A radiometer is a scientific instrument designed to measure the intensity of electromagnetic radiation, particularly in the form of light. It typically consists of a set of vanes mounted on a spindle, which rotate when exposed to light. The rotation occurs due to the difference in temperature between the dark and light sides of the vanes, allowing researchers to quantify the energy of the radiation. Radiometers are often used in various fields, including meteorology, astronomy, and environmental science. They help scientists understand energy transfer processes and the effects of radiation on different materials. By measuring radiation, radiometers contribute to advancements in technology and environmental monitoring.