### KS3 Physics

Energy
Motion and Forces
Waves
Electricity and Electromagnetism
Matter
Space Physics

# What are 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:

• 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).

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