Download Magnetism - Practice - Little Miami Schools

Name: ________________________________________________ Class Period: __________
Magnetism - Practice
1. What area of a magnet has the strongest magnetic effect?
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2. How can two magnets demonstrate force?
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The diagram below shows two magnets. Use the diagram to answer the questions
below in the space provided.
3. Are these magnets attracting or repelling each other? How can you tell?
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4. What would happen if the magnet on the left were turned around, so that its north pole
faced the north pole of the other magnet?
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Use the word bank to complete each statement for questions 5-8.
magnet
magnetism
magnetic force
magnetic pole
5. Any magnet has two ends, each one called a(n) _______________________________.
6. A(n) ______________________________ is any material that attracts iron and materials
that contain iron.
7. The attraction or repulsion between magnetic poles is __________________________.
8. _____________________________ is the attraction or repulsion of magnetic materials.
William Gilbert and the Science of Magnetism
Sir William Gilbert lived in England in the 1500s. He is remembered today for his investigations
into electricity and magnetism. In fact, he is sometimes credited with founding the science of
magnetism. He published descriptions of his many investigations in a book called De Magnete
or “On the Magnet.” In this book, he described carrying out many investigations using
lodestone in the shape of a sphere, or “little Earth.” Through his experiments, Gilbert became
the first person to describe magnetic attraction in terms very similar to the way modern
scientists describe a magnetic field.
Gilbert was the first to use the terms magnetic pole and magnetic force. He showed through
experimentation that a magnet exerts a force through a distance – a force that does not involve
touching. He showed that the strength of a magnet could be increased if pieces of soft iron
were added at the magnet’s poles. He also showed if an iron magnet is red hot, the magnet
loses its magnetism. Another notion he advanced was the Earth itself is a giant magnet. This is
an idea that modern scientists know to be true.
9. When did Sir William Gilbert live and what is known for?
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10. What book did he publish on magnetism?
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11. What did Gilbert show about magnetic force?
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12. What did he prove about magnets and heat?
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13. What notion about Earth did he advance that has proven true?
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If the statement is true, write true. If the statement is false, change the underlined word
or words to make the statement true.
14. _______________ Any material that exerts a magnetic force is considered a magnet.
15. _______________ Like all other forces, a magnetic force is a(n) gravitational force.
16. _______________ The area(s) between the poles of a magnet has the strongest effect.
17. _______________ Magnets attract wood and materials that contain iron.
18. _______________ When freely swinging, one end of a magnet always points east.
19. What is a magnetic field?
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20. Describe the magnetic field of a south-south pole arrangement.
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21. In what ways are Earth and a bar magnet alike?
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22. Draw a magnetic field around the illustration of the bar magnet shown here.
Magnetic Properties of Elements
Ferromagnetic materials are made up of regions known as domains. Within each domain, the
magnetic fields of all the atoms are lined up in the same direction. When exposed to a
magnetic field, the domains tend to line up with the field. Due to the existence of domains,
ferromagnetic materials are easily magnetized. Their ease of magnetization is represented by
a large whole number. (This number is a ratio. It has no units.)
Paramagnetic materials do not have magnetic domains, and their atoms tend to line up
individually with a magnetic field. For this reason, paramagnetic materials are much more
difficult to magnetize than ferromagnetic materials. Their ease of magnetization is represented
by very small numbers.
Diamagnetic materials have no magnetic domains. Therefore, their atoms do not easily align
with a magnetic field. Their ease of magnetization is represented by very small numbers.
However, they are different from paramagnetic materials because their atoms align in a
direction opposite to the magnetic field.
Material
Ease of Magnetization
Iron
Silver
Cobalt
Magnesium
Aluminum
Chromium
Nickel
Gold
Approx. 1,000
-20 millionths
Approx. 170
13 millionths
17 millionths
180 millionths
Approx. 80
-28 millionths
23. Which materials are ferromagnetic? Explain.
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24. Which materials are paramagnetic? Explain.
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25. Which materials are diamagnetic? Explain.
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Use the illustration below to answer questions 26 and 27.
26. What kind of magnets are shown in the figure above?
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27. Assuming the batteries are the same, which magnet do you think is stronger, A or B?
Explain your answer.
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28. What is a solenoid?
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29. What are the four ways to make an electromagnet stronger?
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30. How can a magnetic field be turned on or off?
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31. How can a magnetic field have its strength changed?
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Three electromagnets are illustrated in the diagram below. Use the diagram and your
knowledge of science to answer questions 32 and 33.
32. Will the electromagnet labeled A or B produce a stronger magnetic field? Explain.
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33. Will the electromagnet labeled B or C produce a stronger magnetic field? Explain.
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34. A crane in a junkyard may have an electromagnet to lift heavy metal objects. Explain how
electricity and magnetism work in an electromagnet so that a crane can lift heavy metal
objects.
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