Closed Circuits: A Battery, a Bulb, and a Paper Clip

By — John Wiley & Sons, Inc.
Updated on Dec 13, 2010

An electrical circuit is a closed loop that has a power source, wires to conduct current, and a load. The load is anything that consumes energy flowing through the circuit, such as a light bulb. Some circuits also have switches so the power can be easily disconnected. The power source can be an electrical outlet or a battery. In this activity you will create a circuit that lights a flashlight bulb.


D cell battery


Large paper clip

Flashlight bulb

Masking tape


  1. Examine the materials. A battery has a positive terminal and a negative terminal. When they are connected, current flows between the terminals. A paper clip is a material that will conduct electricity. A flashlight bulb uses current. Masking tape can be used to hold parts of a circuit together.
  2. Sketch a way to hook these materials together to make a complete closed circuit that will light the bulb.
  3. Use the materials and assemble the circuit you sketched out. If it does not work and the bulb does not light, redraw the circuit and try again.

Follow-Up Questions

  1. What was the job of the paper clip in your circuit?
  2. Did both the positive and negative ends of the battery have to be involved in the circuit?
  3. Does an electrical circuit have to be closed? Explain your answer.


  1. The paper clip conducted electricity.
  2. Yes.
  3. Yes. The circuit must be closed for the current to complete the trip from one terminal to the other.


Repeat this activity, but this time attempt to light two bulbs with your setup. If you find you need more batteries and/or paper clips, ask your teacher for permission.

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