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Pick up a clicker, find the right channel, and enter Student ID. Upcoming Deadlines. Second Term Paper – Science Fact or Cinematic Fiction? Due Wednesday, November 17 th (Next week) 100 points (50 points if late) Homework #11 – Building a Scene in Maya - PowerPoint PPT Presentation

Transcript of Upcoming Deadlines

  • Upcoming DeadlinesSecond Term Paper Science Fact or Cinematic Fiction?Due Wednesday, November 17th (Next week)100 points (50 points if late)

    Homework #11 Building a Scene in MayaDue Wednesday, November 24th (Day before Thanksgiving)20 points (10 points if late)

    For full schedule, visit course website:ArtPhysics123.pbworks.comPick up a clicker, find the right channel, and enter Student ID

  • Activating your Clicker* Turn on your clicker.* Enter the channel number or letter for joining this class. Hit Enter/Send key.* Clicker should read AP123S258* Type in your student ID; hit Enter/Send.Clicker is now ready to use; leave it on.Hit any key to wake the clicker from sleep mode.

  • Survey QuestionHow much experience do you have using AutoDesk Maya?

    A lot of experienceA little experienceNever used it but know of itNot familiar with it at all

  • Review QuestionWhich of these is not a mechanism for heat transfer?

    Conduction Radiation Reduction Convection

  • Heat TransferC) ReductionConductionConvectionRadiation

  • Review QuestionFill in the blanks:

    Two objects with positive charge _______ each other and two objects with negative charge _______ each other.

    Attract RepelRepel AttractAttract AttractRepel Repel++--

  • Electric Charges and ForcesD) Repel RepelREPELREPELATTRACTLike charges repel, opposite charges attract.Note that by Action/Reaction, the force on each object is always equal in magnitude, opposite in direction.

  • Review QuestionFlowing electrons strike atoms in a conductor, heating the material.This type of heating is named after:Andr-Marie AmpreNicola TeslaThomas EdisonGeorg OhmAlessandro Volta


  • Ohmic HeatingGeorg Simon Ohm (1789 1854) was a German physicist. As a high school teacher, Ohm began his research with the recently invented electrochemical cell, invented by Italian Count Alessandro Volta.

    Using equipment of his own creation, Ohm determined that there is a direct proportionality between the potential difference (voltage) applied across a conductor and the resultant electric current now known as Ohm's law.Ohmic heating is also called Joule heating, first studied by James Prescott Joule in 1841Georg Ohm

  • Effects Animation:Electricity & MagnetismPart 2

  • WARNINGStrong magnets will be passed around the room. Keep these magnets away from iPods and laptops (especially my laptop)!

  • ElectrocutionElectrocution (death by electric shock) is usually due to ohmic heating of the internal organs of the body.

    True or False

  • ElectrocutionFalse

    It is due to the disruption of the nervous system, especially that which controls the heart beat.

  • Nervous SystemNervous systems in animals use electrical currents to signal the contraction and relaxation of muscles.Frog leg jumps when electrical current passes through it.

  • Presto (2008)Common visual gag is the uncontrollable twitching of a persons muscles. Notice Jacobs Ladder in Prestos hairhttp://www.youtube.com/watch?v=mw-fs19kTGM

  • Sherlock Holmes (2009)The electric shock does not exert a force, rather it causes muscles to contract; this scene is not realistic.

  • Conduction in Human HeartThe most important electrical signal in our body is the periodic signal that contracts and relaxes our heart muscle to pump blood.Without a constant flow of blood the brain can suffer permanent damage.


  • Electric ShockThe damaging effects of shock are the result of electrical current passing through the body. Effects of Electric Shock on Human BodyCurrent depends on the voltage and on electrical resistance.

    When dry, skins resistance around 100,000 .

    Resistance drops as low as 100 when wet and salty.

    Current (A)Effect0.001Can be felt0.005Is painful0.010Causes involuntary muscle contractions (spasms)0.015Causes loss of muscle control0.070If through the heart, serious disruption; probably fatal if current lasts for more than 1 s

  • Frankenstein (1931)Electricity brings Frankensteins monster to life in the 1931 horror classic yet its not mentioned in the original book, written in 1818 by Mary Shelley.

    Bolts for electrical contact http://www.youtube.com/watch?v=8H3dFh6GA-A

  • Magnetohttp://www.youtube.com/watch?v=rKc4BWvWtuMThe majority of the animation and lighting in this scene was done in Maya.Magneto, the villain in the X-men movies, controls the force of magnetism.

  • Magnetic ForcesGeneral observations regarding magnets:

    Iron (and a few other metals) are ferromagnetic, which means they can become magnetized.

