Radiometer facts for kids

A radiometer is a cool device that helps us measure how much energy, like light or heat, is coming from something. Think of it like a special sensor for different kinds of invisible energy waves, such as infrared (which is like heat) or ultraviolet (which is what gives you a sunburn).

Radiometers: Measuring Light and Energy

A radiometer is a special tool used to measure the power of electromagnetic radiation. This fancy term just means different types of energy waves. These waves include visible light, but also invisible ones like infrared (heat) and ultraviolet (UV) light.

An example of a Crookes radiometer. The vanes rotate when exposed to light

Different Kinds of Radiometers

There are several types of radiometers, each working a bit differently to measure energy:

• The Crookes radiometer is often called a "light-mill." It's an older device with a rotor (a spinning part) inside a glass bulb with a little bit of air removed (a partial vacuum). When light hits it, the rotor spins.
• The Nichols radiometer is newer and much more sensitive than the Crookes type. It measures the tiny push that light (radiation pressure) creates. It has two small, shiny mirrors hanging from a very thin quartz fiber.
• A microwave radiometer is designed to measure energy waves in the microwave range. These are the same types of waves used in microwave ovens.
• The MEMS radiometer is a tiny device made using MEMS technology. It can work like either a Nichols or Crookes radiometer. It can measure a wide range of energy waves and even tiny particles.