This page last changed on Oct 11, 2007 by ehazzard.

### Discovery question

How do you use electricity to light up a bulb?
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Build a circuit to light a bulb with a battery.

### Engage

Electric current is created when electric charges move along a wire. This electric current is very useful because it can move energy from one place to another and do many valuable tasks.

Think of an example in your house for each of these tasks:

• Electricity produces light.
• Electricity produces heat.
• Electricity makes something move.
• Electricity produces sound.

### Materials

• AA or D size battery
• rubber band
• 2 pieces of wire about 10 cm long
• holiday light
 note to teacher: Use a string of holiday lights that has been discarded because one of them burned out. Use the kind with two wires stranded together, not three. Prepare each holiday light by stripping the ends of the wires.

### Explore

Batteries push electric charges through a circuit. They store electrical energy, and the current carries that energy to such things as lights, heaters, and motors.

Every battery has a positive end and a negative end. At the positive end there are extra positive electric charges, and at the negative end there are extra negative charges. Look at your battery and identify the positive and the negative ends. How do they look different? How can you tell them apart?

To work, electric devices need a circuit, which is a loop that allows the current to flow in a continuous circle.
Here is a picture of a light bulb and a battery. Using the pencil tool, draw where you think you should run wires to make the bulb light up.

 DRAWING TOOL WITH BACKGROUND IMAGE: BATTERY AND HOLIDAY LIGHT WITH TWO WIRE CONNECTIONS

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Experiment with the holiday bulb, the wires, and the battery to make a circuit that lights up the bulb. If you have trouble, click on the for suggestions.

 need thoughtful scaffolding here

### Explain

Draw a picture of your circuit.

 DRAWING TOOL
 scaffolding could include specific instructions of what to draw, ie draw the battery and the bulb. Draw in the wires to show how they are connected.

When your drawing is complete, draw a red line in a loop to show the path of your circuit.

### Elaborate

Draw a picture of how you can use your circuit to test whether a material allows electric current to flow.
DRAWING TOOL
Now test several materials and record your results. For example, try a paper clip, a plastic pen, a penny, or a wood pencil.
Materials that allow electricity to flow are called conductors. If they don't allow electricity to flow, they care called insulators.
TABLE
Material Conductor Insulator
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line
line
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### Evaluate

Explain why electrical devices such as lights and appliances need two wires, not just one.