Question #0d3af

Waves of light, especially those coming directly from the sun, are composed of electromagnetic waves. Each wave vibrates in a certain plane. But since there are many waves that make up direct sunlight, we get a wide variety of different planes in which the wave oscillations occur.

A polarizing filter (like you find in sunglasses and in camera lens attachments consist of many tiny dark lines that will allow only waves oscillating in a particular direction to pass, and will block, or greatly reduce the intensity of all others.

This is a main reason why sunglasses are effective in reducing reflective glare from roadways for instance. The reflected light consists many of waves that oscillate in a horizontal plane. The polaroid lens in the glasses is designed to block just this plane of polarization, while allowing most other waves to pass through.

As a second example, many crystalline compounds are able to rotate the plane of polarization of the light - meaning that the waves are rotated in their plane of vibration. This gives rise to what organic chemists call "right-handed" and "left-handed" nature of the type of chemical isomer called an enantiomer.