    Magnets attract ferromagnetic metals.

    Two magnets can either attract or repel each other depending on poles.Iron Ore

  • Ferromagnetic MetalsFerromagnetic metals have similar atomic structure.Iron, Cobalt, NickelSpin of the electron in these metals produces a net magnetic fieldMany ferromagnetic alloys (blends of metals)

  • Demo: Magnetism & MoneyMost US coins are not made of ferromagnetic materials but many other countries use iron steel in their currency.Some pennies were made of steel during World War IIBuffalo nickels are 25% nickel metal, which is ferromagneticSome Euro coins contain steelIron is in the ink used in US paper currency to avoid counterfeiting.

  • Magnetizing IronS NS NStrongMagnetStrongMagnetMagnetic domains can be induced to align by an external magnetic field.N

  • Demo: Magnetizing IronMagnetic domains in iron nails are induced to align by proximity of the strong magnetEach nail becomes itself a magnet, which in turn magnetizes the nail below it, forming a chain.When the strong magnet is removed, most of the domains un-align and nail lose most of their magnetization.

  • Demo: Demagnetizing IronIron nail is attracted to the large magnet due to alignment of domains in the nail.

    Heat the nail to a high temperature and the domains become randomized so the nail is no longer attracted to the magnet.

  • Magnets & Wile E. CoyoteWile E. Coyote is surprised when a big metal can of TNT comes flying in, pulled in by his magnet.In reality, the force of the can on the magnet is just as strong as the pull of the magnet is on the can of TNT. True or False?

  • Magnets & Wile E. CoyoteTrue.

    Another example of action/reaction principle (Newtons Third Law).

    Action force is magnet pulling TNT can.Reaction force is TNT can pulling magnet.From Zipping Along

  • Demo: ElectromagnetsElectromagnet created by passing current through a coil of wire.Electromagnet is stronger when an iron bar is inserted within the coil.Connect to battery or power supplyWireCoilNSIron Bar

  • LoudspeakersLoudspeaker has a membrane but oscillations are created by variations in electrical current, which cause an electromagnet to be pulled towards and away from a second, permanent magnet.These oscillations cause the membrane of the loudspeaker to vibrate with the same frequency as the oscillations in the electrical current.Headphones work essentially the same way, theyre just smaller.

  • Earths Magnetic FieldThe configuration of the Earth's magnetic field resembles a strong bar magnet located near the center of the Earth.

    The magnetic South pole is near the geographic North pole (so North pole of compass attracted towards Northern direction).

    There isnt an giant underground magnetized chunk of iron; Earths interior is simply too hot.

    N S

  • Origin of Earths Magnetic FieldEarth is an electromagnet with electric currents deep below the surface. Moving charges, looping around within the molten part of the Earth, create the magnetic field.These currents are possibly the result of thermal convection rising from the central core combined with the rotation of the Earth about its axis.

  • Demo: Electric MotorCan create an electrical motor by passing a current through a set of electro-magnets mounted on a rotating shaft. Current inCurrent outElectro-magnets

  • Electric Motor, AnalyzedElectromagnet mounted on a shaft with opposing magnets on each side.Current direction always such that electromagnet is repelled, causing shaft to turn. NSNSCurrentCurrent

  • Demo: Magnetic Force & CurrentMoving charges in an electric current experience a force due to magnetic field.

  • Demo: Crookes TubeElectron beam in a Crookes tube is deflected when a magnet is brought near the tube.

  • *Television TubeElectron beams, deflected by magnetic fields, are used to create TV images.Electromagnets

  • Demo: Magnets & TV setsN

    SPicture on a TV set is distorted by presence of a magnet since picture formed by an electron beam.Warning: Strong magnets can permanently damage a television or a computer.

  • Demo: Magnet Induces CurrentVoltage and current are induced when a magnet moves towards or away from a coil of wire.Faster the magnets motion, the greater the induced current.

  • Demo: Electric GeneratorTurn the shaft by hand and as the coils pass the magnets a voltage is induced.DC current is generated.MagnetMagnetCoilsDC OutputSHAFT

  • Magnetic RecordingWrite data by magnetizing recording media (e.g., video tape, hard disk) using electromagnets.Data is read back using the induced current produced when magnetized media moves past receiver coils (reverse of writing data).Hard disk

  • EMP (ElectroMagnetic Pulse)A strong, rapidly fluctuating magnetic pulse can induce high voltage, causing strong currents.In 1962, a nuclear test in the Pacific produced an EMP that knocked out 300 streetlights and telephone servi