A colorimeter is a scientific instrument used to measure the concentration of colored solutions. It works by passing light through a sample and measuring the amount of light absorbed by the solution. The more concentrated the solution, the more light it absorbs, allowing for quantitative analysis of the substance. Colorimeters are commonly used in various fields, including chemistry, biology, and environmental science. They help in determining the concentration of substances like chlorophyll in plants or pollutants in water. By providing accurate measurements, colorimeters play a crucial role in research and quality control processes.