1. Magnetism

2. Magnets… Always have a North & South Pole
The magnetic field is produced by the motion of electrons spinning in the same direction.
In most substances, the spins cancel each other, but Iron electrons & a few others can be made to spin in the same direction, producing a magnetic field

3. Ferromagnetic
A magnetic domain is a region that has a very large number of atoms with aligned magnetic fields. If a substance has this domain it can be magnetized. This substance is called ferromagnetic
But being ferromagnetic does not mean it is a magnet
When a material is magnetized, most of its magnetic domains are aligned

4. Magnetic Fields
Magnetic Fields surround a magnet and can exert magnetic forces
These fields are strongest near a magnetic pole

5. The magnetic field around the earth shields us from harmful radiation

6. Electricity and Magnetism
Electromagnetic force:
Electricity and magnetism are different aspects of one force.
Moving electric charges create a magnetic field.

7. Solenoids and Electromagnets
A solenoid is a coil of current-carrying wire that produces a magnetic field
A solenoid with a ferromagnetic core is called an electromagnet
Changing the current in an electromagnet controls the strength and direction of its magnetic field

8. The strength of an electromagnet depends on the current in the solenoid, the number of loops in the coil in the solenoid, and the type of ferromagnetic core.
Increase the current – increase the strength
Increasing the number of turns, leaving current the same, increases the field strength

9. Uses of Electromagnets
An Electric Motor is a device that uses an electromagnet to turn an axle

10. MRI- Magnetic Resonance Imaging
This device is used by doctors to create more detailed images of the human body than are possible with x-rays

11. Electrical Energy Generation And Transmissions
Electromagnetic induction is the process of generating a current by moving an electrical conductor relative to a magnetic field

12. Faraday’s Law
Michael Faraday’s law states that a voltage is induced in a conductor by a changing magnetic field
This allows for the generation of electricity by power plants

13. Generators
A Generator is a device that converts mechanical energy into electrical energy by rotating a coil of wire in a magnetic field.
Two types of generators AC and DC Generators

14. Transformers
A Transformer is a device that increases or decreases the voltage and current of two linked AC circuits
A transformer changes voltage and current by inducing a changing magnetic field in one coil.
This changing field then induces an alternating current in a nearby coil with a different number of turns

15. Transformers Step down transformers Step up transformers
decrease voltage and increase current
Step up transformers
increase voltage and decrease current

17. Energy in our homes
Most of the electrical energy generated in the U.S. is produced using coal
Other sources of energy are water (hydroelectric), nuclear energy, wind, natural gas, and petroleum
These generators have a large device with fanlike blades that turn when pushed. This device is called a turbine