Waves can be described as oscillations or vibrations, which are back-and-forth movements.
All waves transfer energy from one place to another, but they do not transfer matter.
There are two types of waves:
1. Transverse waves
2. Longitudinal waves
In a transverse wave, the oscillations are perpendicular (at a 90° angle) to the direction of wave travel.
Most waves we think of are transverse waves, which include all electromagnetic waves. Some examples of transverse waves are:
In a longitudinal wave, the oscillations are parallel to the direction of wave travel.
In a longitudinal wave, there are regions of compression and rarefaction, as you can see in the diagram above. Some examples of longitudinal waves are:
On the wave diagram below, you can see the basic features, such as the peak and trough of the wave.
Peak – The highest point above the midpoint.
Trough – The lowest point below the midpoint.
To display and analyse the waveform of longitudinal waves, you can use an oscilloscope.
For example, if you use an oscilloscope to study a sound wave (which is a longitudinal wave), you can view the sound wave as if it is a transverse wave.