ElectricityElectricity

Question:Question:

•What is What is electricity?electricity?

Answer:Answer:•Electricity is a form of Electricity is a form of energy. Like light, heat, energy. Like light, heat, and sound, electricity and sound, electricity can be found free in can be found free in nature. Electricity nature. Electricity completely surrounds completely surrounds us!us!

F. Y. I.F. Y. I.

•Electricity starts Electricity starts with electrons.with electrons.

Law of Electric Charges:Law of Electric Charges:

•The law that states like The law that states like charges repel (move charges repel (move away from one another) away from one another) and opposite charges and opposite charges attract (move towards attract (move towards one another)one another)

Electric Force:Electric Force:

•The force of The force of attraction or attraction or repulsion on a repulsion on a charged particle that charged particle that is due to an electric is due to an electric fieldfield

Friction:Friction:•A method of charging A method of charging an object by an object by RUBBINGRUBBING it against another it against another object – electrons are object – electrons are “wiped” from one “wiped” from one object to anotherobject to another

F. Y. I.F. Y. I.•When a balloon is When a balloon is rubbed against a rubbed against a person’s hair, friction is person’s hair, friction is created.created.

•When a person rubs When a person rubs their feet on carpet, their feet on carpet, friction is created.friction is created.

Conduction:Conduction:

•A method of charging A method of charging an object that occurs an object that occurs when electrons move when electrons move from one object to from one object to another by another by DIRECT DIRECT CONTACTCONTACT..

F. Y. I.F. Y. I.

•You will see conduction You will see conduction happen this week happen this week during a demonstration during a demonstration with an electroscope!!with an electroscope!!

Induction:Induction:•A method of charging an A method of charging an

object that occurs when object that occurs when charges in an uncharged charges in an uncharged object are rearranged object are rearranged WITHOUT DIRECT WITHOUT DIRECT CONTACTCONTACT with a charged with a charged object.object.

F. Y. I.F. Y. I.

•You will see several You will see several examples of examples of induction in class induction in class this week.this week.

F. Y. I.F. Y. I.• Metals have electrons that can Metals have electrons that can

detach from their atoms and detach from their atoms and move around. The detached move around. The detached electrons make it easy for electrons make it easy for electricity to flow through electricity to flow through these materials. These these materials. These materials are called materials are called conductors.conductors.

Conductor:Conductor:

•A material in A material in which charges which charges can freely move.can freely move.

F. Y. I.F. Y. I.• The following objects are examples The following objects are examples

of conductors:of conductors:– SilverSilver BronzeBronze– CopperCopper MercuryMercury– GoldGold GraphiteGraphite– IronIron Dirty waterDirty water– SteelSteel EarthEarth– BrassBrass PeoplePeople

Question:Question:

•What do these What do these objects have in objects have in common (other than common (other than the fact that they the fact that they are all conductors)?are all conductors)?

Answer:Answer:

•They are all They are all metals or metals or contain metal contain metal materials!materials!

Question:Question:

•Why are people Why are people conductors (we conductors (we certainly are not made certainly are not made of silver or gold)?of silver or gold)?

Answer:Answer:•We have trace amounts of We have trace amounts of

metals in our bodies. metals in our bodies. Examples: IronExamples: Iron

CalciumCalcium

MagnesiumMagnesium

ZincZinc

F. Y. I.F. Y. I.• Many materials contain Many materials contain

electrons that are bound tightly electrons that are bound tightly to atoms. These materials are to atoms. These materials are not able to conduct electricity not able to conduct electricity because the electrons in them because the electrons in them are not able to detach from the are not able to detach from the atom. These materials are atom. These materials are called insulators. called insulators.

Insulator:Insulator:

•A material in A material in which charges which charges cannot move cannot move freely.freely.

F. Y. I.F. Y. I.

• The following objects are examples The following objects are examples of insulators:of insulators:– GlassGlass Dry cottonDry cotton– RubberRubber Dry paperDry paper– OilOil Dry woodDry wood– PorcelainPorcelain PlasticPlastic– CeramicCeramic AirAir– QuartzQuartz DiamondDiamond– Pure WaterPure Water

Question:Question:

•If air is an insulator, If air is an insulator, how can a bolt of how can a bolt of lightning flash from a lightning flash from a cloud to the ground cloud to the ground through a non-through a non-conducting material?conducting material?

Answer:Answer:• There is so much electrical energy There is so much electrical energy

stored up between the cloud and the stored up between the cloud and the ground. Eventually the energy is able to ground. Eventually the energy is able to rip the electrons off the atoms in the air. rip the electrons off the atoms in the air. Once the ripping process starts, the air Once the ripping process starts, the air becomes plasma. The plasma can easily becomes plasma. The plasma can easily conduct electricity with the free conduct electricity with the free electrons. The bolt of lightning shoots to electrons. The bolt of lightning shoots to the ground through the plasma the ground through the plasma conductor.conductor.

Question:Question:

•Is water a Is water a

conductor or an conductor or an

insulator?insulator?

Pure water is an insulator, Pure water is an insulator,

but the water you get but the water you get

from the tap is a from the tap is a

conductor because of the conductor because of the

added chemicals.added chemicals.

Answer:

Static Electricity:Static Electricity:

•Electric charge at Electric charge at rest: generally rest: generally produced by friction produced by friction or inductionor induction

Electric Discharge:Electric Discharge:

•The release of The release of electricity stored electricity stored in a sourcein a source