Download General Science Mr. Tiesler Magnetism Test Study Guide

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General Science
Mr. Tiesler
Magnetism Test Study Guide
Vocabulary
Electromagnet – Strong, temporary magnet made by inserting an iron core into a wire coil &
passing an electric current through the coil.
Electromagnetic Induction – The process of generating a current by moving an electrical
conductor in a magnetic field.
Ferromagnetic Material – A material that can be magnetized because it contains magnetic
domains
Generator – A device that produces electric current by rotating a loop of wire in a magnetic field.
Magnetic Field – Area around a magnet where forces act.
Magnetic Poles – Area of a magnet where the magnetic force is the strongest.
Magnetism – A property of matter in which there is a force of attraction or repulsion between
unlike poles.
Magnetosphere – The area surrounding the Earth that is influenced by the Earth’s magnetic field.
Motor – A device that uses an electromagnet to turn an axle.
Permanent Magnet – A magnet made of iron, cobalt, or nickel that retains its magnetic properties
over a long period of time
Soleniod – A coil of current-carrying wire that produces a magnetic field.
Temporary Magnet – Magnets that lose their magnetic properties easily.
Transformer – A device that increases or decreases the voltage of a current.
Turbine – A device with fan like blades that turn when pushed, for example, by water or steam.
Things to Know
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Like magnetic poles repel, opposite magnetic poles attract.
Earth’s magnetic field
o Changes over time.
o Protects us from harmful solar radiation.
o Reverses direction every few hundred thousand years.
o Changes position.
 Magnetic Fields
o Magnetic fields are strongest at the poles.
o Magnetic field lines travel from north to south.
o The strength of a magnetic field decreases as distance from a magnet increases.
 Moving electric charges produce magnetic force and moving magnets produce electric
force.
 Galvanometers detect electric current using a solenoid.
 A commutator is also called a reversing switch. It reverses the direction of the current in
an electromagnet.
 Electromagnets convert electrical energy into mechanical energy.
 The strength of an electromagnet can be increased by inserting iron into the wire coil,
adding more turns to the iron, or increasing the amount of current
 Michael Faraday discovered electromagnetic induction.
 Hans Christian Oersted discovered moving electric charges create a magnetic field.
 Superconductors
o Materials that have no resistance at very low temperatures.
o Uses of superconductors include trains, medicine (MRIs), superfast computers
o Advantages:
 Current flows indefinitely
 Eliminates electrical waste
o Disadvantages
 Hard to shape into wires
 Only work at very cold temperatures
Step up transformers increase voltage produced at power plants so electricity can be
transported over long distances with minimal loss of energy.
Step down transformers decrease voltage at substations to distribute electricity to
consumers.
Electricity generated in power plants cannot be stored in large quantities. It must be
generated at the same moment it is used.
The majority of the electricity used in Connecticut is generated from nuclear energy.
There are three interconnected electric grids in the United States.
The electric utility measures your family’s electrical usage in kilowatt hours.