It depends, mostly coal.
A steam engine uses a hydrocarbon based fuel source. The combustion of the fuel releases the chemical energy in the bonds in the form of thermal energy.
Burning fuel.Burning fuel.Burning fuel.Burning fuel.
The main source of locomotive engine fuel historically was coal, which was used in steam locomotives to generate steam for powering the engine. As technology advanced, diesel fuel became the primary energy source for diesel locomotives, offering greater efficiency and power. In recent years, there has been a growing interest in alternative fuels like electricity and biofuels to reduce environmental impact.
Other to coal I suppose you mean. Burning of any fuel like oil, wood, etc. Nuclear reactors. I suspect solar energy would make steam. It would be possible to use natural steam from deep in the ground.
In a steam engine, fuel is burned in the boiler. The combustion of the fuel generates heat, which converts water into steam. This steam is then used to drive a piston or turbine, producing mechanical work. The efficiency of the steam engine largely depends on the design of the boiler and the combustion process.
Steam engine
The steam engine was primarily powered by coal, which was burned to heat water in a boiler, creating steam. This steam then expanded and drove pistons or turbines, converting thermal energy into mechanical work. In some cases, wood or other biomass was also used as a fuel source before coal became the dominant choice.
In an Internal Combustion Engine, the Fuel is burnt in the cylinder or vessel eg. Diesel or Petrol engine used in Cars.Gasoline engines, Wankel engines, diesels, gas turbines are all examples of internal combustion.In an External Combustion Engine, the internal working fuel is not burnt. Here the fluid is being heated from an external source. The fuel is heated and expanded through the internal mechanism of the engine resulting in work. eg. Steam Turbine, Steam engine Trains.
Nothing, a steam boat runs not on steam, but on a heat source GENERATING steam. this heat source is usually coal but could be wood or a fossil fuel.
Firebox
You can't. No internal combustion engine will run on water except a steam engine, and even that requires another fuel to produce the steam.
A steamboat requires a steam engine, which operates by heating water in a boiler to create steam. This steam then powers pistons or turbines that drive the boat's propellers or wheels. Additionally, a fuel source—such as wood, coal, or oil—is needed to generate the heat for the boiler. Finally, a water source is essential for producing the steam.