A lever is a simple mechanism that uses a bar to pivot around a fixed point called a fulcrum. Levers can be joined together to form linkages. Simple linkages can be used to change the direction of ...

(The ancient Greek mathematician reputedly said, “Give me a lever long enough and a fulcrum on which to place it, and I shall move the world.”) Ben Yagoda, author of such books as “How to ...

But something remarkable happens the moment you vent the can: The tab becomes a first-class lever, in which the force you apply changes direction around the fulcrum, like a seesaw. "Part of the ...