PURPOSE: To challenge the students' thinking about the buoyant force by considering the question: "Will a round object, without a flat top and bottom surface, experience a buoyant force, as does a cylinder?"
DESCRIPTION: A round steel ball and a hollow metal can hang from the scale. The pressure is always normal to the surface of a body and increases linearly as the depth increases. When the steel ball is immersed it too experiences a buoyant force, because the upward vertical component of pressure applied to the lower hemisphere is greater in magnitude than the downward vertical component of the pressure exerted on the upper hemisphere.
REFERENCES: (PIRA unavailable.)
EQUIPMENT: Archimedes' Law Demonstrator with small steel ball.
SETUP TIME: None.
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