Download How do magnets interact with other

Learning Cycle I: How do magnets interact with other things?
Engaging Your Prior Knowledge
Indicate whether you agree with each of the statements below and explain your reasoning.
___ Agree
____ Disagree
____ It depends…
___ Agree
____ Disagree
____ It depends…
___ Agree
____ Disagree
____ It depends…
___ Agree
____ Disagree
____ It depends…
Magnets attract
metals.
Magnets repel other
magnets.
Magnets can attract
and repel through
other things.
Magnets must touch
objects in order to
pick them up.
We’ll share our answers with the whole group before moving on.
Exploring Your Ideas
Obtain two magnets and a set of objects for this investigation (see bag in supply box).

What happens when you bring magnets near each other and near other objects (without touching)? Does the
distance appear to affect the interaction?

How do the different areas (top/bottom/sides/ends) of the magnets interact with each other and/or other
objects? Does it matter which way the magnets are oriented/ facing?

Can a magnet attract an object through other materials? Does it matter what material? Does it matter how
thick the material is? How heavy the object is?

How do objects that are not magnets interact with each other?
Developing Explanations from Evidence
Sort the magnets and objects into three groups based on how they interact with items in the same group and items in
the other groups as shown below. For example, group 1 objects attract and repel each other, attract objects in group
2, and do not interact with objects in groups 3.
INTERACTIONS
Group 1:
Group 2:
Group 3:
Group 1:
attract and repel
attract
no interaction
Group 2:
attract
no interaction
no interaction
Group 3:
no interaction
no interaction
no interaction
What do you notice about the kinds of objects you sorted into each group? How are they alike? Different? What types of
materials and interactions are unique to each group?
Scientists refine their ideas based on new evidence. Revisit your responses from the ENGAGE portion of the
lesson—are there any answers you’d like to revise in light of your new evidence?
Check with your instructor before moving on.
We’ll use interactions to distinguish between three categories of materials:
 Magnets (group 1) attract and repel each other and certain types of metals.
 Ferromagnetic objects (group 2) interact with magnets by attraction. These include:

Nonferromagnetic objects (group 3) experience no interaction with magnets.
How could you use this as a basis to identify an unknown object?

Object ‘X’ attracts objects in group 1, but doesn’t interact with objects in Group 2 or 3. In which group
would you classify this object? Why?

You observe object “Z” repels an object in Group 1. Can you classify this object using only this
observation? Explain.

Object “Q” doesn’t interact with items in Group 2 and 3. Can you classify this object based on these
observations? Explain.

A friend claims a ring is made of silver, yet you notice it is attracted to a magnet. Should you trust the
person who sold it to her? Why or why not?
Extending your Thinking
Hold a paperclip above one of the bar-shaped magnets and slowly move it back and forth above
the magnet from one end to the other. Now hold the magnet above the paperclip and slowly
move it from one end to the other. Record what you observe (feel/see).
 Does the magnet equally attract all parts of the paperclip? Is the paperclip equally
attracted to all parts of the magnet? Explain and/or make a drawing to show where
you found any variations in the strength of the interaction:
Suppose you were given two identical-looking metal bars. Only one of them is a magnet, however.

How could you tell which is the magnet? Explain what materials you would use.

