1. Ch 1 –
What Are Magnets
http://www.sodahead.com/
By
Mrs. Horvath

2. Properties of Magnets
• Magnet – an object that attracts, or pulls on,
certain materials made of iron and steel
http://totalwealthco
aching.com/wp/wp-
content/uploads/20
09/05/magnet.png
• Magnetism – a magnet’s property of
attracting metal

3. Two Kinds of Magnets
Permanent Magnets
• Keeps its magnetism for a long time
• Made in a factory
Ex: refrigerator magnet
Temporary Magnets
• don’t keep its magnetism for a long time
Ex: nail stroked with a permanent magnet
http://crafts.preschoolrock.com/uploads/images/Finished%20Magnets.jpg
http://www.all-science-fair-projects.com/phase2/app/webroot/files/image/387/nail2.gif

4. North and South Pole
• North Pole – one end of a magnet always
points north (called north-seeking)
• South Pole – one end of a magnet always
points south (called south-seeking)
http://commons.wikimedia.org/wiki/File:Bar_magnet.jpg

5. Attract & Repel
• Unlike poles  ATTRACT
• Like poles  REPEL
http://www.ngfl-cymru.org.uk/vtc/ngfl/science/107/PP-electricity.html

6. Maglev Trains
• Mag = magnetic
• Lev = levitation (rise or float in the air)
• Goes fast
• Quiet and smooth (no friction)
- friction – force caused by two surfaces http://ww
w.dodevi
ce.com/w
rubbing against each other p-
content/u
ploads/20
• Eco-friendly (doesn’t pollute) 08/03/ma
glev-
train.jpg

7. Force Fields
Lines of Force
• Formed by iron filings
• Shows how force field spreads between the
poles of a magnet
• Strongest / heaviest at the poles
Magnetic Force
• Space in which the force of a magnet can act

9. Properties of Magnets
• Attract objects made of metal (iron or steel)
• Force is strongest/greatest at the poles (N or S)
• Like poles - - - > REPEL (push away)
• Unlike/opposite poles - - - > ATTRACT (stick)

10. Earth as a Magnet
• Earth is a giant magnet!
Lodestone
• Naturally magnetic rock
• Found near Earth’s surface
• Discovered 2,000 years ago
• Chinese sailors used to make 1st compass
Compass
• Magnetized needle that swings freely
• Points NORTH

12. Earth’s Magnetism
• Earth’s center – made up of IRON
• Earth spins on its AXIS (cause)…
• has magnetized the iron inside (effect)

13. Earth’s 2 Sets of Poles
Earth has 2 sets of poles
• Geographic Pole – end of the imaginary line
(AXIS) around which the Earth spins
(ROTATES)
• Magnetic Pole – 1,000 miles from the

15. Magnetism Lights Up the Sky
Northern / Southern Lights
• Display bright colors in sky
Auroras
• Particles of matter in space attracted to
Earth’s magnetic field (giant magnet)
• Particles collide (crash) together & display
light
• Earth’s force field strongest at the poles so
more lights are seen there

17. What I Know What I Want to Know What I Learned
• Pick up • Pick up metal
metal • Two of same
• Two of same poles can’t
poles can’t attract
attract • Opposite poles
• Opposite attract
poles attract • Different sizes &
• Different shapes (ex: bar
sizes & magnets)
shapes (ex:
bar magnets)