Does sound at 10000Hz or higher travel through concrete? If so how is it possible that solid can vibrate at such a frequency?
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Solids like concrete (let’s ignore air pockets for now) are essentially a lattice of atoms, held in a semi-rigid structure by their interactions.
Sound travels through a solid by displacing some of those atoms – one gets moved a tiny bit to the left of its resting position, which gently pushes the atoms to its left further along before they snap back into their resting position once more. The sound propagates through the solid by transferring this tiny motion through the material.
Atoms in a solid structure like this can actually transfer vibrations at higher frequencies than gases like air! In air, there’s no dense lattice to snap atoms back into place, and molecules have to travel further before they transfer the motion to another molecule. 10,000 HZ (or 10 MHz) is actually not a high frequency, it’s still in the audible range.
The only problem is that the higher the frequency, the more of that energy that gets lost. Every time an atom in that solid lattice gets bumped, it doesn’t transfer *all* of the energy to its neighboring atoms; a lot of it stays trapped as in-place jiggling called heat. The higher the frequency, the more often this loss occurs. And this loss is very considerable in solids.
So while a 10,000 Hz sound *can* travel through concrete, it won’t travel very *far* because you’re losing energy 10,000 times per second. Compare this to audible bass tones, where at 60 Hz you’re only losing energy 60 times per second. This is why you can hear the thump of the bass while outside the club, but you don’t hear the high-end until you open the door.
If you increase the amplitude enough, any frequency can travel through concrete. But you are correct in your instinct that higher frequency sound is dampened much more by concrete than lower frequency sound. In fact, this is generally true in solid materials. Usually the attenuation approximately grows approximately with the square of the frequency, so a 5 kHz signal is attenuated about 25 times more than a 1 kHz signal. Although it is important to note that our hearing is logarithmic so “attenuated 25 times more” really means something more like “sounds 30% softer”, not “sounds 25 times softer”.
The entire thing isn’t moving back and forth simultaneously 10000 times per second. Rather, pressure waves are moving through the material 10000 times per second. This is possible because the bonds between atoms are slightly springy, so a sound wave can enter one point while the rest of the mass is perfectly still, and then move through the mass at high speed as atoms push or tug on one another in rapid succession.
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