Light

            Light is everywhere. It allows us to see, and it reflects off any solid or liquid matter. Light also is used to make different colors. It is also a form of energy (light energy). Light is also made up of a kind of subatomic particle that we will be learning about in this article.

            A property of light is that it always, always travels in a straight line. We see things because it reflects off solids, liquids and sometimes gases and enters our eye. Our eye gives and image into your brain, and you see stuff. White light is made of three colors- red, blue, and green. Green and blue give cyan, red and blue give magenta and red and green give yellow. Hence, all the colors that we see is light.

Light is made up of a subatomic particle called a photon. When the sun fuses hydrogen into helium, it gives out light energy, which reaches us in photons. ‘Photo’ synthesis needs light, so it uses photons, hence the name. Waves of photons coming at us in space are called light waves. Light coming from the sun was raw energy, and could not be used by cells when the first few cells were there, but now cells can absorb the energy. It also has Vitamin D in it, which makes it very healthy.

Light can travel in vacuum as well as air. Its speed is 299,092,458 m per second. It is like saying light can go from Earth to the moon in one second. Very long distances, such as the length and breadth of a galaxy, is measured in light-years. A light year is the distance light travels in a straight line in a single year. Light in water 225,000,000 m per second, and light travelling through glass is 200,000,000 m per second.

Light cannot travel through most solids, as solids are mostly opaque, but some like glass, which are transparent, allow light to pass through them.