An apparatus used to demonstrate thermal expansion and contraction, as well as the forces involved in these processes. It is comprised of a heavy cast metal frame with U-shaped slotted end pillar to carry a sturdy iron bar. This iron bar is threaded at one end and incorporates a knurled tensioning knob. The other end accommodates a cast iron breaking bar.
Using a Bunsen burner to heat the iron bar, the iron bar will expand and its tension will decrease. The initial tension is restored using the knob. The tension increases as the rod cool, until the force on the smaller iron bar causes it to fracture.
Supplied with 10 breaking bars.
NOTE: Bunsen burner required (not supplied).