What's Happening?

A direct current circuit is an electric path that forms a circle. Electricity flows from the battery through a wire to various components (e.g., lights, motors, diodes) and back to the battery.

Watch this ~2 minute YouTube video to see how your airplane circuit works.

If you place the battery on one gray circle in your airplane, it will not touch both wires (as pictured). That means that electricity can't flow from the battery to the LED light and back again to the battery. This is called an open circuit.

When you crease the paper airplane shut (and secure it with the paper clip), the circuit closes--allowing a complete path for electricity to flow, pictured by the arrows. The LED lights up.

Look closely at the copper wires (pictured). Notice that they never touch each other, even when the plane is creased! Each wire only touches one side of the battery and one LED lead wire. For a circuit to function properly, positive wires should never touch negative wires. If they do, the connection will short your circuit. Short circuits drain batteries quickly and may create heat that can damage your wires.

You can prevent wires from touching each other by adding insulating material between them. Insulators do not allow electricity to flow through them easily. Examples of these materials include rubber, paper, plastic, and glass. For paper-based circuits, transparent or masking tape is a good insulator.

There are different approaches to add components to circuits. Watch this ~4 minute video about series and parallel circuits to see two approaches.