How can you tell if a pair of sunglasses is polarizing or not?

[McBain]

How can you tell if a pair of sunglasses is polarizing or not?

[McBaine]

Get another pair of polarized sunglasses and you may figure it out with two pairs of glasses. Put your sunglasses in front of the other and hold up both them.Try looking through both lenses,then rotate your sunglass 90 degrees. If you sunglass is polarized,you will see through both darkened lenses while rotating.It will be completely dark when it’s at 90 degrees.Otherwise,it isn’t be polarized.