1. Agenda: #motivationalmonday Magnet Notes Homework: None ☺
WELCOME BACK!
Monday, March 23, 2015
Objective: Magnet Notes; I will analyze how Ohm’s law affects electricity.
Agenda:
#motivationalmonday
Magnet Notes
Homework: None ☺

2. #MOTIVATIONALMONDAY

3. Spring Break starts in 4 days!!
#motivationalmonday
Spring Break starts in 4 days!!
What are you looking forward to over Spring Break?
What are your plans for Spring Break?

4. MAGNETISM

5. Magnetism:
Magnetism is a property of matter in which there is a force of attraction or repulsion between unlike or like poles.
Magnetic forces are strongest near the ends, or magnetic poles.
The Magnetic Field is the area around the magnet where the forces act.

6. Magnetism:
The rock magnetite, lodestone, is a naturally occurring magnet.

7. Magnetism:
Earth acts like a magnet with a magnetic North and South Pole. These poles are not where you might think they should be! The magnetic north pole is actually located in northeastern Canada about 1600 miles from the the Geographic North Pole. The magnetic south pole is located near the Antarctica Circle. 

8. Magnetism

9. Magnetism
Scientists believe that magnetism is due to the motion of electrons, particularly their spin.
Electrons usually occur in pairs, but in some metals they occur alone. Electrons that occur in pairs spin in opposite directions and their spins cancel out their magnetic forces. If the electrons that are alone are arranged so they are all spinning in the same direction with their north pole all facing one direction and their south poles facing the other direction, they produce a magnetic field that can be felt.

10. Two Types of Magnets
Permanent magnets are made of materials which show strong magnetic properties and don’t lose those properties for a long time.

11. Two Types of Magnets
Temporary magnets are made of materials which accept a magnetic charge from another magnet but don’t hold onto that charge after they are separated from the magnet. 

12. Two Types of Magnets
In iron, nickel and other magnetic materials the magnetic field created by each atom causes groups of atoms to line up their magnetic poles so that all are facing the same direction. These groups of atoms are called magnetic domains.

13. Two Types of Magnets
This is how you can stroke a nail with a magnet and turn the nail into a temporary magnet.

14. Oersted’s Discovery
1820, Hans Christian Oersted lecturing a physics class noticed a wire lying above a compass. When a current was passed through the wire, the compass needle was deflected about 90 degrees. When the current was reversed the needle swung 90 degrees in the opposite direction.

15. Electromagnets
Powerful temporary magnets made by wrapping a coil of wire around soft iron core and passing an electric current through the wire. The strength of the magnet can be increased by increasing the number of loops of wire around the iron core, or by increasing the voltage of the current passing through the wire. 

16. Michael Faraday
This relationship between electricity and magnetism is called electromagnetism.
In 1831, Michael Faraday discovered that an electric current can be produced from a magnetic field. This process is called electromagnetic induction.

17. Michael Faraday
One important use of electromagnetic induction is the operation of a generator which turns mechanical energy into electrical energy.
Electromagnetism and electromagnetic induction are combined in the operation of a transformer, which is a device that increases or decreases the voltage of alternating current.

18. Transformers
A transformer that increases voltage is called a step-up transformer.
A transformer that decreases voltage is called a step- down transformer.

19. Transformers
A.C. Alternating Current-electrons moving back and forth through a wire, changing direction over and over.
D.C. Direct Current- Electrons continuously moving in the same direction through a wire.
Electricity coming into your home is A.C.
Electricity from a battery is D.C.