Suppose you had no access to other materials—only the two bars. Could you still find a way to identify which
was the magnet? Explain.
Check with your instructor before moving on.
Evaluate Your Understanding
PLEASE ANSWER INDIVIDUALLY, RATHER THAN WORKIGN WITH YOUR GROUP!
A student is studying the behavior of 3 bars.
The student observes that:
 1 attracts 2
 1 attracts 3
 Object 2 and 3 do not interact
#1
#2
#3
Classify the three bars as magnetic, ferromagnetic, or nonmagnetic. Explain your reasoning and use evidence from
your earlier explorations to support your answer. If you cannot classify the objects on the basis of the information
given, explain why not and describe what you would need to do to classify the objects.
The student then examines another bar, which is found to attract bar #1. From this observation alone, can the bar be
classified? Explain.
Check with your instructor before moving on.
Learning Cycle II: What are different parts of a magnet?
Engaging Your Prior Knowledge
Two students are discussing different parts of a magnet.
Student #1: The strongest parts of the magnet are the ends of a magnet.
Student #2: I think that the S can also be at other places on a magnet—like the middle or top/bottom.
With which, if either, student do you agree? Explain.
We’ll share our ideas as a whole group before moving on.
Exploring Your Ideas
In the last learning cycle, you found that the interactions between a bar magnet and paperclip were stronger in some
parts than others. Repeat that exploration using different shaped magnets. Place a piece of tape or sticker on the
part(s) of each magnet you believe to be the strongest. Be sure that each member of your group observes each magnet
and agrees with the parts you identify as the strongest. Make a sketch below of the magnets and indicate where each
was strongest:
Developing Explanations from Evidence
The strongest parts of a magnet are referred to as “poles”.
 Are the poles of a magnet always located at the “ends”? Explain.
 Do any of the magnets you observe have just one pole?
 Do any of the magnets you examined have more than two poles?
Check with your instructor before moving on.
Extending Your Thinking
Your instructor has provided you with iron filings enclosed in a case to use in examining the location of the poles of your
magnet. Use these for each of the different shaped magnets you placed tape on in the previous activity—do the filings
cluster in the same locations that you placed the tape? Make a sketch below of what you observe for two magnets with
poles in differing locations.
Evaluating Your Understanding
ANSWER INDIVIDUALLY THEN COMPARE YOUR IDEAS AS A GROUP
Imagine a magnet is discovered that appears to have three poles. What would you expect the iron filings pattern to look
like in this case? Make a sketch below.
Check with your instructor before moving on
Learning Cycle III: What kind and how many magnetic poles are there?
Engaging Prior Knowledge
In the last lesson, you marked the ‘poles’ of several magnets. How do magnetic poles on one magnet interact with
magnetic poles of other magnets? Take a moment to jot down your own ideas about this before discussing with your
group.
Share and discuss your answers with your group before moving on.
Exploring Your Ideas
For this activity, you will use a ‘test box’ with spots labeled A, B, C, etc. and a magnet with poles labeled ‘X’ and ‘O’. Fill
in the chart below to indicate how the poles interact with the test spots A and B only:
Test Spot A
Test Spot B
Pole X
Pole O
Repeat your test with your magnets, using the poles you marked with tape. If the pole interacts identically to one of the
poles of the first magnet you used, then mark the tape with the same letter as that pole (X or O).
 Based on your data, how many different types of magnetic poles ends did you identify?

It is possible there is some other type of magnet end that is different from those you identified above?
What evidence would you expect to find if this were the case?
Developing Explanations from Evidence
Use the same magnets from the previous activity (with the poles still marked ‘X’ and ‘O’), answer the following:
 How do magnets ends with the same labels (XX or OO) interact with each other?

How do magnet ends with different labels (XO or OX) interact with each other?
Extending Your Thinking
For this activity, you will need a test box with spots labeled A, B, C, D, E, and F. Each group members should use a
magnet with poles labeled ‘X’ and ‘O’. Place each pole near the test spots and record the interactions you observe
below.
Test Spot
Interaction with Pole ‘X’
Interaction with Pole ‘O’
A
B
C
D
E
F
Based on the interactions you observed:
 Which test spots conceal magnets? How do you know?

Which test spots conceal objects that are ferromagnetic? Explain.

Can you distinguish between a test spot that conceals a nonferromagnetic object vs. nothing? Why or why not?
Consider the following: A student makes the observations recorded below using a test box with spots labeled
PQRS and two magnets with poles labeled A and B.
Test spot P
Test spot Q
Test spot R
Test spot S
Pole 1A
Repel
Attract
Attract
Repel
Magnet 1
Pole 1B
Attract
Attract
Attract
Attract
Pole 2A
Attract
Attract
Attract
Attract

Which poles of Magnet 1 and Magnet 2 are alike? Opposite?

