What is a Wave?

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

Transverse 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:

  • Visible light
  • Waves in water

Longitudinal Waves

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:

  • Sound waves
  • Seismic P waves

Features of Waves

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.

  • The horizontal line goes through the wave’s 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.