Introduction to Electricity

Introduction to Electricity

Introduction to ElectricityText 10.1: Pages 394-399AgendaMinds On: Inquiry Black Out!!!Case Study Wind farms in OntarioWhat is Electric Charge?Static ElectricityCharges & FrictionLaws of Attraction & RepulsionConsolidation Activity Quick LabLearning GoalBy the end of this class, we should be able to:explain the characteristics and behaviour of electric chargeInquiry TaskHow long could you go without power?How long could you go without your cell phone?How long could you go with out your computer?

Inquiry Task

Black Out! August 14, 2003Inquiry Task Where Does Our Power Come From?

Action Case Study

Unit Big Question How can we meet the growing electrical needs and challenges in Ontario?Read the following article: http://www.cbc.ca/news/canada/story/2012/09/10/wind-farm-injunction-ontario-couple.htmlWhat are the main issues?What questions arise from this article?

Consolidation Electricity Concept MapCreate a concept map about electricity p.g. 391Include the following:QuestionsTerms CategoriesSketches

http://library.thinkquest.org/10aug-oracle-62/636923189/page_694594863.html

Where might you encounter

Action - What is Electric Charge?Electric charges are charged particles that exert an electric force on each otherThese charged particles are very small There are millions of them on each hair standing on endThese differences can also cause more shocking displays

That Sounds Familiar!An element is a pure substance that cannot be broken down into simpler substances.Elements are made up of even tinier particles called atomsSpecifically neutrons, electrons and protonsWhen the number of protons and electrons are the same the atom is neutral

How Can you Charge Something?

Objects can then become charged when electrons move from one object to anotherCharge can then build up on the surface of an object when there is an excess of electronsThis is called static charge or static electricity

Static ElectricityIt is called static because the charge generally stays in a fixed position until given an escape route

What is this Object?Positive, Negative or Neutral?

Tree:

Cloud:

Ground:

What Causes Electrons to Move?All solid materials are charged by the transfer of electronsBut what causes an electron to move?When objects rub against one another: Friction!

FrictionThe force of friction between the two surfaces can remove electrons from one object and transfer them to anotherNo electrons are lost! They are just moved!The protons and neutrons never move

How do we Know Where they Go?But how do we know which surface the electrons are transferred to?We can tell via a measure called electron affinityElectron affinity is the tendency of a substance to hold onto electronsThe higher the electron affinity the more likely it is to loose electrons

Triboelectric Series

How do We Measure This?Charles-Augustine de Coulomb was a French physicist who studied electric charges Closer objects are together the greater the repulsion or attraction Farther the objects are from one another the less the repulsion or attraction

Laws of Attraction and RepulsionHave you heard of the saying opposites attractThe law of attraction states that particles with opposite charges attract to each otherThe law of repulsion states with like charges repel each other

Coulombs (C)In his honour the metric unit for electric charge is in his name sakesCoulomb (C)1C= 6.24 x 1018 electrons added to or removed from a neutral objectSo it measures charge

Consolidation ActivityQuick Lab Characteristics of Electric ChargeRead through lab on page 395 and conduct steps 1-4 with your table groupPurpose: To observe the characteristics of electric charge.Conclusion: Answer Q 7-9 in your notebook