Andrew
savage
lever
A lever is basically just a long stick that you push or pull against a fulcrum to move something. A lever helps you move something heavy, or make something go fast. The earliest levers developed naturally inside animals' bodies. Whenever you pick up anything heavy, your elbow acts as the fulcrum of the lever, and your arm bone acts as the lever itself. Natural body levers first developed in fish around 440 million years ago.
There are three classes of lever
first class
A first-class lever is a stick where the fulcrum is between the weight and the energy moving the weight.
second class
A second-class lever is a stick where the fulcrum is at one end of the stick, you push on the other end, and the weight is in the middle of the stick.Some common second-class levers are doors, staplers, wheelbarrows, and can openers.
third class
A third-class lever is a stick where the fulcrum is at one end of the stick, you push on the middle, and the weight is at the other end of the stick. With a third-class lever, you have to put in more energy than you would just lifting the weight, but you get the weight to move a longer distance in return. Some common examples are a broom, a hoe, a fishing rod, a baseball bat, and our own human arms.