A steam boiler is a device that heats water to create steam, which can then be used for various applications, such as heating buildings or powering machinery. The boiler operates by burning fuel or using electricity to heat the water in a closed system, allowing the steam to build pressure. Steam boilers come in different types, including fire-tube and water-tube boilers, each designed for specific uses and efficiency levels. They are commonly found in industries, power plants, and residential heating systems, playing a crucial role in energy production and thermal management.