Thermobile: Nitinol wire loop heat engine- the memory wire forcibly straightens out when heated (contact with heat conducting smaller wheel) causing the wheels to spin and providing mechanical kinetic energy from a cup of warm tea water. Nitinol wire is a special alloy of nickel and titanium that can be trained to a specific shape at high temperature- bend it up at room temperature and it will snap back into shape when exposed to moderate heat such as hot water. This remarkable property is a typ

Nitinol memory wire Facts... - Metallurgical engineering