What is a rainbow?
A rainbow is like a big, colourful smile in the sky. It shows seven colours that come from white sunlight and little drops of rain.
Step-by-step: How a rainbow is made
- The sun makes white light. White light looks plain, but it is actually made of many colours mixed together.
- Raindrops are tiny clear balls. Each raindrop acts like a tiny glass ball or prism.
- Light goes into a raindrop and bends. When the sunlight goes into the drop, the light bends and the colours start to spread apart because each colour bends a little differently.
- The light bounces inside the drop. Some of the light reflects inside the drop and then comes back out.
- We see colours in a special order. Because the colours come out at slightly different angles, we see red on the top edge of the arc and violet on the inside edge.
Why is the rainbow an arc (a big curve)?
Each raindrop sends one colour to your eyes at the right angle. Many raindrops together send many little bits of colour in a circle around a point opposite the sun. We usually see the top part of that circle (an arc) because the ground hides the rest.
The seven colours
The colours you can see in a rainbow are: Red, Orange, Yellow, Green, Blue, Indigo, Violet. People use the name ROYGBIV to remember them.
Fun and safe rainbow experiments (ask an adult to help)
- Glass of water and paper: Put a white sheet of paper on the floor. Put a clear glass half full of water on the paper and shine sunlight or a flashlight through the glass so the light hits the paper. Move the glass until you see colours appear on the paper.
- Spray a little water: On a sunny day, have an adult spray a fine mist with a garden hose while you stand with the sun behind you. You may see a rainbow in the drops.
- Use a CD or a prism: A CD can make rainbow colours when you tilt it in light. A prism (with an adult) will split white light into colours too.
Quick safety tips
- Never look directly at the sun.
- Always have an adult help when using glass, prisms, or a hose.
Have fun finding rainbows and making your own! Look for the bright red on the top and violet on the inside — that is how nature arranges the seven colours.