They’re so very polarizing…

Polarized rainbow, what does this mean???

Rainbows are created when sunlight reflects inside water droplets, bouncing back to you. When the light enters the droplet and also when it leaves, it bends a little bit as well (like how a spoon looks bent in a glass of water). Different colors bend by different amounts, so the sunlight colors get spread out, forming an arc in the sky.
The light forming the rainbow gets polarized when it reflects off the back of the raindrop. The amount of polarization is pretty strong, as the video shows. When I hold the glasses horizontally the light gets through, but as soon as I rotate the glasses, the rainbow disappears entirely! Almost all the polarized light is blocked, and the rainbow vanishes.
But wait, there’s more!

This is the same effect that makes it easier to see through heavy rain or fog with polarized sunglasses.