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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 • Drop it out of alignment • 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