Basics of Magnetism Ch. 1

USES OF MAGNETISM FIND YOUR WAY OUT OF THE WOODS PICK UP STUFF PROTECT YOU FROM COSMIC RADIATION SHUT OFF ELECTRICITY IF CURRENT GETS TOO HIGH TAKE A LOOK INSIDE YOUR BODY PICK UP STUFF HANG STUFF FROM YOUR REFRIDGERATOR FORCE TO DRIVE TRAINS KEYS TO GET INTO DOORS CREATE ELECTRICITY HELP ANIMALS MIGRATE

Magnetism Attractive force between objects made of magnetic materials Lodestone  magnetite Characteristics Magnetic pole Every magnet has a North and a South Pole Likes repel; unlikes attract Magnetic field – area around a magnet where the magnetic force can be observed

Magnetism Magnetic Domains – clusters of atoms inside a material that acts like a magnet Aligned same direction  magnetic Random arrangement  NOT magnetic Ferromagnetic material – domains are arranged easily Iron, nickel, cobalt Destroying Magnets – disrupt the domains Impact – dropping, smashing, hammering Heating Breaking Magnets Two new magnets, each with North and South Poles

Magnetism Making Magnets - Align the domains Rub magnet in one direction Place magnet in magnetic field of another magnet Domain will align in same direction of the field Compass – needle aligns with Earth’s Magnetic Field Electromagnets – current carrying wire (solenoid) wrapped around a ferromagnetic material (core) Power of the magnetism depends on 1) number of coils 2) strength of current 3) type of core material

Earth as a Magnet Acts like a huge bar magnet near geographic North and South Poles Magnetic Declination – difference between magnetic poles and Geographic Poles Depends on where you are Figure 13, Page 26 Circulation of molten rock in core Reverses over time Pattern observed in rocks containing iron

Earth as a Magnet Magnetosphere Earth’s magnetic field Shaped by solar winds – electrical particles coming from the sun Causes it to be spread out on side away from sun Protects us from too much radiation Van Allen Belts Aurora – charged particles from the sun interacting with our atmosphere Most common near poles Aurora borealis – Northern Lights Aurora australis – Southern Lights