What Keeps Things From Falling Over?

Step 1 of 5

Every object has a balance point.

Gravity pulls on all of an object, but it behaves as though it pulls at one single spot — the centre of gravity.

Step 2 of 5

Stay above your base and you stay up.

Draw a line straight down from that point. If it lands inside the area your feet cover, gravity holds you steady. If it lands outside, you rotate and fall.

Step 3 of 5

Wider base, harder to topple.

Feet apart, a tripod, a pyramid — a bigger base means the balance point can shift much further before it crosses the edge.

Step 4 of 5

Low is stable, high is wobbly.

A low balance point moves less sideways when the object tilts. Racing cars sit low for this reason; double-decker buses have to be careful.

Step 5 of 5

You are constantly rebalancing.

Standing still is not passive. Your muscles make small corrections many times a second to keep your balance line inside your feet.

Carry a heavy bag on one side and you lean the other way — you are moving the combined balance point back over your feet.