Magnetism and Motors

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					Magnetism and Motors (Lesson Plan)
(Magnets, Electricity, Electromotors, and MagLev Trains)
Suggested Grade Level        7-10

Standard Statements
   3.1.10 D Apply scale as a way of relating concepts and ideas to one another by some measure.
   3.2.10 B Apply process knowledge and organize scientific and technological phenomena in
             varied ways.
   3.4.10 C Distinguish among the principles of force and motion.

Content Objectives
Students will know that
   1. Electricity and magnetism function as two aspects of a single electromagnetic force.
   2. Motors function using inductive magnetism.
   3. Magnets vary in type, utility, and composition, influencing the transportation endeavors
       throughout the world.

Process Objectives
Students will be able to
   1. Calculate the magnetic force of a permanent magnet.
   2. Identify examples of transportation technology using magnets.
   3. Make measurements and calculations in both SI and English units.
   4. Create a method to assess the relationship between magnetic force and strength in
       understandable ratios.
   5. Make predictions using knowledge gained from previous experimentation.

Assessment Strategies
   1. Evaluation of completed student handouts.
   2. Group discussion.

Materials
Per group or per individual:
      Rubber bands
      1.5 volt D cell battery
      Copper wire, 22 gauge w/ enamel coating
      Wire cutters
      Compass
      2 paper clips
      Pliers
      Iron filings
      Exacto knife or sand paper
      2 permanent bar magnets
      2 Magnetic strips (24”x ½”x ⅛”)
      2 Magnetic strips (6”x ½”x ¼”)
      Foam-core board (6”x 3 ⅞”x ¼”)
      4 Permanent ceramic magnets

Magnetism and Motors                                                         Lesson Plan         1
Penn State University GREATT Project
        2 Pieces of wood (24”x 4”x ¾”)
        2 Pieces of wood (3”x 4”x ¾”)
        Plexiglas (24”x4”x ¾”)
        Nails

Procedures
Part 1                                                                                    (30 min)
   1. Utilizing the Teacher Notes accompanying this activity or your class textbook, discuss the
       principles of magnetism with your students.
   2. Split your class into small groups. (Use your own discretion to determine the optimal size of
       the groups.)
   3. Distribute all necessary materials and instruct your students to follow the directions for Part
       1 in the Student Handout. Allow them to play with the magnet and iron filings and have
       them discuss their observations.
   4. Instruct the students to draw diagrams of their observations.
   5. In a class discussion, have the students reveal their findings and ask them to explain the
       phenomena behind the behavior of the iron filings. Be sure that each student understands
       the concept of magnet field lines and why they look different for attractive and repulsive
       forces.
Part 2                                                                                      (20 min)
   1. In this part of the activity, students will be using an electric current to induce a magnetic
       field. Be sure your students understand key concepts such as current, voltage, and
       resistance.
   2. Distribute all necessary materials to the students.
   3. Follow the directions included in Part 2 in the Student Handout for building a simple circuit.
       Be careful after connecting the wire to the battery! If the circuits are left connected for
       an extended period of time the wires and terminals will get hot.
   4. Place a compass underneath the wire of the circuit and observe what happens to the
       compass’s needle.
   5. Help the students to understand that the electrical current is producing a magnetic field that
       is felt by the compass’s needle.
   6. Discuss electromagnetism and the right-hand rule with your students.
   7. Allow your students to experiment further with this circuit. They could observe the right-
       hand rule in action if they switch the direction of the cathode and anode in relation to the
       compass. If the cathode was facing north, point it south and observe the direction in which
       the compass’s needle now turns.

Part 3                                                                                  (40 min)
   1. Distribute all necessary materials needed for Part 3 (see Student Handout).
   2. Demonstrate to your class how to coil the copper wire around the pencil. Be sure to leave 3”
       of wire uncoiled at each end.
   3. Demonstrate how to unbend the paper clips as illustrated in Figure 2 of the Student Handout.
   4. Have your students assemble their “motors” as described in their handout.
   5. Discuss question 1g with your class before they move on to question 2 in this section. Make
       sure your students understand the relationship between electric currents and magnetic fields.



