Page 325 - Canadian BC Science 9

9-1A
Turn Out the Lights
Find Out ACTIVITY
In this activity, you will construct two different circuits and compare the flow of electrons in each circuit.
Safety
• Disconnect the circuit if any wires become hot.
Materials
• 1.5 V cell
• two 2.0 V light bulbs • switch
• connecting wires
What to Do
1. Using the materials provided, build circuit 1 as shown in the diagram.
2. Close the switch and observe the two light bulbs.
3. With the switch still closed, gently unscrew one of the light bulbs. Observe what happens to the remaining light bulb.
4. Replace the light bulb so that both bulbs are again lit. Gently unscrew the other light bulb. Again observe the remaining light bulb. Open the switch after you have made your observations.
Circuit 1
Circuit 2
5. Take circuit 1 apart. Build circuit 2 as shown in the diagram.
6. Close the switch and observe the two light bulbs.
7. With the switch still closed, gently unscrew one of the light bulbs. Observe what happens to the remaining light bulb.
8. Replace the light bulb so that both are again lit. Gently unscrew the other light bulb. Again observe the remaining light bulb. Open the switch after you have made your observations.
9. Clean up and put away the equipment you have used.
What Did You Find Out?
1. Imagine you are an electron leaving the negative terminal of the cell in circuit 1.
(a) Howmanywaysarethereforyoutotravel through the circuit in order to arrive at the positive terminal?
(b) Howmanylightbulbsdoyouhavetotravel through?
2. In circuit 1, when one bulb is removed is the other bulb still lit? Why?
3. Imagine you are an electron leaving the negative terminal of the cell in circuit 2.
(a) Howmanywaysarethereforyoutotravel through the circuit in order to arrive at the positive terminal?
(b) Inanyoneofthesepaths,howmanylight bulbs do you have to travel through?
4. In circuit 2, when one bulb is removed is the other bulb still lit? Why?
Chapter 9 Circuits are designed to control the transfer of electrical energy. • MHR 307