1. The problem statement, all variables and given/known data coursework - I will be varying the temperatures of steel ball bearings as they drop onto a metal plate, with the bounce heights, i can work out the coefficient of restitution. however, i need help on the theory behind how temperature will actually effect the coefficient. e.g: how temperature effects the elasticity of the materials as the impact will depend on this, or how temperature is related to the coefficient of restitution. 2. Relevant equations coefficient of restitution = squareroot (bounce height/original height) 3. The attempt at a solution My theory on this would be that the temperature will increase the coefficient of restitution as the heat energy will cause the lattice to vibrate - thus making the solid less 'stiff' and increase in elasticity which will increase bounce height -> increase in coefficient of restitution however, some articles say that increase temperature should decrese the coefficient of restitution? anyhelp on the theory behind this would be greatly apprreciated, any more infomation needed.. please ask :) Thanks in advance!