Playground Machines: Writing with Science Words

Simple Machines on the Playground

1A playground is a place for fun, but it is also full of science. Some of the equipment works like simple machines. A simple machine is a tool with few or no moving parts that makes work easier. It can change how much force you need or the direction of a force. A force is a push or a pull.

2A seesaw is a kind of lever. A lever is a stiff bar that turns on a fixed point. That point is called the fulcrum. On a seesaw, the fulcrum is the support under the middle of the board. When one rider pushes down on one end, the other end rises. The rider who is lifted is the load. A smaller child can even lift a bigger friend if the bigger friend sits closer to the fulcrum.

3A slide is an inclined plane. An inclined plane is a flat surface with one end higher than the other. A ramp is an inclined plane, too. Pushing a wagon up a ramp takes less force than lifting it straight up, but the wagon must travel a longer distance. On a slide, gravity pulls you down the slanted surface. Gravity is the force that pulls objects toward Earth. Friction is a force that slows down objects when they rub against each other. Friction between your clothes and the slide slows you down.

4The flagpole beside the playground uses a pulley. A pulley is a wheel with a groove around its edge. A rope fits into the groove so it does not slip off. At the top of the flagpole, the rope runs over the pulley. When you pull down on the rope, the flag moves up the pole. The pulley changes the direction of the force, so you can raise the flag without climbing.

5The next time you visit a playground, look for levers, inclined planes, and pulleys. When you write about them, use these science words. Exact words help your reader understand how each machine works.