What is a magnet? What are the two poles called? S-72 Students will investigate the properties of electricity and magnetism?

SPS10 Students will investigate the properties of electricity and magnetism. c.Investigate applications of magnetism and/or its relationship to the movement of electrical charge as it relates to - electromagnets - simple motors - permanent magnets Chapter 21 Magnetism

How do magnetic poles interact? How can a magnetic field affect a magnet that enters the field? Why are some materials magnetic while others are not? 21.1 Magnets and Magnetics Fields

Magnetic force – the push or pull a magnet exerts on –Another magnet –On iron or a similar metal –On moving charges 21.1 Magnets and Mag Fields How do magnetic poles interact?

Magnets have two poles –North and south –Like poles repel –Opposite poles attract 21.1 Magnets and Mag Fields How do magnetic poles interact?

Magnetic field – an area around a magnet that will attract or repel other magnets –Begin at the north pole –End at the south pole –Can be seen using iron dust –Arrows point in the direction of force on a north pole –The earth has a magnetic field 21.1 Magnets and Mag Fields How can a magnetic field affect a magnet that enters the field?

Magnetic fields are cause by spinning electrons –Most of the time magnets are paired, and the fields cancel out –Magnetic domain – a region that has a large number of electrons with fields in the same direction –Magnetized – most of the domains are pointed in the same direction 21.1 Magnets and Mag Fields Why are some materials magnetic while others are not?

Doin’ The Happy Test Day Dance S-73

What does an electron do to create a magnetic field? What is a domain? What must happen to the domains in a substance for it to be a magnet? S-74

How can an electric charge create a magnetic field? How is an electromagnet controlled? How does an electric motors work? 21.2 Electromagnetism

Electricity and magnetism are two faces of the electromagnetic force. –Electric force from charged particles –Magnetic force caused by spinning of charged particles 21.2 Electromagnetism How can an electric charge create a magnetic field?

Magnetic fields are formed by moving electric charges (Hans Christian Oersted) –If the charge moves down a wire, the magnetic field circles the wire 21.2 Electromagnetism How can an electric charge create a magnetic field?

Magnetic fields will put a force on a current carrying wire –These ideas are used to build Electromagnets Electric motors Electric generators 21.2 Electromagnetism How can an electric charge create a magnetic field?

Solenoid – a coil of current carrying wire that produces a magnetic field –A ferromagnetic rod inside a solenoid will increase the field strength –This is an electromagnet 21.2 Electromagnetism How is an electromagnet controlled?

The strength of an electromagnet can be controlled by –Changing the current –Changing the number of loops –Changing the type of core 21.2 Electromagnetism How is an electromagnet controlled?

Electric motor –Electricity produces an electromagnet –The electromagnet is attracted or repelled by another magnet –A commutator ring changes the poles as after ½ a spin 21.2 Electromagnetism How does an electric motor work?

What is needed to make an electromagnet work? S-75

Using the right hand rule, what is the direction of the magnetic field around a wire if the current is traveling upward? S-76

How does a generator work? What are some sources of electrical energy in the United States? 21.3 Electrical Energy Generation

Electromagnetic Induction – producing a current by –Moving an electrical conductor in a magnetic field –As simple as running a magnet through a coil –The faster the movement the higher the current –Current stops when the motion stops 21.3 Electrical Energy Gen. How does a generator work?

Generator – converts mechanical energy to electrical energy –Movement to current –Rotates a coil in a magnetic field –Power plants produce AC current 21.3 Electrical Energy Gen. How does a generator work?

Generator –Loops of wire are spun –Whatever runs the power plant spins the wire –Every half spin the direction of current changes –Takes about 3300 watts to run a house 21.3 Electrical Energy Gen. How does a generator work? Generator Simulation

Sources of energy in the US –49.8%Coal –19.9% Nuclear –17.9%Natural Gas –6.5%Hydroelectric –3%Petroleum –2.3%Wind, Solar, Geothermal, Biomass 21.3 Electrical Energy Gen. What are some sources of electrical energy in the United States ?

What is electromagnetic induction? What kind of current does it produce? S-77

A.What is the direction of the magnetic field around the wire (arrow points the direction of the current) B.Draw the field around the magnet below. S-78 NS

Test Day! Happy, Happy! Merry, Merry! S-79