Sound travels faster in steel than air because of molecules, in air molecules are apart from each other while in the steel they are more closer and tightly.

And light is faster in vacuum because of it has less density than the steel.

Dear Tahani, thanks for your contribution, best regards...

Rather than looking at people waving hands as a means of explaining, look at the simple equation* that relates the speed of sound inside a material, to that material's density and bulk modulus, and keep in mind that those parameters may depend on pressure and temperature.

* https://en.wikipedia.org/wiki/Speed_of_sound#Equations

Dear Denis, thanks for the link, it's helpful... Best regards....

You're welcome, Lekan

You're welcome Kifilideen...

I agree with Denis Jaisson. It is difficult to make the simple comparison sought because sound and vibration are compressional waves that need a medium in which to propagate. Light, by comparison, is an electromagnetic wave that does not require a medium. Accordingly, light and other electromagnetic waves are able to propagate through vacuum, air and other media.

As stated by Eric, Sound is a mechanical wave (which requires a medium), so it propagates through a medium when a particule move another particule, and, since in steel particules are close to each other than in air, it is easier for a mechanical wave to propagate through steel than to air.

On the other hand, ligth is a electromagnetic wave (which doesn't requires a medium) which see the particles as barriers, so , in that case, having closer and closer particules make the propagation more dificult, resulting in ligth being faster in air than in steel.

best regards.

How do you quantify the «ease» of propagation through a particular medium, Juan?

You can quantity it though the equations you show earlier, but the question was why, not how much :)

Best regards

I asked you how you quantify the said ease, for I do not know what you mean by that non scientific term, in the context of the question posed herein.

So can you please tell us what you mean by «ease» of sonic propagation?

Thank you all for your contribution. Best regards.

You're welcome. I am sorry that Juan could not do better than waving hands and resorting to fuzzy concepts.

I regret nothing, and is a shame that there are people like you that think that whitout an equation is imposible to explain a concept, maybe thats why so many people hate physics, not because they don't want to understand the concept, but because for some people like you is more important to be a good mathematician than to understand the concept.

(by the way, i understand perfectly all the physic and mathematics involved, but i prefer to adres the cuestion of why explaining how, and not by explaining how much, it's simple semantics.

but the speed of the sound have inverse relation with square root of the density of the medium and steel have higher density than air, but still speed of sound is much higher in steel than air, why?

Vague words that you wave in the air, like Don Quixote would fight a windmill, is as good as no explanation at all, Juan. It serves only to hide your own inability to explain a phenomena in simple terms... I never asked for an equation by the way. You are putting words in my mouth, which you then turn against me; isn't that a little weak? Regardless; as you fancy the subject of semantics, as you put it pedantically, what have you published for didactic purposes, and which supports your high stance, young man?

The speed not only depend on density but elasticity of the material and the speed is the ratio of both elasticity/density