Transverse waves are easily visualised. They are typically what people think of when they are asked to picture a wave. A transverse wave is such that as the wave moves, oscillations occur perpendicularly to the direction of travel of the wave.
The wave above oscillates perpendicularly to the x – axis, and travels parallel to the x – axis. If the x – axis is labelled with position then the distance between crests is the wavelength, but if the x axis is labelled with time, then the distance between crests is the period. Either way the wave equation 
is obeyed where
= wave speed
= frequency
= wavelength
Water waves, s – waves produced in earthquakes, all electromagnetic waves and vibrations on a string or wire are all transverse waves. Some transverse waves – electromagnetic – do not need a medium to travel through and may travel through a vacuum.