MAGNETISM AND ELECTROMAGNETISM. Magnetism = the phenomenon of physical attraction for iron observed in magnets, inseparably associated with moving electricity

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  • MAGNETISM AND ELECTROMAGNETISM

  • Magnetism = the phenomenon of physical attraction for iron observed in magnets, inseparably associated with moving electricity and characterized by fields of force

    Magnetic force increases as magnets move closer together!

  • A magnetic field surrounds a magnet and is strongest at the poles; it is produced by the motion of electric charge.

    Both the orbital & spinning motion of every electron in an atom produce magnetic fields.

  • Magnetic field lines: arrows drawn from north to south poles representing the magnetic field.

    Number of field lines indicates the relative strength of the magnet

  • All magnets have a north pole and a south poleLike poles repel. Unlike poles attract

  • A compass needle is a small bar magnet that can freely rotateA compass needle always points north, or rather is north-seeking

  • INTERESTING FACTThe northern lights (aurora borealis) & southern lights (aurora australias) are results from the interaction between the solar wind and earths magnetic field (makes the air glow).

  • MAGNETIC DOMAINSMicroscopic groups of atoms with aligned magnetic poles

  • MAGNETIC MATERIALSMaterials in which the domains will line up in order to form a magnetic fieldExamples: iron, cobalt, and nickel

  • WHAT HAPPENS WHEN YOU CUT A MAGNET IN HALF?

  • PERMANENT MAGNETSMaterial that keeps its magnetic properties, even when it is not close to other magnetsMade by placing a magnetic material in a strong magnetic field, which causes the domains to remain aligned.

  • The domains of temporary magnets are only aligned when the material is influenced by a magnetic field. (ex. Refrigerator, white board)

  • Electromagnet temporary magnet that is created by electric current flowing in a wire, usually in the form of a wire coiled around a piece of ironMagnetic field is present only when current is flowing in the wire coil

  • Strength of an electromagnet depends on three factors:amount of current in the wireamount of iron or steel in the core number of turns in the coil

  • PRODUCING ELECTRIC CURRENT Electromagnetic induction the production of an electric current by moving a loop of wire through a magnetic field or moving a magnet through a wire loop (which changes the magnetic field near the conductor; no battery!)

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