Transverse and Longitudinal Waves Model

Frequency f (set by the source) 1.5 Hz

Amplitude 0.40 m

The rope sets the wave speed v.

marked bead or coil, and its direction of vibration direction of propagation (energy) one crest followed along wavelength λ amplitude wavefront

Drawn to scale: lengths along the rope, the spring and the water, and every wavelength and amplitude, match the metre ruler. The waves move at their real speed (the timeline speed setting does not change them). Not to scale: the rope is drawn about 10 cm thick and the spring about 50 cm across, roughly 5 to 10 times thicker than a real rope or toy spring, so that you can see them. Only 8 m of each is shown; imagine they are long enough that no waves come back.

Transverse and longitudinal side by side

	Transverse	Longitudinal
Vibration	at right angles to the direction of propagation	parallel to the direction of propagation
Shown with	a rope moved up and down; a spring moved side to side	a spring pushed and pulled along its length
Features	crests and troughs	compressions and rarefactions
Examples	electromagnetic radiation, water waves, seismic S-waves	sound, seismic P-waves
Matter	Both transfer energy without transferring matter.

How to write it in the exam

Waves transfer energy from one place to another without transferring matter.
In a transverse wave the vibrations are at right angles to the direction of propagation. Examples: electromagnetic radiation, water waves, seismic S-waves.
In a longitudinal wave the vibrations are parallel to the direction of propagation. Examples: sound waves, seismic P-waves.
The amplitude is the greatest distance of a point from its rest position (rest line to crest, not crest to trough).
The wavelength is the distance from a point on one wave to the same point on the next wave, for example crest to crest. Unit: m.
The frequency is the number of waves passing a point each second. Unit: hertz (Hz).
A wavefront is a line joining points on a wave that are in step, such as a line along a crest. Neighbouring wavefronts are one wavelength apart.
The wave speed is the distance a wavefront travels each second. Write v = fλ, substitute the values, then give the answer with its unit (m/s).