Air Presses Down

Open to everyone until Wednesday, September 30

To keep it, print it while it is open.

Air is real stuff, so a tall stack of it weighs something and pushes down on everything below. When that push is strong the sky is usually clear, and when it is weaker rain clouds often gather.

In the picture

An arrow in the wide blue column: air pushing down hard
An arrow in the narrow grey column: air pushing down more gently
The needle on the dial: leaning towards the stronger push

Examples

A balloon feels a little heavier once you blow it up, because you have added air inside.
Your ears pop going up a hill, as the push of the air around you gets weaker.

Key takeaways

Air has weight, so the air above us presses down on us all the time.
That push is measured in hectopascals: it drops in rainy lows and rises in fair highs.