Which of the test spots are magnetic, ferromagnetic, or nonmagnetic?
Magnet 2
Pole 2B
Repel
Attract
Attract
Repel
Check with your instructor before moving on.
Evaluating Your Understanding
Obtain the ‘floating magnet’ demonstration from your materials box. How does this work? Explain below in terms of the
poles of the magnets. (Label the picture shown)
Check with your instructor before moving on.
Learning Cycle IV: What should we call the types of magnetic poles? Why?
Engaging Your Prior Knowledge
Two different ideas about what to call magnetic poles have been proposed—“north and south” versus “positive and
negative”. How would scientists resolve this? Would they vote? Stage a debate? Ask the most famous scientist his/her
opinion? Or ask their science teacher?  Explain how you think scientists would handle this disagreement.
Share and discuss your answers with your group before moving on.
Exploring Your Ideas
In this activity, we’ll use a device called an electroscope, a scientific instrument that can be used to detect positive and
negative charges. This will help us determine whether the poles of a magnet are positive and negative. We have some
electroscopes already built, but you can also use the internet to search for online instructions and videos if you
encounter problems.
You have been provided several nonmagnetic materials (plastic, cloth, balloon, etc.) and magnets at your table. Use the
space below to record your observations as you explore the following questions:
 What happens when you bring the poles of the magnets near the electroscope?
 What happens when you bring each of the other objects near the electroscope?
 What happens when you rub the other objects together then bring the objects near the electroscope? (Try this
with various items and magnets.)
Check with your instructor before moving on.
Developing Explanations from Evidence
All physical objects are made up of atoms. Inside an atom are smaller particles called protons, electrons and neutrons.
The protons are positively charged, the electrons are negatively charged, and the neutrons are neutral. While the
protons and neutrons reside in the nucleus, or center, of the atom, the electrons are found outside of the nucleus.
Therefore, all things are made up of charges. Opposite charges attract each other (negative & positive). Like charges
repel each other (positive & positive or negative & negative). Most of the time positive and negative charges are
balanced in an object, which makes that object neutral, however, these charges can sometimes become imbalanced (an
object with more negative charges than positive charges will have a “negative charge” and vice versa).
Static electricity is the result of an imbalance between negative and positive charges in an object. The rubbing of certain
materials against one another can transfer negative charges, or electrons. For example, if you rub your shoe on the
carpet, your body collects extra electrons and becomes negatively charged (the carpet, in turn becomes positively
charged when it loses the electrons). The electrons cling to your body until they can be released. As you reach and touch
another object or person, you may feel a “shock” as the electrons are discharged.
Based on your observations so far and the information above, which of the following claims can you support?
 Magnetic poles are positive and negative
 Magnetic poles are north and south
 Magnetism and static electricity are different phenomena
Check with your instructor before moving on.
Extending Your Thinking
Magnetism and static electricity are commonly confused with one another… let’s have some science fun as we
distinguish between when the phenomena of static electricity and magnetism are involved. Many magic tricks aren’t
magic… they’re science! Check which phenomena (static electricity or magnetic) you think would be useful in each of the
“magic” tricks below, then try them out!
Examples
Static Electricity
Magnetism
You are able to move an aluminum can without touching it.
You make a paperclip appear to move across a table on its own.
You create a ‘hair raising’ experience (literally) for a volunteer.
You can make small paper pieces rise off the table.
Like magic, electricity shoots out of your finger and shocks someone!
Check with your instructor before moving on.
Evaluating Your Understanding
Teachers must understand their science in order to teach it! Otherwise, you may unwittingly fall victim to inaccurate
information on the web. Surf the internet to locate examples of elementary science lessons that teach about the
magnetic poles. Do you think the information in the lessons you find is complete? Accurate? Bring back and example to
share with your group.
Complete this assignment on your own as
homework.
Learning Cycle V: Which Way is North?
Engaging Your Prior Knowledge
Based on our evidence in the last learning cycle, we’ve ruled out referring to the poles as ‘positive’ and ‘negative’. This
suggests that the poles are north and south, but which is which? How do you think we could differentiate between a
north vs. a south pole of a magnet?
Share and discuss your answers with your group before moving on.
Exploring Your Ideas
Using the string apparatus provided, hang a magnet (with poles marked X and O) somewhere in the room so that it
hangs parallel to the floor and is able to swing freely. Once all magnets hung by the class have stopped swinging/hang
motionless, make a map of the room that shows the position and orientation of all magnets (including those hung by
other groups), indicating the poles of each.
Discuss as a group:
 What patterns do you notice? Are there any exceptions?
 Are the magnets aligned in any particular direction? (north/south/east/west)
 Carefully consider the environment in which each magnet is hanging. List any objects with which the
magnet might be interacting.
Map:
What happens when you bring another bar magnet near the hanging magnet, holding it in the palm of your hand,
parallel to and beneath the hanging magnet? What do you observe when you rotate your hand under the magnet?
Check with your instructor before moving on.
Developing Explanations from Evidence
In the last activity, you found the X poles of the magnets aligned similarly when suspended in the room. Does
this help us identify which pole is north and south? Complete the concept cartoon below with your ideas:
I think the X pole is
south because it’s
attracted to the north
pole of the Earth.
I think the X is the
north pole because it
helps you find north.
I’m confused…
what do YOU
think?
Wait for instructions before moving on!
Extending Your Thinking
Take an unlabeled magnet—using your compass, identify the north and poles of this magnet. Be prepared to show how
you did this. (Each person at your table should choose a different magnet).
Check with your instructor before moving on.
Evaluating Your Understanding
Label the poles of the magnets below (north or south), based on their positions and the compass needle.
Check with your instructor before moving on.
Learning Cycle VI: What Makes a Magnet Magnetic?
Engaging Your Prior Knowledge
What do you think would happen if you were to break a magnet in half? What if you continued breaking it into smaller
and smaller pieces? Would the pieces still have magnetic properties? Explain.
Share and discuss your answers with your group before moving on.
Exploring Your Ideas
Make a stack of 12 ring magnets as shown. Does this magnet “stack” act as many
individual magnets, or does it seem to behave as one large magnet? The next few
questions will help you answer this.

