Download PHET Magnetism

Names (BOTH Partners): __________________________________________________ Period: ______
PHET -- Electrical and Magnetic Forces
Standards
9-11 PS1G
Electrical force is a force of nature independent of gravity that exists between charged objects.
Opposite charges attract while like charges repel.
• Predict whether two charged objects will attract or repel each other, and explain why.
9-11 PS1H
Electricity and magnetism are two aspects of a single electromagnetic force. Moving electric charges
produce magnetic forces, and moving magnets produce electric forces.
• Demonstrate and explain that an electric current flowing in a wire will create a magnetic field around the wire
(electromagnetic effect).
• Demonstrate and explain that moving a magnet near a wire will cause an electric current to flow in the wire
(the generator effect).
Part I:
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Magnetism
Go to http://phet.colorado.edu
Click on : “Play with Simulations” (blue box)
Click on : “Physics” on the left side
Click on : “Electricity, magnets, and circuits”
Click on: “Magnets and Electromagnets” and “Run Now”
a.
Move the compass slowly along a semicircular path above the bar magnet until you’ve put it on
the opposite side of the bar magnet. Describe what happens to the compass needle.
b.
What do you suppose the compass needles drawn all over the screen tell you?
c. Move the compass along a semicircular path below the bar magnet until you’ve put it on the
opposite side of the bar magnet. Describe what happens to the compass needle.
d. How many complete rotations does the compass needle make when the compass is moved once
around the bar magnet?
e. Click on the electromagnet tab on the top left of the screen. Place the compass on the left side of the
coil so that the compass center lies along the axis of the coil. (The y-component of the magnetic field
is zero along the axis of the coil.)
f. Move the compass along a semicircular path above the coil until you’ve put it on the opposite side of
the coil. Describe what happens to the compass needle.
Names (BOTH Partners): __________________________________________________ Period: ______
g. Move the compass along a semicircular path below the coil until you’ve put it on the opposite side of
the coil. Describe what happens to the compass needle.
h. How many complete rotations does the compass needle make when the compass is moved once
around the coil?
i. Based on your observations, summarize the similarities between the bar magnet and the coil.
j. What happens to the current in the coil when you set the voltage of the battery to zero?
k. What happens to the magnetic field around the coil when you set the voltage of the battery to zero?
l. Play with the voltage slider and describe what happens to the current in the coil and the magnetic
field around the coil.
m. What is your guess as to the relationship between the current in the coil and the magnetic field?
Part II: Electric Circuits
1. Go back to the “Electricity, magnets, and circuits” simulators
2. Click on: “Circuit Construction Kit (DC Only)” and “Run Now”
Series Circuits: The current can only take one path
Names (BOTH Partners): __________________________________________________ Period: ______
a. 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.
Draw a picture of your circuit here.
b. What do you think that the moving blue dots represent?
c. 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?
d. Right click on the battery and adjust the resistance and voltage. 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.
e. Click the advanced tab and alter the resistivity of the wire. Record your observations.
Raise your hand and let your teacher check off your working series circuit.
Click the reset button to begin working on a parallel circuit.
Names (BOTH Partners): __________________________________________________ Period: ______
Parallel Circuits: The current can take more than one path.
a. Parallel circuits provide more than one path for electrons to move. Build a parallel circuit that
includes 10 wires, 2 light bulbs and 1 voltage source. The blue dots will be moving and both
lights will be on once the circuit is complete. Raise your hand so that your teacher can check off
your parallel circuit. Sketch your circuit below:
b. Use the voltmeter and non-contact ammeter to measure electron flow and push.
Voltage:_______
Ammeter:______
How does this compare with your observations in the series circuit? Is this surprising? WHY or
WHY NOT?
c. Alter resistance and voltage and record your observations below.
d. Now right click on one of the wires connected to a light bulb. Remove the wire and record your
observations.
e. Does this affect the voltage, amperes, or visually change the appearance of the light bulb?
f. Replace the wire. Now remove one of the wires touching the voltage source. What happened?
g. What is the difference between removing the first wire and the second? Why is this significant?