PURPOSE: To demonstrate heating air by compression.
DESCRIPTION: A few pumps of the tire pump into a mostly filled basketball warms the end of the pump noticeably. You can show that this is not due to friction by moving the pump handle back and forth in the same style with no load. You can simultaneously demonstrate cooling by expansion by observing that while the pump and the needle get rather warm, the air inside the ball actually cools.
REFERENCES: (PIRA unavailable.)
EQUIPMENT: Basketball with hand pump and needle.
SETUP TIME: None.
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