Radiometer From the Manufacturer It's the spear powered by
the sun! When light strikes the diamond wings it tranfers heat to each one,
but not to the same degree. The light wing reflect the rays and the darker
wing absorbs the rays. The stronger the light the more energy there is to heat
up the darker side causing the wings to spin faster.

• Modeled after Crookes Radiometer with white and black vanes, stands 6" Tall.
• When placed in the Sun vanes will move based on Thermal Transpiration.
• Changes of temperature of the gases inside create an unequal balance in pressure on the black side and on the white side of the vanes.
• Vanes are pushed into the area of lower pressure. Gases must always find equilibrium, so the radiant energy causes movement of the vanes.
• Made of hand blown Glass (very fragile) and vacuumed sealed. For ages 14+