MAGNETS OF MAGNESIA

You may have wondered about magnets at one time or another. From where do they come? Greek scientists visiting Magnesia, a town in present day Turkey, noticed that certain rocks found in the area are attracted to pieces of iron. They referred to this attraction as “magnetism,” since it occurred in Magnesia. What are magnets? Why are some materials magnetic? In this investigation you will determine why certain materials are magnetic.

Objective

When you have completed this investigation you should be able to analyze magnetic domains in order to explain the property of magnetism.

Materials (per group)

paper clips

bar magnet

metal scissors

Activity 1: Amazing Scissors

  1. Read the procedures, “Amazing Scissors.”

AMAZING SCISSORS

A.  Obtain materials from your teacher.

B.  Place a handful of paperclips on your table.

C.  Hold the scissors above the paperclips.

D.  Record your observations in the “Initial Observation” column of Chart 1, “Magnetic Observations.”

E.  Stroke the scissor blades in the same direction several times using the bar magnet.

F.  Repeat step C.

G.  Record your observations in the “After Stroking” column of Chart 1, “Magnetic Observations.”

H.  Strike the scissors on the table several times.

I.  Repeat step C.

J.  Record your observations in the “Final Observation” column of Chart 1, “Magnetic Observations.”

  1. Reread “Amazing Scissors” and highlight the verbs.
  2. Conduct the investigation.

CHART 1

MAGNETIC OBSERVATIONS

INITIAL OBSERVATIONS / AFTER STROKING / FINAL OBSERVATIONS
The paper clips were not affected by the scissors. / The paper clips are attracted slightly to the scissors. / The paper clips were not affected by the scissors.

4.  Brainstorm with your partner possible explanations for what you observed in “Amazing Scissors.”

1. The scissors were not magnetized at the beginning.

2. Stroking the scissors with a magnet turned the scissors into a magnet.

3. Banging the scissors on the table destroyed the magnetism.

Activity 2: Pre-Reading

Read each statement. If you agree with the statement, place a “√” in the “Agree” column. If you disagree with the statement, place a “√” in the “Disagree” column. If you are not sure, place a “?” in both columns.

Agree Disagree

1.  The magnetic properties of a material depend upon the structure of its atoms.

2.  A bar magnet will have all or most of its domains facing the same direction.

3.  A non-magnetized piece of iron cannot become magnetized because

the domains in the iron are fixed.

Activity 3: During Reading

  1. Read “Inside a Magnet” on pages 14-17 in Prentice Hall: Science Explorer, Electricity and Magnetism.
  1. Refer to the predictions you made in Activity 2. Based on what you have read, determine if your predictions were correct or incorrect. If you now believe the statement to be correct, place a √ in the “Agree” column. If you think the statement is incorrect, place √ in the “Disagree” column. Justify your choice with support from the text.

Justification:

Agree Disagree

1. Magnetic properties depend on the magnetic fields of atoms.

X

2. If the domains are lined up then they all work together creating a magnet.

X

3. In some metals you can line up the domains creating a magnet.

X

Activity 4: After Reading

  1. Study Figure 1, “Sample Materials.”

FIGURE 1

SAMPLE MATERIALS

SAMPLE 1 SAMPLE 2

Nonmagnet Magnet

  1. Explain what the arrows in each sample in Figure 1, “Sample Materials,” represent. Justify

your response using evidence from the reading.

The arrows represent magnetic domains. A domain is a cluster of billions of atoms that have their magnetic fields all in the same direction.

9.  Label sample 1 and sample 2 on Figure 1, “Sample Materials,” as either a magnet or a non-

magnet. Justify your response using information from the reading.

Sample 1 is a nonmagnet because the domains point in random directions. Sample 2 is a magnet because all of the domains are aligned in the same direction.

Analysis

1.  Draw the domains as they would appear in the metal scissors from the “Amazing Scissors Investigation” for each situation.

2.  Explain why the scissors in “Amazing Scissors” can become magnetized for a short period of time. Justify your response using information from the investigation. Mention the domains.

EEM - 101