Ring and Ball Apparatus
For demonstrating the expansion or contraction of metals. Consists of two brass rods with insulated handles. One of the rods has a ring and the other one has a ball of approximate diameter 1" (25mm), attached at the end. The brass ball passes through the ring when both are at room temperature, but when the ball is heated it expands and can not pass through the ring.
Comes with a Teacher's guide.