By Derek M Alex F William A and Jacob C
What do a fork, a pair of scissors, and the little handle that flushes your toilet have in common? Well, apart from being common devices found in most modern households, they're all levers, and levers are some of the most important machines going. They've been around for thousands of years.
Simply put, levers are machines used to increase force. We call them "simple machines" because they have only two parts the handle and the fulcrum. The handle or bar of the lever is called the "arm" it's the part that you push or pull on. The "fulcrum" is the point on which the lever turns or balances. In the case of a fork, the fulcrum is the fingers of your hand. Scissors are really two levers put together. The handle on the toilet flusher is commonly called a fixed lever. Take a quick look around you and see how many levers you can find.
To make a lever to lift those snacks, you would need a long bar. You would place the board on a rock, log, or sturdy box, which makes a fulcrum or pivot. You would push down on the empty end of the board (effort), causing the board and the snacks to rise into the air. Think about how hard it would be to drag a heavy bag of snacks straight up a tree. A lever can simplify heavy work and make lifting heavy objects much safer.
Longer the lever, the higher you can lift an object.
In a type 1 lever, the fulcrum (pivot) is between the object to be moved and the effort.
A see-saw is a very simple type 1 lever. Pliers, a hammer’s claw and even scissors are also type 1 levers. Scissors are really two levers joined at the fulcrum.
In a type 2 lever, the load is between the fulcrum and the effort. Wheelbarrows are type 2 levers.
In type 3 levers, the effort is between the fulcrum and the object. Tweezers are a type of type 3 lever.