1The two things to know about air
Air carries invisible water — but only so much
There are really just two ideas here. Watch each one move:
Air holds hidden water
The air all around you is carrying water vapor — water so spread out it's invisible. It floated up off oceans, lakes, and puddles.
There's a limit
Air can only hold so much. Think of an invisible bucket. And here's the trick: warm air has a BIG bucket, cold air has a tiny one.
Try the ingredient below. Make a prediction before you compare the completed cases.
2Your turn — fill up the air
Pour water into a puff of warm air
This model starts with warm air below saturation. Add water vapor within the slider range and watch its amount rise. The range stops below the warm saturation limit; warm air cannot contain unlimited vapor.
3Now the real experiment
What if we cool the air down? ❄️
Take that same muggy puff and send it up high, where it gets cold. You won't add a single extra drop of water. You'll only cool it down. Guess first:
Guess before you find out
The warm puff contains 62 model units of vapor, below its saturation line. Cool it without adding water. What will you observe?
Open circles represent vapor; filled circles represent liquid. Each symbol is one model unit of water, not one real droplet. The model shows condensation; rain needs a later growth step.