How Does a Parachute Slow You Down?

Step 1 of 5

Falling is only fast because air is thin.

Gravity pulls everything down equally hard for its mass, and the only thing that ever slows a fall is the air being pushed out of the way.

Step 2 of 5

Pushing air aside takes real force.

Air has mass, so shoving it out of your path requires a push, and by the usual rule the air pushes back on you just as hard.

Step 3 of 5

A bigger surface shoves far more air.

A falling body meets a narrow column of air. A canopy metres across meets an enormous one, so the upward push is vastly larger.

Step 4 of 5

Faster falling also increases the push.

The quicker you fall, the more air you meet each second, so the upward push grows rapidly as speed builds until it matches your weight.

Step 5 of 5

Then you stop speeding up entirely.

Once the push matches your weight there is no net force left, so the fall settles at a steady speed that a canopy makes gentle.

A skydiver reaches about 200 km/h before opening, and a canopy brings that down to roughly 20 km/h — a survivable landing.