For a teaching degree we did the following experiment:
Drop a rubber and a glass ball of approx. same size from approx. same height onto laminate flooring.
As we expected, the rubber ball bounced higher than the glass ball.
Our explanation: The rubber ball is more efficient in converting the kinetic energy into deformation energy and back. So the rubber ball transforms less energy into heat.
But alas, attempted verification with a heat camera showed otherwise: While there was a big blotch of heat left behind on the table by the rubber ball, the mark by the glass ball was barely visible.
The lecturer was very vague and eluded our question for an explanation.
So my question is:
What is the correct explanation of this?
And why does the glass ball not produce at least an equal amount of heat?
Before posting here I googled this problem and to my dismay found the following blog entry which contradicts our experiment:
https://sciencenotes.org/why-a-glass-ball-bounces-higher-than-a-rubber-ball/
Best Answer
because the glass ball is stiffer than the laminate flooring, when it hits the floor it deforms the floor, thereby performing work on the floor and subtracting from the energy available to bounce the ball back. that work is lost because laminate flooring exhibits viscoelastic hysteresis which absorbs the work as deformation on short timescales but then releases that work on far longer timescales. So whatever springback you get out of the laminate flooring doesn't occur until long after the glass ball has exited the scene of the crime.