If sound travels best through soilds and worst through air why do solids make the best ear protectors?

I was doing an experiment with my son, and he was taught that sounds travels best through solids and worst through air. The experiment was to test different items to see what would make the best ear protectors. The results showed that solid items works the best and he wanted to knwo why, since it came out the exact opposite of what he thought it would.

It does not travel better per say
it does travle faster though. That being said sound is energy and the more things this energy runs into the more it looses

Plus the sound dampenings things usual involve some air spaces

Here is an intersring tidbit. If you hear a low base sound but its being drowned out by other noises put a pillow over you head you will hear the base better

because it is difficult for sound waves to transition from air to a solid. the sound waves usually bounce off (echo).

sound does however travel from solid to air easily (most sound is created this way).

you have to strike directly against a solid object to hear sound through it.

also.. .ear plugs are most often not solid. they are usually a foam. foam does not allow sound travel very well.

That's an excellent question. It may be easier to deal with sound as a wave of energy. It is very easy to initiate a sound wave in a steel rod by striking one end of the rod with a hammer. The disrupted metal atoms at the strike zone shove adjacent atoms, etc. etc. and a wave travels the length of the rod. It is harder to 'hammer' air although the tip of a whip can initial a shock wave of sound with a 'crack.' An old steam pipe (in an old school?) could make a loud bang as a slug of condensate reached an obstacle (shut valve?) suddenly expanding the pipe which initiated a sound wave in the (classroom) air. The transfer of sound energy from metal to air or from air to metal is less efficient than from hammer to metal rod. When metal ear protectors are worn, sound energy in the air reflects off of the metal rather than entering it. An echo in a canyon works because most of the sound energy is reflected by solid surfaces (back to a focal point). Sound travels faster in metal than air because the metal atoms are packed more densely and are nearly incompressible. Sound also travels faster in water than air for the same reason.