P7: Permanent & Induced Magnetism, Magnetic Forces & Fields

• What are the ends of a magnet called?

  Poles
• How many poles do magnets have?

  Two
• What happens when two magnets are held close together?

  They exert attractive or repulsive forces
• What do opposite poles of magnets do?

  They attract each other
• What do like poles of magnets do?

  They repel each other
• What does the Law of Magnetism state?

  Like poles repel, unlike poles attract
• What type of force is the attraction or repulsion between magnetic poles?

  Non-contact force
• What materials are attracted to magnets?

  Magnetic materials
• Which metals are considered magnetic?

  Iron, cobalt, nickel
• Why is steel considered magnetic?

  It contains iron
• How can you test if a material is a magnet?

  Bring it close to a known magnet
• What indicates that a material is a magnet when tested?

  If it can be repelled by a magnet
• What are the two types of magnets?

  Permanent and induced magnets
• What is a characteristic of permanent magnets?

  They produce their own magnetic field
• What happens to a magnetic material in a magnetic field?

  It can become an induced magnet
• What occurs when magnetism is induced in a material?

  One end becomes a north pole
• What happens to a magnetic material when removed from a magnetic field?

  It loses most or all magnetism quickly
• What is the strongest part of a magnetic field?

  At the poles
• How are magnetic field lines represented?

  With arrows indicating direction
• What does the spacing of magnetic field lines indicate?

  The strength of the magnetic field
• What do closely spaced magnetic field lines indicate?

  A strong magnetic field
• What do widely spaced magnetic field lines indicate?

  A weak magnetic field
• What direction do magnetic field lines always go?

  From north to south
• What must magnetic field lines never do?

  Touch or cross each other
• Where is the magnetic field strongest around a bar magnet?

  At the poles
• How does the magnetic field change with distance from the magnet?

  It becomes weaker as distance increases
• What happens to the magnetic field lines when two bar magnets repel each other?

  They look slightly different than attracting magnets
• What is a uniform magnetic field?

  Same strength and direction at all points
• How is a uniform magnetic field created?

  By holding opposite poles close together
• What indicates that a magnetic field has the same strength at all points?

  Equal spacing between magnetic field lines
• How is the direction of a magnetic field determined?

  By the force on a north pole at that point
• What does a plotting compass represent?

  A small bar magnet with a north and south pole
• What is the first step in investigating the shape of a magnetic field?

  Place the magnet on top of paper
• What should you do after placing the plotting compass next to the dot?

  Draw a new dot at the other side of the compass needle
• What should you do after creating a chain of dots?

  Link the dots using a smooth curve
• What does the direction of the magnetic field line indicate?

  The direction of the force on a north pole
• What does the Earth's magnetic field do to a compass?

  It makes the compass point north
• Why does the north arrow of a compass point towards the geographic North Pole?

  Because the geographic North Pole is a magnetic south pole
• What is the relationship between the geographic South Pole and the Earth's magnetic field?

  The geographic South Pole is a magnetic north pole
• What happens to the north pole of a compass near the Earth's magnetic north pole?

  It is repelled from the Earth's magnetic north pole