Purpose:Stimulate discussion about radiative heat transfer and conservation of momentum with photons.
Description:A match or other source of light is brought near the radiometer, resulting in rotation of the vanes. The REAL reason has to do in a very important way with details regarding how molecules interact with each other. The explanation is not nearly as simple as the difference in the momentum of photons when they are absorbed or reflected, or even as simple as the heating effect on the black side, which absorbs more photons, compared with the white side, which reflects more. This appears to be one of those physics devices that is typically explained incorrectly, even in the literature from the supplier that accompanies the radiometer.