16cm high Solar Radiometer | 4 Blades rotating glass windmill Crookes solar radiometer |Measures Radiant Flux of Electromagnetic Radiation | desk ornament | weather station | light mill

• This DECORATIVE SOLAR RADIOMETER is sure to impress and will make a great gift for science lovers, demonstrate the conversion of radiation energy into kinetic energy. Place the radiometer in a sunny spot and watch thermodynamics in action, once it soaks up some rays it becomes a real solar engine, the stronger the light, the faster it will spin.
• These CURIOUS AND MESMERISING instruments measure the power of electromagnetic radiation. Made from a glass bulb with much of the air removed to form a partial vacuum, inside is a set of fine metal vanes, each with one dark and one light side, mounted on a spindle.
• The vanes rotate, as if by magic, when exposed to sunlight, artificial light, or infrared radiation (even the heat of a hand nearby can be enough) – the more intense the light, the faster the rotation.
• The radiometer stands 15cm | 6 inches high the glass ball has a diameter of 8cm | 3.1 inches, carefully made of high borosilicate glass, clear to see what happening inside, the base and stem are blue coloured.
• Solar radiometers are also known as LIGHT MILLS because light moves their blades as opposed to wind for windmills. Invented by the chemist Sir William Crookes as the by-product of some chemical research is more of a beautiful science gizmo than a means of accurate measurement.

Product description This decorative Solar Radiometer is sure to impress and will make a great gift for science lovers, demonstrate the conversion of radiation energy into kinetic energy. Place the radiometer in a sunny spot and watch thermodynamics in action, once it soaks up some rays it becomes a real solar engine, the stronger the light, the faster it will spin. These curious and mesmerising instruments measure the power of electromagnetic radiation. Made from a glass bulb with much of the air removed to form a partial vacuum, inside is a set of fine metal vanes, each with one dark and one light side, mounted on a spindle. The vanes rotate, as if by magic, when exposed to sunlight, artificial light, or infrared radiation (even the heat of a hand nearby can be enough) the more intense the light, the faster the rotation. The radiometer stands 15cm | 6 inches high the glass ball has a diameter of 8cm | 3.1 inches, carefully made of high borosilicate glass, clear to see what happening inside, the base and stem are blue coloured. Solar radiometers are also known as light mills because light moves their blades as opposed to wind for windmills. Invented by the chemist Sir William Crookes as the by-product of some chemical research is more of a beautiful science gizmo than a means of accurate measurement. The purpose of a radiometer is to measure the electromagnetic radiation strength, it is fascinating to hold it in the sun or to a light bulb and see vanes spin. When exposed to sunlight, artificial light, or infrared radiation, even the heat of a hand nearby can be enough. The vanes turn with no apparent motive power, the dark sides retreating from the radiation source and the light sides advancing. The reason for the rotation was a cause of much scientific debate in the ten years following the invention of the device, but in 1879 the currently accepted explanation for the rotation was published. Today the device is mainly used in physics education as a demonstration of a heat engin Safety Warning Choking hazard - Keep out of reach of children. Avoid looking directly into the glass bulb to prevent eye irritation.