Why Fire Colours Come First in a Rainbow: Kids' Quiz 2026

Why do fire colours come first in a rainbow? This kids' quiz explores the science behind the order of colours in a rainbow, answering a question many curious children ask. Hosted by Molly Oldfield on the podcast Everything Under the Sun, we dive into the fascinating world of rainbows.

The Science Behind Rainbow Colours

Rainbows are formed when sunlight is refracted, or bent, as it passes through water droplets in the atmosphere. This bending separates white light into its component colours, creating the spectrum we see. The colours always appear in the same order: red, orange, yellow, green, blue, indigo, and violet. But why does red come first?

The answer lies in the wavelength of light. Red light has the longest wavelength, while violet has the shortest. When light enters a water droplet, it slows down and bends. Different wavelengths bend by different amounts—a phenomenon called dispersion. Red light bends the least, so it appears at the top of the rainbow, while violet bends the most and appears at the bottom.

What Are Fire Colours?

Fire colours typically refer to the warm colours: red, orange, and yellow. These are the colours we associate with fire, and they happen to be the first colours in a rainbow. This is why some people say 'fire colours come first'—it's a memorable way to remember the order.

Why Red Comes First: The Role of Wavelength

To understand why red is at the top, we need to look at how light behaves. White light from the sun contains all visible wavelengths. When it enters a raindrop, it refracts (bends) and then reflects off the back of the droplet. As it exits, it refracts again, further separating the colours.

Because red light has the longest wavelength, it is refracted the least. This means it exits the droplet at a slightly different angle than the other colours, appearing at the top of the arc. Violet, with the shortest wavelength, is refracted the most and appears at the bottom.

Key Takeaways

• Rainbows form when sunlight is refracted and reflected inside water droplets.
• Red light has the longest wavelength and bends the least, so it appears at the top.
• Fire colours (red, orange, yellow) are the first three colours in a rainbow.
• The order of colours is always the same: red, orange, yellow, green, blue, indigo, violet.
• You can remember the order with the acronym ROYGBIV.

Fun Facts About Rainbows

Did you know that no two people see the same rainbow? Because a rainbow is created by light entering your eyes from specific droplets, each person sees a slightly different rainbow. Also, rainbows are actually full circles, but we usually see only the top half because the ground blocks the rest.

Another fun fact: you can sometimes see a double rainbow, where a second, fainter rainbow appears above the first. This happens when light reflects twice inside the droplets, reversing the colour order.

FAQ

So next time you see a rainbow, remember: fire colours come first because of the way light bends! For more fun science questions, check out Molly Oldfield's podcast Everything Under the Sun and her books.