"Kids! go look outside, theres a HUGE rainbow!" my mom shouts through the front door as my brother and I race like NASCAR to the door to see the sight of amazement and wonder. As we stand in the middle of the road barefoot, our feet soggy and stinging with the puncture of little pebbles, my brother and I start to swap observations, "I see red, orange, yellow, green, blue, AND purple" "yeah, well I see red, orange, yellow, green, aqua, blue, pink, purple, and BROWN". Sure, some of these colors arent actually possible to see in a rainbow, but with us kids it was always a competition. But even at a young age my brother and i knew that no one person sees a rainbow completely the same. We knew that it happened, but we didnt know why.
It's actually a pretty interesting observation. You may be standing and looking at a rainbow to the south of you, while another person may be standing 10 miles west of you and not see a cloud in the sky, and another person could be standing 10 miles south of you and be in the middle of a downpour. This is obvious. But even a person standing only a few inches from you will view the rainbow differently. It may not be a huge difference, or even a noticeable difference, but its there.But why does this happen? why is there even a difference at all?
Firstly, Rainbows are created through refraction. Refraction is the bending of a wave when it enters a medium where it's speed is different. Because light is made up of many different colors, when the light hits the rain drops (water, a different medium) and is refracted, all of the colors (different wavelengths of light) are visible. With all of the colors combined it looks white, but once its refacted all of the colors separate creating a rainbow. If there is very little water or only a little light, it can create "mini" rainbows of only two or three colors, like when youre jumping through a sprinkler or looking at Niagara Falls.
Heres where it gets a little scientific. Because no two people can occupy the same point at once, it is impossible to be standing at the exact same angle from the sun, and the exact same angle from the rainbow. Therefore, when Susie looks at a rainbow she may notice that it spans the length of the street, but Bobby might think it spans the length of 2 streets.
Also, because the thing you're observing, the rain droplets, are constantly moving,the angle at which the droplets are interfearing with the sunlight is constantly changing. At some points you may notice it starts to get dimmer or brighter, this can be caused by the lessening of moisture in the air, or from the movement of the cloud away/toward you.
Also, if you try to run towards the rainbow to find the pot of gold, you will never actually find it. Because you are moving the rainbow that you see will also be moving. Therefore, the rainbow will always be moving away from you.
So, next time you head outside to see the span of color across the sky, just think about refraction and its constant change. and who knows, maybe one day you'll catch the leprechaun.