1. Magnets and
Magnetic Forces

2. Magnets
Magnets got their name from a region in Greece formerly known as Magnesia.
The first naturally occurring magnets, lodestones, were found here almost 3000 years ago.

3. Magnets
Naturally occurring magnets (lodestones) are called permanent magnets.
Permanent magnets are magnetic all the time.

4. Magnets
Permanent magnets can be used to magnetize other pieces of iron.
Magnetic items are classified one of two ways:
Magnetically hard – Hard to magnetize and does not lose magnetism easily
Magnetically soft – Easily magnetized and easily loses magnetism

5. Magnetic Forces Magnets exert magnetic forces on each other.
Like Poles repel
Opposite poles attract
The closer the magnets are to each other, the more intense the force (Attractive or repulsive).

6. Magnetic Fields What is a magnetic field? MAGNETIC FIELDS
A magnetic field is a region where a magnetic force can be detected.
MAGNETIC FIELDS
All magnets produce magnetic fields
Some magnetic fields are stronger than others

7. Magnetic Fields MAGNETIC FIELD STRENGTH DEPENDS ON TWO THINGS:
The material from which the magnet is made
The degree of magnetization

8. Magnetic Fields
Atoms have electrons that are in constant motion. The moving charges constitute a tiny current and produce a magnetic field.
Every spinning electron is a tiny magnet. An electron pair spinning in the same direction make up a stronger magnet. Electrons spinning in opposite directions work against one another.

9. Magnetic Fields
Iron triad – Iron, Cobalt, and Nickel are the only magnetic elements.

10. Earth’s Magnetic Field
Earth’s magnetic field is like that of a bar magnet
It has both direction and strength
It has changed direction throughout geologic time

11. Earth’s Magnetic Field
Earth’s magnetic poles are not the same as its geographic poles

12. What can track magnetic Fields?
Compasses can track magnetic fields.
A compass is a magnet suspended on top of a pivot so that the magnet can rotate freely.