ID Code: I3-42
Purpose: Amusing demonstration of Boyle's Law.
Description: A marshmallow is placed in a bell jar. As the air is pumped out of the jar the pressure inside becomes smaller and the little bubbles of air in the marshmallow increase in size, inflating the marshmallow. Eventually much of the air originally in the marshmallow is pumped away. When the air is let back in, atmospheric pressure compresses the marshmallow to a small fraction of its original size.
An alternative demonstration uses a balloon with a small amount of air in it in place of the marshmallow. The photographs above show the marshmallow: before pumping, after pumping, and after the air is let back into the bell jar, and the balloon: before pumping and after pumping.
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