07 magnetism
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Transcript of 07 magnetism
MagnetismMagnetismResources:Grob: Basic Electronics Textbook: Chapter 14http://www.coolmagnetman.com/magindex.htmhttp://www.sayedsaad.com/fundmental/3_Basic%20AC%20Generation.htm
http://micro.magnet.fsu.edu/electromag/java/index.htmlhttp://www.regentsprep.org/Regents/physics/phys03/dinduction/default.htm
http://www.exploratorium.edu/snacks/iconmagnetism.html
http://www.school-for-champions.com/science/magnetism.htmhttp://www.school-for-champions.com/science/magnetism.htm
ObjectivesObjectives Formulate a definition of magnetism.Formulate a definition of magnetism. Identify types of magnets.Identify types of magnets. Define permeability.Define permeability. Describe the principle of Describe the principle of
electromagnetism.electromagnetism. Describe how to determine the polarity of Describe how to determine the polarity of
an electromagnet using the left hand rule.an electromagnet using the left hand rule. Describe some uses of magnetism.Describe some uses of magnetism. Define electromagnetic induction /how to Define electromagnetic induction /how to
increase induced current.increase induced current.
Historical PerspectiveHistorical Perspective 44thth Century Chinese & Ancient Greeks in Century Chinese & Ancient Greeks in
city of Magnesia: Loadstone from lava city of Magnesia: Loadstone from lava flowsflows
1212thth Century Chinese: Compass Century Chinese: Compass
1616thth Century: William Gilbert, Century: William Gilbert, Physician to Queen Elizabeth Physician to Queen Elizabeth suggested that the earth must suggested that the earth must be a magnet. be a magnet.
Modern CompassModern Compass
Earth’ Magnetic FieldEarth’ Magnetic Field MagnetosphereMagnetosphere
Van Allen beltVan Allen belt Aurora BorealisAurora Borealis
Types Of MagnetsTypes Of Magnets PermanentPermanent
Electromagnet (Temporary)Electromagnet (Temporary)
Permanent Magnets: Permanent Magnets: What Causes Magnetism?What Causes Magnetism?
Electron Spin and OrbitElectron Spin and Orbit Dipoles Lining UpDipoles Lining Up
Magnetism PropertiesMagnetism Properties Like Poles RepelLike Poles Repel Unlike Poles AttractUnlike Poles Attract
DefinitionDefinition
Definition: Magnetism is an invisible Definition: Magnetism is an invisible force field which acts upon some force field which acts upon some materials but not upon others. materials but not upon others.
Magnetism has an effect on all Magnetism has an effect on all materials but some materials have the materials but some materials have the ability to strengthen this effect more ability to strengthen this effect more than others.than others.
Permeability (ability to concentrate flux)Permeability (ability to concentrate flux)
PermeabilityPermeability
0
5000
10000
15000
20000
25000
Al Cu Steel Permalloy Mumetal Alnico Ferrite
Permeability
Electromagnetism: The Catalyst For Electromagnetism: The Catalyst For Technological Invention and Innovation Technological Invention and Innovation
Hans Oersted
Revolutionary War
Abraham2000 BC
Moses 1400 BC
Isaiah800 BC
Jesus andApostles
Constantine300 AD
Gutenberg1400 AD
Watt1765 AD
Volta / Galvani 1800 AD
Dark Ages
Columbus1492 AD
Transportation (mph)
Communication
Information Management
Electromagnets: Hans Electromagnets: Hans OrstedOrsted
Demo of Orsted's ExperimentDemo of Orsted's Experiment
Effect of Oersted’s DiscoveryEffect of Oersted’s Discovery
Hans Oersted
ComputersFax MachinesCell PhonesCD’s / DVD’sInternet
Edison: Light Bulb1879
Ampere: Electrodynamics 1821BC
FaradayElectromagnetism1821 Wright Bros
Air Flight1903
Benz: Automobile1885
1890Electric PowerAvailable
Bell Labs: Transistors1947
Marconi: Radio1896
Bell: Telephone1876
Transportation (mph)
Communication
Information Management
Farnsworth: TV1927Morse: Telegraph
1835
Oersted’s discovery wasIn the Spring of 1820
Ways to strengthen an Ways to strengthen an ElectromagnetElectromagnet
Coil the WireCoil the Wire
Increase the number of Increase the number of coils per given areacoils per given area
Add a permeable coreAdd a permeable core
Increase the current!Increase the current!
Determining the Polarity of an Determining the Polarity of an ElectromagnetElectromagnet
Using your left hand, wrap your Using your left hand, wrap your fingers around the coil the same fingers around the coil the same direction that the electrons will flow. direction that the electrons will flow. Your thumb is pointing to the north Your thumb is pointing to the north pole of the electromagnetpole of the electromagnet
_ +
Left Hand Rule Left Hand Rule (Checking for Understanding)(Checking for Understanding)
Draw on BoardDraw on Board Change polarity of sourceChange polarity of source Change direction of windingChange direction of winding
Common uses of magnetismCommon uses of magnetism MotorsMotors InductorsInductors GeneratorsGenerators TransformersTransformers RelaysRelays SolenoidsSolenoids Speakers/MicrophonesSpeakers/Microphones Information Storage DevicesInformation Storage Devices
Teacher Note: Scattegories Game??Teacher Note: Scattegories Game??
SolenoidSolenoid
Draw Operation on boardDraw Operation on board Solenoid Operation: DoorbellSolenoid Operation: Doorbell
Speaker / MicrophoneSpeaker / Microphone Speaker Operation Speaker Operation (continue through step 6)(continue through step 6)
Speaker Operation #2Speaker Operation #2
Electric MotorElectric Motor Electric Motor OperationElectric Motor Operation Beakman’s motor labBeakman’s motor lab
Single Pole Pulse Motor Single Pole Pulse Motor (Beakman’s)(Beakman’s)
1.1. Choose a dowel the size you want to Choose a dowel the size you want to make your motormake your motor
2.2. Using enamel coated wire loop the Using enamel coated wire loop the wire in the following configurationwire in the following configuration