Mechanical advantage is how much a simple machine multiplies your effort force. You pound a nail into a 2x4 stud and try to remove it without a hammer. Then you use the hammer as a lever, and it multiplies your effort force enough to pull the nail out easily.

A lever is a bar that pivots on a fixed point. It changes how much force you need to lift something heavy. When the effort arm is longer than the resistance arm, you need less force. You can even lift a heavy weight with your pinky finger by placing the pivot in the right spot.

Can you lift a heavy weight using only your pinky finger? With the right setup, yes. A lever — a bar that pivots on a fixed point called a fulcrum — lets a small push move something much heavier. You start by pounding a nail into a wooden stud and trying to pull it out bare-handed. Then you use a hammer as a lever: the claw grips the nail, and pressing the handle becomes surprisingly easy. Next you set up meter sticks across plastic mugs as fulcrums and move the pivot to different positions along the stick. The weight lifts easiest when the effort arm is longer than the resistance arm.