Question

How can you tell if a pair of sunglasses is polarizing or non-polarizing? Try to describe more than one method.

Answer 1

looking through water ,main purpose of polarized glasses  is to reduce glare so if glasses are polarized, instead of only surface you will be able to see through the glare and inside  the water,not just water you can use mirror or anything which produces glare

Looking at laptop screen at full brightness put those glasses and till your head at 60 degrees to the left or right in front of screen ,since laptops have antiglare screens ,the screen will appear black due to the anti-glare properties of laptop and glasses try to  cancel out each other