LIGHT ENERGY SC6

Light

What is light?

When we're very young, we have a very simple idea about light: the world is either light or dark and we can change from one to the other just by flicking a switch on the wall. But we soon learn that light is more complex than this.
Light arrives on our planet after a speedy trip from the Sun, 149 million km (93 million miles away). Light travels at 186,000 miles (300,000 km) per second, so the light you're seeing now was still tucked away in the Sun about eight minutes ago. Put it another way, light takes roughly twice as long to get from the Sun to Earth as it does to make a cup of coffee!

Why are there different colours of light? 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.
What are the primary colours of light? Red, green and blue are the primary colours of light. Mixing them in various ways will make all other colours, including white.
What is reflection? The bouncing back of light waves when they hit an object with a very smooth and shiny surface, like a mirror, is called reflection.
What is refraction? The bending of light as it passes from one transparent substance to another, like air to water, is called refraction.
What makes a rainbow? When sunlight is intercepted by a drop of water in the atmosphere, some of the light refracts into the drop, reflects from the drop's inner surface, and then refracts out of the drop. The first refraction separates the sunlight into its component colours, and the second refraction increases the separation. The result is a rainbow.