Archimedes
Syracuse
The law of the lever, and buoyancy
Why does a small weight far from the pivot balance a large weight near it?
Forget the wood and the stone. Weigh only the distances. If the balance does not tip, then weight times distance on one side must equal weight times distance on the other — and that is true whatever the object is made of. The shape of the thing is a distraction. The ratio is the law.
What broke open
Machines become calculable. You can now predict a crane before you build it.