<p>Magnificent Glass Radiometer, makes a great gift Compatible with who have everything.</p> <p>All made of glass. Globe is 3 inch in diameter and stands 5.2 inch tall.</p> <p>This physical and technical miracle shows you in a clear way how sunlight is converted to energy.</p> <p>Place near a window or under incandescent light and watch as the vanes rotate.</p> <p>Invented in 1873 by the chemist Sir William Crookes as the by-product of some chemical research, the radiometer is made from a glass bulb from which much of the air has been removed to Compatible withm a partial vacuum. Inside the bulb, on a low friction spindle, is a rotor with several (usually four) vertical metal vanes spaced equally around the . The vanes are polished or white on one side and black on the other. When exposed to sunlight, artificial light, or infrared radiation (even the heat of a hand nearby can be enough), the vanes turn with no apparent motive power, the dark sides retreating from the radiation source and the light sides advancing. Just place near a window or under a direct incandescent light as the vanes only rotates in light (sunlight or incandescent light). The shine on the globe the faster the vanes rotates.</p> <p>Colour:Photo Color</p> <p>Material:Glass</p> <p>Type: A: Blue base</p> <p>Package Contents:</p> <p>1x 4 Blades Rotating Glass Windmill</p> <p>Only the above package content, other products are not included.</p> <p>Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +\/- 1-3cm.</p>