Waves are vibrations that transfer energy through a medium without causing the individual particles of a medium to move significantly from their equilibrium or position of rest. Once a wave has passed, the particles that comprise a medium tend to return to their respective position.
The particles and substance of a medium move in a direction that is perpendicular to the movement of a wave. Waves exchange kinetic energy for potential energy, meaning that particles begin to slow down the further they move from their original position. Once the kinetic energy of a wave has passed through a medium, its constituents are restored to a resting state that has been little altered by the passage of a wave.
Waves are known as an energy transport phenomenon, a disturbance that travels through a medium from one particle to the next. Waves may be compromised of sound, water and even electromagnetic energy. The energy of a wave can be measured in terms of frequency and wavelength, regardless of the type of wave or through which medium it can travel. Waves that are made of electromagnetic energy do not require a medium and are able to transfer energy through the vacuum of space.