Diffraction in Waves

Diffraction in Waves

1. The process by which a beam of light or other system of waves is spread out as a result of passing through a narrow aperture or across an edge, typically accompanied by interference between the wave forms produced.

2. Diffraction reduces the quality of images seen in microscopes and telescopes. It can cause rings or spikes around the image of the object being viewed.

3. When waves meet a gap in a barrier, they carry on through the gap. However, the waves spread out to some extent into the area beyond the gap. This is diffraction.

4. The extent of the spreading depends on how the width of the gap compares to the wavelength of the waves. Significant diffraction only happens when the wavelength is of the same order of magnitude as the gap.

   • For example: a gap much larger than the wavelength causes little spreading and a sharp shadow eg light through a doorway a gap similar to the wavelength causes a lot of spreading with no sharp shadow eg sound through a doorway

5. The effects of diffraction are often seen in everyday life. The most striking examples of diffraction are those that involve light; for example, the closely spaced tracks on a CD or DVD act as a diffraction grating to form the familiar rainbow pattern seen when looking at a disc.

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