This document discusses magnetism and magnetic substances. It defines three categories of substances: magnetic, ferromagnetic, and non-magnetic. Magnetic substances have their own magnetic field and can attract iron, cobalt, or nickel. Ferromagnetic substances are attracted to magnets but do not repel them, and must contain iron, nickel or cobalt. Non-magnetic substances are not attracted to magnets. All magnets have two poles, north and south, and opposite poles attract while like poles repel. The magnetic field around a magnet has directional lines of force from north to south. A compass works because its magnetic needle orients itself to be attracted to the south magnetic pole.

1. Module II – MAGNETISM
Objective:
2.1 Distinguish magnetic substances
from ferromagnetic, and non-
magnetic substances.
2.2 Map the magnetic fields of
magnetized objects.

2. History of Magnetism
 First recorded use: Greece,
India, China c. 500 BCE
 Found in Magnesia, Greece
 Lodestone/Magnetite used in
navigation.
 Magnetic Hill, New Brunswick
 Bermuda Triangle

3. Categories of Substances
 Three Categories
 Magnetic
 Ferromagnetic
 Non-magnetic

4. Magnetic
 Object that has a field and that can
attract some objects containing
iron, cobalt, or nickel.
 Example: horseshoe magnet
Invisible fields Attract or repel

5. Ferromagnetic
 Is attracted by a magnet
 Will NOT repel a magnet
 Can be magnetized
 Must contain iron,
nickel or cobalt
 eg: paper clip or nail
Not a magnet

6. Non-Magnetic
 Is not attracted by a magnet
 Example: glass, plastic, or wood

7. Important Facts about Magnets
Facts:
 All magnets are DIPOLES with 2 poles,
North (N) and South (S).
 Fields are infinite in size & 3-D.
 LIKE poles repel & OPPOSITES poles attract.


8.  Around a magnet there are lines of
force that have direction and strength
(magnetic field).
Mapping Magnetic Fields
Remember
•the lines never cross
•Always goes from North to South
•Closer the lines, stronger the attraction

9. Compass
 The needle of the compass is
magnetic
 Red Tip of needle is North
 Red Tip will always be attracted towards
South
Important
North
end
Example #1
Example #2
Tip of arrow
Is North
therefore
It is attracted
to South

10. Why the Compass Works

11.  Magnetism is a property that makes certain material
attract or repel.
 Ferromagnetic
 Attracted by magnet
 Must contain Fe, Ni, Co
 Nonmagnetic
 Not attracted by magnet
 Opposites attract (i.e N & S)
 Likes Repel (i.e. S & S or N & N)
 Magnetic Field
 Arrows always go from north to south (outside magnet)
 Lines of force never cross
 The closer the lines, the stronger the field
 Compass
 Red portion of compass needle is North and is always
attracted to South
HINT
Nerd
to
Sexy