Download PhET Electric Circuit Simulator

PhET Electric Circuit Simulator
Measuring Current and Voltage
Go to
http://phet.colorado.edu/simulations/sims.php?sim=Circuit_Construction_Kit_DC_Only
Measuring battery voltage:
1. Click on the battery on the side-bar and move it onto the construction area (blue).
2. On the “tools” options check the voltmeter.
3. Move the voltmeter under the battery and touch the red lead to the black (+) end of the battery
and the black lead to the grey (-) end.
What is the potential difference across the battery?
______________________
Simple Circuit:
4. Remove the voltmeter from the ends of the battery.
5. Make a simple (one loop) circuit consisting of battery, switch, wires and light-bulb.
6. Close the switch.
7. What do you think the potential difference (voltage) across the battery will be when it is
lighting the bulb? Make a prediction
Prediction: ___________________
8. While the bulb is lit, measure the voltage across the battery using the voltmeter. Remember
red on the positive side and black on the negative side.
Reading _________________
How does the voltage of the battery compare with its voltage when it is not lighting the bulb?
_________________________________________________________________________
9. Put the voltage leads on a wire but not across the battery or bulb. Measure the voltage.
Reading _________________
Why isn’t the reading the same as that read when the voltmeter was placed across the battery?
_________________________________________________________________________
10. Put the voltage leads across the bulb. Make sure that the red lead is on the positive side of the
bulb (connected to the black end of the battery). Measure the voltage.
Reading ______________
Compare the voltage across the bulb with that across the battery (part 8). Explain your
answer!
_________________________________________________________________________
_________________________________________________________________________
Measuring the current in the circuit:
11. Remove a wire in your circuit. (control-click or right-click on the wire)
12. In the tools menu check ammeter.
13. Click on the ammeter in the side-bar and place it where you removed the wire. Connect the
ends with wires to make a one loop circuit again. The bulb should light.
14. Record the current
Current Reading _________________
15. Check the “non-contact ammeter” in the tools menu. Place the cross hairs of this meter on
different wires at different points in the circuit.
Does the current reading change for different points around the circuit?
_____________________
Answer the following questions
1. What is the flow of charge in a circuit called? ______________________
2. What pushes the current through the circuit?
______________________
3. Why is there a voltage reading across the light-bulb when current is flowing through it?
______________________________________________________________________
4. A student measures the voltage across two 1.5 V batteries.
a) How many volts will the meter read? ___________
b) If the batteries are placed into a circuit with two light bulbs, what will the voltage across
the batteries read?
_______________________
Explain your answer
_______________________________________________________________________