Module II – MAGNETISM

Objective:2.1 Distinguish magnetic substances

from ferromagnetic, and non-magnetic substances.

2.2 Map the magnetic fields of magnetized objects.

History of Magnetism

Discovered by the Chinese Used by magicians and sailors Illusions…..

Magnetic Hill, New Brunswick Bermuda Triangle

Categories of Substances

Three Categories Magnetic

Ferromagnetic

Non-magnetic

Magnetic

Object that has a field and that can attract some other objects. Example: horseshoe magnet

Invisible fields Attract or repel

Ferromagnetic

Is attracted by a magnet Can be magnetized Must contain iron, nickel or cobalt

eg: paper clip or nail

Not a magnet

Non-Magnetic

Is not attracted by a magnet Example: glass, plastic, or wood

Important Facts about Magnets

Facts: All magnets have two

poles, a North (N) and a South (S). They are known as dipoles.

Fields are infinite in size & 3-Dimensional

Similar poles repel & opposite poles attract.

Repulsion

AttractionImportant

Poles

N attracts SouthS attracts North

N repels NorthS repels South

Important

Oppositesattract

Likesrepel

Around a magnet there are lines of force that have direction and strength (magnetic field).

Mapping Magnetic FieldsRemember

•the lines never cross•Always goes from North to South•Closer the lines, stronger the attraction

Compass

The needle of the compass is magnetic Red Tip of needle is North Red Tip will always be attracted towards

South

Important

Northend

Example #1

Example #2

Tip of arrowIs North thereforeIt is attracted to South

Why the Compass Works

Why the Compass Works

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

HINTNerd

toSexy

Activities

Worksheet Mod II, # 1