What at first sight looks very toy-like, is in fact a very clever physical system: The main driving mechanism consists of a small boiler and two connected pipes. With a pipette put a small amount of water into the boiler, light the candle (pipette and 3 candles included) and put the boat on the surface of a bath of water, garden pond, etc. As the water boils, the steam escapes through the two pipes; the resulting reaction force pushes the boat along. When the boiler runs out of water, the condensation of steam in the pipes creates a negative pressure that sucks fresh water back into the boiler and starts the cycle again. A great example of the self-stabilization of oscillating systems.