POLARIZED LIGHT BY: Rachel

When you look at regular sunglasses, what do you see? Nothing much. Polarized sunglasses are better. I chose this topic because it seemed interesting what these kind of sunglasses can do.

Can sunglasses completely block light? I thought of this question because I was getting new sunglasses for the summer and my Dad said that some glasses can block light.

Light is a form of energy that your eyes can see. There are two main sources of light. One comes from heat energy and is called incandescent light. The other is luminescent light. The sun is an incandescent light source. Its heat comes from nuclear reaction. A light bulb is also a type of incandescent light. Luminescent light comes from a fluorescent light and is caused by a chemical reaction.

Light acts like a particle sometimes and a wave at other times. When light is like a particle, it is called a photon. The constant speed of a photon is 186, 000 miles per second. When light acts like a wave it has vibrating electric and magnetic fields. The sun's light waves vibrate the electric field in all directions. This is called un-polarized light. Reflected sunlight from a surface is horizontally polarized. Polarized sunglasses block light that is horizontally polarized. That's how polarized sunglasses reduce glare.

First, to do my experiment I got two pairs of polarized sunglasses. Next, I turned them together. One was sideways and one was upright so that they were at 90 degree angles. I looked through both lenses and the lenses were black. The light would not pass through. After all of that I got regular sunglasses and did the same thing. I turned them opposite ways. The regular sunglasses did not do anything. They stayed the same color. Later, I tried to take two polarized lenses. I put a flashlight underneath of the turned polarized lenses and the whole flashlight went black. I could not even tell that I turned it on. Finally, I took three sunglass lenses, all polarized. It still went black. In fact, it seemed blacker.

Polarized sunglasses are kind of like horizontal window blinds. The light comes from the sun in all directions. Then it goes through the polarized lens.

Most of the horizontal polarized light will be blocked. Next it goes through the other lens vertically since it's perpendicular. When the light goes through the second lens it turns black.

Regular sunglasses do not turn black. Regular sunglasses protect UV light. They do not reduce glare. Polarized sunglasses reduce glare and of course what you see is not so bright.

There are many other experiments to do with polarized light. In other years, people can try many different things. People can try to work with polarized sunglasses in different kinds of light, such as fluorescent or black light. You could try to get more than two polarized sunglasses and lots of regular sunglasses and see if it still can turn black. They could do more things with light and see what protects your eyes best! There still are many things you could do with light!

Bibliography

Encarta Encyclopedia 2000, Microsoft Corporation.