Guinea and Feather Tube.

This counter-intuitive experiment has to be seen to be believed. Galileo used the traditional guinea (coin) and feather to show how items fall at the same rate in a vacuum despite their relative weights and sizes. Includes 81 cm plastic tube for safety; 2 rubber caps, one with hose cock and hose for evacuating the tube; weight set; instructions. You need a vacuum pump, not included (electric pump preferred).