1. Discovery and Applications of Electromagnetism

2. Watch a brief video about magnets here:

3. FERROMAGNETIC PARAMAGNETIC DIAMAGNETIC
Materials may be classified as:
FERROMAGNETIC
strongly attracted to magnets
iron, steel, cobalt, nickel
PARAMAGNETIC
slightly attracted by strong magnets
wood, aluminum, platinum, oxygen
DIAMAGNETIC
slightly repelled by strong magnets
zinc, bismuth, sodium chloride, water

4. Like poles repel; unlike poles attract.
BASIC LAW OF MAGNETISM
Like poles repel; unlike poles attract.
Although it is possible to isolate positive
and negative charges, it is impossible to
isolate NORTH and SOUTH magnetic poles.
Magnetic monopoles do not exist.

5. Include a variety of metal, plastic, and wooden objects.
A common activity for young students is for them to be given a magnet and an assortment of materials, and for them to determine which materials are attracted to the magnet.
Include a variety of metal,
plastic, and wooden objects.
Suggestions include:
metal paper clips, plastic paper clips,
pennies, nickels, dimes, quarters, aluminum
foil, copper wire, soft drink cans, pencils,
erasers, rulers, drink cups, balls, paper,
cardboard, buttons, small toys, live plants,
etc…

6. Click here to view some magnetic fields.
Magnetic fields surround magnets.
Field lines point from North to South
outside the magnet. N S
Click here to view some magnetic fields.

7. Magnetism is a property of charge in motion.
Orbiting and spinning electrons (negative charges in motion)
in the atom produce a magnetic field.
The domain theory is used to explain why
some materials are, or may become, magnetic.
No one knows exactly why
moving charges cause magnetism.

8. The north magnetic pole is not caused by protons,
Even though magnetic properties are
similar to electric properties, it is
erroneous to directly relate positive
and negative electric charges to
north and south magnetic poles.
The north magnetic pole
is not caused by protons,
nor is the south magnetic
pole caused by electrons!!!!

9. In 1820, Danish physicist/ chemist Hans Christian Ørsted (Oersted) noticed that when current from his Voltaic pile was switched on and off, a compass needle placed near the
wire deflected from true magnetic north. Within
a few months of careful study, he deduced that a magnetic field circles a current-bearing wire.

10. You can replicate Oersted’s discovery by connecting wire to a battery and a switch. Place a compass underneath the wire such that the compass needle is directly in line with the wire above it. Observe the needle deflect when the current is switched on and off.
Place the compass
above the wire and
make further
observations.

11. A magnetic field surrounds a current-bearing wire.
The direction of the magnetic field can be determined
by the “Right Hand Rule for a Current-Bearing Wire.”
“Grasp wire with right hand so that thumb
points in the direction of conventional
(positive) current. Your fingers circle the
wire in the direction of the magnetic field.”

12. This discovery, coupled with the knowledge that magnetic fields interact with other magnetic fields, quickly resulted in many important technological applications, including the electromagnet, the telegraph, and the electric motor. Google honors Oersted’s August 14 birthday in typical Google fashion.