Is the attraction experienced by a paperclip stronger at some points along the stack than others?

What do the mini-compasses and iron filings indicate about the poles of the stack of magnets? How many poles are
there?

How does this stack behave when other magnets are brought near it?
Check with your instructor before
moving on.
Developing Explanations from Evidence
In this part of the activity, we’ll develop a model for magnetism by examining what happens when a magnet is broken
into smaller pieces. However, rather than actually breaking a magnet, we will use the magnet stack you created in the
previous activity.
“Break” the stack of magnets in half. Examine both ends of each half.
 Does each half have a north and south pole? If so, where are these located?
 Examine the interaction between the paperclip and the stack. Does the new stack behave in the same way as
the original magnet stack?
Now, “break” each stack in half, observe its behavior, and continue breaking into individual magnets.
 Draw a diagram below that shows the poles of each part and how the parts originally fit together.
Check with your instructor before moving on.
Extending Your Thinking
In this activity, we’ll explore ways to magnetize materials and will explain this process using the model for magnetism you
developed and the concept of magnetic domains.
 Obtain a bar or cow magnet, mini‐compass, and several paperclips. If the poles of the magnet are not
already labeled, identify the north and south poles.
 Bring one end of the paperclip near the compass, then the other end. What do you observe? Does it
behave like a magnet? (*If your answer is YES, check with your instructor.)
 Place the paperclip on the south pole of the magnet as shown, and tape it in place for three minutes. (Enjoy
some socializing or get a drink of water while you wait!)








