PME. Chemistry Matter and Energy

Benchmark 5Describe how electric currents can be produced byinteracting wires and magnets, and explainapplications of this principle.

A BAR MAGNET is a certain type of magnet that looks like a bar.

Around a bar magnet are MAGNETIC FIELD LINES which show the direction of the magnetic FORCE at that point.

If you were to put a piece of magnet (let’s say a north pole) at any point, the force on it would be TANGENT to the field line.

Two North Poles will REPEL.

Two South Poles will REPEL.

A North Pole and a South Pole will ATTRACT.

Force

N

Magnetism Bar Magnets

Magnetism is an inherent property of some minerals.

Magnetism can be INDUCED in metal by applying an electric current. This is cleverly called an ELECTROMAGNET.

Electric Current is the flow of electric charge through a wire.

ElectroMagnetism

If wire is wrapped around nail, for example, it will make the nail magnetic! And either pick up iron filings or deflect a compass.

Just as magnetism can be created from electricity, electricity can be created from magnets!

ElectroMagnetism

By moving a Bar Magnet in and/or out of a coil of wire, an Electric Current is produced!

Generators & Motors

A fan spins a wire near a magnet. This is the same as moving a magnet near a wire – which produces electricity!

Electricity is run through a wire which creates a magnet. This magnet either repels or attracts the magnet in the motor causing motion.

Web Explorationhttp://lectureonline.cl.msu.edu/~mmp/applist/induct/faraday.htm

http://micro.magnet.fsu.edu/electromag/java/faraday2/

http://micro.magnet.fsu.edu/electromag/java/generator/ac.html

http://micro.magnet.fsu.edu/electromag/java/generator/dc.html

http://www.state.hi.us/dbedt/ert/electgen.html