It is possible to construct a Stirling engine using household materials. The website DIYStirlingEngine.com has multiple plans on how to construct Stirling engines, including one that is built from soda cans and other household items and is powered by tea candles.
A Stirling engine uses the expansion of a gas or a liquid to pump a cylinder and spin a flywheel to generate electricity or power a machine. The gas or liquid is sealed between two pistons, and a heat source is applied to the space. As the fluid heats, it expands and pushes one piston that pulls the second one, allowing cooler liquid in. As the liquid cools, the opposite piston is pushed out, and the first piston is pulled back in, beginning the process again.