PhET Faraday's Law

Task Steps:

• 1. Access the website above. You will need to download the simulation.

  2. Start with the pickup coil tab. Use the bar magnet to try to light the light bulb. Write down your observations.

  3. Try adjusting the number of coils and the area of the coils. Observe how this affects your ability to light the light bulb.

  4. Try changing the polarity and strength of the magnet. Observe how this affects your ability to light the light bulb.

  5. Observe the movement of electrons inside the coil. Record the relationship between the movement of the magnet and the movement of the electrons.

  6. Try to keep the light bulb continuously lit.

Analysis:

• 1. Describe how you were able to light the light bulb.

  2. Describe the factors that led to a brighter light bulb.

  3. Describe how the motion of electrons in the coil depended on the motion of the magnet. Discuss both approaching and moving away from the coil, and explain the movement of electrons in terms of the changing magnetic flux.

  4. A student makes the following statement: “When a magnetic field is increasing inside a coil of wire, electrons flow into the wire.” Do you agree with her statement? Cite evidence to support your argument.

Motors and Generators

• 1. Click on the generator tab in the simulation.

  2. Turn on the flow of water. Observe how this affects the electrons in the wire and the brightness of the bulb.

  3. Change the flow rate of the water. Observe how this affects the electrons in the wire and the brightness of the bulb.

  4. Change the number of loops. Observe how this affects the brightness of the bulb.

  5. Change the area of the loops. Observe how this affects the brightness of the bulb.

Analysis:

• 1. Describe why the bulb lights up when the magnet spins. Refer to your observations from the pickup coil tab.

  2. Describe the effect of the flow rate of water on the brightness of the bulb. How is this similar to what you observed in the pickup coil tab?

  3. Describe how the number of loops and area of the loops affected the brightness of the bulb. How is this similar to what you observed in the pickup coil tab?

  4. Compare the flow of electrons in this system to the flow of electrons in a circuit powered by a battery.

  5. Scientists have created the names alternating current and direct current to describe the two most common ways of causing electrons to flow. Which name do you think applies to the spinning magnet generator and which name applies to a battery powered circuit? Cite evidence to support your answer.

  6. Most people assume that a generator creates electricity. Are they correct? Use evidence from the simulation to support your argument.

Transformers

• 1. Click on the tab titled transformer.

  2. Attempt to light the bulb using the DC circuit.

  3. Change the bulb to a voltmeter and repeat your actions from step two. Observe the direction of voltage relative to the motion of the DC circuit.

  4. Change the DC circuit to an AC circuit. Again, attempt to light the bulb.

  5. Change the bulb to a voltmeter and repeat your actions from step four. Observe the direction of voltage relative to the motion of the AC circuit.

  6. Change the number of loops and the area of the loops and observe the way they interact with the AC and DC circuits.

Analysis:

• 1. Describe the difference in how the DC circuit was able to light the bulb vs the way the AC circuit was able to light the bulb. Describe why you think this is happening.

  2. Describe how the number of loops and area of loops affected the amount of current induced in the coil with the bulb.

  3. Is the current that we receive from a power plant the result of a battery or the result of a spinning magnet? Why do you think so? What advantages would one have over the other?

  4. Power plants typically generate voltages of about 25,000 volts. The electrical outlet in your home is rated at 120 volts. How do you think the power plant is able to lower the voltage in the wire between the generator and your house? Cite evidence from the experiment to support your claim.