Magnetism and Motors                                                           Lesson Plan        2
Penn State University GREATT Project
Part 4                                                                     (1, 50-min Class Period)
   1. Follow the directions in the Teacher Notes to assemble the levitating frames. Make one
       frame for each group of students. If you feel comfortable allowing your students to use
       hammers in your classroom, then this part of the activity can also be completed by them
       under your instruction and supervision.
   2. Review the links in the Additional Resources section of the Teacher Notes to familiarize
       yourself with MagLev transportation.
   3. Briefly discuss with the students how MagLev trains operate.
   4. Have the students follow directions provided in 4a through 4f of their handout to complete
       the assembly of their MagLev trains.
   5. Have the students answer question 4g and then discuss this question aloud as a class.
   6. Allow the students to search the web to conduct research about MagLev trains.
   7. Ask the students to discuss what they found in their web search.
   8. Have the students answer questions 5a and 5b in their handout. Discuss these questions as a
       class or have 2 or 3 teams merge and discuss the questions in small groups.




Magnetism and Motors                                                          Lesson Plan       3
Penn State University GREATT Project
Magnetism and Motors (Teacher Notes)
(Magnets, Electricity, Electromotors, and MagLev Trains)
General Lesson Notes
   Magnets and Magnetism. Common terms like permanent magnets, dipoles and polarity, field
    lines, and ferromagnets should be used in the exercises. Magnetism is a force that acts at a
    distance and is caused by a magnetic field. This force strongly attracts ferromagnetic materials
    such as iron, nickel and cobalt.
   Permanent magnets. Permanent magnets are materials with uni-directional magnetic domains,
    or regions, that result in a net magnetic charge.
   Ferromagnets. Ferromagnets are materials with domains in which the magnetic fields of the
    individual atoms align, but the orientations of the magnetic fields of the domains are random,
    resulting in a zero net magnetic field. When an external magnetic field is applied to a
    ferromagnet, the magnetic fields of the individual domains line up in the direction of this
    external field, which causes the external magnetic field to be enhanced. This unique
    characteristic makes ferromagnets exceptional as the core of a solenoid in an electromagnet.





    Figure A. Ferromagnet                            Figure B. Ferromagnet w/ External Field

   Common uses of ferromagnetic materials. Ferromagnetic materials are employed in
    magnetic recording devices, such as for cassette tapes, floppy discs for computers, and the
    magnetic stripe on the back of credit cards. These devices essentially take information in the
    form of electrical signals and permanently encode it into a magnetic material.
   MagLev Trains. “MagLev” is an abbreviation for “magnetic levitation.” There are three
    components to a magnetic levitating system: large electrical power source, metal coils lining a
    guideway or track, and large guidance magnets attached to the underside of the train. MagLev
    trains are propelled by alternating the electromagnet’s polarity. This change in polarity causes
    the magnetic field in front of the train to pull the vehicle forward, while the magnetic field
    behind the train adds more forward thrust. Many projects are under construction internationally
    - in such countries as Germany, China, Japan, and the United States. Many of these projects can
    be referenced via the internet (see Notes on Additional References for helpful links on these
    projects).




Magnetism and Motors                                                                Teacher Notes    1
Penn State University GREATT Project
   Precision of measuring units. The British and SI unit measurements for length and mass are
    considered in the experimental portions of the student exercises. Beyond comparative or
    intuitive understanding of the measurements, students can compare the precision of using
    centimeters versus inches, or ounces versus kilograms. To demonstrate, have students measure
    in both systems, then use a standard conversion rate of 1 in = 2.54 cm and 1 oz = 28.349 g. See
    whether the metric actual results (measured) are equal to the calculated results from British
    units. Possible extension to variance, percent error, absolute error, and other values.
Part 1 Notes
   Magnetic field lines. Magnets are dipolar (di- meaning two), having a north and south end, or
    positive and negative. Fields lines, or lines of force, represent a magnetic field and by
    convention, point from north to south outside a magnet (and from south to north inside a
    magnet). Magnetic lines of force form complete loops that never cross. The units for magnetic
    field strength are the weber/m2, called the tesla. More familiar units representing the same thing
    are N/(A * m).




