Download Chapter 15 Lesson 2 How are Electricity and Magnetism Related

Chapter 15 Lesson 2
How are Electricity and Magnetism Related?
MAGNETS- objects that attract iron and a few (not all) other metals
Magnets attract steel because it contains iron
Magnets can look different-bar, u shaped, circle…
Distance affects the strength of a magnet’s attraction.
Barriers can interfere with a magnet’s pull
Magnets can make some other objects magnetic.
MAGNETIC POLES AND MAGNETIC FIELDS
Magnets have the strongest force at the poles
A free swinging magnet will point north with its north seeking pole-that end is marked with an
N.
Like electrical charges, opposite forces between magnetic poles attract, N-S, positive –negative
Like poles repel: south repels south; north repels north
Magnets keep their poles even when cut in two.
A compass needle will point toward the N pole and away from the South Pole
A Magnetic Field is the space around a magnet in which the force of a magnet acts
ELECTROMAGNETS
An electric current produces a magnetic field around a wire. The field around a single wire is
weak. But many wires close together will create a stronger field. The coils around an iron core
(nail) make an electromagnet.
This is a temporary magnet- the current can be switched off.
GENERATORS AND MOTORS
Electricity can produce a magnetic field!
A magnetic field can produce electricity!
Generator- a device that produces an electric current. If you move a coil of wire near a magnet
current electricity flows in the wire.
ANY source of energy that can turn a coil of wire in a magnetic field can produce electricity
(hand cranked, gasoline power)
Power plants use huge generators. They burn coal, oil, or natural gas to power a turbine. The
turbine spins a coil inside the field of a magnet to produce electricity.
Generators use motion to produce electricity….and electricity can produce motion!
An electric motor is a device that changes electrical energy into mechanical energy (drill, mixer)
In some motors an electromagnet lies between permanent magnets..the interaction between them
keeps the motor shaft spinning.
OTHER USES OF MAGNETS
Compasses to help people find directions
Computers, CD players VCRs, speakers, doorbells, and phones all work because of magnets
Used for recording information (pg. 628)