Can I touch a Rainbow?

Akku: Mommy how is a rainbow formed?

Akku, you got a really complicated question this time. It’s a hard thing to explain. Before I start, you need to understand two things – reflection and refraction..

rain drop

 
Akku: Yes I know it’s something related to bending and bouncing of light, right mom?

That’s correct. The bouncing back of rays of light from a shiny surface is called Reflection of light. Whereas, the change in the direction of light when it passes through a different medium is known as Refraction of light.

So rainbows are formed when the sunlight passes through raindrops. The light is refracted as it enters the droplet and then reflects off its inside. And this causes all the amazing colors of the rainbow.

vibgyor

 
Akku: But why do we see only 7 colors?

Visible light, that is sunlight is made up of various wavelengths, and each wavelength appears as a different color: red, orange, yellow, green, blue, indigo and violet. Red light, for example, bends at a different angle than violet light. A great way to remember these colors is to think of a man’s name: ROY G BIV. When the sunlight passes through raindrop, it acts like a tiny prism and each color bends differently due to different wavelengths, thus splitting the light into seven colors.

Akku: Wow thanks for that ROY tip. Can we see a rainbow every time it rains?

Not all the time. The best time to catch a rainbow is when it’s sunny and raining. There is an even better chance when the sun is at a lower angle, so early or later in the day. On the other hand, if the angle is not right, the rainbow formed will not be visible. The key is to face the rain and have your back to the sun.

clay rainbow

 
Akku: Next time I am definitely going to see a rainbow. Hurray!! And Mom, can we touch a rainbow?

Can you touch light? No, right? Same way rainbow is just an optical illusion, so you just can’t catch up to it. When you move, so does it. We can’t touch it, neither feel it. It’s just light.

Akku: Oh yeah. Can we at least go the end of the rainbow and find the treasure?

I wish we could. But that’s also not possible. There is no end to a rainbow, it’s an optical illusion! Even though they look like an arch to us, rainbows are actually full circles. We see only part of the circle because the horizon blocks the rest of it from our view. Pilots high in the sky do sometimes report seeing genuine full-circle rainbows.

Akku: Wow!! I never knew that rainbow has a full circle. Cool! But I have seen a double rainbow. How does that happen?

Oh yeah ! A double rainbow happens when the light bends and reflects off the water drops in the air twice. In other words, the second rainbow is a reflection of the first rainbow. The second rainbow formed will be lighter in color and the colors will be reversed, just like a mirror reflection.

double rainbow

Akku: Nice! A mirror effect. Can a rainbow appear during night?

Oh yes, they’re called moonbows! The night time rainbow is extremely uncommon and occurs only when the moon is sufficiently brilliant and positioned properly with respect to falling rain to produce the delightful effect.

lunar rainbow
Photo of a Lunar Rainbow taken from the Zambia side of Victoria Falls. Photo courtesy Calvin Bradshaw (calvinbradshaw.com)
Akku: That must be really beautiful. Thanks so much mom for this amazing facts about rainbows! See you later, Bye!

Mom: You are welcome dear!

The way I see it, if you want the rainbow, you gotta put up with the rain.
― Dolly Parton