Text of MAGNETISM AND ELECTROMAGNETISM. Magnetism = the phenomenon of physical attraction for iron observed...
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!)