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Electricity Simulation
Electricity CD-ROM
Activity 2
Introduction
An electric circuit is a pathway of wire from a power source to the “load,” or object that uses electricity, and back
to the power source. The power source can be a battery, a small electromagnetic generator, or a large power station.
The current is the flow of electrical charge through the circuit. The amount of current that flows through the circuit
depends on the voltage of the power source and the load that is connected to the wire using electricity. A circuit also
has a switch. An open switch prevents the flow of electrons. A closed switch closes the circuit and allows electrons
to flow through it. .
Electricity can flow directly in what is called direct current, or DC. This means that the electricity only flows in
one direction. A disadvantage of direct current is that the wire in the circuit acts as a resister and decreases the
available current. Over a short distance, this is not noticeable. Alternating current, or AC, moves electrons first
one way and then the other through the wires. This allows electrical energy to be transmitted long distances without
losing current.
Thomas Edison used direct current in his early efforts to provide electricity to office buildings. Nikola Tesla was
able to show that AC current was better. Today, homes are wired with 120-volt alternating current. Batteries are
used to provide direct current to flashlights, radios, tape players, cameras, and many other small portable devices.
Directions
Use the Electricity simulation to learn more about circuits. After identifying the parts of a circuit, explore the
differences between series and parallel circuits.
Procedures
1. From the Main Screen select the Simulations icon. Then click the Electricity icon.
2. Click on the Start Here button and read the text. If you need more information, click and read the
Background. Close the window when you are done.
3. From the pull-down menu under Strength of Magnet, select Small. Under Number of Turns of Coil in
Wire, select Many. Under Speed to Crank Generator, select Fast. These choices create an electricity
generator.
4. The variables that test the current are How To Wire Light Bulb and Wattage Of Light Bulb. You have three
choices under each, giving you nine tests on the generator created above. Start with 1 Bulb, and a light bulb
that is 35 watts. Click on the Start Generator button.
5. Observe the coils turning, the reading on the ammeter, and the light bulb.
6. What did you do to close the switch? What happened when you closed the switch?
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7.
Repeat this with one 60-watt bulb, then a 100-watt bulb. Describe your observations. What changed when
different light bulbs were tested?
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8.
Do you think this circuit is using DC current or AC? Why?
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Procedures (continued)
Part 2
Most circuits have a load of more than one object. These objects or electrical devices can be wired in a series or in a
parallel circuit. When connected in series, there is a single pathway for the electron flow. When the switch is closed,
the current flows through all the objects equally. But a break anywhere in the circuit stops the flow. Strings of party
lights are often in series. When one bulb burns out, all the other lights stop working because the circuit is now open
and there is no current flowing.
A parallel circuit uses branches of wire so that each object is on its own branch. The current flows equally through
all the branches, but each has its own separate path for the electron flow. This allows the current to continue
flowing even when one device is turned off or stops working.
9. Below are two circuits. Identify which is series and which is parallel. On each, draw line to the power source,
load, switch, and wire.
Power
source
Load
Switch
Wire
_________ circuit
________ circuit
10. Return to the simulation. From the pull down menu under Strength of Magnet, again select Small. Under
Number of Turns of Coil in Wire, select Many. Under Speed to Crank Generator, select Fast. Use this
generator to test the differences between series and parallel circuits.
11. Complete the table below by combining choices under Wattage of Light Bulb and How to Wire the Light
Bulb. Under comments, record anything that is different about the circuit, the wire, or the bulbs.
Circuit
Ammeter
reading
Other observations
35-watt series
35-watt parallel
60-watt series
60-watt parallel
100-watt series
100-watt parallel
12. Summarize the differences you observed between series and parallel circuits.
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