What is this?

Thermoacoustic pipe is a thermally driven oscillator. Basically it is a prime mover which accepts heat at room temperature, rejects heat at lower temperature and emits sound.

It is very simple: we hold the pipe with the hand (body temperature, around 96°F), cool the other end of the pipe in liquid nitrogen (low temperature, around -321°F) and the pipe 'sings'.

The name of the pipe comes from the effect which makes the pipe emit sound. It is the thermoacoustic effect where heat (thermo-) is converted into acoustic oscillations - sound (-acoustic).

The beauty of the thermoacoustic pipe lies mainly in its simplicity. In everyday life one is used to many different prime movers: internal combustion engines in cars, motor scooters, lawn mowers, steam engines in oldtimer railway engines etc. All mentioned prime movers are pretty complicated mechanisms with parts which rotate, slide and swing during the operation. The thermoacoustic pipe... (here comes the beauty) ...consists only of three parts, which do not move in either way during operation.

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