Purpose:Demonstrate thermal expansion in a dramatic way.
Description:A pin is inserted into a hole in a long steel rod, one end of which is fixed on the apparatus. The pin sticks out of the hole and rests against a fixed plate at the right side of the device, under the shield. When the rod is heated over period of several minutes, it expands such that the pin pushes against the plate, as seen in the photograph at the right, until the pin snaps. This is a fairly dramatic demonstration which illustrates the magnitude of the forces which can build up during thermal expansion.