Basics in MagnetismElectromagnetism

Force on a Current-Carrying WireEM Induction

TransformerGenerators

Electric Motors

ELECTROMAGNETISM

The ABCs of Magnets

How was magneti sm discovered?

What are the two poles of a magnet?

What materials do magnets att ract?How do magnets att ract objects?Is the earth a magnet?What was first invented out of magnets?

How was magnetism discovered?

Magnetite or lodestone

What are the two poles of a magnet?

North and South Pole

Magnetic Domains

Like poles repel; opposite poles att ract.

What materials do magnets att ract?

nickeliron

cobalt

“Magneto

att racts

Ironman.”

How do magnets att ract object?

Magnetic Field

Region of space around a magnet that applies

an att racti ve or repulsive force

Directi on is from North to South

Magneti c Field Lines

1

34

2

Drawing magneti c fi eld lines

Arrows are from North to South

Field lines of att raction

Field lines of repulsion

Is the Earth a magnet?

Magnetic South Pole

Magnetic North Pole

Auroras

What was fi rst invented out of magnets?

Compass 指南针

Making Magnets: Which makes bett er magnets?

iron steel

Magneti zes quickly Keeps magneti sm longer

Temporary magnets(electromagnets)

Permanent magnets

Some uses of permanent magnets

Fridge door

tools

locks