## Simple Electric Circuits

Science Process Skills
• observing
• communicating
• comparing

Materials (per group)
• D-cell battery
• 2 strips of aluminum foil, about 1/2 inch wide by 5-6 inches long
• flashlight bulb (about a 3 volt rating)

Doing the Activity
1. Look at your battery. What differences are there between the two ends?
2. Which end is positive (+) and which end is negative (-)?
3. Take your battery, light bulb, and one strip of aluminum foil and try to connect them so that the bulb will light. Try as many different ways of connecting them as you can.
4. Draw your arrangements and mark the ones that worked.

Reflecting
• Which circuits that you drew caused the light bulb to light?
• Why do you think the other circuits did not cause the bulb to light up?
• Is there current flowing through the battery?

Applying
What do you think happens when one bulb in a string of Christmas lights is defective?

What's Happening
You have experimented with electrons moving in materials in a particular direction. This is what makes electric current. Electrons can move more easily in some materials than in others. When there is a path for electrons to move in a loop, we have a circuit. If the path of the current is interrupted, we have a break in the circuit and current cannot flow through the wire. When you switch off your light at bedtime, you are putting a break in the circuit. When you turn on the switch, you close the break, completing the loop for the current to flow, and the light bulb glows. If there is more than one path for the current, some of it will go through each path.

More Challenges
• Connect two bulbs to the battery with foil going from one end of the battery to bulb 1, then to bulb 2, and back from bulb 2, to the other end of the battery. What do you notice about the brightness of the bulb? (The bulbs are in series in this arrangement).
• Now connect the ends of the battery to bulb 1 so it lights up. Do the same with bulb 2. Now do both at the same time. What happens to the brightness? (The bulbs are in parallel in this arrangement).
• What is the difference in the current through the bulbs in series and in parallel?

Activity Source
"Funtivities: Hands-on Science and Math." Iowa State University Program for Women in Science and Engineering. Extension Distribution Center (515) 294-5247, order # 4H-952 for grades 4-5, #4H-952LDR for grades 4-5 leader's guide, #4H-953 for grades 6-8, #4H-953LDR for grades 6-8 leader's guide.

IOWA STATE UNIVERSITY
University Extension

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