Download Magnetic Domains

Physics: Magnetism WebQuest
Name
Directions: Go to my website and click Magnetism Webquest. Use the information found at the website
to answer the following questions.
http://www.ndt-ed.org/EducationResources/CommunityCollege/MagParticle/Physics/Magnetism.htm
Magnetism
1. What is a magnetic field?
A space where there is a charge of energy
2. What is a magnetic pole?
Location where a magnetic field can be detected
3. What is a dipole?
A magnetic pole at 1 end and on the opposite end an opposite pole. N on one end and S on
the other
4. Based on your reading and the principal of dipoles, explain what you think will happen if the
magnet shown below is cut in half.
Answer the question___________________________________________
N
S
Source of Magnetism
5. What produces a magnetic field?
Electrons carrying a negative charge as they move through space
6. Define magnetic moment.
The strength of the field
7. How can a magnetic field be detected?
It can be detected by using a compass
Click the “next” button.
Diamagnetic, Paramagnetic, and Ferromagnetic Materials
8. Why are unpaired electrons more significant than paired electrons in terms of magnetic
properties?
Paired electrons will not cause a magnetic field because their opposite spins around the nucleus
will cancel out
9. Distinguish the differences between diamagnetic and paramagnetic materials. Give examples of
each type of material.
Diamagnetic- examples: copper, gold, silver. Traits: weak, negative magnetic field
Paramagnetic-examples: magnesium, lithium, molybdenium. Traits: small, positive magnetic
field
10. What causes a material to be classified as “ferromagnetic”?
Exhibit strong attraction of magnetic fields and hold their properties after external field has
been removed
11. Name 3 examples of ferromagnetic materials. Nickel, iron, cobalt
Magnetic Domains
12. Define domain.-all the atomic dipoles are coupled together in a preferred direction
13. How do the domains differ in a magnetized state from those in an unmagnetized state? Sketch a
picture of domains in both states.
Magnetized domains align. Unmagnetized domains are random
Click the “next” button.
Magnetic Field Characteristics
14. Label the North and South poles on the bar magnet shown below. Draw the field lines (with
direction) both inside and outside of the magnet
.
North
South
15. List at least 3 general properties of magnetic field lines.
-Never cross
-same strength
-seek the path of least resistance
16. Consider your previous knowledge of electric field lines. Make at least one comparison between
electric field lines and magnetic field lines.
OMIT
Click the “next” button.
Electromagnetic Fields
17. What is another source of magnetic fields besides magnets?
An electric current in a wire generated magnetic field
18. Who made this discovery?
Hans Christian Oersted
19. Identify 3 characteristics he discovered about the nature of this field.
-direction of field depends on direction of current
- magnetic field was in a circular form around the wire
- strength of field strongest next to the wire and became weaker with distance
GO TO PHET: GENERATOR
Part 2: Go back to my website and click on the Magnet Simulation.
Click on the button Run Now and follow the directions below. You may need to download the simulation.
Bar Magnet Tab-General Magnetism
1. Click on the Bar Magnet Tab and you should see a bar magnet and compass on the screen. Please
note that the color red refers to North and white refers to South. Place the compass near the North
end of the magnet and observe which way the “red tip” of the compass points. Move the compass
to the South end and observe where the “red tip” of the compass points.
a. What conclusions can you draw about like poles?
b. What conclusions can you draw about unlike poles?
c. How are your observations similar to those previously made about like and unlike electric
charges?
Click the tap: Pickup Coil Tab-General Electromagnetic Induction
2. Set the number of loops to “1” and note what happens to the light bulb when
a. The magnet is not moving and is not in the loop
b. The magnet is not moving and is in the loop
c. The magnet is moving in and out of the loop
3. Does the speed of the magnet affect your results? If so, describe how.
4. Increase the number of loops to “3” and see if it affects your results in #2. If so, describe how.
5. What can you conclude about a magnetic field and electric current?
Electromagnet Tab-Is Electromagnetism Reversible?
6. You should see a battery attached to a loop of coil (an electromagnet) and a compass on the
screen. Move the compass around the electromagnet and describe the effect on the compass.
7. Draw a picture of the electromagnet and label the North and South poles.
8. Change the current source from DC to AC and describe the effect on the compass.
9. Observe the electrons in the AC current source and compare their movement to those in the DC
current source. Explain the difference between DC and AC in terms of electron movement.
Transformer Tab-Applications of Electromagnetism
10. We have learned from the reading and from the previous activity that an electric current can
create a magnetic field. Can this magnetic field generate electricity? In other words, can we use
electricity to generate more electricity? Move the electromagnet back and forth through the coil
and record what you observe.
11. Change the DC to an AC source. Note what happens even though the electromagnet is not
moving. Explain why the light bulb lights up even though the magnet is not moving.
Generator Tab-Putting it All Together
12. Click on the generator tab. Turn on the water faucet by sliding the tab on the faucet to the right.
Sketch the arrangement and describe what is happening.
13. Consider the following statement: A generator converts mechanical energy into electrical energy.
Do you agree or disagree with this statement? Write a one sentence response and give evidence to
back up your position.