Waves

Waves

1. What are waves?

   • Waves transfer energy from a source without transferring matter.
   • Longitudinal waves oscillate in the same direction that the energy travels in.
   • Transverse waves oscillate at right angles to the direction the wave travels and includes electromagnetic waves.

2. Changing Direction

   • The normal is an imaginary line drawn at a right angles to a surface.
   • Waves can be reflected (bounce off a surface), the angle between a reflected ray and the reflected ray is at the same angle from the normal ray.
   • Waves can be diffracted (spread through a gap or round an obstacle). Diffraction is at its greatest when the wave length is almost the same size as the gap.
   • Waves can be refracted because they change speed in different materials so if the wave goes through something it travels slower in then it refracts towards the normal.

3. Using Waves

   • Radio waves, microwaves, infrared and visible light are electromagnetic waves used in communication systems.
   • Radio waves are used for radio and TV broadcasts. Radio uses long wave lengths and TV uses show wave lengths.
   • Microwaves are used in mobile phones and satellite communication as the atmosphere does not absorb microwaves.
   • Infrared radiation comes from anything warm and is used in remote controls.

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