Laboratory Notebook A laboratory notebook is a scientist s most important tool. The notebook serves as a legal record and often in patent disputes a scientist s notebook is crucial to the case. While you may not be making ground breaking scientific discoveries as an undergraduate student you want to practice the same habits as a research scientist. You will use your lab notebook to record what you did and what you observed in each lab. It should be neat and understandable by someone who hasn t done the lab. Always record your data directly into your notebook, never write data on a scrap of paper to be included in your notebook later. Everything should be written in ink as data in pencil can too easily be erased or changed. If you make a mistake in recording something, draw a single line through the incorrect entry. Those errors are sometimes useful pieces of information and you want to be able to retrieve that data later, if necessary. Similarly, never use whiteout to correct a mistake. Use the right hand side of the page for your official work, the left hand side can be used for rough work and pre-labs. Likewise you never want to remove pages from your notebook, you may lose valuable information. For this reason your notebook will ideally be a bound notebook, there are hardcover lab notebooks available in the bookstore. Alternatively you could use the notebooks you may have last used in elementary school; these are bound and are often 3-hole punched so they will fit in a binder. A spiral bound notebook is also acceptable, although not preferred as it is easier to remove pages, if you choose a spiral bound notebook, don t go bigger than about 150 pages. You can also use the same notebook for different chemistry courses. A research scientist will date and sign every page in their notebook and will also have a witness sign and date anything of potential importance. In the lab you will want your lab instructor to sign off your lab notebook at the end of each lab, this helps to insure you have collected all the data you need in order to complete your lab report. Preparing your lab notebook ahead of time will help you get ready for the lab and ensure you know what you will be doing ahead of time. You should include: Title: what experiment you are doing Date: when you did it Partner: if you are working with someone, you want to have a record of who you worked with Objective: what is it you intend to do, what you hope to accomplish in the experiment, why are you doing this experiment Data: whenever possible prepare tables for your data ahead of time, for labs with handouts, the handout can give you a good idea of what data is going to be required and you can use these as a guide for your data tables. Try to produce your own tables rather than gluing or stapling handouts into your notebook, glue dries, staples wear out and these pieces of paper are more likely to disappear from your notebook. Your data tables should be neat, but they do not have to be perfect, your notebook is a work in progress, not the finished product. Observations: along with quantitative data you always want to include qualitative observations about the materials you use and the reactions you observe, be as thorough as you can with observations.
Two examples of a laboratory notebook follow, one is an example of what you should do, the other is somewhat lacking.
Laboratory Report A research scientist communicates their experimental findings by publishing their results in a scientific journal. Students communicate their experimental findings by completing a laboratory report. Through your report you will communicate what it is that you did, what you found out, and what your results mean. The following document outlines the various parts of a laboratory report and provides some questions to consider as your write your report. You will be focusing on different aspects of reports as you work your way through the semester, and will include all aspects in one or two complete laboratory reports. TITLE, DATE, EXPERIMENT NUMBER The title, date and experiment number should be the first things a reader sees, the date and experiment number should also be placed at the top of every new page. You can include this as a header if you are word processing your report. OBJECTIVE The objective tells the reader what it is you intend to accomplish by performing the experiment. The objective should be written in complete sentences; it should include all major aims of the experiment and should be concise. The objective should be identified before you do the lab and should be included in your lab notebook. Questions to consider in writing an objective are: What is the specific goal of the lab? What results am I going to be reporting? Am I trying to illustrate a specific law or equation? For example an objective might be: To determine the percent (by mass) of acetic acid in a vinegar sample, using volumetric analysis. Not: To titrate a vinegar sample with sodium hydroxide. Although the second example describes what you will be doing it does not express what the goal of the experiment is. PROCEDURE The procedure does not need to be a detailed description; rather you can give the reference to where the detailed procedure can be found. If there were any changes to the referenced procedure you would want to include them. Your reader should be able to duplicate what you did based on the information you provide. An example might be: See KPU CHEM 1105 lab manual pages 50-54. Two dropperfuls of redox indicator were used in both parts 1 and 2 instead of one dropperful.
OBSERVATIONS Record the number and physical appearance of all unknown samples. Record the physical appearance of all substances used in the experiment. If a chemical reaction occurs, describe the changes that you see, these may include, colour changes, temperature changes, physical appearance of precipitates formed, description of gases formed, essentially anything you observe. If you are performing a titration, always record the colour change that occurs, the appearance of the solution after the endpoint has been reached, and how long the colour change lasts (e.g. faint pink lasting 15 seconds, dark pink does not fade). This can help you later deduce if a sample was over titrated. DATA Data includes all the numerical measurements that you make; you will always be recording your data in your lab notebook. Data should be presented in tables and should reflect the uncertainty of the equipment used to make the measurement. With every piece of data you record should also be recording units, a measurement without its associated unit is meaningless. CALCULATIONS Show all calculations that you do in obtaining a result. If multiple trials are done you need only show one example of each type of calculation. Pay attention to significant figures in your calculations and include all relevant balanced chemical equations. Just like with data, you should be recording and carrying units through your calculations. Including units throughout the calculation will help prevent careless mistakes like multiplying instead of dividing by molar mass. RESULTS Present the results of your experiment, results may be numerical or not. Results may include a graph. Graphs should follow the guidelines given elsewhere and should be produced using Excel, Graphical Analysis or another computer based graphing application. DISCUSSION The discussion section includes an analysis and interpretation of your results. Questions to consider in writing a discussion include: Was the theory behind this experiment verified by your results? What evidence do you have to show this? What assumptions were made in obtaining your results? What are the potential sources of error that may be affecting your results? Note: unless you have made a gross experimental error like dropping a beaker full of precipitate you are not
considering human errors. You are looking for aspects of the experiment itself that may cause your results to differ from the true result. In identifying errors you should always consider if the error would cause your result to higher or lower than expected. Whenever possible you want to compare your result to the expected or correct value. For example if you are determining an experimental value for the gas constant, you can compare your answer to the accepted value. You would want to determine the percent difference between your answer and the correct and identify which of the errors you suggested are most likely responsible for the difference. If you do not know the expected value you can comment on the precision of your results, how close they are to each other. A good discussion should cover all the points above in a clear and concise manner. Complete sentences should be used, and the entire discussion should be no more than ¼ to ½ of a page. In general a single paragraph should suffice. CONCLUSION The conclusion is essentially the answer to the objective, re-state the objective indicating what you learned by performing the experiment. A conclusion should be no more than one or two complete sentences. QUESTIONS If any questions have been assigned they should follow the conclusion, note however that often the questions can inform your discussion, you will want to complete the questions before writing your discussion.