What are filters, and why are they important?
As well as adding colours to produce new ones, colours can also be subtracted from one another by using special filters that only allow certain wavelengths of light to pass through. For example, if you pass white light through a red filter, then red light comes out through other side. This is because the red filter only allows wavelengths of red light through. The other colours- or wavelengths- of the spectrum are blocked.
In our daily life, different types of glasses can act as filters. They are known as photochromatic glasses, and they are used most commonly in the sunglasses that we wear.
The ozone layer, high up in the atmosphere, is a filter that blocks out wavelengths of ultraviolet light that are harmful to us. A pigment called melanin in our skin also acts as a filter against the damage that too much sunlight can cause.
No comments:
Post a Comment