Waves

By: Saimah Siddiqui

What is a wave?

A wave is a disturbance in energy that transfers energy from one place to another.

Parts of a longitudinal wave

There are 3 main parts of a longitudinal wave.


  1. Compression
  2. Rarefaction
  3. Wavelength
Compression is the compressed part of the wave.

Rarefaction is the spread apart part of the wave.

Wavelength is the length of a full wave.

Some example of waves

Parts of a Transverse Wave

There are 5 main parts of a transverse wave. The 5th one is not included in the diagram to the left, but is represented by the x axis.
  1. Amplitude
  2. Crest
  3. Trough
  4. Wavelength
  5. Rest Position
Amplitude is the distance from the crest or the trough to the rest position.

The crest is the top part of the wave.

The trough is the bottom part of the wave.

Wavelength is the length is the length of one full wave.

The rest position is a horizontal line that goes through the middle of the wave which represents the place where the wave rests.

Relationship among Wavelength, Amplitude, Frequency, and Speed

The frequency determines the wavelength. This is because the frequency decides how many waves there will be at a certain point. For example if there is 1 it the wavelength will be longer. However if there is about 50, then the wavelength will be shorter because there will be more waves at a certain point. The wavelength and the frequency determine the speed. This is because the equation for speed in waves is wavelength x frequency = speed. For example, say the wavelength was 8 and the frequency was 3. 8 x 3 =24, so the speed would be 24 cm/sec. The amplitude affects the height of the wave. This is because amplitude is from the rest position to the crest or the trough. The higher the amplitude, the higher the wave. Another relationship is that frequency follows speed. If the frequency is high, the speed is high. If the frequency is low, the speed is low.