Polarisation of Waves - A Level Physics

In the video I explain the polarisation of waves (including the polarisation of light) for A Level Physics.

Only transverse waves can be polarised, this video explains why. It also shows why sunglasses are known as 'polaroids' and how you can test this yourself on a sunny day.

Update - Please note that the reflected light waves from water are actually horizontally polarised:

Thanks for watching,

Lewis

This video is recommended for anyone studying A Level Physics in the following exam boards:
AQA
CIE
Edexcel
Edexcel IAL
Eduqas
IB
OCR A
OCR B
WJEC

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[megacraig]

Best physics channel on YouTube, can't thank you enough

[rabinkandel]

I think that light reflected from the water surface is plane polarised in horizontal plane(not in the plane as you drew) .
When you use sunglasses it only allows light in vertical plane blocking glare ( that is horizontally polarised when reflected. Typical question of this type appeared in June 2011 G482.

[aerotriangle]

thanks so much for this video :D i'm doing classes from home (corona) and it's really clear and useful

[jessylyn-nr]

omg small sneak peek of what physicsonline looks like i love ur vids btw best physics channel

[uawulf]

Glad i got to know about tjis channel even though i've only got one month for my AL's here in Sri Lanka!!!! Thank You Sir!!! Your awesome!!

[hamdaniyusuf_dani]

4:29 the polarized reflected light should be drawn as dots, since the direction of the field oscillation is in & out of the drawing plane.

[zakariyaabdullahi]

After a year of looking for a good physics Youtube channel, finally found it.

[boopalansubaldunmanss]

very detailed, clear explanation. An improvement would be to do a worked example as well .Thanks

[chriswesley]

Another nice video, thanks. At 4:37 you combine two phenomena by saying the reflected light is polarised and creates a glare. But I don't understand what one has to do with the other - since polarisation REMOVES light from a source, why should the polarised light cause more glare than otherwise would be the case?

[inconspicous_dude]

i have an exam on Tuesday. thank you very much!

[ht-vefe]

fantastic explanation thank you very much. Had my book in front of me and all the diagrams made more sense the further I got into the video.

[hamdaniyusuf_dani]

At Brewster's angle, the reflected and refracted rays are mutually perpendicular

[Roshenakthar]

Nice way of teaching. Now only i understand this

[chemilabchemistry]

5:24 face 😅😅 anyway thnxx sir ur video fits enough to remember p6 👌👌

[googleuser]

How come when you put sellotape over the filter, light can pass through it even when the second filter is perpendicular? Whats the reason to this?

[Adnansolanki]

great video but please make it a bit darker. Its too bright and it hurts my eyes, maybe put a polarized filter on the camera, ;P

[rokotrstenjak]

one thing, when you polarize light. the rays that go through are perpendicular to the filter. so lets say the opening in the filter was vertical. only horizantal light would go through. its hard to draw tho

[dhwaniselvam]

Its hard to study this but made it easy with illustration

[momenibrahim]

That was so cool! Thank you for this!

[swalstar]

Please can you explain the selotape bit at the end?