Calorimetry is the science of measuring heat transfer during chemical reactions or physical changes. It helps scientists understand how much energy is absorbed or released in a process. By using a device called a calorimeter, researchers can accurately determine the heat involved, which is essential in fields like chemistry, biology, and environmental science. In calorimetry, there are two main types: constant pressure and constant volume calorimetry. Constant pressure calorimetry measures heat changes at atmospheric pressure, while constant volume calorimetry measures heat changes in a sealed container. These methods provide valuable insights into energy changes, helping us learn more about reactions and materials.