Simple machines make our lives easier by helping us do things that would be very hard, maybe even impossible, to do without them. Imagine trying to move a car or wagon without wheels. Try pulling a nail out of a piece of wood without the lever (the claw) on a hammer. How hard would it be to split wood without the wedge on the end of an axe? Simple machines also help us lift, push, and pull things over a distance. They make work easier.
There are six basic types of simple machines: lever, pulley, wedge, wheel and axle, inclined plane, and screw. These cards show some of the common ways that these tools help us. Read the examples, then from your own experience or with some help from the Internet, give other examples of each simple machine.
An inclined plane makes moving and lifting things easier. It is a flat, slanted surface that works like a ramp. Have you ever seen someone load heavy items into the back of a large truck? The may have used a ramp, or inclined plane, to load the truck more easily.
A wedge is a pair of inclined planes attached back-to-back. A wedge is used to force things apart. Have you ever seen someone chop wood with an ax? The head of an ax is a wedge.
A screw is a spiral wrapped around a center post. When you turn it, it can lift objects or hold two objects together. Have you ever opened a bottle of water? When you turn the cap one way, it opens. If you turn it the other way, it seals the bottle shut. The cap is a screw.
A lever is a bar that pivots or turns on a fixed point. The fixed point is called the fulcrum. Have you ever played on a seesaw? The seesaw is a lever. The support in the middle is the fulcrum.
A pulley is a wheel that is used with a cord or rope. When you pull it downward, the other end lifts upward. Have you ever seen someone hoist a flag up a flagpole? The flag is attached to a rope. At the top of the flagpole is a pulley. When you pull the rope downward, the flag rises up the pole.
A wheel and axel is made up of a wheel with a rod attached to it. When the wheel is turned, it turns the axle with it. Have you ever turned a round doorknob to open a door? When you turn a doorknob, you are using a wheel and axle. The knob is a wheel. The rod that it is attached to is an axle.
Simple machines all have a property called mechanical advantage