We tested hardness by seeing how high a golf ball would bounce off different materials.
Apparatus we used
How we made it fair
We dropped the ball from the same hight each time and measured it from the top of the ball each time.
The hardest material is the brick because the golf ball bounced the highest hitting off of it.
The softest material is the cotton because the golf ball didn’t really hit off of it.
A hard material is one which gets the most bounce.