Basics of Magnetism North pole South pole and

Basics of Magnetism • North pole, South pole, and magnetic field • Magnets and domains • How magnets pick things up • Wires with current • Whiteboard – direction of B field around wire • Loops • Whiteboard – direction of North pole

Demo Magnet in dish on overhead Definition of N and S poles Compass on overhead Finding polarity of a magnet Shocking revelation THE EARTH’S NORTH POLE IS A MAGNETIC SOUTH POLE!

There is no magnetic monopole Demo Magnet on pivot Demo - iron filings B field is N to S

N How do magnets pick things up? Induced magnetism Distance/Force Demo with compass Magnet S N Magnet S Ferrous material (No induced) N S Induced

Remember electric field + + + - + to - Direction of B is from N to S Demo: Magnaprobe and fixed magnet Remember – B Field Lines: • Leave the N pole • Enter the S pole

Magnetic fields encircle wires Thumb in direction of I, fingers wrap as B (Magnetic field) Demo with Magnaprobe/Giant Solenoid

Whiteboards Direction field around wire 1|2|3|4

Which direction is the magnetic field in front of this wire? I right

Which direction is the magnetic field behind this wire? I left

Which direction is the magnetic field behind this wire? I up

Which direction is the magnetic field around this wire? I ?

Loops of wire act as magnets with a N and S pole: S N Show with giant solenoid

N I Wrap your Rt. fingers with the current, and your thumb is the N pole

Whiteboards Direction North Pole 1|2|3|4

Where da North Pole? outa da page

Where da North Pole? into da page

Where da North Pole? Current goes up in the front of the coil left side

Where da North Pole? Current goes right in the front of the coil Top

Where da North Pole? Current goes down in the front of the coil right side

Where da North Pole? Current goes left in the front of the coil bottom