Steam was the energy that powered the early industrial revolution. Steam pistons drove factories. Steam turbines were and still are, responsible for generating most of the world's electricity. A number of steam powered projects are good for demonstrating physics principles and engineering principles. The first step to creating a steam powered machine is to make a steam generator.
The first phase to building your steam generator is the type of power to use for heat. Antique steam generators and engines used coal or wood. Although both of these will work well, an electric immersion heater may be a safer alternative as it isn't as much of a fire hazard.
The exact tank design will depend on the power source you will use. If you are going to use an immersion heater, fashion a bracket to suspend the immersion heater in the water tank. A good water tank can be made form an empty grapefruit juice can. Cut the top out of the can and make holes for the immersion heater elements so the electrical component will not be inside the tank. Solder the top of the can in place with the immersion heater protruding through the top. Seal the area of the lid where the immersion heater protrudes. Good, high heat tape is a good start, but clay may be necessary for better steam pressure. If you use clay, make sure you allow the clay to harden and cure.
Water Inlet & Steam Outlet
Install a re-sealable plumbing fixture on the can. This will serve as a fill point for the tank. Drill a hole for a small metal tube. Fish tank air connectors work well. Solder a small steel pipe through this hole. Using flexible pipe will allow the steam to be routed to something like a piston or a turbine.
Steam is very hot. It can cause severe burns. The tank and the steam pipe will both become dangerously hot, handle these with extreme caution. Do not put too much water in the tank to prevent dangerous pressure buildups. If you are making a larger steam generator, consider installing a pressure relief valve to lessen the danger of explosion.