1. Electricity

2. Definition The flow of electrical power or charge.
It is a secondary (2o) energy source, which means that we get it from the conversion of other sources of energy, like coal, natural gas, oil, and nuclear power which are all called primary (1o) sources of energy

3. Major Players Benjamin Franklin – kite experiment
Thomas Edison – light bulb
Nicola Tesla – discovered AC (alternating current) in 1879 (only direct current [DC] had been used up to that point)

4. Atoms
Everything in the universe is made of atoms (the smallest basic unit of matter)
One teaspoon of water contains about 500,000,000,000,000,000,000,000 atoms! (that’s 500 sextillion atoms – million, billion, trillion, quadrillion, quintillion, THEN sextillion)

5. Atoms
Atoms are made of small particles called protons, neutrons, and electrons
Protons (+) and neutrons (neutral – no charge) form the nucleus of the atom (the center)
Electrons (-) spin around the nucleus in shells – think Saturn’s rings

6. Atoms
The protons and electrons of an atom are attracted to each other. They both carry an electrical charge. An electrical charge is a force within the atom. When an atom is in balance, it has an equal number of protons and electrons. Opposite charges attract each other.

7. Static Electricity Electrons jump from one object to another
For example, you walk across a carpet while wearing socks. You touch a doorknob and you get a shock because electrons jumped from the doorknob to you.

10. Circuits Electricity travels in circuits (closed loops)
Circuit comes from the word ‘circle’
Circuits must be closed for electrons to flow

11. Open
Closed

12. What is the little wire inside a light bulb called?
Filament

13. Measuring Electricity
Electricity is measured in units of power called watts
Named after James Watt, the inventor of the steam engine
One kilowatt = ____ watts
One kilowatt = 1000 watts

14. Electric Charge
Protons and electrons have an electric charge – a property that allows an object to exert an electric force on another object without touching it
Electric force = push or pull
Protons = positive (+) charge
Electrons = negative (-) charge

15. Electric Field Def. – An area surrounding a charged object
Opposite charges attract each other

16. Electric Field
Similar (like) charges repel each other

17. Electric Field

18. Static Charge Protons and electrons have electric charges
Objects and materials can also have charges
Static Charge – a buildup of electric charge in an object caused by the presence of many particles with the same charge

19. Static Charge
Some objects with high static charge:

21. Net Charge
Def. – The total number of unbalanced positive or negative charges in an object
Material with excess protons = positive net charge
Material with excess electrons = negative net charge
Net charge is measured in coulombs

22. Two Methods of Charging
1. Charging by Contact
2. Charging by Induction

23. Charging by Contact
When two uncharged objects made of certain materials (such as rubber and glass) touch each other, electrons move from one material to the other

24. The balloon and the glass rod each have balanced, neutral charges+
The balloon and the glass rod each have balanced, neutral charges - + - - + + - + - - +
When they touch, electrons move from the rod to the balloon - - + + - +
Afterwards, the net charge of the balloon is negative, and the net charge of the glass rod is positive + - - + - +

25. Charging by Contact
Materials higher up on the list are more likely to give up electrons than materials lower on the list
Skin
Glass
Hair
Nylon (Under Armour)
Wool (Socks, Sweaters)
Fur
Silk
Paper
Rubber (Balloons)
Polyester

26. Charging by Induction
If a material already has a net charge, charging by induction can occur
Induction – the build up of charge without direct contact