1. Magnetism
Physics 1

2. History and Background
Lodestones are rocks with magnetic properties
Were commonly found in regions of Magnesia in Greece
Attracted other rocks, iron filings, etc.
12th century started using as compass for naval navigation
Charles Coulomb started experimenting with them in 1700’s and noticed forces between lodestones

3. More History
In 1820 Hans Christian Ørsted (Oersted) discovered that a wire carrying current would deflect a compass
Michael Faraday built on this
<< watch Faraday’s discovery from video “Einstein’s Big Idea”>>

4. What is a Magnet Magnets are objects displaying a magnetic field
Magnetic fields (B)
produced by electric currents
Expressed in terms of force on moving charge
dipolar in nature, having a north and south magnetic pole.
The SI unit for magnetic field is the Tesla

5. Earth as a Magnet
Note that ‘magnetic north’ is NOT the same as geographic north (i.e. is NOT at the north pole)
If the north end of a magnet points to magnetic north, but opposites attract, what does that say about the earth as a magnet?`

6. Magnetic Fields

8. Right Hand Rule
B – Magnetic Field
F - Magnetic Force
I - Current

9. Right Hand Rule

10. Ex 1

11. Ex 2