Weird Physics with Laser Beams

What happens if you take a laser beam and pass it through a tiny, thin slit?  You should end up with a tiny, thin laser beam on the other side, right?!  

Wrong!  Physics is much weirder than that!

The laser beam actually gets spread out.  This effect is known as diffraction – the curving of waves into the region where you might expect shadow.

Diffraction is an effect that our IB HL (Higher Level) Physics students first encountered in Topic 4 of the course in Year 12, but now they are in Year 13 and working on Topic 9, so the experiments are becoming more complex!  

What happens if you change the wavelength of the light incident on the slit by using red, green and violet lasers?  What happens if you use double slits, triple slits, quadruple slits or diffraction gratings?  Ask the next Year 13 IB HL Physics student you meet!