Guinea & Feather Apparatus. Apparatus to show the equality of acceleration under gravity between light and heavy objects in the absence of air resistance.Comprises 100 cm acrylic tube with bungs at either end. valve with stopcock at one end allows vacuum pump to be attached, and the air evacuated from the tube. Inside the tube is coin, and piece of paper (various laws prevent supply of feather for this apparatus).When air is in the tube, the coin falls quickly but the paper is subject to air resistance and falls more slowly. With the air evacuated, the only force acting is gravity, so the two fall at equal rate, despite the difference in weight.The famous experiment on the Moon with hammer and feather can be seen here: http://timstar.co/HammerFeather
