Batteryless ‘Light-Powered’ Radiometer

Anita | Jan 07, 2021

Radiometer Educational Toy

The Radiometer is a device that spins when it is placed in light. This device, invented back in 1873, still entertains adults and children today, as the vanes within the light bulb shaped dome spin. The spinning of the vanes gives the devices its other name, the light mill.

Radiometer Educational Toy

The Radiometer helps children to explore and learn about light and physics. The device is made from a light bulb shaped glass dome that is secured onto a plastic base. Within the dome there are 4 vanes which have been painted white on one side and black on the other. These vanes have been mounted onto a spindle which allows them to spin when in the presence of light. The speed that the vanes spin in is dependent on the intensity of the light, the greater the intensity the faster the vanes rotate.

There are a mixture of explanations of how radiometers work, often mentioning photons or infrared energy. Essentially the black side of the radiometer absorbs more energy than the reflective side, which causes the vanes to turn.

The device is supplied with an instruction booklet which also helps to explain the scientific principles that cause the device to work. The vanes can alternatively be turned by using heat near one side of the device, they can also be made to spin in the other direction by using ice to chill the glass, ideally in a darkened area. The radiometer is an entertaining scientific device that can show how movement can be generated from the tiny amounts of heat in light. Using no batteries, it can also make an eco-friendly ornament for any home or office.

This Radiometer is yours for $9.98 plus a small shipping fee.

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Anny spent most of her time dwelling on useful things, and she drives all her research visible through her articles. Most of her unique and challenging topics include product reviews and descriptions of eco-friendly products and technologies.

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