# How Rain Forms

How water rises from the sea as vapour, gathers on dust specks into cloud droplets, and merges into heavy raindrops that fall back to the ground\.

By YUSI YE

Topic: Earth & Geography

[Open the interactive Jig](https://ask.jig.com/j/R13cXo8Chgep)

## Transcript

### 1. Where does rain come from?

Every raindrop was once water in the sea, a lake or a leaf\. It rises into the sky, becomes part of a cloud and falls back down\. Let’s follow it on that journey\.

Drag anywhere to turn this little world around\.

### 2. The Sun lifts water

The Sun warms the sea\. Some water escapes into the air as water vapour, a gas too fine to see\. Warm, damp air is light, so it rises\.

Plants give off water vapour from their leaves too\.

### 3. Rising air cools

The higher the air climbs, the colder it gets\. Cold air cannot hold as much vapour, so some of it turns back into liquid water\. A cloud begins to grow\.

### 4. Water needs a seed

Zoom into the cloud\. The air is full of tiny specks of dust, sea salt and smoke\. Vapour gathers on these specks and becomes tiny cloud droplets\.

Without these specks, clouds would hardly form at all\.

### 5. Tiny droplets float

A cloud droplet is about 0\.02 millimetres across, much thinner than a hair\. It is so light that rising air keeps it floating\. A cloud is billions of them\.

One cubic metre of cloud can hold around 100 million droplets\.

### 6. Bump and join

A slightly bigger droplet falls a little faster than the rest\. On the way down it bumps into smaller droplets, and many of them join it\. Each join makes it bigger and faster\.

### 7. A million make one drop

A raindrop is about 2 millimetres across, a hundred times wider than a cloud droplet\. It takes around a million cloud droplets to build one raindrop\.

Real raindrops are round or shaped like a bun, never like a teardrop\.

### 8. Too heavy to float

Once drops are too heavy for the rising air to hold up, they fall as rain\. A 2 millimetre raindrop falls at roughly 6 metres every second\.

In colder clouds, rain often starts as snowflakes that melt on the way down\.

### 9. Back to the sea

Rain soaks into the ground, fills rivers and flows back to the sea\. Then the Sun warms the water again and the journey starts over\. This endless loop is the water cycle\.