Sound is caused by the vibration of particles but not all vibrations can be heard as sound. Common ideas about sound come from the limited range of vibrations that human ears can detect.
Part of Combined ScienceWaves
Sound travels faster through liquids and solids than it does through air and other gases.
The table gives some examples.
This is because the particles of gases are further apart than liquids and finally solids.
Sound waves move more slowly when particles are further apart.