» In Motion

Imagine a world without gravity, momentum, or friction. How would airplanes stay in the sky? How would a runner's shoes grip to a track? Find out why forces are so important and how they hold your world together.

You can explore how friction works by doing a simple experiment. Use a smooth surface like an oven tray. Raise one end so it's about 15 centimetres off the table. Place a wooden block at the highest point. Does the block slide? Now spread some cooking oil onto the tray. Raise the tray again. If the block slides, it's because the oil has helped to overcome the force of friction.