Can other sources of light make rainbows at night?

In one line

The rule

A rainbow forms when light passes through water droplets, bends (refracts), splits into different colours, and reflects inside the droplet before coming out.

Let's understand it simply

Imagine you are holding a torch (flashlight) at night and it is raining. If you shine the torchlight towards the rain, you might see tiny rainbows in the water droplets. This happens because the torch acts like the sun: it gives light, and the water droplets act like tiny prisms (glass pieces that split light). The light bends and splits into many colours, just like sunlight does during the day.

How it works

1. Light from a source (like a torch or street lamp) hits water droplets in the air.
2. The light enters a droplet and bends (refracts).
3. Inside the droplet, the light reflects off the back of the droplet.
4. The light bends again as it leaves the droplet.
5. The bending splits the light into different colours, making a rainbow.

The story behind it

Rainbows have been seen and wondered about for thousands of years. Isaac Newton, in the 1600s, showed that white light is made of many colours. He used a glass prism to split sunlight into a rainbow of colours. The same thing happens in nature with water droplets.

Where you see it in real life

• Using a garden hose at night: Shine a torch through the water spray and you may see a rainbow.
• Streetlights and rain: Sometimes, if it is raining at night and there are bright streetlights, you can see faint rainbows around the lights.
• Car headlights and mist: On a foggy night, car headlights can create small rainbows in the mist.
• Diwali fireworks: Some fireworks release water vapour and bright light, making small rainbows in the smoke.
• Water fountains with coloured lights: At night, fountains with strong lights can create rainbow effects in the spray.

Why it matters

• Shows that rainbows are not just a daytime event—they depend on light and water, not the sun alone.
• Helps us understand how light behaves—important in science, photography, and art.
• Used in making colourful effects in stage shows and festivals.
• Knowing this helps in designing safe car lights and streetlights (to avoid glare and distractions).

Common mistakes

• Thinking only the sun can make rainbows. Any strong light can, if there are water droplets.
• Believing rainbows only happen during the day. They can happen at night if conditions are right.
• Expecting night rainbows to be as bright as daytime ones. They are usually fainter because artificial lights are not as strong as the sun.

Remember it

Rainbows need light and water, not just the sun—try a torch and water spray at night to see for yourself!