Warm-Up Pick up two sheets and packet in the back. Work on Mini Lab at your desk.

Electricity and Magnetism Chapter 7

Objectives Relate electron movement to electric charge Compare charge production by friction, induction, and conduction

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Atomic Structure Proton (+) Electron (-) Neutron (0)

Gaining or Losing Electrons Electrons can move from one atom to another Lose electron = + charge Gain electron = - charge Law of Attraction

Static Electricity When a charge builds in an object

Charging Objects Electric Charge can occur in 3 ways: Friction Induction Conduction

Static Hair Friction “rubs off” electrons to another object Objects become oppositely charged Will attract each other (Hair to Balloon)

PhET Simulation pages/simulations-base.htmlhttp://phet.colorado.edu/web- pages/simulations-base.html

Static Cling Dryer Steals – by friction Clothes have + and attract to your – Pulled apart leads in shock or - transfer

Review How Occurs Same/Opp Charge Repel/ Attract Friction Rubbing objects together Opposite charges Attract Induction Conduction

Induction A charged object is brought near a neutral object Charge repels similarly charged particles Develops opposite charge Will attract (balloon to balloon)

PhET Simulation (Again) pages/simulations-base.htmlhttp://phet.colorado.edu/web- pages/simulations-base.html

How Occurs Same/Opp Charge Repel/ Attract Friction Rubbing objects together Opposite charges Attract Induction Bringing charged object close to uncharged object Opposite charges Attract Conduction

A charged object touches a neutral object Charge transfers Develop similar charge and will repel

Van de Graff

Review How Occurs Same/Opp Charge Repel/ Attract Friction Induction Conduction Rubbing objects together Bringing charged object close to uncharged object Touching charged object to uncharged object Opposite charges Same charges Attract Repel

When you build up a charge then touch something, what happens???

Electric Shock When a charged object touches a neutral or oppositely charged object, electrons are transferred called static discharge Leads to a shock

John Travoltage and Shock pages/simulations-base.htmlhttp://phet.colorado.edu/web- pages/simulations-base.html

Lightning Winds separate charges Pushes charge on ground Attracts to Meet in middle

Question: Some say your hair will stand on end just before a lightning strike? Does this make sense to you? Why or why not?

Grounding Grounding allows for removal of excess charge to protect from lightning, appliances

Warm-Up 1. What are 3 ways an object can receive a charge? Will they be attracted or repelled by the object that charged them?

Circuits – Open vs. Closed Switches open and close circuits. back

Wires Resistors Light bulbs Switches Chemical cell Battery circuit with 2 cells wired in series Battery circuit with 2 cells wired in parallel. AC source (generator) Circuit Diagram

Complete “Conductor or Insulator” then do “Principles of Electrical Circuits”

Warm-Up Draw circuits with the following components. 1 bulb, 1 cell 2 bulbs, 2 cells, switch 1 switch, resistor, alternating current

Back

Warm-Up What is the difference between an open and a closed circuit? Why are switches important in circuits? Why are circuit breakers important in circuits?

Review Circuit Lab

Circuit Circus Lab Answer all questions and draw diagrams in your composition notebook.

Continue working on your Circuit Circus Lab until you are finished.

Types of Circuits Draw Diagrams for two bulbs and two cells Closed Open Series Parallel – Put in a switch that will turn one light off but not the other.Parallel

Circuits - Series Current flows through one loop If remove a bulb, all go out Examples: flash lights and some holiday lights. back

Circuits - Parallel Contain two or more branches for current to flow through The voltage in each loop is equal. If remove bulb, others stay lit Houses contain these circuits.

Circuit Lab II Complete the Circuit Lab II.

Review Circuit Lab II Circuit Simulation

Study for Circuit Quiz

Ohm’s Law Explains the relationship between current flow and electron source

First… What is Current, Voltage, and Resistance Try it out… Battery Simulation

Voltage Provides source of energy for electron flow. Electrons will flow from High Voltage (negative) to Low Voltage (positive or less negative) Measured in Volts (V) Batteries or Generator (Outlet)

Current The flow of electrons through a wire or any conductor is called electric current. Measured in Amperes (A) Battery Simulation

AC/DC What is the difference? Faraday’s Simulation

Direct Current DC One-Way Flow Batteries

Alternating Current AC Two Way Flow Generators – from your outlet

Resistance Resistance opposes the flow of electrons. Measured in Ohms Resistance leads to energy transformations that make appliances work (Light Bulb, Oven Filament)

Resistance in Wires depends on thickness and length Return to Battery Simulation

Ohm’s Law EquationLaw V = I x R Voltage = Current x Resistance Volts = Amps x Ohms 1 Volt pulls 1 Amp through 1 Ohm

Working Problems with Ohm’s Law

Warm Up Any questions about Ohm’s Law problems that you did for homework?

Review Static Electricity Build up of a charge? –Friction –Induction –Conduction Series and Parallel characteristics Circuit diagrams Voltage, current, resistance Ohm’s Law problems

Magnetic Domains Groups of atoms with aligned magnetic poles

Inducing Magnetic Fields or Currents Running a current around an object realigns magnetic domains –Electromagnet, electric motors Running a magnet past an object forms a current –generator Simulations

Electromagnets Temporary magnet made by wrapping a current around a conductor

Electromagnets Electromagnet Lab Strengthened by: Increasing Number of Coils Increasing Core Increasing Amperage of Current

Producing Electricity with GeneratorsElectricity Generators Electromagnetic Induction – production of electricity by moving a loop of wire through a magnetic field Mechanical Energy to Magnetic Energy to Electrical Energy

Electric Motors Electrical Energy to Magnetic Energy to Mechanical Energy Opposite of a generator

Electric Motor Operation