Building a Motor Lab




What is the smallest-strength magnet we can use to build a functioning* motor?

*"Functioning motor" is henceforth and herewith defined to be a coil of wire connected to a 6 volt battery in the presence of a magnetic field (supplied by one of the classroom magnets provided to you) that spins continuously when connected to said 6 volt battery.

Step #1: Research "how to build a motor" on the infobahn.

Step #2: Take a few moments to figure out how to use the magnetic field probe.

Step #3: Your motor MUST include the 6th volt battery provided to you, along with the wire and various magnets available for your use. You cannot bring in magnets, batteries or other wire from outside of class.

Step #4: Take a moment to smell the coffee! Realize you probably should have worked out the physics of the situation first. Do that now.

Step #5: Re-jigger your model.

Step #6: Refine your model further and strive to make it work with smaller and smaller magnets.

Step #7: Write-up your results. DO NOT PHONE this in. Refresh yourself on our classroom lab manual and the Mr W addendum to said document here and "How to Write an Abstract" here.

Specific write-up instructions for this lab:

    • This lab is result specific so we aren't going to worry about % error or error propagation. If your motor spins, it works, if it don't, it don't. There ain't no error to discuss.

    • Ditto to Sample Calcs. There ain't none so don't give me none.

    • There ain't much in the way of data here, so I don't wanna see none.

    • Having said that, and being rather contarian by nature, I'm very curious to see how you will graph this lab (no doubt you are concerned how you can possibly graph your results without data. Keep in mind I said I don't want to see any data, what you record for your own group's way of thinking is, of course, up to you-- and should be guarded jealously). Be creative, innovative and illustrative. If you give me a bar graph (or anything LIKE a bar graph) I'll BARf... and then dock you ALL graph points). No, I don't know how you'll do this and YES, I have faith that you will do quite nicely.
    • Your error analysis should emphasize the steps you took to make your motor work more efficiently. This should be rather extensive and be mostly qualitative in nature.

Finally -- This is a (gentle!) competition. So... the group that manages a fully functioning motor (as defined above) with the smallest magnet wins. In the event that two or more groups TIE (based on magnetic field strength as determined by MY Vernier Probe taken at a distance of 5.00 cm and witnessed by the class). The winner will be determined by the number of revolutions of said motor per minute (we'll need video evidence methinks).

If your group succeeds in building a functioning motor (as described above), you'll earn a bonus point.

If your group wins the competition (as described above), you'll earn 2 bonus points.

If your group ties (initially) but doesn't win, you'll earn 1.5 bonus points.