We wanted to find out which materials create the most friction and cause the car to slow down. We made sure it was a fair test by always having the ramp at the same height, not pushing the car but allowing it to fall naturally once released and ensuring we measured the distance the car travelled as it came to a natural stop. We tested foil, net, faux fur and artificial grass. Do you remember which one created the most friction and caused the car to slow down the most? Can you remember why?