1. Magnets & Magnetic Fields
Magnetism
Magnets & Magnetic Fields
Earth’s Magnetic Field
protects us from the
deadly solar wind.

2. For an object to be a magnet, its’ magnetic domain
must be aligned.
A magnetic domain is a region within magnetic material that has uniform magnetization. This means that the atoms are aligned with one another and they point in the same direction.

3. Magnets have magnetic poles.
Definition: Magnetic Poles-- Either of two regions of a magnet, designated north and south, where the magnetic field is strongest.
Electromagnetic interactions cause the north poles of magnets to be attracted to the south poles of other magnets, and conversely.

4. Each atom of magnetic material has its own invisible magnetic field.
Definition: magnetic field – a region where magnetic force can be detected.
This magnetic field is produced by a spin of the electrons.

5. Moving magnetic fields can produce electric charges.
This is called electromagnetic induction

6. Definition: magnetic force – the push or pull produced by a magnetic field as it interacts with matter.
Magnetic force causes:
Opposite Poles to attract.
Like Poles to repel.

7. Magnetic forces are also related to electric forces:
Moving electric charges produce magnetic forces, and moving magnets produce electric forces.
Accelerating electric
charges produce
electromagnetic
waves around them.

8. Electromagnets
When an electric current passes through a wire, a magnetic field is created around the wire.
Definition: solenoid – a coil of wire with an electric current in it.

9. By placing a piece of metal inside a solenoid, the metal becomes a temporary magnet.
Magnetic Field

10. Electromagnets
Definition: electromagnet – A coil with an iron core inside it.
It becomes a magnet when an electric current passes through the coil.

11. Make it Stronger To increase the strength of an electromagnet:
Increase the amount of electric current (amps)
Increase the number of coils of the solenoid.
Inserting an iron core (nail).

12. Motors Electromagnetism has endless uses.
One of the most important uses of electromagnets is the electric motor.
Definition: electric motor – a device that converts electrical energy into mechanical energy.

13. Electric Motors
When an electric current passes through an electric motor…
Magnetic forces are produced, which causes the motor to spin.

14. A current can be induced in a conductor when it is exposed to a changing magnetic field.
Definition: EM induction – creating an electric current by using a magnetic field.
EM induction is how we generators to produce electricity for our homes & businesses.

15. For example, the Hoover Dam is one large generator.
Generators
Definition: electric generator - a machine that uses induction to convert mechanical energy into electrical energy.
For example, the Hoover Dam is one large generator.
Inside the dam are generators that use EM induction to produce electricity.

16. Every generator operates the same way:
A turbine is forced to spin.
The spinning turbine is attached to a solenoid.
On either side of the solenoid is a very powerful permanent magnets.
As the solenoid spins, the magnets cause electrons to move through its wires.
Electricity is produced as the electrons move.

17. Turbines
Definition: turbine – a rotating wheel with blades. It uses the KE of water, wind, or steam to spin.

18. ELECTRICTY IS GENERATED!
The steam moves over the turbine, causing it to spin.
A magnet attached to the turbine spins inside a wire coil
ELECTRICTY IS GENERATED!