Lesson 3

This lesson uses a strong magnet included in the kit to go through materials.
Students explore common materials a magnetic field will penetrate: paper, plastic, water and tables.
Students temporarily induce magnetism in ferromagnetic materials: iron and steel.
They distinguish the differences between temporary and permanent magnets.

1 What did you do last time? 2 north poles south iron attract repel PRINT the word next
to the image on the next slide.
MAG-lesson L3 iro rep pol att sou nor
4 And the ends of a magnet are called POLES ATTRACT! Remember: Unlike colors stick together. 5 Opposite poles ATTRACT. So, replace the word "sides" with POLES. Opposite sides ATTRACT. 6 Like sides REPEL. AGAIN replace the word "sides" with POLES. Like poles REPEL! 7 Without looking back, can you say these two rules for magnets? Close your eyes. Like poles REPEL! Opposite poles ATTRACT. Attraction rule Repulsion rule 8 You just learned
a fundamental law of nature
worth remembering!
9 To test it you will need: duck paper clips bar magnet paper plate Does the force of magnetism pass through materials? 10 Move the magnet to make the duck swim. Slide a paper clip onto
the slit on the bottom
of your duck.
Put the magnet under
the plate directly
below the duck.
1 2 3 Place the duck
on the paper plate.
11 What materials will
your magnet go through?
Try a piece of paper
or a cloth.
Try a table. Does your ring magnet work as well?
12 Does it work
with water
in the cup?
Does magnetism
go through water?
Try an
empty cup.
Stronger magnets will attract through thicker materials.
13 Not all magnets are the same.
They can be different shapes, sizes and strengths.
Which magnet can pick up
the most stainless steel spoons?
Remember some spoons will not stick at all.
14 Do you know how to turn a nail into a magnet? Hold the bar magnet against
the head of the nail. WAIT.
Does the magnetism in the nail lessen over time? How many paper clips can you pick up with the tip
of the nail?
Now remove the bar magnet.
How many paper clips remain?
15 Dropping or striking
a temporary magnet
can degauss it.
TEMPORARY MAGNET! Temporary magnets
lose their magnetism over time.
South Pole You just made a
16 dee mouse, dee house, dee louse! Degauss rhymes with Degaussing removes
a magnetic field.
You can degauss a temporary magnet
with a hammer or degauss magnetic data
on a credit card with a magnet.
17 Testing Credit Cards and Magnets 18 Remember Hairless Harry? What metal was in Harry's hair What pole does the north end of a magnet attract What pole does
the north end of
a magnet repel
When you recycle cans, how can you tell which cans are made with steel 1 2 3 4 IRON - iron filings south north A magnet will stick to a steel can.
19 Permanent and Temporary Magnets A 1 minute video The red and blue bar magnet is a permanent magnet.
Each nail can become a temporary
or induced magnet.
They hold their magnetism only temporarily.
Click on Electra.
20 21