Sound is a mechanical vibration. Needs a medium to carry it, solid, liquid or gas. Light is electromagnetic vibration, carries great in a vacuum, ok in gas, fair in liquid, not so good in solids. Two astronauts floating outside the shuttle, shouting at each other, can't hear each other, until they touch helmets and the solids can carry the sound. Or when they put new batteries in their radio because radio waves are electromagnetic. Caveat, this is a pretty rudimentary explanation and there is somewhat more to it.

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