It consists of a 25 mm dia brass ball, secured to a brass ring by a chain, with wooden handle. Brass ball when cold will pass through the ring, but when heated, it will not. Thus this simple apparatus demonstrates effectively the thermal expansion.

Demonstrates the linear expansion of solids. Comprising two cast metal uprights linked by a pair of parallel plated metal support rods and supporting an expansion bar at the top. The expansion bar is fixed to one upright and rests beneath a friction pointer on the other upright. The pointer moves along a scale reading 0 to 90°. Expansion of the bar on heating causes the pointer to move along the scale. Supplied complete with expansion bars, one each of aluminium, brass and iron.

Two cast metal legs joined together by a pair of plated metal rods, with each leg having provision for horizontally supporting the ends of plated brass tube about 50cm long. The tube has a riffled nozzle near each end, facing opposite each other for use as inlet and outlet of steam, and another outlet at the center with holed rubber bung for inserting thermometer to measure the inside temperature. The test rod is inserted in the brass tube supported in rubber bungs at its each end. At one end is fitted a micrometer screw head reading to 0.01mm. A 4mm terminals provided on each leg for connecting an electric bell or galvanometer to indicate make/break of contacts. Supplied complete with 3 metal test rods, one each of copper, brass and steel.