Eli5: what happens to the energy created by mechanical/sound waves in a vacuum?

Question

I know that mechanical waves need a medium to travel through, but what happens when there is no medium and how does it it follow the first law of thermodynamics ?

In: Physics

Answer 1

Any vibrations would remain within the object generating them. If you make a sound on a spacecraft, it doesn’t leave. Sound waves may reflect within it. At some point, the sound dissipates and the energy becomes heat.