A steam engine is a machine that converts the energy from steam into mechanical work. It operates by heating water in a boiler to create steam, which then expands and pushes against a piston or turns a turbine. This process was crucial during the Industrial Revolution, powering trains, ships, and factories, and significantly changing transportation and manufacturing. The invention of the steam engine is often attributed to James Watt, who improved earlier designs in the late 18th century. His enhancements made steam engines more efficient and practical, leading to widespread use. Today, steam engines are mostly of historical interest, as modern engines use different technologies.