Polaroid sunglasses

[Toerag]

Orange/yellow/brown lenses will also filter out blue light, which is the colour that's 'scattered' most by reflections/prisms (eg. waves).

To tell if a pair of glasses are polarised, look at a reflection (the sun in the sea for example) and tilt your head on it's side. The reflection should get brighter as you turn the glasses on their side, and darker when your head's the right way up.

[magicdog]

Thanks Toerag I just fell in trying that...lol

[Socksy Squirrel]

Testing polarised glasses is easy. Just take two pairs and hold a pair in each hand so two of the lenses overlap and the tops of the glasses are in line with each other. At this point it is like looking through two pairs of sunglasses, dark but you can see most things. Then gradually rotate the lenses until they are a right angle to each other, almost complete blackness.

This works because light that has been polarised by passing through one polarising filter is blocked by a second filter at right angles to it.

 

 

 

{2008 Editor's Note - please click here to view fishing glasses for sale}