Download Week 2: Current and Intro to Circuits

Week 5: Magnetism
October 16th, 2015
Katie Hellier
IRIS Science Academy
Last Week
• Electric Fields
• Where do they come from?
• How do they work?
• What effects do they have on us?
Magnetism
• Moving charges interacting with moving
charges
• Ex: two wires
• Electro-magnetic interactions are linked
• Magnetic forces are electrical forces in a
different frame of reference (relativity)
• Comes from what the material is made
of (atoms, structure)
How does it work?
Think about electricity – attraction vs
repulsion
Video
• Bill Nye the Science Guy
Magnetic Fields
B~I
Units: T (Tesla)
• Create the force exerted on a charge due to
magnetism
• Field lines move from North to South
• Objects align along field (ie compass)
• Magnetic poles are where field lines start and end
• Direction – Force is perpendicular to both the
magnetic field and direction of motion
Earth’s Field
• Molten Iron core
• Field keeps radiation and solar winds
out
• Creates Aurora Borealis
• Like to bar magnet
• Why is North actually
South?
Video
• The Science Behind Magnets
Different Types of Magnets
• Ferromagnetic:
• Permanent magnet – creates own field, is
attracted to other magnets
• Paramagnetic:
• Temporary magnet – attracted by an
external field, goes away
• Electromagnets:
• Adjustable magnets created by running
current through a coil of wire
Phets
• Magnet and Compass
• Magents and Electromagnets
Magnetism Lab
• Mapping the magnetic field
• Pick a partner
• Select a magnet
• Work with the table to graph the
magnetic field