Have you ever noticed that your voice sounds funny underwater? That is because the speed of sound is different depending on the material it passes through. Sound is created by vibration that passes from molecule to molecule. In materials with more dense molecular structure, it takes less time for the vibrations to pass from molecule to molecule. That makes the sound faster.







Sound passes most quickly through solids, because the molecules are packed closely together. The molecules are further apart in liquids, so sound passes more slowly through it than solids. Sound passes most slowly through gas, because gaseous molecules are farther apart than solids or liquids. The velocity of a sound wave is affected by two properties of matter: the elastic properties and density. The equation below shows this relationship:

