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Light is a type of energy which our sense of sight can detect. It is made of electro-magnetic radiation and it travels in a straight path.There are different colours of light because they are light waves which have different wavelengths. Red light has the longest wavelength while violet light has the shortest wavelength. Red, green and blue are the primary colours of light. Mixing them in various ways will make all other colours, including white.
Do you know white light is made of different colors. To see this, take a prism, keep it against sunlight, you would find 7 colors coming our from other side of prism.We see different things colors because when white light falls on them ,different things absorb different colors but some of the colors are not absorbed by them. Like when white light falls on an apple, it absorbs all colors of white light except red color. Red color is reflected back by apple ,that is why apple appears red. Reflection means bouncing back, like when you throw a ball against a wall, it bounces back. Similarly some colors bounce back (reflect) from different things, that is why we see colors.
The speed of light is the speed at which light travels. It is about 300,000 kilometers per second. Nothing travels faster than light. It is faster than speed of sound. That is why when lightning happens, we see the light first & hear the sound later.
Do you know what is refraction?The bending of light as it passes from one medium substance to another, like air to water, is called refraction.Try to put a pencil in a transparent glass ,full of water, it would seem that pencil has been bent.
Do you know why we see a rainbow, it happens due to refraction. Rainbow happens on rainy or cloudy days. On these days, raindrops act like prism,they refract & break the white light into different colors & we see rainbow.
Like mentioned earlier, light is also a form of energy which generates heat. That is why we should wear light colored clothes in summer days as light -color clothes reflect most of the colors so they absorb less energy & color & we feel cooler.In winters, we should wear dark colored clothes.This is because ,dark colored clothes absorb most of the colors which means most of the heat energy is absorbed & is passed to our body .That is why darker color clothes keep us warm in cold..
