Steam turbines are mechanical devices that convert thermal energy from pressurized steam into mechanical energy, typically used to generate electricity. They work by directing steam onto a series of blades mounted on a rotor, causing it to spin and drive a generator. Steam turbines are classified into **impulse** and **reaction** types, depending on how they extract energy from the steam. They are widely used in power plants, industrial processes, and marine propulsion systems, valued for their high efficiency, reliability, and ability to handle large power outputs.