Transverse & Longitudinal Waves (Oxford AQA IGCSE Combined Science Double Award)

Transverse Waves

• Waves are disturbances caused by an oscillating source that transfer energy and information without transferring matter

• Waves can exist as one of two types:

  • Transverse

  • Longitudinal

• Transverse waves have vibrations that are at 90° to the direction of wave travel (and energy transfer)

• Transverse waves:

  • Oscillate perpendicularly to the direction of travel

  • Transfer energy, but not the particles of the medium

  • Mechanical waves move in solids and on the surfaces of liquids but not through liquids or gases

  • Electromagnetic waves are transverse waves that can move in solids, liquids, gases and in a vacuum

• The point on the wave that is:

  • The highest above the rest position is called the peak, or crest

  • The lowest below the rest position is called the trough

Example of a transverse wave

• Examples of transverse waves are:

  • Ripples on the surface of water

  • Vibrations in a guitar string

  • S-waves (a type of seismic wave)

  • Electromagnetic waves (such as radio, light, X-rays etc)

Longitudinal Waves

• Longitudinal waves have vibrations that are parallel to the direction of wave travel (and energy transfer)

• Longitudinal waves:

  • Oscillate in the same direction as the direction of wave travel

  • Transfer energy, but not the particles of the medium

  • Move in solids, liquids and gases

  • Cannot move in a vacuum (since there are no particles)

• The key features of a longitudinal wave are where the points are:

  • Close together, called compressions

  • Spaced apart, called rarefactions

Example of a longitudinal wave

• Examples of longitudinal waves are:

  • Sound waves

  • P-waves (a type of seismic wave)

  • Pressure waves caused by repeated movements in a liquid or gas