A lightweight motor-driven propeller mounted on a low-friction cart provides a nearly constant thrust over a moderate range of velocities and can be a powerful pedagogical tool for investigating force and motion. A variety of homemade and commercial versions are now available. This article revisits and extends the topic of fan unit use described earlier.1 It looks at the rationale for use of fan units, gives examples of teaching ideas, and describes construction of two homemade versions of fan units.

1.
Robert A.
Morse
, “
Constant acceleration: Experiments with a fan-driven dynamics cart
,”
Phys. Teach.
31
,
436
438
(Oct.
1993
).
2.
See EPAPS Document E-PHTEAH-43-009503.
This document may be retrieved via the EPAPS homepage (http://www.aip.org/pubservs/epaps.html) or from ftp.aip.org in the directory epaps in the phys_teach folder. See the EPAPS homepage for more information.
3.
David R.
Sokoloff
and
Ronald K.
Thornton
, “
Using interactive lecture demonstrations to create an active learning environment
,”
Phys. Teach.
35
,
340
347
(Sept.
1997
).
This content is only available via PDF.

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