# Waves

Waves can be described as oscillations or vibrations, which are back and forth movements.

All waves transfer energy, however, they do not transfer matter.

There are two types of waves:

1. Longitudinal waves

2. Transverse waves

### 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.

Transverse Wave

In a transverse wave, the oscillations are perpendicular (at a 90° angle) to the direction of wave travel.

### Features of Waves

Peak – The highest point above the midpoint.

Trough – The lowest point below the midpoint.

The line horizontal line goes through the wave midpoint. To display and analyse the waveform of longitudinal waves, you can use an oscilloscope.

### Properties of Waves

Wavelength – The distance between two peaks, which are next to each other or any two identical points which are next to each other. In the diagram above, the wavelength is measured at the midpoint, not the peak.

Amplitude – The distance between the midpoint and the peak of the wave, or the midpoint and the trough of the wave.

Frequency – The number of complete waves that go past a given point per second. – Frequency is measured in Hertz (Hz).