[ul]
[li]Diffraction is when a wave passesa through a gap or object, and it spreads[/li]
[li]For maximum diffraction to occur, the wavelength of the wave must equal or be roughly the same size as the gap ([lambda] = gap-size)[/li]
[li]The wavelength of laser red light is [b]630nm[/b], or 6.3[multiply]10^-7[/li]
[li]Plane wave fronts are equally spaced and travelling at the same speed[/li]
[/ul]
[b]Plane wavefronts:[/b]
[img src='https://res.cloudinary.com/deylrqt2d/image/upload/v1488032966/plane_wavefronts_pdw6t1.svg']
These wavefronts then become circular when they pass through a gap roughly the same size as their wavelength:
[img src='https://res.cloudinary.com/deylrqt2d/image/upload/v1488033575/diffraction_example_ok6udj.svg']
This is called [b]diffraction[/b].
In the above example, they diffract a lot.
In the below example they just reflect, as the gap isn't large enough:
[img src='https://res.cloudinary.com/deylrqt2d/image/upload/v1488035447/ezgif.com-resize_juodfl.gif']
In the below example the gap is a bit bigger, so not much diffraction occurs:
[img src='https://res.cloudinary.com/deylrqt2d/image/upload/v1488035821/diffraction_example_ray2_idmmti.svg']
