Diffraction

Diffraction is when waves spread out as they pass through a gap or around an obstacle. The amount of diffraction depends on the size of the gap compared to the wavelength of the waves.

Diffraction through a gap

When waves pass through a gap, they spread out on the other side. The amount of spreading depends on the size of the gap relative to the wavelength of the waves:

• If the gap is much larger than the wavelength, the waves spread out only a little.
• If the gap is about the same size as the wavelength, the waves spread out quite a lot.
• If the gap is much smaller than the wavelength, the waves spread out a lot.