⚙️ Simple machines

A lever is a stiff bar that rests on a support called a pivot. When you push down on the long end, the short end lifts a heavy load with far less effort than lifting it directly. The longer the bar on your side, the easier the load feels. A seesaw is a lever you can sit on.

A pulley is a wheel with a rope running over it. Pulling down on one end of the rope lifts a load on the other end, and using several pulleys together shares the weight so it feels much lighter. It also lets you pull down while the load goes up, which is often easier.

A ramp is a slope that lets you raise something without lifting it straight up. You push it a longer distance, but with much less effort at each step, so heavy things feel easier to move. Trading a bigger distance for less effort is one of the oldest tricks in building.

Gears are wheels with teeth around the edge that lock into each other. When one gear turns, its teeth push the next gear along, so they all spin together. A small gear turning a big one makes it go slower but stronger, while a big gear turning a small one makes it go faster.