1. Diffraction and polarisation
Unpolarised
Plane polarised
Partially polarised
Describe what is meant simply by the term ‘polarised’ or ‘polarising’
Differentiate between ‘plane polarised’ and ‘partial polarisation’
Explain why sound waves cannot be polarised but light waves can

2. Polarisation
“restricting the vibrations of a transverse wave wholly or partially to a specific direction”
An unpolarised light source (e.g. bulb/sun) will emit light in lots of different planes
However we are able to use filters to restrict these planes (i.e. block some planes and let others through!)
What would you observe once a second filter that was set horizontally was placed after the first filter?
Delta

3. Have a try!
π/2
Here we have two polarising filters placed perpendicular to one another
Notice how as you rotate on the of the filters, the intensity of light that is let through changes.
When is the intensity at it’s maximum and why?
Delta
When is the intensity at it’s minimum and why?

4. Plane Vs Partial
When light reflects off a surface, it will experience partial polarisation.
Here, the light is not restricted to a single plane but often only the horizontal planes get reflected
Delta

5. Polarising Sunglasses