Balls: ''Happy & unhappy' balls. Large. (TS0968)

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Balls: ''Happy & unhappy' balls. Large. (TS0968) A pair of visually identical black balls 38 mm in diameter. While each appears identical by sight and feel they behave differently when dropped to the ground.One ball bounces up when dropped the other is dead - no bounce, when dropped.An ideal demonstration aid for Physics teachers or a very interesting novelty for the amateur magician.The 'Happy Ball' is made from conventional Neoprene rubber. The 'Unhappy Ball' is made from a synthetic rubber compound known as 'Norsorex'.Physical PropertiesLow vs. High Hysterisis: Hysteresis is a measure of the retardation of the natural tendency of rubber to return to its original shape after deformation.This retardation is caused by internal frictional forces resulting from the molecular structure of rubber. The daed or 'unhappy' ball exhibits the greatest hysteresis.Rate of Restitution.The ball with low hysteresis, the 'happy' ball, exhibits a more rapid return to its original shape, resulting in its greater bounce. It has a high rate of restitution.Ineresting fact.If the two balls are cooled below room temperature, the bounce of the 'happy' ball decreases and the bounce of the 'unhappy' ball increases.