Waves

Types of Waves

  • Transverse waves are waves in which the vibrations are at right angles to the direction of travel. Examples include light and other electromagnetic waves and waves on strings.
  • Longitudinal waves are waves in which the vibrations are in the same direction as the wave is traveling. Complete understanding of sound waves requires knowledge of these.

Wave Properties

  • Discuss wavefronts and rays to represent waves diagrammatically.
  • Wave amplitude: the maximum displacement of a point on a wave from its undisturbed position.
  • Wave wavelength: the shortest distance between two points on a wave where the wave pattern is repeated.
  • Wave frequency: The number of waves produced by a source each second. It is also the number of waves that pass a certain point every second.
  • Wave speed: the speed at which energy is transferred (or the wave moves) through the medium.
  • Wave period: the time taken for one complete wave to pass a given point, reciprocal of wave frequency.

Wave Behaviours

  • Reflection: the bouncing back of a wave after hitting a boundary.
  • Refraction: the bending of a wave as it enters a medium where its speed changes.
  • Diffraction: the spreading of waves when they pass through a gap or around obstacles.
  • Interference: the superposition of two or more waves resulting in a new wave pattern.

Electromagnetic Spectrum

  • Recognise radio, microwave, infrared, visible light, ultraviolet, x-ray, and gamma rays in the electromagnetic spectrum.
  • Consider the waves’ different characteristics, including their different wavelengths, frequencies, and uses.

Sound Waves, their Characteristics and Uses

  • Sound waves are longitudinal waves and need to travel through a solid, liquid or gas.
  • The speed of sound is different in different media.
  • The frequency of a sound determines its pitch, and the amplitude determines its volume.
  • Echoes can be used for sonar and ultrasound scanning.

Seismic Waves and the Earth’s Structure

  • The Earth’s crust generates seismic waves. There are two distinct types: S-waves (secondary) and P-waves (primary).
  • Seismic waves are used to evidence the Earth’s composition and structure, providing information about the Earth’s internal layers.