1. Circuits
Series or Parallel

2. Circuit Challenge # 1 Circuit Challenge # 2
Materials: 1 battery, 2 light bulbs, as many wires as you need
Build a circuit so that if one light bulb is removed the other goes out.
Circuit Challenge # 2
Materials: 1 battery, 2 light bulbs, as many wires as you need
Build a circuit so that if one light bulb is removed the other stays on.

3. Circuit Symbols
Wire:
Switch:
Light Bulb:
Resistor:
Battery: - +

4. Possible Circuit 1 What will happen when I close the switch?
The light bulb lights up!

5. Current
Moving electrical charges are called current.

6. *Note: no current flows unless the switch is closed.
Series or Parallel?
Make a current loop.
Trace the current from the positive side of the battery to the negative side. *
*Note: no current flows unless the switch is closed.

7. Series or Parallel? Make a current loop. Series Parallel
Trace the current from the positive side of the battery to the negative side.
Series
Circuit elements are on the same current loop.
Parallel
Circuit elements are on different current loops.

8. Series or Parallel?
Are the switch and the light bulb on the same current loop?
 YES
Are the switch and light bulb in series or in parallel?
 SERIES

9. Remember
Light bulbs only light up if there is current flowing through them.

10. Example Circuit 2 A B Switch A Switch B
What will happen when I close Switch A?
What will happen when I close Switch B?

11. Series or Parallel? A B Switch A Switch B
Are Switch A and Light Bulb A in series or in parallel?
Are Light Bulb A and Light Bulb B in series or in parallel?

12. Example Circuit 3

13. Why?
Current takes the path of least resistance.

14. Circuit Challenge # 3
Make a circuit with three light bulbs: A, B, & C.
Truth Table A B C
A is unscrewed
off on
B is unscrewed
C is unscrewed