                                              Figure C.



Part 2 Notes
   Electromagnetism. (This explanation pertains to Questions 2b to 2d in the Student
    Handout.) Common terms like Ampere’s Rule or right-hand rule and solenoid should be used
    in the exercises. Electromagnetism is a magnetic field induced due to a flow of current in a
    conductor. The magnetic field forms a series of concentric circles around a straight conductor

Magnetism and Motors                                                            Teacher Notes      2
Penn State University GREATT Project
    where the field strength decreases with increased distance radially from the
    conductor. Though the strength of the magnetic field increases directly with
    the amount of current in the conductor. Ampere's Rule (right-hand rule)
    describes the direction of the magnetic field about a straight conductor. If the
    conductor is grasped with the right hand in such a way that the right thumb
    points in the direction, v, of the current, the fingers wrap around the conductor in the direction
    of the magnetic field, B (see picture). By coiling the conductive wire into a series of loops, the
    strength of a magnetic field can be intensified. A solenoid, a large number of loops forming a
    coil creates a magnetic field resembling the field formed outside a bar magnet. Inside the
    solenoid, the magnetic field consists of straight, uniformly spaced lines of flux. Ampere's Rule
    also states that if the solenoid is grasped in the right hand in such a way that the fingers curl in
    the direction of the current, the right thumb points in the direction of the north pole of the core.
    (Magnetic field lines point from south to north inside the core, in the same direction that the
    right thumb is pointing.)
   Electricity. (This explanation pertains to questions 2b to 2d in the Student Handout.)
    Common terms like charge, voltage, current, and resistance should be used in the exercises.
    Charge is a fundamental property of matter, as is mass, length, and time, with units of coulombs
    (C ). Opposite charges attract and likes repel. Voltage is a measure of potential energy in units
    of volts (V). A voltage difference from one end of a circuit to the other is what pushes electrons
    in the circuit. Current is the flow of electrons (i.e. charge) in a conductive material like copper
    wire measured in Amperes (A) or amps for short. It represents the amount of charge that passes
    a point in an amount of time, such as 120 C per 1 sec. Resistance is a circuit element that
    impedes the current, the flow of charge, in units of Ohm ().
   Water analogies. Water analogies are frequently used to describe electricity on a macroscopic
    level. The volume of water flowing past a point is similar to current. Voltage is the potential
    energy of the water, such as water running over a dam. The height of the water is the potential
    of the water to fall/move. Resistance acts like rocks, dams, and pipes that slow the flow of
    water or force it in a particular direction.
   Simple and short circuits. Two different types of circuitry are used: simple and short. A
    simple circuit has a voltage difference, resistance to current or means of doing work (a light
    bulb), and a conductive connection. A short circuit has a voltage difference and conductive
    connection, but no resistance. Charge flows freely and quickly, which is the case in Part 3.
    This is why the battery may drain quickly and wire may become hot if connected for a long
    period of time.
   Related scientists. These scientists contributed to the scientific understanding of electricity:
       William Gilbert
       Charles A. de Coulomb
       Alessandro Volta
       Andre Marie Ampere
       Georg Ohm
Part 3 Notes



Magnetism and Motors                                                               Teacher Notes       3
Penn State University GREATT Project
   Motors. For a comprehensive explanation of the science behind motors, reference the website
    provided here: http://electronics.howstuffworks.com/motor4.htm
   (See Electromagnetism in Part 2 Notes to answer questions 3e through 3j.)
   Questions to consider for review during a class discussion:
        What materials are magnetic? How do we know?
        Where do we see examples of magnetism?
        What is current and electricity?
        How does electricity turn a motor?
        What is an electromagnet?
        Where are these useful?
Part 4 Notes
   Assembly of the Levitating Frame. Follow the instructions provided for constructing the
    levitating frame.

                          1. First, obtain two pieces of wood, both 24”x 4”x ¾”. Lay one piece
                             flat and hold the other piece at a right angle to it (See Figure D).
                             Securely nail the two pieces of wood together.




