From NCERTAsked by Anonymous from Mountain View, United States30 Sep 2026, 4:52 PM ISTUpdated
In one line
Clouds look white because they scatter sunlight in all directions, mixing all colours to make white.
Cloud — Visible mass of particles suspended in the atmosphere A real photograph of white clouds, showing how sunlight makes them appear bright and white. Image: Wikipedia
The rule
Clouds appear white because the tiny water droplets or ice crystals inside them scatter all colours of sunlight equally, making the light look white to our eyes.
Let's understand it simply
Imagine sunlight as a mix of all colours, like a box of crayons. When sunlight hits tiny water drops in a cloud, these drops act like millions of tiny mirrors. They bounce the sunlight in every direction. Since sunlight has all colours, and all get mixed up, our eyes see this mixed light as white. It’s like mixing all your paint colours together — you get something close to white or light grey.
How it works
Sunlight reaches the cloud. Sunlight is made of all colours (like a rainbow).
The cloud is full of tiny water droplets or ice crystals.
These droplets are just the right size to scatter (spread out) all colours of light equally.
The scattered light from all the colours mixes together.
Our eyes see this mixed light as white.
How clouds scatter sunlight to look white
Sunlight hits cloud
Tiny droplets scatter all colours
Scattered light mixes
We see the cloud as white
The story behind it
Scientists like Lord Rayleigh and John Tyndall studied how light scatters in the air and in clouds. They wanted to know why the sky is blue and clouds are white. Their work helped us understand that the size of the particles (like water droplets) decides how light is scattered.
Where you see it in real life
Fluffy clouds on a sunny day: The clouds look bright white because they scatter sunlight.
Steam from a pressure cooker: The steam looks white for the same reason — tiny water droplets scatter all colours.
Mist in the morning: Mist appears white as sunlight passes through tiny water droplets.
Milk: Milk looks white because fat droplets scatter all colours of light, just like clouds.
White smoke from a fire: Tiny ash or water droplets scatter light, making the smoke look white.
Why it matters
Helps us understand weather and why clouds change colour before rain.
Used in photography and lighting to make soft, white light.
Explains why fog and mist look white, helping in road safety.
Connects to later science topics like the rainbow, blue sky, and light scattering.
Common mistakes
Thinking clouds are white because the water itself is white. (Water is clear; it’s the scattering that makes clouds look white.)
Believing all clouds are always white. (Thick clouds can look grey because less light passes through.)
Remember it
Clouds look white because their tiny drops scatter all sunlight colours, mixing them into white.
Check yourself
Why do clouds look white when the water in them is clear?
Because tiny water droplets scatter all colours of sunlight, mixing them into white.
What happens to the colour of clouds when they get thicker?
They look grey or dark because less sunlight passes through.
Why does steam from a pressure cooker look white?
Tiny water droplets scatter all colours of light, just like clouds.
Quick recap
Clouds look white because they scatter all colours of sunlight.
Tiny water droplets in clouds act like mirrors for sunlight.
All colours mixed together appear white to our eyes.
Thicker clouds can look grey because less light gets through.
