The students work in teams of four or five. Each team uses a pre-made buggy on which they experiment to find the most suitable gearing to achieve the fastest time over two metres. They can change three things: the size of the motor or axle pulley or the size of the wheels. The information is recorded on two tables, which are then used to interpolate what the time would be for different sized pulleys. These predictions are then tested. We end up with a knock out race with each teamís best pulley combination.