Now, remove the paperclip and bring the end that was touching the south pole of the magnet near your compass.
What do you observe? What do you predict will happen when you bring the other end of the paperclip near the
compass?
As you explore the interaction of the paperclip with the compass, can you tell which type of pole the end touching
the south pole of the magnet became? How does this fit with your prior investigations and interactions?
Bang the paperclip on a hard surface several times. Again observe its interaction with the compass—has anything
changed? (If not, bang it some more and try again…) How would you explain this? Make a diagram below to illustrate
what is happening to the magnetic domains within the paperclip:
Before placing it near the
magnetic pole:
After placing it near the
magnetic pole:
After banging it on the table:
Evaluating Your Understanding
(Answer individually before comparing your ideas as a group).
A student attaches the paperclip, as shown, to a magnet with unknown poles A and B, shown below.
A
B
When the paperclip is removed and held near a magnet, the following is observed.
Of A and B, which is the north pole versus south pole? Explain how you can tell.
Check with your instructor before moving on.
Learning Cycle VII: How can we compare the strength of magnets?
Engaging Your Prior Knowledge
Consider the discussion between two students, who are investigating the strength of magnets:
Student 1: I think that if we stack a bunch of magnets together, they will be stronger than just one magnet.
Student 2: I think that a stack of magnets acts like one magnet, and so it won’t be stronger.
With which, if either, student do you agree? Explain your reasoning.
Share and discuss your answers with your group before moving on.
Exploring Your Ideas
If we want to compare the strength of magnets, we must first consider how we would define strength. For example, in
the case of people, we might define that based on how much weight someone could benchpress, how many pull-ups
someone could do, or perhaps how much pain someone could endure. When you define something that can be tested,
we refer to this as an operational definition. This definition outlines a series of steps through which a value could be
measured and compared. Discuss as a group how you might define ‘strength’ for a magnet.
Using this operational definition, as a group, you should develop a method to compare the strength of single magnets
versus multiple, stacked magnets. You have access to various magnets and a variety of materials (rulers, cups, tape,
rubber bands, paperclips, washers, compasses, etc.).
Conduct a “pilot test” of your method that you will demonstrate to your instructor. Do not proceed with further testing
before you check out.
Our operational definition of strength:
Check with your instructor before moving on.
Developing Explanations from Evidence
Each group has devised a method for testing magnet strength—and perhaps devised different methods. To
help share your investigation and findings with others, you are going to create a poster.
As you create your poster, consider the following:
 What principles related to magnetism did you utilize in the design of your test?
 How did you ensure you conducted a ‘fair test’? Were there any factors that may have unintentionally
influenced your results?
 How did you decide whether you had collected ‘enough’ data to trust your results?
 How certain are you of these conclusions? Do you think that your results are dependent on the method
you chose? Why or why not?
 Can you generalize the findings from your investigation to all magnets? Why or why not?
Check with your instructor when you have finished your poster.
Extending Your Thinking
Below are different tests that elementary students have come up with when asked to design a way to compare magnet
strength. Discuss as a group:
 What are the similarities/differences in how “strength” is defined in each?
 What are the strengths and limitations of each test?
 What considerations would students have to make to ensure their test was fair and valid?
 Do you think each of these tests would yield the same results for the same set of magnets? Why or why not?
 If the test were repeated by someone in another country, could you compare your results with theirs—under
what circumstances?
Kid’s Investigation of Strength
The Paperclip Thief.
Matthew and Lara decided that the stronger magnet
would be the one that could ‘steal’ the paperclip from
another magnet. They took two magnets from their
set at a time, placed a paperclip on one, then tried to
‘steal’ it using the other magnet. The magnet that
could steal the paperclip from all others was the
strongest, and the weakest was the one that all other
magnets could steal the clip from.
Stretch Test.
Kayla, Tessa, and Melanie attach a paperclip to a
rubber band. They then use a magnet to attract the
paperclip and stretch the rubber band. For several
magnets, they compare how long the rubber band will
stretch before the paperclip is released by the
magnet. They decide that the longer the rubber band
stretches, the stronger the magnet is.
Your Comments/Evaluation
Thickness Test.
Robert and Joe see a dictionary lying on their desk
and recall that a magnet can attract through other
materials, but that the thickness may be a factor.
They decide to figure out how many pages a magnet
can attract a paperclip through and to compare. They
decide that the more pages the magnet can attract
the paperclip through, the stronger it is.
The Weight Lifter.
Maya, Kai, and Doug get the idea to see how much
weight a magnet can hold. They attach several strings
from the edge of a paper cup, then tie them together
with a paperclip. They then suspend this from a
magnet, then begin putting coins in the cup. They
count and compare the maximum number of coins
held by each magnet. They decide the magnet that
holds the most coins is the strongest.
The Magnetizer.
Luke and his partner remembered that a magnet can
make ferromagnetic materials become temporarily
magnetized. They hypothesized that the stronger a
magnet was, the better able it would be to magnetize
a paperclip. They aligned the tip of 5 paperclips with
the poles of 5 different magnets and left them for 10
minutes. Then, they checked to see whether or not
the clips had become magnets, and how many other
clips they could pick up with each.
Check with your instructor before moving on.
Evaluating Your Understanding
Watch the video of preservice teachers’ test of magnet strength (“Magnetism experiment”):
http://youtu.be/f6pxtfrbxSU


