few pages for a table of contents. Each time you have a session with your notebook (pre-lab calculations, during lab, or post-lab summary) start a new page and make an entry in the table of contents. At the top of the first page of a session, write the date, lab number, title, and the names of the team members. Indicate which member is actually doing the writing.

Make all entries in ink. If you make a mistake, draw a single line through it, leaving it legible. Some of the greatest advances in modern technology began life as mistakes. Use all pages consecutively; leave no blank pages.

Content

Your lab notebook will contain a record of each of the phases of your weekly lab cycle. Here are a few guidelines:

Before Lab.
Before you come to lab, you should have a plan for what you're going to do. As you formulate this plan, put any calculations, designs, ideas, questions for the labbie, etc. in your notebook. To save time in lab, you can set up the tables and graphs for the data you will be taking. Another timesaver is to build some (or all) of your circuits on your breadboard before lab. Be sure to enter the diagrams into the notebook too.
During Lab.

  1. Describe the experimental setup completely but succinctly.
  2. Include a complete diagram for each circuit you design or construct. Label the values of each component, including units.
  3. Indicate clearly the points in the circuit where voltage or current measurements were taken.
  4. All data should be recorded directly in to the notebook at the time it is taken. Never write data on scrap paper, the backs of envelopes, or the palm of your hand.
  5. Multiple or sequential measurements should be recorded in a table. Table headings should include the name of the variable and the units.
  6. Graphs in this portion of the notebook are mainly for your own benefit: to verify that the data are reasonable and that there is nothing amiss. You may sketch them by hand or use Matlab and glue or tape them in place. In either case, the actual data should be recorded in a table.
  7. Label each axis of a graph, including units, and give each graph a title describing what it is.
  8. If something doesn't work or behaves unexpectedly, make a note of it. When you fix something, describe what was wrong and how you fixed it.
  9. There are two types of questions in the lab handout: numbered questions (labeled "Question 1:", etc) and the "in-line" questions that are interspersed with the description of the procedure (e.g. "Did the bulb light?", "What was the current?"). The numbered questions are expected to require some thought or analysis and are meant to be answered after lab (see below). The answers to the in-line questions should be written down as you go along, as part of the experiment record.

    Answers to both types of questions will form part of your grade. To make it easier for the graders to find the in-line answers, you should mark them in some fashion (underline, box, highlighter). Also, give some hint as to which question is being answered. (E.g. "Yes" and "300 mA" are not satisfactory answers. "The bulb lit" and " $I_1 = 300\rm mA$ " are.)

After Lab.
After each lab you will write a "mini lab report" in your lab notebook. It should consist of two parts. The first is a summary of what was accomplished and how it fits into the grand plan. Remark whether the data were what you expected and discuss any significant discrepancies.

Each Lab handout has a sequence of numbered questions interspersed with the steps of the experiments. In the second part of your mini report, briefly answer each of these questions.

Grading.
Your lab grade is intended to reflect both how well you perform the lab and how well you understand it. It will be determined by the contents of your lab notebook, based on the following criteria: