A fluorometer is a scientific instrument used to measure the fluorescence of a sample. Fluorescence occurs when a substance absorbs light at one wavelength and then emits light at a longer wavelength. This property is useful in various fields, including biology, chemistry, and environmental science, for analyzing the presence and concentration of specific substances. Fluorometers can be used to study chlorophyll in plants, detect pollutants in water, or measure fluorescent dyes in laboratory experiments. They are often portable and can provide real-time data, making them valuable tools for researchers and environmental monitoring.