See how electricity flows through a circuit that you build.

Safety note: The battery can become hot when wires are attached to it.

Materials

• String of holiday lights
• Insulated wire (about 7 feet)
• Wire strippers
• 9-volt battery
• 12 small nails or metal fasteners
• File folder or 8” x 11” piece of cardboard
• Masking tape
• Two paper clips
• Ruler
• Pen
• Paper

Directions

1. Cut a section of holiday lights, leaving about six inches of wire before the first light on the string and after the last light. Strip the ends off the last half-inch of wire on both ends. You can use just one bulb, or a string of bulbs.
2. Cut the insulated wire into seven sections that are about 12 inches long. Strip the ends off the last half-inch of wire on both ends.
3. Use the ruler to draw a line on the left side of the cardboard, starting about an inch from the top. Draw another line the same length on the right side of the cardboard. Write “questions” above the line on the left side of the cardboard. Write “answers” above the other line.
4. Starting at the top of the line, mark six evenly spaced dots along each line. They should be at least one inch apart. Label each hole in the “question” column 1 to 6. Label each hole in the “answer” column A to F.
5. On a separate piece of paper, write six questions and number them 1 to 6. These could be questions about anything: what you learned in school, your favorite things, information about your friends or family. It’s good to write some questions that will be hard to answer. Now write the answers to each question and label them A to F BUT put the answers out of order so that the questions and answers don’t line up.
6. Poke a small nail or metal fastener through each dot on both lines on the cardboard. Metal fasteners work well because the ends can be bent to hold the wire in place.
7. Using your question-and-answer sheet as a guide, turn over the cardboard and use a piece of wire to connect each “question” nail to the correct “answer” nail. Attach the wire by twisting the stripped ends of wire around each nail. Tape the wires in place if needed.
8. Twist one end of a piece of wire around one prong on the battery and tape it into place. Twist the other end around a large paper clip.
9. Take one end of the holiday lights, attach it to the other prong on the battery and tape it into place. Twist the other end of the lights around a paper clip. Safety note: The battery can become hot when wires are attached to it.
10. Time to test your circuit board! Find someone to answer your questions, and give them the two paper clips. Have them touch one paper clip to the “question” nail and the other paper clip to what they think is the correct “answer” nail. What happens when they get the correct answer? What happens when they get the wrong answer?

What's happening?

A basic circuit consists of three parts: a source, the conductor, and the use. A switch can be added to turn the flow of electricity on or off. In this activity, the electrical current begins at the source (battery), moves along a conductor (wires) and performs a use (turning on the holiday lights) that is regulated by the switch (paper clips).

The holiday lights will only turn on if the circuit is complete. That means the paper clips must touch two nails that are connected by a wire on the back of the cardboard. The challenge is to figure out what connection will complete the circuit – by getting the right answer – without seeing the wires on the back of the cardboard.

Extension

Write some new questions and answers and test other people. Remember to re-wire the back of the cardboard so the correct question and answer nails are connected.