* Sound travels fastest in solids, then liquids, and slowest in gases. This is because the molecules in solids are tightly packed, allowing vibrations to transfer quickly.
* The speed of sound is dependent on the density and elasticity of the medium. Denser and more elastic materials generally allow sound to travel faster.
While there's no common material that makes sound travel *exactly* four times faster than air, here are some examples of how sound travels faster in different media:
* Steel: Sound travels about 15 times faster in steel than in air.
* Water: Sound travels about 4.3 times faster in water than in air.
Important Note: The exact speed of sound can vary slightly depending on factors like temperature and pressure.
