# Levers

Let’s say you have a tree house. You need to lift a large bag of snacks up to the tree house. How could you do it? Several simple machines might come in handy. You could make a simple pulley with a rope strung over a branch to lift the bag. But if you didn’t have a rope, you could use a lever. Levers were first mentioned in history by the ancient scientist and mathematician, Archimedes. They’ve probably been around since prehistoric times though.
To make a lever to lift those snacks, you would need a long board. 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.

Fun Facts

• The 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.

Vocabulary

1. Lever: a simple tool that uses an effort and a pivot to lift or move objects
2. Fulcrum: also known as a pivot, a fulcrum is a point or object for a lever to rest and rotate on
3. Pulley: another simple machine that uses a rope and a wheel or other device to move the rope