AQA GCSE Physics Topic 7 - Magnetism & Electromagnetism

Magnet

something that attracts iron and steel

Magnetic Field

The area of magnetic force around a magnet

Magnetic Domains

A group of atoms whose magnetic fields are aligned

North Pole

the end of a magnet that seeks the earth's north magnetic pole.

South Pole

the end of a magnet that seeks the earth's south magnetic pole.

Magnetite & Lodestone

A mineral with magnetic properties

Compass

an instrument that has a magnetized needle generally in line with the magnetic poles of the earth.

Electromagnets

A magnet created by electricity. It only works when surrounded by electric field

Attraction

When two magnets or magnetic objects are close to each other, there is a force that pulls the two poles together

Repulsion

When two magnetic objects have like poles facing each other, the magnetic force pushes them apart.

Magnetic poles

The two areas of a magnet with the strongest magnetic force.

Atoms

The smallest particle of an element, has all the properties of an element

Proton

A positively charged particle found in the nucleus of an atom

Neutrons

Neutron a particle that does not carry an electrical charge (neutral)

Nucleus

The core at the center of every atom

Electron

Tiny, negatively charged particle that usually exists in outer region of an atom

Magnetic Poles

Where magnetic field lines are strongest, ends of a bar magnet

Ferromagnetic Material

A material that can be magnetized because it contains magnetic domains

Magnetic Domain

Region where electrons are aligned into magnetic fields---spinning electrons are unpaired.

Cobalt, Nickel, Iron

Materials with strong magnetic properties (Fields)

Magnetic Declination

the angle between the geographic north pole and the magnetic north pole.

Magnetic Field Lines

Lines that map out the magnetic field of an object. They are closer at the poles of the magnet where the field is stronger. The lines are parallel and never cross.

Ways to destroy a magnet (rearrange the domains)

Drop it
heat it
put it in an alternating current's field

Ways to magnetize an object

Magnetic Induction
Rubbing an object to align domains
Run electric current through it

Magnetic Induction

Magnetizing an object by putting it in a strong magnetic field.

Breaking a magnet

Will create 2 magnets, each with a north and south pole

Temporary Magnets

Materials that become magnetized easily, but lose magnetism easily as well.

Permanent magnets

Materials that maintain their magnetism

Electric Current

Moving electric charges

Solenoid

Coil of wire with electric current---wrap around a solid ferromagnetic core to produce an electromagnet.

Strength of electromagnet depends on

Strength of power source
Coils on solenoid
Core size of solenoid

Galvanometer

Uses a solenoid to measure an electric current
ex. gas gauge in a car

Electric Motor

Uses an electromagnet to turn an axel or coil of wire
Transforms electrical energy to mechanical
Ex. appliances

Electromagnetic Induction

Creating a current using an electrical conductor in a changing magnetic field.

Generator

A device that uses a coil of wire (turbine) rotating in a magnetic field to convert mechanical energy to electrical energy

Transformers

Increase (Step up) or decrease (Step Down) the voltage of a current as it goes to and from a power plant to your home.