Answer card
What makes a rainbow?
Want to guess first?
Write a guess down before you look, and you will notice what surprises you. You can’t get it wrong.
What we know
- True: “As the light beam enters the surface of the rain drop, it is bent (refracted) a little.” Then it reflects off the inside of the drop and bends again on the way out. National Weather Service, Flagstaff — How Do Rainbows Form?
- True: Sunlight is made of many colours, and “each color becomes slightly separated from the others as the light ray is refracted and reflected”. National Weather Service, Flagstaff — How Do Rainbows Form?
- True: “You need to be standing with the sun to your back and the rain in front of you,” and “the sun needs to be less than 42° above the horizon.” National Weather Service, Flagstaff — How Do Rainbows Form?
- True: “Since the raindrop is circular, the reflection it creates is also circular.” The ground usually hides the bottom of the circle, which is why we see an arc. National Weather Service, Flagstaff — How Do Rainbows Form?
What we made simpler
We left out why one angle, about 42°, gets so much of the light, and how a second, fainter rainbow forms.
Still open
Not much: scientists understand rainbows well. Each person sees a slightly different rainbow, made by different raindrops.
Next why
Why is the second rainbow’s order of colours the other way round?
PrismForge — Prisms and Dispersion →Try it
Written by people and checked against the sources named beside each line. All answer cards