A cloud is full of water — so why doesn't it fall on your head?

A puffy cloud can hold as much water as a hundred elephants. Yet it just hangs there. What's holding all that water up? Let's find out… then make it rain.

1The two things you need

Rising air, and how size changes falling

Two simple ideas do all the work. Watch each one move:

Air keeps puffing up

Air isn't empty. Warm air near the ground rises, like a slow invisible fan blowing straight up. It pushes on anything light.

Size changes falling

Tiny things drift, big things drop. A speck of dust floats forever. A fat drop plummets. Same stuff — the size is what changes.

2The two kinds of water drop

A floater and a faller, side by side

A cloud is not "light water." It's water split into two very different sizes:

The floater

A tiny droplet

Smaller than a speck of flour. The gentle puff of rising air holds it up easily.

The faller

A fat raindrop

Hundreds of droplets clumped into one. Too heavy for the puff — it drops.

3Your turn — set the size

Drop one droplet into the rising air

The puff of air blows up at the same gentle speed the whole time. You only change one thing: how big the droplet is. Watch where it goes.

floating
Droplet sizea tiny speck
TINY SPECKFAT DROP

4Now grow the whole cloud

What if every droplet got bigger? 🌧️

Here's a whole cloud of tiny droplets, all floating. The rising air stays just as gentle. You're going to grow every droplet at once. But first — a guess.

Guess before you find out

You grow the droplets bigger and bigger while the puff of air stays the same gentle speed. What happens to the floating cloud?