Physics 221 Laboratories: Spring 2002

See the Laboratory Schedule for times and rooms. This page applies only to sections taught by Dr. Yost.

The laboratories are 10% of your course grade. The grade is based on your lab reports, as described below. There will also be a Lab Final testing your understanding of experimental concepts used in the laboratories. This is worth 100 points, the same as one lab report. You cannot pass the course if you fail the lab. Attendance is required at every laboratory session.

Laboratory Web Site: http://www.phys.utk.edu/physlabs.html

The official Laboratory Web Site is accessible from the Physics Department home page through the Laboratories link. This site contains general information relevant to all of the Physics Department laboratories. See the Physics 221 section for the information for your labs.

Laboratory Manuals: http://thomson4.webct.com/public/utphy221

Be sure to print and read each lab manual before you come to the lab. It is important to try to understand what you will be doing before entering the lab. Otherwise, you may waste valuable time.

Lab Manuals are available through the on-line WebCT system. New students who have never registered for a WebCT course should see the WebCT Instructions for new students. Students who have previously registered for a WebCT course should see the WebCT Instructions for previously-registered students. Substitute "221" wherever you see "XXX" in the instructions. You can purchase an access package at the book store. Be sure you are registered by the end of January! Links to the laboratory instructions for each date will be provided on the web page for your section. You will need a WebCT password to access these, beginning in February.

If you have Javascript errors when trying to access the lab reports through the WebCT site, try accessing them through the schedule on the web page for your section.

Laboratory Notebooks

You will need to obtain a lab notebook, which must be bound in some manner (not loose-leaf). The detailed style of notebook is up to you. Each individual (not each group) will keep records in the log book. The notebook must be reviewed and signed by the instructor before you leave with it. It will not be graded directly, but you will use it to write your lab report. The notebook should contain:

• Your notes and plans written upon reviewing the lab manual before class. You should have some idea of what you will be doing before coming. Note any questions that may arise.
• A rough drawing of the experimental setup, including any relevant dimensions, weights, or other parameters which may be needed during the experiment.
• Tables of data with units, and at least enough significant digits to permit proper data analysis. You should have some idea of the precision level of the equipment you are using, and record the appropriate number of digits. The tables may come from Excel worksheet printouts, when applicable, and should be attached to the page.
• Rough plots should be made whenever applicable so you can tell quickly if the results are as expected. How you proceed may depend on how you analyze the data as you go. Any calculations made should appear in the notebook as well. Usually, you will be making the graphs using Excel,so you can just produce the final plots as you go. Make enough copies so that each person can turn in a lab report.
• Write down any observations you have that may affect the interpretation of the results. For example, if you believe any external influences could be having an effect on your data (systematic errors), write this down. Record any thoughts and conclusions which you may wish to review when writing your report. Include comments on the accuracy of each piece of equipment you use.

Write your lab notes continuously through the experiment. Don't wait until later. The notes must be orderly and timely so that you do not misplace or misinterpret any data.

Laboratory Reports

Your Laboratory Reports will be the basis for your grade. The first two labs are introductions to basic data analysis methods. There is no real experiment. Therefore, no real lab report will be required. You should print out all results you obtain - graphs and final spreadsheets - and turn them in. One copy per group is sufficient.

Beginning with the third lab, the Force Table experiment, you will be doing actual experiments. Each student (not each group) must turn in a laboratory report at the beginning of the next laboratory meeting.

The laboratory report must be based on your own data, and the contents of your lab notebook, which is subject to review by the instructor to verify this. The report must be neatly and clearly presented (typed is preferable) and contain the following elements:

• A title, followed by an introduction defining the problem and stating in a simple manner what you expect to observe or demonstrate. The purpose of this is to show that you understand the physical significance of the experiment. Don't just copy wording from the lab manual.

• A simple discussion of the apparatus and lab setup. Include drawings when they help show the setup and what parameters are being measured. Any special features of the apparatus which make it well suited or poorly suited for the desired measurements should be noted. The degree of accuracy expected from each measuring device should be shown, and any limitations noted. For example, if you are balancing weights, you can note how much variance in weights can be added before a difference is noticed, and write that you used a "balance which could be read with an error of 5 grams".

• A description of your method, showing what you did in the laboratory, and why. Where relevant, discuss the physical reason for doing the measurements the way you were instructed to, to show that you understood this, and were not just blindly following directions. Any limitations of the method, or errors made, should be noted. Do not just copy the lab instructions. Show what your group actually did, and why. This section should not look like an instruction manual.

• A complete summary of your results, with a discussion of the range of validity. Be sure all graphs are titled and labeled, and that all units are shown. Do not include charts of raw data used to produce the graphs. Include only tables of final results. You should include any and graphs that you made during the lab.

• Your conclusions about what was learned from the experiment. Include some statement about the limits of validity of your results (i.e., what range of velocities, weights or other parameters were actually checked). How well do the results match your expectations within the limitations of the apparatus? Include some discussion of possible sources of any departures from expectations.

  Try to be as quantitative as possible. For example, say "our results verified that momemtum is conserved in the collisions to within 5%" rather than "our results proved conservation of momentum" or "our results were pretty good". If something went wrong, try to explain why. The better you can explain the source of the problem, the better your grade will be. For example, you could note that an air track had so much friction that momentum conservation could be verified only to 30%. Better yet, provide some evidence that velocity was being lost along the air track to back up this claim. Can you say what the coefficient of friction was, if you are attributing the error to friction?

• If any questions were asked in the lab instructions, you must attach the answers to the end of the lab. This is really not a part of the lab report, but a separate part of your grade. Read the lab manual carefully to be sure you don't miss any questions at the end.

Do not forget to include your name, section, and date on the lab, and to show the names of your lab partners.

The lab reports will be graded according to whether you included all of these items, and on how well you explained that you did the lab correctly and understood what you were doing. The reports are graded on quality, not length. Commentary should be quantitative, and avoid vague phrases such as "pretty good". The grading will be based on a 100 point scale, as follows:

Section	Basis for Grading	Points
Introduction	Writing a clear introduction showing that you understand the physical significance of the experiment.	20
Apparatus	Discussion of apparatus, including limitations of apparatus.	20
Method	Showing that you did the lab correctly and understood what you did.	20
Results	Selectecting and clearly displaying key results and graphs.	20
Conclusions	Clearly showing how your results compare to expectations, with a quantitative discussion of the errors and the reason the errors were the size that they were.	20

Any questions are graded separately, and added to the lab report score. Normally, each question is worth 2 points.

Late reports will have a minimum 30 point deduction. Reports more than one week late will not be graded. You may turn them in early by placing them in my mailbox beside the physics office, or delivering them in person. If you must miss a lab, you need to turn in the report early to avoid a deduction. If illness prevents you from coming to class, you can e-mail your report in MS Word, PDF, or Postscript format to syost@utk.edu. If you are ill and cannot send the report electronically, you can contact me by e-mail before the class for other arrangements. Any missed labs must be made up the same week, or during the last week of classes. Arrangements to make up a lab must be made before the lab is missed.

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Physics 221

S. Yost's Sections

Department of Physics

University of Tennessee