all of which follow the law of the lever. Class 1 is perhaps the most familiar. Examples of that are a seesaw, a crowbar as well as any time you’ve picked up a stick and placed it on a handy ...

Ezra: You can find levers all around you. Fran: Ah! Well a seesaw is a lever mechanism and here's how it works. Fran: The force of my hand pushing down on the lever makes it move. This is called ...

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 ...