Sound is a longitudinal, mechanical wave. Sound can travel through any medium, but it cannot travel through a vacuum. There is no sound in outer space. Sound is a variation in pressure. A region of increased pressure on a sound wave is called a compression (or condensation). A region of decreased pressure on a sound wave is called a rarefaction (or dilation).

Colorful sound wave set. Neon, black background, voice, frequency. Sound concept. Vector illustrations can be used for topics like music, radio, soundwave