                                                     Figure D.
                          2. Obtain two more pieces of wood, both 3”x 4”x ¾”. Secure one on the
                             left-hand side and the other on the right-hand side producing a frame
                             which has three wooden walls (See Figure E).




                                                     Figure E.
                          3. Obtain a piece of Plexiglas that is also 24”x4”x ¾”, and secure this to
                             the front of the frame, parallel to the back 24”x4”x ¾” wooden panel.

                          4. This fourth wall is Plexiglas so that your students can see their trains
                             levitating above the magnetic track.
   Questions to consider for review during class discussion:
        Why would engineers want to know a weight limit and height of typical levitation? Why
         are these factors important?
        Why might a country seek to use MagLev technology? What does this mean for its
         transportation industry, environmental policy, and/ or social structure? (Stephen Carter’s
         Civility makes reference to society’s influences of train v. car transportation)
Notes on Additional References


Magnetism and Motors                                                            Teacher Notes       4
Penn State University GREATT Project
   Helpful links on MagLev trains:
        http://travel.howstuffworks.com/maglev-train.htm

        http://www.maglev2000.com/

        http://www.calpoly.edu/~cm/studpage/clottich/fund.html

        http://www.o-keating.com/hsr/maglev.htm

        http://www.llnl.gov/str/Post.html
   Related Scientists .   These scientist contributed to the understanding of magnetism and/or
    electromagnetism:
           o Richard Post
           o Klaus Halbach
           o Nikola Tesla
           o Michael Faraday
   Other links which may be helpful for this lesson:
        http://wwwistp.gsfc.nasa.gov/Education/wfldline.html

        http://science.howstuffworks.com/electromagnet1.htm

        http://doe.sd.gov/octa/ddn4learning/themeunits/magnet/general.htm

        http://www.sciencetech.technomuses.ca/english/schoolzone/Info_Magnets.cfm

        http://www.sasked.gov.sk.ca/docs/physics/u7b3phy.html
Notes on extensions / modifications to this activity.
   Adaptive Activity/Experimental Options:
        Test the strength of a magnetic field under different conditions, such as different voltages,
         amperage, nearby electrical signals, coils in solenoids.
        Consider common applications of electromotors or magnets which improve the quality of
         daily living. Have the student report current commercial products or even build a device
         on their own.
        Assign group presentations on: related scientists in MagLev technology or related fields;
         current technological advances and status of MagLev projects internationally, examples
         include those in Baltimore, California, Japan, Germany, and Old Dominion University.




Magnetism and Motors                                                            Teacher Notes       5
Penn State University GREATT Project
Name:________________________

Magnetism and Motors
(Magnets, Electricity, Electromotors, and MagLev Trains)
Overview
In this activity you will learn the relationships between magnetic and electrical forces. You will
examine magnetic fields and how they interact. You will understand how electrical currents
produce magnetic fields, and how this phenomenon is being used in advanced transportation
technologies.

Part 1 Magnetic Fields
In this part of the activity you will be studying magnetic field lines using bar magnets and iron
filing.
1)      Obtain 2 bar magnets and a bag of iron filings from your teacher. Be sure to keep the filings
sealed in the bag. Follow the directions below and answer the accompanying questions.

   a) Lay the bag of filings flat on your desk and move a bar magnet slowly toward the bag. At
      what distance from the bag did you see a change in the configuration of the filings?


   b) Were there observable changes as you moved the magnet even closer to the bag?



   c) Use the box provided to draw a diagram of what you observe when you place the magnet
      over the filings.

                                Interaction between magnet and filings




Magnetism and Motors                                                            Student Handout      1
Penn State University GREATT Project
   d) Place both bar magnets end to end so that the ends repel each other. Hold the magnets in
      this configuration and move them slowly toward the bag of filings.

   e) Observe what happens to the filings and draw what you see in the space provided.

                           Filings’ Configuration Due to Repelling Forces




   f) Place the magnets end to end so that the ends attract each other. Hold the magnets in this
      configuration and move them slowly toward the bag of filings

   g) Observe what happens to the filings. Draw what you see in the space provided.

