✅ What you'll learn
- The science concept behind the experiment
- How to set it up safely
- What to observe and record
- Why the result happens
💡 Perfect if you're thinking...
The Rainbow Cloud (also called Rain Cloud in a Jar) is a beautiful experiment that shows how rain works! You build a 'cloud' from shaving foam on top of water, then add coloured 'rain' that falls through it. It teaches kids about clouds, condensation, and the water cycle.
🧪 What You Need
- A clear glass jar or tall glass
- Water (almost full)
- Shaving foam (cream)
- Several small cups
- Food colouring (different colours)
- Pipettes or droppers
How to Make a Rain Cloud Step by Step
- Fill the jar with water — leave about 3cm space at the top.
- Add a thick layer of shaving foam — spray it on top of the water to make a fluffy 'cloud' that sits on the water's surface.
- Let it settle — give the cloud a minute to settle so it floats firmly.
- Mix the rain — in small cups, mix water with food colouring to make different colours of 'rain'.
- Fill the dropper — suck up some coloured water with a dropper or pipette.
- Squeeze drops onto the cloud — gently drop the coloured water onto the top of the foam cloud.
- Keep adding — the colours sink into the cloud, and once the cloud is 'saturated' (full), the colours start to fall through into the water below as 'rain'.
- Watch the rainbow rain — beautiful streams of colour rain down into the clear water below!
🔬 What's Happening? (The Science)
This experiment models how real clouds and rain work. A real cloud is made of tiny droplets of water floating in the sky. As more water collects in the cloud — through condensation (water vapour from the air turning back into liquid droplets) — the cloud gets heavier and heavier. When the cloud is 'saturated' and can't hold any more water, the droplets join together until they're heavy enough to fall as rain. In your jar, the shaving foam acts as the cloud and the food colouring acts as the water in the cloud. Just like a real cloud, when the foam can't hold any more 'water', the colour falls through as rain.
🌟 Did You Know?
Real clouds can hold an enormous amount of water — a single average cumulus cloud (the fluffy white ones) contains about 500 tonnes of water, the same weight as 100 elephants! It floats because the water is in tiny droplets spread out over a huge area. Clouds only rain when the droplets join together to make drops big enough that gravity pulls them down faster than they can float.
🎯 Try This: Experiment Variations
- Try adding just one colour of rain — see how long it takes to fall through.
- Try several colours one after another — do they mix in the cloud or rain down separately?
- Predict: will warm water rain through faster than cold water? Test it.
- Draw your jar at different stages — write what's happening like a scientist's notebook.
📚 Sources & Further Reading
Written by Parikshet More (KidsFunLearnClub, Dubai) and reviewed for accuracy. Facts checked against the references above.
🧠 Quick Quiz — Test What You Learned!
Created by Parikshet & Dad
Hi! I'm Parikshet, an 11-year-old creator from Dubai who loves drawing, art, science experiments, and golf. My dad and I run KidsFunLearnClub to share fun learning activities with kids around the world. We've created over 1,900 tutorials and videos to help you learn and have fun!
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Explore AI for Kids → What is AI? Start hereFrequently Asked Questions
How is this like a real cloud?
Real clouds are made of tiny water droplets floating in the air. They form when water vapour rises from the ground, cools down high in the sky, and changes back into liquid droplets — this is called condensation. The droplets stay floating because they're so small, just like the shaving foam stays on top of the water. When the cloud collects too many droplets, they fall as rain — just like in your jar.
What is condensation?
Condensation is when water vapour (an invisible gas) cools down and turns back into liquid water. You see it when water droplets form on the outside of a cold glass on a hot day, or when your warm breath makes mist in cold air, or when steam from a hot kettle hits a cool window. In the sky, condensation is what forms clouds.
Why does rain fall?
Rain falls because of gravity. The tiny water droplets in a cloud are normally light enough to float, but when many droplets join together they form bigger, heavier drops. Once a drop is heavy enough that gravity pulls it down faster than the air can hold it up, it falls — and we call that rain. The same thing happens in this experiment when the foam can't hold any more coloured water.
How much water can a real cloud hold?
An average fluffy white cumulus cloud holds around 500 tonnes of water — about the weight of 100 elephants! Storm clouds can hold many times more. The reason all that water can float in the sky is that it's spread out as billions of tiny droplets, each one too small to fall on its own — until they join together and become rain.