A pulse wave is a single disturbance that is non-repeating and has one major crest. It often refers to some type of one-time disturbance. A pulse has a velocity and an amplitude but since there is only one crest, there is no frequency or true wavelength, although the width of the pulse relates to its wavelength. To measure a pulse wave’s speed, we use v=d/t.
This type of wave repeats at regular intervals and requires regularly recurring disturbances. Periodic waves are usually characterized by their amplitude, frequency, and wavelength. A wave whose displacement has a periodic variation with time or distance or both.
This type of wave occurs when the spring is pulled sideways. It’s a moving wave that consists of oscillations in which the direction of displacement is perpendicular to the direction of propagation. Transverse waves may occur on a string, on the surface of a liquid, and throughout a solid. Transverse waves cannot propagate in a gas or a liquid because there is no mechanism for driving motion perpendicular to the propagation of the wave.
A longitudinal wave is one in which the direction of displacement is the same as (parallel) the direction of propagation. It involves a wave consisting of a periodic disturbance or vibration that takes place in the same direction as the advance of the wave.