One really can’t make it through the month of March without thinking of rainbows. Between the talk of leprechauns and gold, use these fun facts and rainbow resources to inject a little science into the mix. Here are the fun facts I found this week when I decided to take a look at:
Rainbows are actually circles.
When light hits the center of a drop of water, it is split apart at an angle in all directions. The resulting color bands form a circle around the point opposite the sun (the antisolar point) and that light is reflected back at an angle toward the sun. With the sun behind you, you can see the colors of the rainbow because the light is also reflected back into your eyes. The reason we only see a bow shape is that the earth gets in the way. When the sun is high in the sky, we can only see a little bit of the rainbow over the horizon. If the sun is very low on the horizon, the rainbow will be higher. If you were in an airplane high enough in the sky, you would be able to see the rainbow’s full circle.
Only one person sees each rainbow.
The rainbow you see is meant only for your eyes. This is because what you are seeing is the result of the light being reflected out of the raindrop at a very specific angle. Your eyes will see the light reflected toward them while the person next to you gets their own set of reflections to view. In fact, each of your eyes its very own rainbow too.
You can see rainbows at night.
Raindrops are a prism so they can reflect light from any source. Light from the moon can create a “moonbow” at night when it hits a raindrop at just the right angle. Our eyes sometimes perceive these moonbows as white, but really the water drops are reflecting faint colors. Moonbows are easiest to view near waterfalls, where the steady supply of water droplets in the air increases your chances of having just the right combination of water and light. You can view a series of stunning moonbow images here.
Gold may be at the end of the rainbow, but you’ll never find it.
Because the spectrum of light from the rainbow can only be detected by your eyes when you are standing in just the right place, whenever you move your rainbow does too. That is why it was easy for people to say that if you found the end of the rainbow, you would find a pot of gold- they could never be proven wrong.
Because the sun must hit the water drop at a 42-degree angle, rainbows aren’t seen at noon.
When the sun is low, the rainbow is high; when the sun is high, the rainbow is low. When the sun is at its highest at noon, the rainbow is so low that we can’t see it at all. The sun is still hitting water droplets and light is still refracting but it isn’t reflecting toward us anymore. So, there may be rainbows at noon but not for us to see.
Inside each water drop is a tiny rainbow.
Each tiny water droplet is a natural prism. Just like a diamond or a sun catcher, these drops create their own rainbows by refracting the light that hits them. The rainbow created by refraction is then reflected out of the drop. All of these tiny drops so close together projecting their rainbows out into the world are what we see.
Very rarely there can be triple or even quadruple rainbows.
The light refracted by a water droplet can be reflected more than once, creating a double rainbow. You may have seen these from time to time. But, there can actually be triple or even quadruple rainbows visible in rare instances. Capturing a true quadruple rainbow in a photograph is no easy task, but you can view an image taken in Germany in 2011 here.
You can read more about these fascinating rainbow facts and learn how to make your own rainbow using just a glass of water and a sunny day at Science Kids.
To learn more about how sunlight is first refracted and then reflected by each raindrop to form a rainbow complete with video demonstrations, visit Canon.com’s Science Lab.
Here are some fun lessons plans and worksheets for your classroom rainbow study:
This post was brought to you by my friend Tonya!