ELECTRICITY

ELECTRIC CHARGE SI unit for electric charge is Coulomb (C).

ELECTRIC FORCE Force of attraction or repulsion LIKE charges REPEL OPPOSITE charges ATTRACT

STATIC ELECTRICITY Static Discharge – when a pathway for charges to move forms suddenly –Ex: Lightening, shock

CHARGING 1.Charging by Friction – friction between two objects transfers electrons. EX: Balloon and hair; electrons move from the hair to the balloon and now the balloon is neg. and the hair is pos. 2.Charging by Contact – when someone touches a something to allow the charge to travel. EX: When a person touches a generator to cause their hair to stand up 3.Charging by Induction – when charge is transferred without contact EX: when you touch a doorknob and get shocked – neg. charges in your hand cause charges to move in the metal.

ELECTRIC CURRENT Continuous flow of electric charge The SI unit for electric current is ampere (A), or amp

TYPES OF CURRENTS Direct Current (DC) – charge flows in ONLY ONE direction –EX: Flashlight Alternating Current – (AC) – charge that can reverse its direction in several ways. –EX: House

CONDUCTORS AND INSULATORS Conductors – material where charge can flow easily. –Metals Insulators – material through which charge cannot flow easily. –Coating on wires, wood, plastic, rubber, glass, and air

RESISTANCE Opposes the flow of electric charges SI unit for resistance is Ohm A materials thickness, length, and temperature affect its resistance. As temp. increases the resistance increases

OHM’S LAW V = I x R or I = V R V = voltage I = Current R = resistance * Increasing the voltage increases the Current

Electricity Quiz 1.What is the SI unit for electric charge? 2.Like charges ______ while opposite charges ________. What is it called when a pathway for charges to move forms suddenly? Charging by __________– when charge is transferred without contact What is SI unit for electric current? What current flows only one direction? What is a material that a charge can flow easily? What is a material that a charge cannot flow easily? What is SI unit for resistance? A material’s ________, _________, and _________ affect its resistance.

Answers 1.Coulomb (C). 2.Repel, attract 3.Static discharge 4.Induction 5.ampere (A), or amp 6.Direct current 7.Conductors 8.Insulators 9.Ohm 10.thickness, length, and temperature

ELECTRIC CIRCUITS

Complete path through which charge can flow. Switches can be opened to allow electricity to flow or closed.

TYPES OF CIRCUITS Series Circuit – charge has ONLY ONE way to flow (direct current) –If one element stops working they all stop –EX: Flashlight, car

Parallel Circuit – charge can flow through TWO or MORE pathways (alternating current). –If one element stops functioning the rest will still operate –EX: House

POWER AND ENERGY Electrical power – the arte at which electrical energy is converted to another form of energy. SI unit for electrical power is Watt (w) P = I x V

ELECTRICAL SAFETY Fuse – prevents current overload in a circuit Circuit Breaker – switch that opens when the current in a circuit is too high Grounding – transfer of excess charge through a conductor to Earth

Electric Circuits Quiz 1.What is a series circuit? 2.What is an example of a series circuit? 3.What is a parallel circuit? 4.What is an example of a parallel circuit? 5.What is the Scientific Unit for electrical power? 6.What is the definition of electrical power? 7.What is a circuit breaker? 8.What does a fuse prevent? 9.What is grounding? 10.What is the Scientific Unit for electric current?

1.Series Circuit – charge has ONLY ONE way to flow (direct current) If one element stops working they all stop 2.EX: Flashlight, car 3.Parallel Circuit – charge can flow through TWO or MORE pathways (alternating current). If one element stops functioning the rest will still operate 4.House 5.Watt 6.the arte at which electrical energy is converted to another form of energy. 7.switch that opens when the current in a circuit is too high 8. current overload in a circuit 9.transfer of excess charge through a conductor to Earth 10. Ampere or Amp

Magnetism

Magnetic Force- LIKE repels LIKE, LIKE attracts UNLIKE Magnetic Field- Surround a magnetic and always starts at the North Pole and extends toward the South Pole

Ferromagnetic Materials- materials that are easily magnetized and demagnetized. a. Magnetized objects have ALIGNED magnetic domains. b. Demagnetized materials have RANDOM magnetic domains.

Permanent Magnets- always have aligned domains and it is very difficult for them to lose their magnetism.

ELECTROMAGNETISM

Electromagnetic Force- caused by electric forces a. Moving electric charges create a magnetic field b. Changing the current in an electromagnet controls the strength and direction of its magnetic field

Electromagnetic devices- convert electrical energy into motion that can do work 1. Galvanometers- uses a coil of current carrying wire that produces a magnetic field to measure small amounts of current that moves a pointer. Ex. Gas gauge

2. Electric Motors- uses an electromagnet to turn an axle 3. Loudspeaker- a magnetic force moves the coil back and forth causing the thin membrane to vibrate producing sound waves