                           Filings’ Configuration Due to Attractive Forces




   h) Compare your diagrams for questions 1c, 1e and 1g.




Magnetism and Motors                                                         Student Handout       2
Penn State University GREATT Project
   i) What is different about the configuration of the iron filings in question 1c verse the
      configurations in questions 1e and 1g?
   __________________________________________________________________________
   __________________________________________________________________________

   j) How do these configurations help to explain the forces you were feeling and observing
      while you were holding the magnets above the filings?
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________


Part 2 Electricity
2) Obtain a rubber band, battery, copper wire (9 inches long), wire cutters, and compass from your
teacher, and construct a simple circuit by following the directions below. Answer the accompanying
questions.
    a) Place the rubber band around the length of the battery. Place one of the ends of the wire
       between the rubber band and positive terminal of the battery.Bend the copper wire around
       and place the other end underneath the rubber band, in contact with the negative terminal of
       the battery (See Figure 1).

                                          +
                                                               N
                         Rubber band
                                                           W        E   Compass

                                                               S


                                         -           e-
                                       Copper wire

                                                Figure 1

   b) What happens when the copper wire is connected in this manner?




   c) If left for a long period of time, what would happen to the battery and wire?




Magnetism and Motors                                                          Student Handout   3
Penn State University GREATT Project
   d) Now take your compass and place it over top of the connected copper wire (See Figure 1).
      Describe what you observe. Make comments about why you think this occurs.

   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________

Part 3 Motors
3)      Obtain a ceramic magnet, 2 large paper clips, an exacto knife, pliers, and another piece of
copper wire (3’ long) from your teacher. You will also need your rubber band, battery, and wire
cutters from Part 2. Follow the directions below to create your own motor.

   a) Take the copper wire and, using a pencil, coil the copper wire 20 to 30 times around it
      leaving 3” of wire uncoiled at each end of the wire. Strip the coating off of the top of one
      end of the wire and the bottom of the other end

   b) .Un-bend a paper clip to resemble the configuration below (See Figure 2). You may need
      pliers to accomplish this task. Repeat this procedure again with a second paper clip.




                                               Figure 2.

   c) Place a rubber band on the battery lengthwise and place the one end of one paper clip
      between the rubber band and the positive terminal of the battery. Place the second paper
      clip between the rubber band and the negative terminal of the battery (See Figure 3).




Magnetism and Motors                                                            Student Handout       4
Penn State University GREATT Project
                                               Figure 3.

    d) Place the coiled copper wire so that each end is resting on a paper clip (See Figure 4).

    e) Considering the previous experiments, predict what will happen when you place a magnet
       underneath the copper wire as illustrated in Figure 4. Write your prediction in the box
       provided.


                                                  Prediction:




    f) Place the magnet underneath the copper coil(See Figure 4.). You have now created a
       simple DC motor


                                                Paper Clips




                 Rubber Band
                                                                           Copper
                                                                            Coil
                                                     Magnet

                                               Figure 4.

.

Magnetism and Motors                                                            Student Handout   5
Penn State University GREATT Project
   g) Discuss with your group memebers how the “motor” is operating. Write your conclusions
      below.
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________

   h) What extra parts would this motor need so that it could run a toy car?
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________


   i) Can you make your “motor” operate faster or slower? If so, design an experiment to test
      your hypothesis. Write your hypothesis and procedure in the box below.

                                       Hypothesis and Procedure




   j) Implement your procedure. Discuss your results with your group and write your conclusion
      in the space provided.
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________


Part 4 Magnetic Levitating Trains



Magnetism and Motors                                                       Student Handout      6
Penn State University GREATT Project
4)     Take a moment to think about the number of people who commute to school or work each
day. How many use personal vehicles (cars, trucks, vans, etc.)? How many use public
transportation (subways, buses, etc.)? How many walk or ride their bike?



