Students will compare and contrast the patterns that they create using iron fillings and different types of magnets.
For each group:
- Bar magnet
- Horseshoe magnet
- Disc or ring magnet
- 8 oz bottle of vegetable
- Two clear Ziploc
- 1 tbs. Iron filings
- Box of large paperclips
- Usborn Science Activities--Vol. 1, by Joan and Maurice Martin
(Usborn Publishing Ltd, Usborn House, 83-85 Saffron Hill,
London, EC1N 8RT, England. Copyright 1992, www.edcpub.com or www.ubah.com); ISBN 0-7460-0698-5
- Usborn Science Activities--Science With Magnets, by Joan and
Maurice Martin (Usborn Publishing Ltd, Usborn House, 83-85
Saffron Hill, London, EC1N 8RT, England. Copyright 1992,
www.edcpub.com or www.ubah.com); ISBN 0-7460-1259-4
- World Book, Young Scientist--Light & Electricity--Magnetic Power,
by Hemesh Alles (World Book Inc., 525 West Monroe Street,
Chicago, Illinois 60661. Copyright 1992); ISBN 0-7166-2791-4
- The World Book Student Discovery Encyclopedia--Vol. M,
(World Book Inc., 233 N. Michigan Ave., Chicago, Illinois 60601.
http://www.worldbook.com, 1-800-975-3250. Copyright 2000);
- The Magic of Magnetism, (100% Educational Videos; 4921 Robert J.
Matthews Pkwy, El Dorado Hills, California 95762,
http://www.schoolvideos.com/index.cfm); VHS Product #1010S,
DVD Product #S1401
Background for Teachers
We know that magnets have forces that draw iron and steel objects
toward them. We also know that magnets have poles usually referred to
as North and South. Opposite poles attract each other and like poles
repel. North ends attract South ends, South ends attract North ends. North
ends repel North ends and South ends repel South ends. If they are close
enough, depending upon the strength of the magnet, they will come
together with great force and must be treated with care.
There are unseen magnetic fields around magnets. North and South
polarized ends of magnets are where the strong pulling and repelling
occurs. Bar, ring, disc, and horseshoe magnets each have different,
distinctly-shaped magnetic fields. Lines within these fields and the
patterns they create are referred to as magnetic field lines. These lines
seem to flow away from the North end of a magnetic field and return
again to the South end.
Earth has a magnetic field very similar to a bar magnet, with
magnetic field lines flowing away from the North and returning in an
oval pattern to the South Pole. The magnetic North and South Poles are
not the same as the true North and South poles as depicted on globes and
maps. The North Magnetic Pole is slowly drifting across the Canadian Arctic. The Geological Survey of Canada keeps track of this motion by
periodically conducting magnetic surveys to determine the Pole’s
location. The most recent survey, completed in May 2001, determined an
updated position for the Pole and established that it is moving northwest
at approximately 40 km per year.
Intended Learning Outcomes
1. Use Science Process and Thinking Skills
2. Manifest Scientific Attitudes and Interests
Invitation to Learn
Duct tape a strong magnet under a table or sheet of cardboard or
poster board. Ask the students what the forces are around a magnet. Slide
paper clips along the table/cardboard until they are attracted to the
magnet. Explore the patterns.
- Have students pour vegetable oil into one Ziploc bag.
- Mix in iron filings.
- Zip the first bag closed and place it inside the second bag; zip the
second bag closed. (Clear bags are best. The kind with white
labels on the side work, too, however the labels make the
magnetic lines of a force field difficult to see.)
- Gently shake the bags up until the iron filings are equally
distributed in the vegetable oil.
- Place a bar magnet as flat as possible on a smooth, hard surface.
- Place the shaken plastic bag on top of the bar magnet.
- Observe the lines that occur. (You may want to gently tap the top
of the bag and loosen some of the iron particles to move in the
- Label and draw the pattern that occurs.
- Repeat this procedure for horseshoe, disc, and ring magnets.
- Compare and contrast the patterns.
- Students record the results in a science journal.
- Clean-up: Have students pour their oil from the Ziploc bags
through a funnel back into the original bottles and label them.
(Make sure they label them, CONTAMINATED, and only good for
detecting magnetic fields.)
Note: Ziploc bags are great for freezers and short term
storage, but oil left in Ziploc bags overnight makes a mess.
- Have students write down and describe what happened and how
they think these patterns were formed.
- Allow students to hypothesize if the position of the magnet effects
the appearance of the magnetic field?
- Partner special needs students responsibly to assure success
during this activity.
- Have students teach their parents about magnetic fields.
- Allow students to check out magnets and bottles of
CONTAMINATED oil to test the hypothesis mentioned above.
- Assess writing using the Science Writing Rubric.
- Students create compare and contrast drawings to assess accuracy.
- Have students compare and draw the patterns created by a bar,
horseshoe, ring, and disc magnet.