1. Magnetism and Its Uses
7.1 Magnetism

2. Magnets
The earliest magnets were found naturally in the mineral magnetite which is abundant the rock-type lodestone.
Magnets were used by the ancient peoples as compasses to guide sailing vessels.
Magnets produce magnetic forces and have magnetic field lines.

3. Magnets
Magnets can be found on your refrigerator door and in many devices that you use every day, such as TVs, headphones, video games systems, and telephones.

4. What is magnetism?
Magnetism is the properties and interactions of magnets

5. Magnetic Force Magnets apply attractive or repulsive force.
Interaction of two magnets depends on orientation.
Force between two magnets increases as they move closer together.

6. Magnetic field
a force exerted on other magnets and objects made of magnetic material
strongest close to the magnet
represented by lines with arrows to show direction

7. Magnetic Poles All magnets have a north and south pole.
Magnetic field is strongest at the poles.
Magnetic field lines go from north pole to south pole.

8. Interaction of two magnets
Unlike poles of magnets attract each other
Like poles of magnets repel each other

9. Earth as a magnet South magnetic pole is near geographic north pole.
North magnetic pole is near geographic south pole.
Cause is unknown—perhaps related to inner core of iron and nickel.

10. Compass needle is a small bar magnet
turns to line up with Earth’s magnetic field
points north toward Earth’s south magnetic pole

12. What Materials are Magnetic?

13. Magnetic Domain
Magnetic substances like iron, cobalt, and nickel are composed of small areas where the groups of atoms are aligned like the poles of a magnet.
These regions are called domains.

14. All of the domains of a magnetic substance tend to align themselves in the same direction when placed in a magnetic field.