The Lab Notebook

The laboratory work as presented in your Notebook is worth 50% of your grade.  The Notebook must have a Table of Contents and should include all of your data, observations, and results.  The pages must be dated and numbered.  Don’t record data on random scraps of paper. This is not only poor laboratory practice, but it increases your chances of losing a crucial piece of information.  All entries must be in ink, and all material from a particular experiment should be grouped together on consecutive pages.  If necessary, you can continue an experiment on later pages by noting where the continuation begins. If you must change an entry, draw a single line through it (like this) and enter the corrected value.  When you are doing two experiments at once make sure you leave sufficient space between them.  Tape your Mathcad documents, including graphs, and instrument output into the appropriate sections of the notebook.  The grade you earn for an experiment will be determined from your submitted copy of all of the notebook pages for that experiment.

For each experiment the Notebook must include:

Purpose:     This is a very brief explanation of the goal of the experiment, including the identification code of your unknown sample.

Procedure:  This is a brief summary of the laboratory methods used in this experiment with particular attention to the reactions involved.  Include in this section a complete reference to the more detailed procedure in the textbook.  You must also describe any changes you made to the procedure and also reference any other sources you used in planning and carrying out your experiment.  This is a complete record of how you made the measurements.  Another lab worker should be able to reproduce the work if necessary.

Observations: Give an accurate and complete description of the observations and measurements you made during the experiment as well as your raw numerical data.  Numerical data must be in clearly presented Tables.  You should prepare blank Tables in your notebook before coming to lab.  The Tables should label the entries, include the uncertainties and the  units.  Enter your results directly into the tables as you collect them.  Be sure to use the correct number of significant digits.  After lab you can transfer the data into the Mathcad worksheet on your computer and continue to the calculations phase of your write-up by continuing the same worksheet.  Once you develop a worksheet for an experiment, you can often adapt a copy of it for later experiments with minor modifications.  Use Mathcad to do all of the calculations, it is much easier to find and fix an error, if it happens.  You can check one trial with a calculator to be sure the worksheet is correct. 

Calculations and Treatment of Data: Complete your worksheet by doing all of the necessary calculations and graphs needed to get to the desired quantities.  Since a worksheet is self-documenting if planned correctly, you don't need to recopy each formula, just use meaningful identifiers and textboxes to explain what all of the numbers mean.  See the links on Mathcad examples page for examples. 

Summary of Results:  This part is the Conclusion section of your experiment write-up.  Include, in tabular form, (1) the results of your individual trials, (2) the mean of the individual trials, (3) the absolute and relative uncertainties for the trials, and (4) the absolute and relative 95% confidence limits.  Be sure to also include your sample identification code.  In a sentence report your result for the experiment.  It might look something like "It would be wrong only 5 times in 100 to conclude that the value of the percent chloride in unknown #1234 is in the range 48.34 ± 0.05 %".  

The first two sections and part of the Observations section, in the form of blank data tables, should be completed before you begin laboratory work.  When following the procedure from the book, pay special attention to maximizing your lab time.  Tasks such as drying samples should be done the week before actually doing the experimental work.  This way by the time you get your glassware set up your samples will be dry and cool enough to weigh. The lab time is limited and precious.  Don't waste it by doing things such as creating Tables in your Notebook, in the lab that you could do before arriving.  Remember, an incomplete or illegible report can not be evaluated.  If you are not sure, please ask.  Writing a Lab Notebook is not a test, it is a learning process.  Remember also that using an exact copy of another person's Mathcad page in your Notebook, is not acceptable. 

Please don't be tempted to turn in MathCad pages which are duplicates of another person's pages.  I can accept them only if you split the points evenly.