What did the preservice teachers do well? How could their investigation be improved?
Is it a fair test? Are all variables that could affect the outcome considered?
Discuss your answers then check with your instructor.
Learning Cycle VIII: Can we observe magnetic fields?
Engaging Your Prior Knowledge
You’ve been making lots of observations in this unit so far… but is science just about observation? Consider the
discussion between two students:
Student 1: I think science is limited to what you can directly observe—if you can’t observe it, then you can’t
prove it.
Student 2: I disagree—there are plenty of things in science that can’t be directly observed, and yet we
know about them!
With which, if either, student do you agree?
Check with your instructor before moving on.
Exploring Your Ideas
Place a large piece of chart paper on a flat surface away from any magnetic or ferromagnetic materials. Tape a cow
magnet to the center of the paper, sketch its outline on the paper, and identify and label its north and south poles.
If you are an odd# group, orient your paper so that the magnet is aligned north/south with the Earth’s poles; if you are an
even # group, orient your magnet east/west.

Take a small compass and slide it toward the magnet until it touches the end.

Make two dots on the paper, one at the end of the compass needle where it touches the magnet, and one
at the other end of the compass needle.

Move the compass so that the end of the needle that was next to the magnet is now directly over the
second dot you drew. Now make a dot where the other end of the needle is located.

Continue to move the compass away from the magnet in this manner, until you come to the edge of the paper.

Connect the dots you made to form a line.

Repeat the process, starting with the compass touching a different part of the magnet each time, working your
way around the entire magnet to fill the paper (approximately 30 lines)
Now, find a group that aligned their magnet differently with the Earth’s poles. Place your two chart papers side by side
and examine the pattern of lines on each. Answer the following questions as a group.

How can you account for any differences between the patterns for the two orientations?

Imagine you were to remove the magnet from the paper, and to repeat the activity without a magnet. What
would the pattern of lines look like? Explain.

