1. Electricity & Magnetism
Chapters 6,7,8,9 & 10
Electricity & Magnetism

2. Electrons are free-moving (can be lost or gained)
The Atom
3 Subatomic Particles
1. Proton: (+), nucleus
2. Neutron: neutral, nucleus
3. Electron: (-), outside
Electrons are free-moving (can be lost or gained)

3. Force of Repulsion: Like charges repel each other
Electrical Forces
Force of Repulsion: Like charges repel each other
Force of Attraction: Opposite charges attract each other

4. Region around a charged particle where the force is noticeable
Electrical Field
Region around a charged particle where the force is noticeable
Strongest near the charged particle.

5. Energy created by electrons moving from one place to another.
Electricity
Energy created by electrons moving from one place to another.
Static Electricity: build up of electrons
Ex) Lightning
Click hear for more information

6. 1. Friction: rubbing objects together to separate charges.
Methods of Charging Objects
1. Friction: rubbing objects together to separate charges.
Ex) rubbing feet on carpet, a car seat, balloon, etc...

7. 2. Conduction: transfer of electrons through direct contact.
Conductors: easy flow of electrons
Insulators: inhibit flow of electrons

8. Ex) sticking a balloon to wall
3. Induction: rearrangement of electrons by indirect contact.
Ex) sticking a balloon to wall

9. Electroscope
Detects electrical charges; leaves spread apart in the presence of charges

10. Voltage: The “push” that makes electrons move.
Flow of Electricity
Voltage: The “push” that makes electrons move.
Unit: volt Symbol: “V”
Current: the flow of electrons through a wire
Unit: ampere or amp Symbol: “I”

11. Resistance: opposition to the flow of electricity.
Unit: ohm Symbol: “R”
1. Type of Material: good conductors = less resistance
2. Thickness of Wire: large wire = less resistance

12. Ohm's Law
Current (amp)
Voltage (volt)
I = V R
Resistance (ohm)

13. Wet Cell: Uses liquid (cars). Dry Cell: Uses a jelly-like fluid.
Batteries
Wet Cell: Uses liquid (cars).
Dry Cell: Uses a jelly-like fluid.

14. Current Direction
1. Direct current: electron flow is always in the same direction (batteries)
2. Alternating current: electrons reverse the direction of flow 60 times per second (homes)

15. Electrical Circuits
Parts of a Circuit:

16. Series Circuit
One path for the electrons to take; if one part goes out, the circuit is open electricity will NOT flow.

17. Parallel Circuit
More than one path for the electrons; if a break occurs in one branch, the electrons can still flow.

18. The amount of energy an appliance uses depends on:
Electrical Energy
The amount of energy an appliance uses depends on:
1. Total power used
2. Total time

19. A force of attraction or repulsion due to an arrangement of electrons.
Magnetism
A force of attraction or repulsion due to an arrangement of electrons.
Forces are strongest at the poles
North and South Poles
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20. Attraction vs. Repulsion
Opposites attract
Likes repel

21. 1. Natural Magnet: occur naturally
Magnetic Materials
1. Natural Magnet: occur naturally
2. Magnetic Induction: creating temporary magnets
3. Temporary: soft iron is easy to magnetize but loses it quickly.

22. 4. Permanent: cobalt & nickel are harder to magnetize but stay permanently.

23. Earth is surrounded by a magnetic field.
Earth as a Magnet
Earth is surrounded by a magnetic field.
Magnetic Variation: compasses point to magnetic north, not geographical north. (smallest at equator)

25. Magnetic Domains
In magnetized objects, all the north and south poles point in the same direction.

26. There are 3 ways to disturb the domains...
Disturbing the Domains
There are 3 ways to disturb the domains...
1. Heat up
2. Drop repeatedly
3. Hit hard

27. Uses electricity and magnets
Electromagnets
Uses electricity and magnets
Wrap wire around a soft iron core and pass electricity through the wire.
Increase strength by:
1. Increase # of loops
2. Increase current flow

28. 1. Motors: converts electrical energy into mechanical energy.
Electric Devices
1. Motors: converts electrical energy into mechanical energy.
2. Generators: converts mechanical energy into electrical.

29. Step-up: increases voltage Step-down: decreases voltage
3. Transformers: increase or decrease the voltage of an alternating current.
Step-up: increases voltage
Step-down: decreases voltage

30. 4. Circuit Breaker: protects your household circuits from overloading.
Fuse: a piece of metal that melts when overloaded