Ball and Ring, 4A30.21

Topic and Concept:

• Thermal Properties of Matter, 4A30. Solid Expansion

Location:

• Cabinet: Thermodynamics Cabinet

• Bay: (A3)

• Shelf: #1

Description:

Two sets of a brass ring and a brass ball.

Important Setup Notes:

• This demonstration requires a supply of methane gas usually provided by the red and white gas carts found in rooms 2103, 2241, (and 2223 upon request).

• This demonstration requires a supply of liquid nitrogen. The main supply is located at the loading dock. If 12 hours notice given to lecture demo, supply will be provided.

Setup and Procedure:

1. Heat the ball from the set that a ball can get through a ring.
2. Put the ring from the set that a ball cannot get through a ring on the liquid nitrogen holder.

Cautions, Warnings, or Safety Concerns:

• Wear the safety glove and glasses.
• Beware of the heated ring and the cooled ring.

Discussion:

The extended ball demonstrates the thermal expansion property of the material. And the shrink ring demonstrates the opposite effect of thermal expansion property. You can show the students two ways.

1 : Extended ball

1. First demonstrate to student that the ball is smaller than the ring. So, it can get through the ring.
2. Heat the ball until it expands. Demonstrate to student, this time the ball is larger than the ring. So, it cannot get through the ring.

2 : Shrink ring

1. First demonstrate to student that the ring is larger than the ball. So, the ball can get through the ring.
2. Put the ring in the liquid nitrogen until you are sure that it shrinks. Demonstrate to student, this time the ring is smaller than the ball. So, it cannot get through the ring.

References:

• Wikipedia - Thermal Expansion

• Wikipedia - Coefficient of Thermal Expansion

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