Electricity and Magnetism Web Quest
Name: ___________________________
Begin by visiting
http://micro.magnet.fsu.edu/electromag/java/faraday/
1. In the space below explain what you observed.
When you close the switch, a current passes through the first coil and the iron ring becomes magnetized. Note that
the compass in the second coil deflects momentarily and returns immediately to its original position.
2. What does the deflection of the compass indicate?
The deflection of the compass is an indication that an electromotive force was induced causing current to flow
momentarily in the second coil. When you open the switch, notice that the compass again deflects momentarily,
but in the opposite direction. The closing and opening of the switch cause the magnetic field in the ring to change:
to expand and collapse respectively. Faraday discovered that changes in a magnetic field could induce an
electromotive force and current in a nearby circuit.
3. Define:
Electromagnetic Induction: The generation of an electromotive force and current by a changing magnetic field is
called electromagnetic induction.
http://micro.magnet.fsu.edu/electromag/java/faraday2/
Read about Faraday's Magnetic Field Induction Experiment then use the mouse to move the magnet
inside the coil.
4. In the space below explain what you observed.
When you move the magnet back and forth, notice that the galvanometer needle moves, indicating that a current
is induced in the coil. Notice also that the needle immediately returns to zero when the magnet is not moving.
Faraday confirmed that a moving magnetic field is necessary in order for electromagnetic induction to occur.
5. What is necessary to induce a current in a nearby circuit?
When Michael Faraday made his discovery of electromagnetic induction in 1831, he hypothesized that a
changing magnetic field is necessary to induce a current in a nearby circuit. To test his hypothesis he made a coil
by wrapping a paper cylinder with wire. He connected the coil to a galvanometer, and then moved a magnet back
and forth inside the cylinder.
6. What does a galvanometer measure?
The galvanometer measures the current induced in the coil.
7. Analyze Faraday's Magnetic Field Induction Experiment and determine how it helped lead to the
development of modern day power plants. Please include examples and at least one diagram.
Michael Faraday built two devices to produce what he called electromagnetic rotation: that is a
continuous circular motion from the circular magnetic force around a wire. Ten years later, in 1831, he
began his great series of experiments in which he discovered electromagnetic induction. These
experiments form the basis of modern electromagnetic technology.
In 1831, using his "induction ring", Michael Faraday made one of his greatest discoveries electromagnetic induction: the "induction" or generation of electricity in a wire by means of the
electromagnetic effect of a current in another wire. The induction ring was the first electric transformer.
In a second series of experiments in September he discovered magneto-electric induction: the
production of a steady electric current. To do this, Faraday attached two wires through a sliding contact
to a copper disc. By rotating the disc between the poles of a horseshoe magnet he obtained a continuous
direct current. This was the first generator. From his experiments came devices that led to the modern
electric motor, generator and transformer.
Michael Faraday continued his electrical experiments. In 1832, he proved that the electricity induced
from a magnet, voltaic electricity produced by a battery, and static electricity were all the same. He also
did significant work in electrochemistry, stating the First and Second Laws of Electrolysis. This laid the
basis for electrochemistry, another great modern industry
Now go to:
http://www.energyeducation.tx.gov/energy/section_3/topics/where_does_electricity_come_from/c/inside
_a_generator_animation.html
Watch the short animation on electric generators and answer the following questions.
8. What does an electric generator do?
A generator is a device that converts mechanical energy into electrical energy by electromagnetic induction
- it "generates" (or creates) electricity.
9. Explain why the generator in the animation is considered an AC generator. Predict how an AC generator is
different then a DC generator.
AC Generator the coil rotates, it naturally produces an alternating current.
Prediction: DC generator would only produce direct current.
Now go to: http://electronics.howstuffworks.com/motor.htm
Watch the video (optional), read the page information then click “Next”
Read “Inside an Electric Motor” and complete the following.
10. What does a motor use to create motion?
A motor uses magnets to create motion
11. Explain what causes rotational motion in an electric motor.
On the other hand, the north end of one magnet will repel the north end of the other (and similarly, south will repel
south). Inside an electric motor, these attracting and repelling forces create rotational motion.
12. In the space below draw a diagram of an electric motor and label the 6 main parts.
Now go to: http://www.andythelwell.com/blobz/
Click “enter” and follow the directions on the web page. Note that there are 5 sections; each section has
an information portion, an activity and a quiz. Please complete all three for each section.
Now go to: http://education.jlab.org/vocabhangman/magnets_03/2.html
Click on “Basic Magnetism (9)” which is about ¼ of the way down the page under Electricity and
Magnetism heading. Complete the interactive hangman game. There are several questions so be sure to
click “next question”.
After you complete the hangman activity, visit:
http://micro.magnet.fsu.edu/electromag/java/transformer/index.html
Read all the information on the page then answer the following questions.
13. Briefly explain what transformers are used for.
Transformers are used to increase or decrease AC voltages and currents in circuits. The operation of
transformers is based on the principal of mutual inductance. A transformer usually consists of two coils of wire
wound on the same core. The primary coil is the input coil of the transformer and the secondary coil is the output
coil. Mutual induction causes voltage to be induced in the secondary coil.1
4. Compare and contrast a step up transformer and a step down transformer.
If the output voltage of a transformer is greater than the input voltage, it is called a step-up transformer. If the
output voltage of a transformer is less than the input voltage it is called a step-down transformer
15. Now change the voltage and winding levels and closely observe the changes in the input/output voltage. In
the space below, briefly summarize your observations.
The lower the voltage, the lower the amplitude.
Finally: Visit: http://ippex.pppl.gov/interactive/electricity/
Read the introduction then click on the right arrow.
Now read the information that follows and answer the questions below.
16. Define Electricity: The movement of charged particles.
17. Briefly explain what static electricity is? Charges that are not moving are static.
18. Now that you have explained static electricity, you are ready to try the balloon activity found on the site.
Why does the balloon stick to the wall? The balloon was able to stick to the wall because the balloon is now
holding a static charge (an excess of negative charge (electrons) from rubbing on the wool. Continue to click
on the right arrow.
19. Define Current electricity: electrons flowing the wires
20. What does a common circuit consist of? Cell, lamp, switch, and wires
(HINT) It is a good idea to bookmark this website at home so you may use it as a reference for
homework/studying
If you have finished early, you may visit http://www.wonderville.ca/v1/home.html
Click on energy street and design your own energy efficient city street.