Thermal Expansion Set

An excellent device for demonstrating thermal expansion.  This set includes a brass ball and ring, both with wooden handles.  When cool, the ball easily fits through the ring.  Heat up the ball with a gas stove and it no longer fits through the ring!

Why does this happen?  The ball expands because at higher temperatures its atoms and molecules vibrate more and push each other further apart. 

Manufacturer's Safety Warning
WARNING! CHOKING HAZARD — Small parts. Not for children under 3 years.