Deck ni p6

• Magnetism


  The property of certain materials to attract or repel other materials based on their orientation and polarity
• Magnetism


  • The field of physics that studies the behavior of magnetic materials and the interactions between magnetic fields and electric currents
  • The ability of an object to generate a magnetic field around itself, which can influence the behavior of other objects in the vicinity
• Magnetism is the basis of technologies such as electric motors, generators, MRI machines, and magnetic storage devices
• Lodestone (leading stone)


  A fragment of an iron ore called magnetite that has the property of attracting iron fillings and other small bits of irons
• Magnetic materials


  Materials having the property of attracting iron fillings and other small bits of iron
• The word 'magnetic' came from the word 'Magnesia'
• Ferromagnetic materials


  • Iron
  • Cobalt
  • Nickel
• Natural magnets


  • Ferrite
  • Pyrrhotite
  • Coulumbite
• Artificial magnets


  • Horseshoe magnet
  • U-shaped magnet
  • Bar magnet
  • Cylindrical magnet
  • Circular magnet. Oval shaped magnet. Needle magnet
  • Ring magnet
  • Rod magnet
• Artificial magnets


  Made by man using different techniques, stronger than natural magnets, they can be temporary or permanent magnets, available in different shapes and sizes
• Natural magnets


  Found in nature, weaker than artificial magnets, are always permanent magnets
• Strongest permanent magnets


  • Neodymium (Nd) magnets
• Diamagnetic substances


  • Gold
  • Mercury
  • Bismuth
• Paramagnetic substances


  • Aluminum
  • Platinum
  • Oxygen
• North-seeking pole


  North pole (N)
• South-seeking pole


  South pole (S)
• Like poles


  Repel
• Unlike poles


  Attract
• Negative electron and positive proton can exist separately from one another while magnets cannot. North pole and South pole of a magnet cannot be separated from one another. They always come in pairs.
• What happens when a magnet is broken in half

  It still has a north and south pole
• Neodymium magnets are made from?

  Alloy of Nd, iron and boron
• Artificial Magnets


  • Made by man by using different techniques
  • Stronger as compared to natural magnets
• Types of Artificial Magnets

  • Temporary
  • Permanent
• Artificial Magnets


  • Available in different shapes and sizes
  • Example: Horseshoe magnet, bar magnet
• Natural Magnets


  • Found in nature
  • Weaker as compared to artificial magnets
  • Always permanent
• Natural Magnets


  • Available in the shapes and sizes as they occur in nature
  • Example: Magnetite (Lodestone)
• Artificial magnets are stronger as compared to natural magnets
• Natural magnets are always permanent
• Artificial magnets can be

  Temporary or permanent magnets
• Artificial magnets are available in different

  Shapes and sizes
• Ferromagnetic material are substance which exhibit strong magnetism like Cobalt, iron, nickel
• Magnets


  Have two poles (ends): North pole and South pole
• Magnets


  • Attempt to line up with the magnetic field of the Earth
• Technological applications of magnetism

  • Large electromagnets used to pick up heavy loads
  • Magnets used in meters, motors, loudspeakers
  • Magnetic tapes used in audio and video recording, and computer disks
  • Regulation of controlled nuclear fusion research
  • Maglev trains
• Magnetic forces


  • Like poles repel (south-south, or north-north)
  • Opposite poles attract (south-north)
• Magnetic poles always occur in pairs
• Magnetic poles can never be isolated
• If you break a magnet, each piece will have a north and a south pole
• Magnetizing unmagnetized iron


  1. Place it near a strong permanent magnet

  2. Stroke it with a magnet
• Permanent magnets


  Can be demagnetized with heat or hammering