The polarizing light of sunglasses

Light waves from artificial sources such as the sun and even light bulbs vibrate and propagate in all directions. Whether the light is propagated, reflected, diverged or refracted, when the light vibrates in one or more plane directions, we say that the light is polarized. The polarizing process can occur naturally or be artificially stimulated. The glare you see every time you look at a lake is an example of natural polarization. The glare reflected from the lake does not pass through the light of the lake's "filter", which is why it is impossible to see objects below the lake even though the water is very clear.
Polarizing filters are generally made by plating a chemical film on a transparent plastic or glass surface. Usually, the molecules in the compounds used are naturally aligned parallel to each other. When they are evenly coated on a lens, these molecules form tiny lenses capable of absorbing all light in the same direction as their alignment.
The vast majority of glare that forces you to wear sunglasses comes from horizontal surfaces, such as water and highways. When light reaches a surface, the reflected light is polarized in the same direction as the Angle of the surface. Therefore, a highly reflective horizontal surface, such as a lake surface, can produce a large amount of horizontally polarized light. Therefore, the polarized lenses of sunglasses are fixed at an Angle so that only vertically polarized light can pass through the lenses. You can observe this principle by putting on polarized sunglasses and then looking at a horizontal surface, such as the hood of a car. Slowly tilt your head to the left or right. You will find that the glare from this surface will become brighter as you adjust the Angle of your sight.
Before you buy, you can tell if it's genuine by doing a simple test. Find a reflective surface, then hold the sunglasses and look at the surface through a lens. Slowly rotate the sunglasses ninety degrees to see if the reflective glare decreases or increases. If the sunglasses are polarized, then you will see a significant reduction in glare.
Sunglasses or prescription glasses that darken in color when their mirrors are exposed to sunlight are called color-changing glasses. The principle of color-changing lenses relies on a special chemical reaction of ultraviolet light.