Is the pattern you obtained due only to the magnet? If not, where do you think the pattern is most
nearly due to the magnet alone? Explain.
Check with your instructor before moving on.
Developing Explanations from Evidence
Read the article Learning to Observe and Infer. What things did you observe about magnets in this activity and what
things did you infer? Fill in examples in the table below.
Observations:
Inferences:
Revisit the scenario with Student 1 and Student 2 at the beginning of this learning cycle. Complete the sentences
below in regard to what you read:
I used to think….
But now I know…
Extending Your Thinking
In this activity, we’ll explore an additional way we can visualize the magnetic field that surrounds a magnet. You
will use a piece of equipment known as a Magnaprobe. The Magnaprobe consists of a small bar magnet suspended
in a mounting so that it can pivot in three dimensions. Using the Magnaprobe, explore its interaction with several
different magnets—what do you notice? Record your observations and inferences below
Observations of the Magnaprobe:
Inferences about the magnetic field:
Check with your instructor before moving on.
Compass Mapping:
Characteristics of Magnetic Fields as Revealed by…
Iron Filings:
Magnaprobe:
Evaluating Your Understanding
Select a different magnet from the one you used previously—such as a horseshoe magnet, ring magnet, or disc-shaped
magnet. Drawing on your observations using all three methods (compass mapping, iron filings, magnaprobe), infer the
magnetic field of this magnet. Make a diagram that represents the magnetic field of this magnet.
Check with your instructor before moving on.
Learning Cycle IX: Electromagnetism
Examining Your Prior Knowledge
Just as positive (+) and negative (−) electrical charges attract each other, the N and S poles of a magnet attract each
other. In electricity like charges repel, and in magnetism like poles repel. Additionally, while a negative or positive
charge can stand alone (e.g., a negatively charged balloon), magnetic poles come in pairs (though physicists continue to
search for a magnetic monopole: see Magnetic Monopoles?!?! In Blackboard).
All materials are made up of atoms, which have positive and negative charges, but only some atoms exhibit magnetic
properties. This is related to the spin of the electrons. In most atoms, the electrons are paired in such a way that their
magnetic fields cancel each other. When all the electrons in an atom are paired, the net magnetic field is zero; however
in atoms of iron, nickel, and cobalt the magnetic fields of the electrons do not cancel each other out, and so each atom
behaves as a tiny magnet.
For a refresher, check out Bill Nye’s video segment: http://youtu.be/ak8Bh9Zka50
Consider the following:
 Why is a paperclip not magnetic, if it contains iron? Explain.

