Description of a Wave

General Properties of a Wave

A wave is a disturbance that transfers energy from one place to another without transferring matter.
They are categorised into two main types; transverse waves and longitudinal waves.

Transverse Waves

Transverse waves move perpendicular to the direction of the wave. This means the medium (water, air, etc.) moves up and down, and the energy moves left to right.
Examples include light waves and waves on a string or water surface.
These waves are characterised by peaks or crests and troughs.

Longitudinal Waves

The particles in longitudinal waves move parallel to the direction of the wave. This causes areas of compression and rarefaction.
Examples include sound waves, ultrasound waves and seismic P-waves.

Wave Parts

Crest: The highest point of a wave.
Trough: The lowest point of a wave.
Wavelength: Distance between two consecutive similar points in a wave such as from crest to crest or from trough to trough.
Amplitude: The maximum height of the wave from its rest position, which indicates the energy of the wave.
Period: Time taken to produce one complete wave.
Frequency: Number of waves produced in one second.

Wave Properties

Frequency is measured in Hertz (Hz), where 1 Hz = 1 wave per second.
Wavelength is measured in metres.
Speed of a wave can be calculated using the formula: speed = frequency x wavelength.
Waves interact with materials through reflexion (bouncing back), refraction (changing direction), diffraction (spreading out), and interference (merging).
Superposition is the principle where two or more waves can add up to create a new wave.
Waves can be polarised, which means restricting the vibrations to one defined direction. This property applies only to transverse waves.

Wave Speed

The speed at which the wave moves depends on the medium through which the wave is moving. For example, sound waves travel faster through solids than gases because particles are closer together in solids.
Wave speed can also be impacted by temperature; in most cases, increasing temperature will increase wave speed.

Remember to practise finding wavelength, frequency, and wave speed with different practise problems to thoroughly understand the concept and formulas behind them.