bp's science: polarized sunglasses (v.1)

Jess and I own polarized sunglasses, and although we feel totally cool wearing them (haha) and appreciate the decrease in glare they provide, we don't really know how they work.  Cue a bp's science post.

Haven't you noticed that a person wearing sunglasses looks at least 3 times cooler than normal?  

Okay, maybe not me, but Oliver and Big Bird are looking hip!

First, we must understand glare.  Light is polarized when it bounces off of something, let's say a lake, and instead of scattering in different directions, it reflects in a horizontal direction causing glare.  This happens on bodies of water, flat roads, and long car hoods to name a few things.  That's why polarized glasses are good for water sports, jogging, and driving.

Now polarized sunglasses are like little window blinds.  Molecules that naturally align parallel to one another (creating very thin horizontal lines for example) are applied to the lens.  These molecules absorb the light that is parallel to it, in our example horizontal light.  This creates a vertical polarization axis (or a vertical filter) which only allows vertical light to pass through while blocking horizontal light, a.k.a. glare. 

To sum up:

Polarized glasses = vertical filter = blocked horizontal light = NO glare

The polarized sunglasses we own have served us well and with summer coming around, I find that I will use them more than ever.  However, even though polarized glasses reduce the glare, there are some downsides.  For example, I can't read the clock in our car because polarized lenses can cause problems viewing LCD screens.  Good old quality sunglasses won't do that.

If you aren't sure whether your sunglasses are polarized or not, first observe the light wearing the sunglasses; then tilt your head 45 to 90 degrees.  If the light changes, you've got polarized lenses.