Electromagnetism : Electromagnetism
Properties of Magnets : Properties of Magnets Any material that attracts iron is a magnet.
All magnets have a north and south pole.
You can cut it in half & the poles remain.
Slide3 : Magnetic force: a push or a pull.
Opposites pull.
Like charges push.
Magnetic field: the region where a force is felt.
Slide4 :
Cause of Magnetism : Cause of Magnetism Depends on the atoms.
Iron, nickel, cobalt
Domains are groups or tiny areas of atoms.
If they line up, magnetic.
If they are scattered, not magnetic.
Slide6 : Losing magnetism:
Dropping, hitting, near opposite field, or heating it.
Making a magnet
Rubbing it with a strong magnet.
Electricity.
Kinds of Magnets : Kinds of Magnets Ferromagnet or electromagnet.
From earth minerals or electricity.
Temporary or permanent.
Easy to magnetize & demagnetize or not.
Earth as a Magnet : Earth as a Magnet Earth’s core is mostly iron & nickel.
Magnetic north
Due to a strong magnetic south pole
Geographical north
The axis where the earth rotates.
Slide9 : Aurora borealis
Northern lights
Aurora australis
Southern lights
Electromagnetism : Electromagnetism Discovered by Hans Christian Oerstad
Made a compass needle move.
Electric current produces a magnetic field.
Slide11 : Solenoid strengthen the field.
A coil of wire.
More loops = stronger.
An electromagnet is a solenoid around an iron core.
Can turn it on/off.
Uses of Electromagnets : Uses of Electromagnets Doorbells
Electric motors
Galvanometers
Electricity from Magnets : Electricity from Magnets Joseph Henry & Michael Faraday discovered this.
Electromagnetic induction.
Current made by a moving magnet and wire.
Electric Generator : Electric Generator Converts mechanical energy into electrical energy. (Ginny)
Produces A/C
Transformers : Transformers Step-up
Increases voltage
Step-down
Decreases voltage
The side with the most loops has the highest voltage.