Previous generations of physics students learned how common machines work, as evidenced by their textbook illustrations (Fig. 1). Such understanding of machines that daily life depends on seems to be evaporating. In response, for two decades I have conducted an introductory physics “engine cadaver lab” (Figs. 2 and 3). It offers opportunities for hands-on engagement with concepts such as moment of inertia, center of mass, Faraday’s law, Bernoulli’s equation, engine efficiency, thermal expansion, etc. Unlike biologists, we put our cadavers back together!
References
1.
Robert
Millikan
and Henry
Gale
, A First Course in Physics
(The Athenæum Press
, Boston, MA
, 1906
), pp. 187
, 189
.2.
Robert
Millikan
, Duane
Roller
, and Earnest
Watson
, Mechanics, Molecular Physics, Heat and Sound
(Ginn and Co
., Boston, MA
, 1937
), p. 83
.3.
John
Rigden
, Hydrogen, the Essential Element
(Harvard University Press
, Cambridge, MA
, 2002
).4.
Dwight E.
Neuenschwander
, “The applied physics of gasoline engines, part 1: Mechanics and thermodynamics
,” SPS Observer
26
–31
(Spring 2014
), andDwight E.
Neuenschwander
, “The applied physics of gasoline engines, part 2: Electricity, magnetism, and caring
,” SPS Observer
(Summer 2014
), https://www.spsnational.org/the-sps-observer/archive. These articles include discussions of automotive history and alternative motor designs, and photos of famous physicists with their cars.5.
If students will remove flywheels, I suggest the instructor remove them in advance and put them back on the motors for students to remove again. Brittle flywheels stick on first removal and break easily; use a flywheel puller with abundant WD-40.
6.
Paul
Dempsey
, How to Repair Briggs & Stratton Engines
(Tab Books
, Blue Summit, PA
, 1978
).7.
Colin
Campbell
, The Sports Car Engine: Its Tuning and Modification
(Robert Bentley Inc.
, Cambridge, MA
, 1965
), pp. 4
–7
.8.
Without special tools, reinserting valves with their springs takes time-consuming persistence.
9.
If disassembling the carburetor, caution students that the parts are very small and should be laid out in a neat pattern for reassembly.
10.
The ratchet is tricky to reassemble—ball bearings scatter everywhere. I recommend leaving it intact.
11.
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2020
American Association of Physics Teachers
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