How to Create a Rainbow Using Water and Sunlight

Welcome! In this tutorial, you'll learn how to create a real rainbow using just sunlight, water, and a simple garden hose. It's a fun and visually stunning experiment that combines beauty, science, and a little bit of everyday magic. Whether you're a curious mind, a science lover, or simply want to capture something amazing on camera, this step-by-step guide will show you exactly how to make it happen—right in your own backyard.

1. A hose with a fine mist or spray nozzle (like a gentle mist or light rain)
2. Running water
3. An open outdoor space (such as a garden, yard, or park)
4. The sun positioned behind you

Stand with your back to the sun.

Make sure the sun is low in the sky—early morning or late afternoon works best—and directly behind you.

Use the fine‑mist or spray setting on your hose and spray the water forward.

Aim at an angle of about 30° to 45°, slightly upward, so the droplets are dispersed in front of you.

Slowly move the hose up or down until the rainbow appears in front of you.

Make sure you're always facing away from the sun.

You’ll see a partial circular rainbow appear where the sunlight passes through the fine water droplets.

If your spray isn’t fine enough, try partially covering the nozzle with your finger to create a mist.

The smaller and more numerous the water droplets, the clearer and more complete the rainbow will be.

You can even take a photo if the lighting is just right—it looks beautiful on camera!

A rainbow is sunlight broken down into colors—just like when light passes through a prism. In this case, the “prism” is made of tiny water droplets floating in the air.

How Does a Rainbow Form?

When sunlight enters a droplet of water (like the mist from your hose), three important things happen:

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1. Refraction:

As the light enters the droplet, it bends. This bending is called refraction. As it bends, the light separates into colors because each color bends a little differently (violet bends more than red).

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2. Internal Reflection:

Inside the droplet, the light reflects off the back of the droplet—just like bouncing off a mirror.

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3. Refraction Again (Exiting):

When the light exits the droplet, it bends once more and the colors spread out even more.

Each droplet sends a specific color in a specific direction.

Why Do You See an Arc?

Your eyes only see the colors that each droplet sends at just the right angle (about 42° for red, 40° for violet).

Since there are millions of droplets in the air, all sending different colors at different angles, your eyes perceive a curve of colors: the rainbow.

The rainbow always appears in front of you, with the sun behind you.Why So Many Colors?

Because sunlight is actually made up of many colors: red, orange, yellow, green, blue, indigo, and violet.

Each color bends slightly differently as it passes through the water, which is why we see them all separated.