refractometer

A refractometer is a device used to measure how much light bends when it passes through a liquid. This bending, called refraction, depends on the liquid’s concentration or quality. For example, in agriculture, it measures the sugar content in fruits or juice; in aquariums, it checks water salinity. The user places a small sample of the liquid on the device’s prism, look through the eyepiece, and read the measurement directly. It provides a quick, accurate way to assess the properties of liquids based on how they refract light.