1Two forces in a tug-of-war
Gravity pulls down — and air pushes back
Every time something falls, two forces fight over it. You only need to watch these two:
Gravity: the steady down-pull
Gravity always tugs you straight down with the same steady force. It depends on your weight — and your weight doesn't change when you open a parachute. Same pull, the whole way down.
Air: the push-back
Moving through air, you have to shove it out of the way — and it shoves back. That push-back grows two ways: the faster you go, and the bigger the shape you push.
2Two shapes falling
The tiny rock vs the wide parachute
Same gravity pulls on both. What's different is how big a bite of air each one grabs:
The rock
Slips through the air with barely any push-back, so nothing slows it — it just keeps speeding up.
The parachute
Catches a huge bite of air, so the push-back gets big — big enough to hold it back to a gentle drift.
3Your turn — make it go faster
Push the speed and watch the air push back harder
Here's one falling shape. Drag the speed up. The gravity arrow never changes — but watch the air's push-back arrow grow the faster you push. Faster means more air to shove out of the way every second.
4Now drop it for real
Same person, same weight — just change the canopy 🪂
This figure weighs exactly the same no matter what you do — gravity's pull never changes. The one thing you control is how wide the canopy opens. Set it, guess first, then let go and watch.
Guess before you drop it
You're going to drop the figure with the canopy only half open — bigger than a rock, but nowhere near full. Is half-open already enough to catch the air and float you down gently? Or does it take a wide-open canopy before the landing turns soft?