Each student must keep a laboratory notebook for this course. A spiral bound notebook is sufficient. Consult Shoemaker, Garland & Nibler, chapter I for guidelines. Record all data and tape or staple in copies of all spectrometer and computer printouts. The notebooks will be graded separately. Your notebook is a proof that you actually did the experimental work. Learn a good habit to write ALL information in your notebook. See for yourself how Linus Pauling did it in his notebook
To protect yourself from loss of data, it is often recommended that notes are taken using carbon copies or that photocopies are made frequently as backup. Keep backup copies separate from originals. I am not enforcing it but I won't accept the excuses of a type 'my dog ate it' either.
Mastering your writing skills, particularly on the subject of scientific research, is imperative for advancing your further carriers in a science-related field. It is one of the topics that we will be working on throughout this class and will be linked to perfecting your written reports. There are numerous books on the subject, for example, Science Research Writing for Non-Native Speakers of English.
Each written lab report is worth a maximum of 30 points. Consult the handout for the report format. An estimated point assignment for each section of the report is indicated in the handout. Grading for each lab may vary somewhat depending on the particular requirements of each. Due dates for reports are given on the attached syllabus. Students are encouraged to turn reports in early. Rewriting of reports for a better grade is possible for early reports. No rewrites allowed after the due date. There is a one point deduction for each day a report is late. This includes weekend days. No reports will be accepted more than 10 days late.
Practice in writing clear, concise and well organized reports is an important part of the course. A significant part of the course grade derives from the quality of the submitted reports. The primary focus of each report should be on the treatment of the data obtained and the presentation of the results. A discussion of report writing with an example is found in Shoemaker et al. "Experiments in Physical Chemistry", Chapter 1. Use this reference as a guide to writing the various sections, but use the format given below. This format is slightly different from that given in Shoemaker.
The use of computer word processing, graphing and spread sheets is encouraged, but not required. In particular, calculations and equations may be hand written, since equation writing by computer can be time consuming.
Physical Chemistry Laboratory Report Format
This is a title of my report
John Dow, class 1999
One paragraph to state the purpose of the experiment. Also, if desired, a paragraph summarizing the historical work or practical applications to put the experiment in perspective.
One or two paragraphs explaining the theory underlying the experiment. Discuss the phenomenon to be studied and how the measurements to be made will lead to the desired quantity. The important equations that will be used in analyzing the data should be given here along with any important assumptions. Do not give detailed derivations of the equations. Reference a source for the derivations (for example a text or journal article). Use superscript numbers to refer to references which will be listed in section VI. As explained in Shoemaker et. al, equations should be part of complete sentences and symbols should be defined when they first appear. Number equations consecutively and use those numbers to refer to the equations later in the report. The ability to give a verbal explanation of an equation is an important skill all scientists should develop.
State or reference the source for the procedures used. Discuss any departures from source procedures or unusual problems encountered. DO NOT include a detailed procedure.
Include data tabulations, graphs and other numerical results here. Graphs and tables must be titled. Axes, columns, and rows should be clearly labeled including units. Graphed data points should show error limits with circles or flags. Table entries should also include error limits. Use graph legends when plotting different data sets on the same graph. Curves calculated from theory or fitting routines (such as least squares line fitting) should also be labeled as such. Often in journal articles, figure captions are used to explain graphs. Take a look at the Journal of Physical Chernistry to see examples of data presentation used by researchers.
This is the heart of the report. Critically assess the results of the experiment. How do your data compare with values in the literature? (For example this can be expressed as % difference.) If you can find no literature values, how do your results compare with related values in the literature, or with theoretical predictions? Be sure to reference your literature sources. Use tables to summarize comparisons when there are several to be made.
Explain isolated and general discrepancies from expected results. Differentiate between systematic and random errors and indicated relative magnitudes of qualitative errors.
Incorporate answers to the questions posed in the lab procedure in the discussion.
Finally, in a short paragraph, summarize your impression of the experiment.
List the references you used in the report. Use the format in Shoemaker et al. or any other commonly used format in scientiflc writing.
Appendix I Calculations
One sample calculation, i.e. complete data reduction for one set of data. Attach computer print-out if used.
Appendix II Uncertainties in Results
One sample of propagated error calculation. Make sure you clearly understand what random and systematic errors are and treat each appropriately. Known systematic errors should simply be used to correct the measurements before doing the calculation in appendix I. State where the values for the errors used in this calculation come from. Statistically derived errors, such as standard deviations from multiple measurements are preferable as a starting point. If you start with estimated errors as opposed to statistically derived errors, justify them. Chapter 2 in SNG is an excellent reference on error analysis. It is strongly recommended that you read it and make use of it.
Lab Reports Grading
Each report is worth 30 points. An approximate point distribution is:
If there are no questions to be answered in appendix III, those points will be distributed to the results and discussion sections.
Note: reports will be judged for organization, clarity, neatness and grammar!
Read chapters 1,2 in Shoemaker et al. It has excellent advice on safety, lab notebooks, reports, data analysis and error analysis. It also suggests sources for literature references. (You can ignore the section on special projects.)