    Due to the environmental concerns associated with the burning of fossil fuels, researchers and
governement officals are trying to find more efficient ways of moving people from place to place.
One idea that has been utilized is Magnetic Levitating Trains (a.k.a “MagLev” trains). MagLev
trains are environmentally friendly because they do not run on fuel that gives off harmful emissions.
Instead, MagLev trains use electromagnetic forces and magnet propulsion systems. Such systems
create magnetic repulsion, which allows trains to levitate above a track and then be propelled
forward or backward due to electromagnetic coil systems. Currently, there are MagLev trains
running in Japan and China, and Germany is constructing a system connecting their capital (Berlin)
to the major city of Hamburg.


5)      In this part of the activity, you are going to construct your own MagLev Train!! Follow the
directions provided.

   a) Obtain the levitating frame and two 24”x ½”x ⅛” magnets from your teacher. The frame
      has one side made of plexiglas so that you can observe the train levitating above the track.

   b) Complete the track by gluing each of the two 24” long magnets to the base of the frame,
      about ⅛” from the side walls (See Figure 5). The North Poles of the magnets should face
      upward.
                        Levitating Frame




                                  Magnetic strips (24”x ½”x ⅛”)
                                                  Figure 5.
                             Source: http://my.execpc.com/~rhoadley/magtrain.htm

   c) Next, complete the train platform. Obtain a piece of foam core-board (6”x 3 ⅞”x ¼”), and
      two magnetic strips (6”x ½”x ¼”) from your teacher. Glue the magnetic strips to the bottom
      of the core-board as shown in Figure 6. Make sure that, once again, the North Poles of the
      magnets are facing outward. Why is this important?

Magnetism and Motors                                                               Student Handout   7
Penn State University GREATT Project
                        Magnetic strips (6”x ½”x ¼”)




                                           Ceramic Magnets
                                                  Figure 6.
                             Source: http://my.execpc.com/~rhoadley/magtrain.htm


   d) Obtain two round ceramic magnets and glue one to the front edge and one to the back edge
      of the core-board as shown in Figure 6. The North Poles of these magnets should be facing
      outward.

   e) Obtain two additional round ceramic magnets and glue them to the inside of the 4” long
      walls of the levitating frame, about ¼” from the base of the frame, as shown in Figure 7.
      Once again the North Poles of the magnets should be facing outward. What is the purpose
      for these magnets?




Magnetism and Motors                                                               Student Handout   8
Penn State University GREATT Project
                                         Ceramic Magnet




                                                  Figure 7.
                             Source: http://my.execpc.com/~rhoadley/magtrain.htm



   f) Place your train on the track and give it a gentle push.

   g) Is the train “levitating” above the track? If so, why is this occurring? If not, why not?
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________

6)     Conduct additional research about MagLev trains. Utilize the sources listed in the
Additional Resources section of your Student Handout, but feel free to look for other sources as
well.

   a) Discuss with your group whether or not you think that this new transporation technology is a
      good alternative to some of the current means of public transportation. Provide reasoning
      behind your opinion.
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________

   b) Where do you think this type of advanced transportation technology can be utilized in
      Pennsylvania?
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________
   __________________________________________________________________________



Magnetism and Motors                                                               Student Handout   9
Penn State University GREATT Project
Additional resources
Helpful MagLev links:
        http://travel.howstuffworks.com/maglev-train.htm

        http://www.maglev2000.com/

        http://www.calpoly.edu/~cm/studpage/clottich/fund.html

        http://www.o-keating.com/hsr/maglev.htm

        http://www.llnl.gov/str/Post.html

A help on converting units. It is often helpful to think of unit relationships in terms of ratios or
conversion factors. The numerator and denominator of a conversion factor are equal quantities.
When trying to convert from one unit to another, choose one or more conversion factors that will
cancel all units except those desired. In other words,
                                                    final unit
                               beginning unit                    final unit
                                                  beginning unit
Helpful unit conversions:
                   1kg 
                   1000g 
1 kg = 1000 g, or         
                          
                   1m 
1 m = 100 cm, or          
                   100 cm 
1 in = 2.54 cm




Magnetism and Motors                                                             Student Handout   10
Penn State University GREATT Project

				
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