This apparatus is used in the experiment?of the expansion of metal plates when heated. This apparatus includes a sheet of wood with dimensions 6x15x1?cm?in size?mounted on?a tripod?base,?a pair?of metal?plates,?steel plates?at?one end is connected to the?scale?pointer.?The side?buttons?are used to adjust?the?space between the pair of?metal plates.?A light bulb is attached below.