Question

can sound propagate without a medium ? if not why​

Answer 1

Answer:

Since a vacuum is defined as lacking a medium, then sound and correspondingly, mechanical waves, cannot propagate through a vacuum. This is why we can't hear voices or sounds in space.

Answer 2

Answer:

no.sound requires medium to travel because without medium like in vacuum speed of sound is zero

and that in steel is approximately 1500m/s

and in air 343m/s