Date post: | 01-Jan-2016 |
Category: |
Documents |
Upload: | naomi-simmons |
View: | 236 times |
Download: | 9 times |
Magnetism & Electromagnetism
The Nature of Magnetism
Chapter 1
Section 1
Magnets
• Magnetism– The attraction of a
magnet to another object
Magnesia (in Greece)
• Used over 2,000 years ago
• Magnetite– Mineral found in some
rocks
– Fe3O4
• Attracts iron
Lodestones
• Magnets swinging on strings will eventually point toward the …– Lodestar
• Means Leading Star– Aka North Star
• Discovered 1,000 years ago
Magnetic Poles
• The area of the magnetic where the magnetic effect is strongest
• North Pole• South Pole
Interactions Between Poles
• Like poles repel, Unlike poles attract
Breaking a Magnet
• Produces smaller magnets
Magnetic Fields
• The magnetic force exerted all around a magnet
• Magnetic Field Lines– Spread out from one
pole, curve around the magnet and return to the other pole
– Never cross
Elements
• One of about 100 basic material that make up all matter
• Atom– The smallest particle
of an element
In an Atom
• Bigger, in Nucleus– Protons
• “+” charge
– Neutrons• No charge
• Electrons– Small– “-” charge– Orbits nucleus
• Produce a small “Atomic Magnetic Force”
Magnetic Domain
• A cluster of billions of atoms that have magnetic fields that are lined up in the same way
• Magnetized Material– All/most of the
domains are arranged in the same direction
Ferromagnetic Material
• A material that shows strong magnetic effects
• Iron, Fe• Nickel, Ni• Cobalt, Co
Making Magnets
• Some materials can be magnetized if rubbed with a strong magnet– Typically just
temporary
• Magnetic Domains become aligned
Destroying Magnets
• Knocking the domains out of alignment
• Drop it• Strike it• Heat it
MagLev
• 400 km/hr– 250 mph
• Floats a few cm’s above tracks– No vibrations– No noise from the
steel tracks