Leslie's Cube demonstrates heat absorption and radiation. The cube features four sides with different finishes:
The top of the cube is fitted with a rubber stopper with a hole for the insertion of a thermometer (not included). When a lamp or other radiation source is shined onto the differing sides, students can investigate the varying properties of surface finishes by measuring the rate of heat absorption in the water inside. They may then measure the rate at which heat is released from the cube through a given side. The thermal difference between the sides may be as great as 20 times. The cube is 4 inches on each side.