A transverse wave is a wave that consists of oscillations occurring perpendicular to the direction of energy transferred. If a transverse wave is moving in the positive x-direction, its oscillations are in up and down directions. Light is an example of a transverse wave, while sound is a longitudinal wave. A ripple in a pond and a wave on a string are examples of transverse waves.
Longitudinal waves are waves in which the displacement of the medium is in the same direction as, or the opposite direction to, the direction of propagation of the wave. An example of this is sound.
A surface wave is a mechanical wave that spreads along the interface between differing media. A common example is gravity waves along the surface of liquids, such as an ocean wave. Gravity waves can also occur within liquids, at the interface between two fluids with different densities.
Crest: The highest peak of a wave before it curves back down to form a trough.
Trough: The lowest part of a wave before it curves back up to form the crest.
Rarefaction: The reduction of an item's density, the opposite of compression
Compression: When a wave goes from long wave lengths to shorter, more frequent wavelengths.
Wavelength: The distance between the crests or troughs on a wave.
Amplitude: The maximum displacement of points on a wave.
Medium: A substance that makes possible the transfer of energy from one location to another, especially through waves.
Energy: the strength and vitality required for sustained physical or mental activity.