Easy Does It

It's the 31st of January 1988 and exactly 130 years ago the biggest ship ever built was launched on the river Thames. The Great Easton, designed by Brunel, had to be launched sideways since the river was too narrow for the length of the ship to allow a normal head-forward launch. So the ship was built parallel to the bank. The hull weighed 12,000 tons and was the heaviest thing anyone had ever been called upon to lift. Constructed on two massive cradles, the problem confronting Brunel was controlling the great ship as it slid sideways into the water. He employed the principle of friction and used a slipway set at an angle of 1 in 12. But it got stuck! The problem confronting the students is to design and build a mechanism to lift a marble one-metre off the floor, transverse 30 centimetres, and then take 20 seconds to lower the marble to the floor. The materials available are; a variable electric power supply to drive a motor with a built-in gear box which can be switched on and off with a toggle switch or a pressure sensitive micro switch; a pulley; some string; a piece of cardboard; some plastic channelling and a length of wooden dowel. Everything can be joined together using glue, double-sided sticky tape, ordinary sticky tape, panel pins and pop rivets. The programme concludes with an explanation of how Brunel solved his problem, and the "test" of the student solutions. A group of teachers also tried their hand at solving this problem. Are they using the same materials?