Radiometer!
The Sphere Powered by the Sun
Experience this sphere powered by the sun! The vanes in the Tedco
Radiometer are alternately dark and light in color. When the light strikes these
vanes it transfers heat to each one - but not at the same degree. The lighter
vane reflects the rays and the darker vane absorbs the rays. The stronger the
light, the more energy there is, causing the vanes to spin faster.