MAGNETISMCHAPTER 21

Essential Question-What is magnetism and how does it relate to electricity?

Vocabulary Magnetic Domain Magnetic Field Magnetosphere Alternating Current Aurora

Direct Current Electromagnet Generator Motor Transformer

How magnets work.

Magnetic field-a space around a magnet where the magnetic force is active.

Magnetic Domain-a group of atoms with their magnetic fields pointing in the same direction.

Magnetosphere- the space affected by the Earth’s magnetic field.

The Sun and the Earth’s magnetosphere.

Charged particles

Aurora-the light given off from the sun’s charged

particles crashing into atoms in the Earth’s atmosphere.

Natures Magnets

The Lodestone- the original natural magnet

Examples of Biomagnetism

Homing Pigeons

Monarch Butterflies

Migratory Birds

Early Uses of Magnetism The Compass

•The needle will point North and South•Turn the compass so that they line up

Electromagnet- a wire with current flowing through it that is wrapped around an iron core.

How do they work?

Uses for Electromagnets Televisions/ Computer- CRT screens Automobiles- ignition, starter motor, automatic

doors Motors Sound/ Speakers-An electromagnet draws the

speaker diaphragm, allowing the music to be played.

Scrap yards-In scrap yards, electromagnets lift cars and other magnetic objects.

Fire Doors and Automatic Doors Relays/ Switches Sorting Metals

Read more: 10 Uses for an Electromagnet | eHow.co.uk http://www.ehow.co.uk/list_5908429_10-uses-electromagnet.html#ixzz1hm19hFDy

Electric Motors- any machine that changes electric energy into kinetic energy. http://www.arthursclipart.org/engineer/engineer/electric%20motor.gif

What is a motor? How does it keep running?

Electric Current- the flow of electric charge.

Alternating Current (AC)-

a current that changes direction. (used in

plug in electronics)

Direct Current (DC)-A current in which

electrons only flow in one direction. (used in

battery powered electronics.

http://sustainableconsciousnessnetwork.wordpress.com/

Electric Generator- uses magnets to convert motion energy to electricity

Magnets are used in machines to create and change current

Power Plants contain Electric Generators, machines that use a magnetic field to turn motion into electricity

Transformer- a machine that changes the voltage of an alternating current without losing much energy.

Superconductors - metals at extremely low temperatures have next to no resistance so next to no loss of energy as heat.

A magnet floats above a superconductor

Particle accelerators use superconductors to get particles up to nearly the speed of light,

http://www.chemistryexplained.com/St-Te/Superconductors.html

http://www.telegraph.co.uk/science/large-hadron-collider/7829090/The-God-particle-may-exist-in-five-forms-Large-Hadron-Colliders-rival-project-finds.html

Magnetic Resonance Imaging (MRI)

MRI Scanner MRI Imagehttp://greglw.blogspot.com/1971/01/item-04-mri-scanner-magnetic-resonance.html

Ferromagnet Ferromagnet- A permanent magnet made from

a material such as iron. Ferromagnetism is the basic mechanism by which certain materials (such as iron) form permanent magnets, or are attracted to magnets.

The shape of a ferromagnet is not important

Electromagnet vs. Natural Magnets

Electromagnet Natural magnet (lodestone)

Specific shapes of magnets Bar

magnet Horseshoe

magnetDisk Magnet

bar magnet horseshoe magnet disk magnet magnetic copper repel ferromagnetic aluminum

pole iron nickel attract core