Place shoes and other objects on the sandpaper. Raise one end of the board and notice how high you can raise it before the shoes slide off the board. The higher you can raise the board, the greater the friction. Find out whose shoes have the highest friction. Place the sole of one of the gym shoes in water and then try to pull each shoe across the inclined board.
Questions Look at the soles of several types of gym shoes.
Friction creates heat. A rope running through the hands of a climber creates heat. Find some exposed bedrock near your house. Examine the rocks and holes. One person should try to pull the rope with both hands while the other person holds the rope with one finger.