Radiometer, The

You have seen them on the science shows and marveled at them in museums, and now you can own one too. The Radiometer is a glass bulb with four suspended vanes inside. The vanes are blackened on one side, and they rotate when exposed to strong light. Just place the bulb in the sun, or next to a lamp, or any other healthy light source, and watch the vanes spin faster and faster according to the light's intensity. No batteries are required - the light makes it go! Learn the mysteries of light, mechanical, and heat energy (but most of all have FUN) with the amazing Radiometer. Note: Radiometers are fragile - you'll want to be careful with them!