Thermal machines are devices that convert heat energy into mechanical work. They operate based on the principles of thermodynamics, which study how heat interacts with energy and matter. Common examples include steam engines and internal combustion engines, which use heat from fuel combustion to produce motion. These machines typically follow a cycle, such as the Carnot cycle or the Otto cycle, to maximize efficiency. In a thermal machine, heat is absorbed, converted into work, and then expelled as waste heat. This process is essential in various applications, from powering vehicles to generating electricity in power plants.