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:

• Longitudinal waves

• 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.

Examples of longitudinal waves are:

• Sound waves

• Ultrasound waves

Transverse Waves

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

Examples of transverse waves are:

• Visible light

• Water

Features of Waves

On the wave diagram below, you can see 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, an oscilloscope can be used.

Properties of Waves

For example, if you use an oscilloscope to study a sound wave (which is a longitudinal wave), you can view the waveform as if it were a transverse wave.

Below, you can see a wave diagram that illustrates the properties of waves.

The three wave properties are:

Wavelength – The distance between one peak of a wave and the next peak directly beside it, or any two identical points on the wave that are right next to each other.

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 pass a given point per second. Frequency is measured in Hertz (Hz).