Download LabSheetForSeriesAndParallelCircuits

Series and Parallel Circuits Lab Project
(Due Monday, December 14, 200)
Name:_____________________________________________
Date:___________________
Purpose: The purpose of this lab is to investigate the relationship between current and voltage in a series and parallel
circuits.
Hypothesis:
 I predict that adding more resistors or light bulbs in a series will cause the current in a circuit to ______________
(increase, decrease, stay the same, stop flowing) and the light bulbs will /will not (circle the right answer) glow
____________brighter / dimmer / the same / will stop glowing (circle the right answer) .

I predict that adding more resistors or light bulbs in a parallel will cause _______ (increase, decrease, no change) in the
flow of current and the light bulbs will /will not (circle the right answer) glow ____________brighter / dimmer / the same
/will stop glowing.
.
Directions:
1. Log on to your computer
2. Go to the following website:
http://phet.colorado.edu/index.php
3. Click the button that says “Play with sims…”
4. Click on the application that says Circuit Construction Kit (DC only). It should be the first box.
5. Click “Run now.”
You now have the raw material to create a circuit. Take a moment to look over the site and find all the different materials. To build
a circuit you will need several wires, a light bulb, a voltage source, a voltmeter, and a non – contact ammeter. Play with it to see
how to grab and manipulate these tools.
Click the reset button.
A. Series Circuits
1. Build a simple series circuit that consists of 6 pieces of wire, 1 light bulb, and 1 battery (voltage source). In order to
complete the circuit, the red circles at the end of each must overlap. Please note that the light bulb also has TWO circles.
Your circuit is complete and working when the light comes on and the blue dots begin moving.
2. Draw a picture of your circuit here.
3. Draw the schematic diagram of your circuit here (using circuit symbols legend).
4. What do you think that the moving blue dots represent?
5. Use the tools at the side to get a voltmeter and a non-contact ammeter. Put the voltmeter near the battery and place the
red tab at one end and the black at the other.
What is the voltage? __________
Place the ammeter crosshairs over the moving blue dots. What is the reading? _______
What does this tell us about the circuit?
6. Use the left button to play with the resistance and voltage of the battery. Make observations on how this changes the
readings on the voltmeter and ammeter. Record your observations below. Be sure to record the changes you made and
then the effects.
7. Click the advanced tab and alter the resistivity of the wire. Record your observations.
8. Draw the picture of your circuit here and next to it equivalent schematic diagram (using circuit symbols legend).
9. Write a statement that summarizes what you have just discovered about the relationship between current and resistance
in a series circuit.
Raise your hand and let your teacher check off your working series circuit.
1. Now, right click on one end of the light bulb and click on “Split Junction” popup option.
Record what happens with ammeter reading and voltmeter reading:
What is the voltage (voltmeter reading)? __________
What is the current (ammeter reading)?__________
Describe what happed with the flow of electrons.
2. Add another light bulb and close your circuit with another wire.
Record what happens with ammeter reading and voltmeter reading:
What is the voltage (voltmeter reading)? __________
What is the current (ammeter reading)?__________
3. Add another light bulb and close your circuit with another wire.
Record what happens with ammeter reading and voltmeter reading:
What is the voltage (voltmeter reading)? __________
What is the current (ammeter reading)?__________
4. Draw the picture of your last circuit here and next to it its equivalent schematic diagram
(using circuit symbols legend).
Click the reset button to begin working on a parallel circuit.
B. Parallel Circuits
1. Parallel circuits provide more than one path for electrons to move. Sketch below a parallel
circuit that includes 10 wires, 2 light bulbs and 1 voltage source.
Create this using the simulator tool. The blue dots will be moving and both lights will be on once the circuit is complete.
Draw the picture of your circuit here and next to it equivalent schematic diagram (using
circuit symbols legend).
Raise your hand so that your teacher can check off your parallel circuit.
2. Use the voltmeter and non-contact ammeter to measure electron flow and push.
Voltage:_______
Ammeter( in the main branch):______
Ammeter( in the branch with the bulb):______
How does this compare with your observations in the series circuit? Is this surprising?
3.
WHY or WHY NOT?
Alter resistance and voltage and record your observations below.
4. Now right click on one of the wires connected to a light bulb. Remove the wire and record your observations.
Does this affect the voltage, amperes, or visually change the appearance of the light bulb?
Voltage:_______
Ammeter:______
Replace the wire. Now remove one of the wires touching the voltage source. What
happened?
What is the difference between removing the first wire and the second? Why is this
significant?
5. Now, right click on one end of the light bulb and click on “Split Junction” popup option.
Record what happens with ammeter reading and voltmeter reading:
What is the voltage (voltmeter reading)? __________
What is the current (ammeter reading)?__________
6. Now add another branch with a light bulb.
Does this affect the voltage, amperes, or visually change the appearance of the light bulb?
Voltage:_______
Ammeter (in the main branch):______
Ammeter (in branches with light bulb)________
Draw the picture of your circuit here and next to it equivalent schematic diagram (using
circuit symbols legend).
C. Comparisons Series vs. Parallel Circuits
5. Create a second series circuit and record your observations about the two once they are side by side.
You may use the tool to play around. Create a circuit using a switch. Diagram your circuit below.
Record any observations below.
Raise your hand and show your working circuit to the teacher to receive extra credit points.
D. Conclusion
Your lab report is due Monday, December 14, 2009. It should contain:
1.
2.
3.
4.
What you did.
How you did it.
The results obtained.
Conclusion after testing your hypothesis.
What you did means what you measured, including a very brief description of the apparatus.
How you did it, means the experimental procedures used, including the type of equipment. It's useful to briefly
indicate the experimental set-up with picture of your circuit and schematic diagram just above the data table (Make
sure you use pencil and ruler). Your title page must include your name, your teacher’s name, be titled, and
dated
Results mean the final numerical results including units and errors.
Conclusion after testing your hypothesis means explain if your hypothesis was correct and what you found out while
doing your lab. All the results should be stated and summarized in a table, including the errors. Summarize the results
briefly in words and try to make some perceptive comments on what you learned and how to improve the experiment.
Series Circuit:
Number of
bulbs
Current [A]
Voltage [V]
Current
through bulb
#1[A]
Current
through bulb
#2[A]
Current
through bulb
#3[A]
1
2
3
Parallel Circuit:
Number of bulbs
1
2
3
Current (in the
main branch)
[A]
Voltage [V]
Current through
bulb #1[A]
Current
through bulb
#2[A]
Current
through bulb
#3[A]