Transcript Magnetism
Magnetism Magnets • What is a magnet? – An item that exhibits magnetism – What is magnetism? • A property of matter in which there is a force of attraction or repulsion between unlike or like poles S S N S N N N S What are magnetic poles? • Often referred to as the north and south ends on a magnet • Defined as the two ends of a piece of magnetic material where the magnetic forces are strongest – Like magnetic poles repel and opposite magnetic poles attract Review • Which group of transition metals exerts a magnetic field? – Iron Triad - Iron, Cobalt, and Nickel – What is a magnetic field? • The region around the magnet where magnetic force act – This sounds very similar to an electric field!!!!!! How are electricity and magnetism similar? • For each, as the distance between the objects decreases, the attraction/repulsion increases or as the distance increases, the attraction/repulsion decreases Greater Attraction or Repulsion Lesser Attraction or Repulsion Do only the metals in the iron triad posses magnetic properties? • Only a few materials show strong magnetic properties – Iron Triad – Items made with these metals are known as permanent magnets • However if you bring a magnet near or in contact with specific items (such as paper clips and nails) you can produce a temporary magnet – Why is this? Magnetic Domain • Explains the grouping of atoms in an object • Defined as groups of atoms with aligned magnetic poles The domains are randomly arranged in an unmagnetized object In a magnetized object, the domains are aligned Can permanent magnets lose their magnetism? • Yes, but not all of there magnetic properties – If the permanent magnet is dropped or heated the atoms will somewhat realign themselves due to jostling or particle acceleration