I know there is a previous post here about this, but it didn't seem to cover the angle I am getting at... I understand sound to be vibrations that travel through a medium such as air or water. However, what actually generates these vibrations? For example, hitting a piece of steel with a rod. Vibrations (sound waves) will be generated that travel through the air to my ear. If I do this in space, no sound waves will travel to my ear, however the initial act remains the same. Put another way, is a sound produced in a vacuum, but just not propogated? I assume without any basis for doing so that sound waves must have some sort of energy component. Where does that go if there is no medium to dissipate it?? And what is it that actually generates the sound waves? What happens physically as the rod meets the iron?