PURPOSE: To illustrate centripetal force and centrifugal reaction with a trick.
DESCRIPTION: Pour water into the can, then rotate the can over your head
in vertical circles. Rotate the can more and more slowly as you move toward the class, so that the can stops upside down over some student's head. Then remove the sponge and squeeze the water back into the can.
REFERENCES: (PIRA unavailable.)
EQUIPMENT: Water bucket with rigid handle and sponge.
SETUP TIME: None.
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