A bomb calorimeter is a scientific device used to measure the heat of combustion of a substance. It consists of a strong, sealed container called a bomb, where a sample is burned in pure oxygen. The heat released during the combustion is absorbed by a surrounding water jacket, allowing scientists to calculate the energy content of the sample. This instrument is commonly used in fields like chemistry and nutrition to determine the caloric value of foods and fuels. By measuring the temperature change in the water, researchers can accurately assess the energy released, providing valuable data for various applications, including food science and energy research.