1. ELECTRICITY

2. OUTSIDE NUCLEUS-ELECTRON CLOUD
ATOMS
Contain subatomic particles
Subatomic particles: protons, neutrons, and electrons
Protons and neutrons are made up of smaller subatomic particles called QUARKS
PARTICLE
SYMBOL
MASS
LOCATION
PROTON p+
1.67 X g
NUCLEUS
NEUTRON n0
ELECTRON e-
1.1 X g
OUTSIDE NUCLEUS-ELECTRON CLOUD

3. The World is Filled With Electrical Charges
Electric Field- force exerted by an e- on anything that has an electric charge
Opposite charges attract; like charges repel

4. Static Electricity Electrical potential energy
Net accumulation of electric charges on an object
Static electrical discharge- movement of the electrons to relieve this build up
Charging can occur through
Friction
Conduction
Induction

5. Friction Rubbing two objects together
Objects gain a negative charge by gaining electrons from another object

6. Conduction Direct contact of two objects
Conductor- any material that allows electrons to move through it easily
e- are loosely held in electric field
Ex: metals

7. Semiconductors
Solid material that has properties between conductors and insulators
Important for electronics (computers, cell phones, MP3, etc.)

8. Insulators
Material that doesn’t allow electrons to move through it easily
e- are tightly held in electric field
Ex: plastic, wood, rubber, glass

10. Induction Charging through an electric field without direct contact

11. Grounding using a conductor to transfer electric charges to the ground
The ground is an infinite reservoir for electrons because of its large size

12. Electroscope
Instrument that detects the presence of an electrical charge
e- are transferred down the metal ball and down to the aluminum leaves
the leaves become negatively charged and repel from each other

13. Electromagnets
Temporary magnet formed when current passes through a wire coiled around an iron core
Also called a solenoid
Increase the strength by increasing the number of coils in the wire or by increasing the current

14. Generator
Machine that produces an electric current by rotating a coil of wire in a magnetic field

15. Generator-How It Works
Wire coil is wrapped around an iron core and placed between the poles of a permanent magnet
Coil is rotated by an outside source of mechanical energy
As the coil turns in the magnetic field an electric current flows through the wire
When the coil turns so that the ends move past opposite ends of the magnet the current reverses directions
The current changes direction twice with each revolution
ALTERNATOR - generator used by a car

16. Electric Current The net movement of electric charges in one direction
Symbol is I
measured in amperes (amps)
Direct current
batteries
Alternating current
Wall outlet, electric generator

17. Voltage (Potential Difference)
Force that causes electric charges to flow
Flows from high voltage to low voltage
Measured in volts
Symbol is V

18. Resistance Tendency of a material to resist the flow of electrons
Conductors have much less resistance and insulators have high resistance
Symbol is R
Measured in ohms (Ω)
Resistance in a wire increases
As the temperature increases
As the wire gets longer
As the wire gets thinner (diameter decreases)

19. Ohm’s Law
The relationship between current, voltage, and resistance in a circuit
I = __V__ R