What Are Simple Machines?

Suppose you needed to move an object. You might use tools to help you. Machines are tools that use energy to do work. Simple machines are machines with a few or no moving parts. Machines make work easier. You probably have used several of the six different kinds of simple machines.

Pretend you need to lift a heavy object like a big rock. You could use a lever to help you. A lever is a simple machine made of a board that is used to move objects. A seesaw or teeter-totter is really a lever. The middle of the seesaw has something under it to hold it up. This is called the fulcrum. The lever moves back and forth on the fulcrum. On a seesaw, each person takes turns lifting the other person.

To lift a rock with a lever, you would need a board to be the lever and a fulcrum to hold it up. Another rock can be a fulcrum. The object being lifted is called the load. You can lift a load most easily by moving the fulcrum close to the load. You move the load by pushing down on the end of the lever.

A hammer is another kind of lever. A hammer pulls a nail out of a piece of wood. Where is the fulcrum on a hammer?

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