(Last Update: 19:35 PST 20 January 2013 )

Overall, I was fairly pleased with how well students did the lab write-ups for the thermistor lab, despite the lab having been longer and more difficult than I had anticipated. Grades ranged from B+ down to C+, plus a couple of "REDO"s.

Any student may redo any lab write-up, but those who get a "REDO" must redo them. Students who turned in a joint report may redo the write-ups individually or together, but once an individual report has been turned in, then joint reports are no longer possible. When redoing a lab report, turn in the old, commented-on report attached to the new one. Don't wait a long time before redoing reports.

Warning: I have higher expectations for late or redone reports, so don't make only trivial changes and re-submit—your grade can go down. Make substantive changes that significantly improve the quality before resubmitting.

Here were some common problems in the lab write-ups:

• The word "derive" does not mean "take the derivative of"—the corresponding verb is "differentiate". Similarly "derivation" is not the same as "derivative".
• The formulas for the B-equation and the Steinhart-Hart equation need citations, including URL and date accessed if they were taken from a resource on the web.
• The formulas used needed to be included in the report—just invoking their names is not enough.
• Screen shots of gnuplot windows don't work well in reports, and some of them were completely unreadable. Try using a script like epsscript:

  set terminal postscript eps color
  load 'script-name.gnuplot'
  

  with the command

  gnuplot < epsscript > script-name.eps
  

  or pdfscript:

  set terminal pdf color
  load 'script-name.gnuplot'
  

  with the command

  gnuplot < epsscript > script-name.pdf
  

  to produce eps or pdf vector images that can be included in documents.
• Including the gnuplot scripts you used as an appendix to your report is a good idea.
• Don't mix unrelated things on the same plot (like resistance vs. temperature and voltage vs. temperature). The axis labels should always correspond to the data and curves plotted.
• Since the goal was to make a recording thermometer, you should have come up with the formulas and scripts necessary to plot temperature as a function of time.
• If you cut and paste formulas from the web, you must provide a citation right after the formula—anything less is plagiarism. In general, it is a bad idea to cut and paste formulas unless they are using exactly the same notation as you use in the rest of the report. You are better off learning how to format formulas in whatever document processor you use, rather than blindly copying stuff in a different notation.
• Many students claimed that the spec sheet had a very wide range of B values for the thermistor (3000K–3500k), but this was a misreading of the spec sheet. The same spec sheet is used for many different thermistors, but the part number encodes more detailed information about which parts of the spec sheet are relevant for this particular thermistor. Re-read the part of the 01-thermistor lab handout that explains how to interpret the part number.

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Biomolecular Engineering Department

BME194 Winter 2013

Questions about page content should be directed to Kevin Karplus
Biomolecular Engineering
University of California, Santa Cruz
Santa Cruz, CA 95064
USA
karplus@soe.ucsc.edu
1-831-459-4250
318 Physical Sciences Building