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 substances. Colorimeters are commonly used in various fields, including chemistry, biology, and environmental science. They help in determining the concentration of specific compounds, such as chlorophyll in plants or pollutants in water. This information is crucial for research, quality control, and environmental monitoring.