Description Radiometer
At first glance, the radiometer resembles an upright light bulb, but its task is not to illuminate. In sunlight or daylight, a small rotor inside it spins as if by magic on a needle tip. The stronger the light that falls on these blades, the faster the rotor spins.
The four blades of the rotor are small discs, painted white on one side and black on the other. The explanation for the constant rotation is that the black-painted sides warm up faster than the white sides, causing the air on that side to also become warmer. The particles in warm gases (and air is a gas) move faster than in colder gases and therefore collide more frequently and forcefully with the discs, which then causes the rotation.
The radiometer is made of glass with a plastic base.
