RING AND BALL
PR-81
This apparatus is used for demonstrating thermal expansion.
It consists of a captive brass ball secured to a mounted brass ring by a chain.
The ring is mounted on a rod with a wooden handle.
The ball passes through the ring when cold, but will not pass through after being heated, since the ball has expanded.
Allow the ball to cool and it will pass through the ring again.
Ball diameter= 25 mm.