Physics 116: Introductory Laboratory Experience

Department of Physics and Astronomy

Sonoma State University

Spring 2006

Prelaboratory Work: A worksheet accompanies each experiment with four questions to help you prepare for that week’s laboratory. This is worth a maximum of 10% of the grade (1 point), if it is handed in before the laboratory.

Laboratory Notebooks: All write ups are done in the laboratory notebooks. Please purchase a lab notebook that has the carbonless copy feature. You will tear out the copies and hand them in at the end of the appropriate laboratory period. They will be graded and returned to you before the next laboratory. This means that your work on the experiment and write up is over at the end of the laboratory period. The notebook is worth a maximum of 90% of the grade (9 point).

Other Policies: Computer assisted analysis of the data where appropriate is expected. You will be taught to use a program called "Microsoft Excel" that has plotting and least square fitting routines that handle uncertainty estimates. EXCEPT FOR EXTRAORDINARY CIRCUMSTANCES, ABSENCES BEYOND ONE LAB CAN NOT BE MADE UP.

Laboratory Notebook Format. Nine points credit.
Always include your name, date and names of laboratory partner(s).

1) A simple sketch is best. This is a useful skill when you design your own experiments.

2) Your original data should be written directly into your notebook. Plan ahead and organize your data taking before any measurement. This is best done before the laboratory period. All data tables need to be labeled with what the quantity is and the units. A print out of data tables using the computer is fine as long as you label the quantity measured (time, distance, etc.) and the units (seconds, meters, etc.).

3) Data reduction, background subtraction, and error estimates are in this section. The computer can be used to great advantage to draw the graphs, to do the least squares fitting, and to provide you with error estimates based on the scatter in the data. All graphs must have a title and axes labeled with units. The conclusions drawn from each graph need to be described in complete sentences (one or two is usually sufficient). A graph with no statement as to what it means is not going to earn the maximum grade.

4) A concise summary comparing theory and experiment demonstrates you know what you are doing and makes for a professional report. Do the results fit the theory within errors? If the final result is many standard deviations from the expected value, try to find reasons why. However, the summary should be brief and based on your experimental results.

5) Answer any questions at the end of the write up.

Additional factors:

a) Have you covered a sufficient range of input parameters to really test the theory? For example, for a pendulum: have you taken data with very short and very long pendulums? The test of a theory is more convincing if you use extreme values of the parameters as well as values in the middle.

b) The instructor is also looking at your original data to see if you made initial trials before taking the final data set. Does the technique and final set up reflect knowledge gained on initial trials? Real science seldom goes right on the first try.

c) Are some points repeated to check repeatability? Have you looked over the data while you are taking it and retaken suspicious points? If you analyze your data before taking down the equipment, you may be able to spot troublesome points, and repeat them.

d) Overall, have you tried during the laboratory to undertake a credible experiment within the limitations of the equipment available?

Do discuss the results with your partners, and perhaps the instructor, if the results seem odd.

If you have any problems which could affect your performance in this course, please contact me. Do not stop attending classes.

Questions, comments? Email me !