Would you be able to temporarily magnetize a piece of aluminum foil? Why or why not?
Check with your instructor before moving on.
Exploring Your Ideas
You observed in a previous lesson that a ferromagnetic object (e.g., paperclip) could be magnetized by placing it in the
magnetic field of a magnet. In this activity, you’ll explore another way that objects can be magnetized.
You’ll need:
 Two bolts (steel and brass)
 A length of wire (enough to coil around the bolt many times)
 A 6-volt lantern battery
 Several ferromagnetic objects, such as paperclips or washers
Wrap a length of wire around the bolt (do not overlap as you wrap) such that you have two ends that can be attached to
a battery.
When connected to the
Steel bolt
Brass bolt
battery:
How does the bolt interact
with ferromagnetic
objects?
How does the bolt interact
with a compass?
What can you infer from these observations? Explain.
Check with your instructor before moving on.
Developing Explanations from Evidence
View “The Strongest Magnet in the World” (see http://youtu.be/QGytW_C6hR8)
One thing I learned is…
One thing that is still unclear is…
Check with your instructor before moving on.
Extending Your Thinking
How does the number of times you wrap the bolt affect the strength of the electromagnet? Your group will
investigating this using the method you developed for comparing the strength of one magnet vs. a stack of magnets.
Our claim (answer to the question):
Our evidence (relevant data/observations that support your claim):
Reasoning (explanation of why these results justify your claim):
Check with your instructor before moving on.
Evaluating Your Understanding
What is another variable you think might affect the strength of the electromagnet? Explain below how you would design
an experiment to determine the effect of that variable. Be sure to specify what materials you would use and how you
would ensure it is a fair test.
Check with your instructor before moving on.
Learning Cycle X – What use are magnets?
Engaging Your Prior Knowledge
A local engineer has proposed selling a machine to the Columbia Civic Recycling Center that will help them sort their
recyclable materials by separating the plastic and paper items from the metal items, using a large magnet.
As a member of the committee asked to review this proposal, would you support purchasing the machine? Why or
why not?
Share and discuss your answers with your group before moving on.
Exploring Your Ideas
Examine the magnetic products and advertisements provided by your instructor. (Or check out Dr. H’s pinterest
board: http://www.pinterest.com/debihanuscin/magnets/) How do these products work? What types of magnetic
interactions do they utilize? What problem do they solve or task do they make easier? Complete the chart below
for several items.
Product
Purpose/problem solved
Magnetic Interactions/ Functions
Involved
Developing Explanations from Evidence
Engineers identify problems that need to be solved, and systematically work towards developing a solution to that
problem by applying scientific knowledge. There are three main stages to this design process, and engineers often cycle
through each of these stages multiple times (see Figure):
1. Define a problem. To fully define the problem that needs to be solved, it is helpful to what limitations or constraints
there are to possible solutions. For example, engineers might consider the maximum cost, how heavy it can be, or
what materials are safe.
2. Develop solutions. In coming up with solutions, it’s helpful to research what past solutions have been used to solve
similar problems and to identify scientific principles. Engineers brainstorm many possible solutions to ideas. At this
stage, its best to allow free flow of ideas, even crazy sounding ones, to inspire creativity and get group members to
build off each other’s ideas. Lastly, the design team selects the best idea or combination of ideas, carefully
considering the trade-offs of each, and how they meet the constraints.
3. Optimize the solution. Before going into production, the engineers test their initial solutions. They might build a
prototype (a simpler version of the solution) and test how well it works. Sometimes they’ll use computer models to
predict its success. In addition to testing how well the idea works, they usually test to see where the designed
solution fails (e.g. if it breaks or doesn’t work under certain conditions). The tests give the design team an idea of
what aspects of the product need to be redesigned or improved upon.
4. Repeat 1-3 until the best solution is found. Throughout the engineering design process, engineers continue to
refine their understanding of the problem and constraints, develop new solutions, and optimize again and again
until they feel they’ve achieved an excellent solution to the design problem.
Consider one of the products you explored.
 What constraints do you think the designers and engineers of this product considered?

What parameters would they have tested to ensure the product was ready for production and sale?
Extending Your Thinking
In this part of the lesson, you’ll engage in the Engineering Design Process yourself!
Defining Problems
What kinds of problem(s) can you identify that could be solved using a magnet? What magnetic interactions would be
useful?
Developing Solutions
With your group, brainstorm possible solutions to the problems you identified. It’s ok to be wild & crazy here. At this
stage, don’t say no to anything!
Now go back and evaluate your ideas. As you discuss each solution (or a combination of solutions), keep these
questions in mind:
 Does it solve the problem?
 Does it meet the constraints of the problem?
 What are the “trade-offs?” (This means to consider the “pros and cons”, trying to find a solution where the
“pros” outweigh the “cons”.)
 Do we expect the solution to work, based on what we know of the scientific principles?
Pick ONE solution you think is feasible to develop, based on your discussions. In the space below, create a schematic
drawing of your ideas for an invention (or magnetic improvement on an existing invention).
Optimize Solutions
Build a prototype (simple model) of your product. Test it to see if it works as expected. Note in the space below what
you did to test it, and what you observed.
Your prototype is a simple model, not what the full-scale final product would look like. In what important ways do you
think your prototype is different than what the final product would be? In other words, in what ways is the prototype
limited?
Based on your tests, and considerations about the limitations of your prototype, what would you do to improve the
design?
Check with your instructor before moving on.
Evaluating Your Understanding (Group Project)
Using a presentation vehicle of your choice (piktochart, powerpoint, prezi, etc.) create a “product pitch” for
your invention that explains how it works. Be sure you include details about how the magnet interacts with
the components of your invention and/or other items. Your pitch should illustrate both your scientific
understanding and the engineering design process in which you engaged to come up with your design. Use
the space below to jot ideas and sketch out a plan.