The rebound of each ball was measured over a range of surface temperatures by using a drop test. Each ball was heated up to playing temperature, by two A level players, and then dropped from a fixed height (14 feet 4 inches) onto a composite board similar to a Fiberesin panel. A tripod mounted video camera, which had a tape measure placed in its field of view, recorded the height of the bounce.
After each drop, the surface temperature of the ball was measured with an Omega HH11 thermocouple digital thermometer.
The drop test was repeated for each ball, as it cooled off over the temperature range.