4A30.21 - Ball and Sleeve
Demonstrate thermal expansion of a brass ball and two sleeves.
A brass ball and two brass sleeves are mounted on wooden handles. When at room temperature, the ball does not pass through the flat plate sleeve. If the flat plate is heated, the hole in the plate expands and the ball can fit through the flat plate sleeve. Next, show that at room temperature, the ball fits through the circular sleeve. If the ball is heated, it will no longer pass through the hole in the sleeve due to the expansion of the material of the ball. Be sure to place hot items onto the aluminum plate to cool them down and not brand the top of the table.
Thermal expansion is created by energizing the bonds between atoms which increases their nominal distance from each other. Stronger bonds and therefore stronger materials, expand less than weaker bonded materials.