Transverse and Longitudinal Waves

Transverse Waves

Transverse waves move in an up and down motion, with the wave energy travelling at a right angle to the direction of the wave.
Some examples of transverse waves include: light waves, radio waves and waves seen on a water surface.
The peak of a transverse wave is its highest point, and the trough is its lowest point.
Within transverse waves, the amplitude is measured from the rest or mid-point to the peak or trough.

Longitudinal waves move in a back and forth motion, where the wave energy travels in the same direction as the wave.
Longitudinal waves involve areas of compression (where the particles are close together) and rarefaction (where the particles are spread out).
Some examples of longitudinal waves include: sound waves, ultrasound waves and seismic P-waves.
The wavelength in longitudinal waves is measured from one compression to the next compression, or from one rarefaction to the next rarefaction.

Both longitudinal and transverse waves transport energy from one place to another, but they do this in two fundamentally different ways.
In contrast to transverse waves, where particles move perpendicularly to the wave motion, in longitudinal waves, particles move parallel to the wave motion.
While light and electromagnetic waves are transverse, sound and seismic waves can be both transverse and longitudinal.
A waveform diagram can be used to illustrate and compare the motion, amplitude, and wavelength of transverse and longitudinal waves.
Using a slinky or a similar device can help visualise the difference between these types of waves - transverse can be demonstrated by moving the slinky up and down while longitudinal can be demonstrated by compressing and expanding the slinky lengthwise.