P4.1 What Magnets Are & Drawing Magnetic Field Lines

• What is a magnet?

  A material that produces a magnetic field
• What is the most common type of magnet?

  Bar magnets
• What do all magnets have in common?

  They have a north and a south pole
• What is the first step in drawing field lines?

  Draw a straight line into the south pole
• How do we represent magnetic fields?

  Using field lines
• How do you draw field lines around a magnet?

  From the north pole to the south pole
• Why is it important to check the direction of arrows on field lines?

  To ensure they go out of north and into south
• What does the density of field lines indicate?

  The strength of the magnetic field
• Where is the magnetic field stronger in relation to the poles?

  Near the north pole
• How can we find the poles of a magnet?

  Using a compass
• What does the needle of a compass represent?

  A tiny bar magnet
• What direction does a compass needle point?

  Towards the south pole of a magnet
• What happens when you push the north poles of two magnets together?

  They repel each other
• What creates the force of repulsion between two magnets?

  The interaction of their magnetic fields
• What occurs when opposite poles of magnets are brought together?

  They attract each other
• What are the steps to draw magnetic field lines?

  • Draw a straight line into the south pole
  • Draw a straight line out of the north pole
  • Add slightly curved lines into the south pole
  • Add similar curved lines coming out of the north pole
  • Draw loops around from north to south
  • Ensure arrows point from north to south
• What is the relationship between field line density and magnetic field strength?

  • Closer lines indicate a stronger magnetic field
  • More dense lines show higher field strength
  • Sparse lines indicate a weaker magnetic field
• How can you recreate a magnetic field line diagram using a compass?

  • Place the compass near the magnet
  • Draw an arrow in the direction of the compass needle
  • Repeat in different locations around the magnet
  • Join the arrows to form field lines
• What are the interactions between like and opposite poles of magnets?

  • Like poles repel each other
  • Opposite poles attract each other
  • This interaction is due to magnetic field lines
• What is a magnet?


  A magnet is any material or object that produces a magnetic field.
• What do we call the 2 poles of a magnet?


  North and South poles.
• What are magnetic field lines?


  Magnetic field lines are arrows that show the magnetic field around an object.
• What direction do magnetic field lines point?


  North to South poles.
• How can field lines show you the strength of a magnetic field?


  The denser the field lines (closer together they are), the stronger the magnetic field will be.
• What would magnetic field lines look like around a magnet?


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• How can you use a compass to visualise field lines?


  The needle of a compass always points along a field line towards the south pole, so can be used to find the lines of a magnet.

  1. Place the plotting compass near the magnet on a piece of paper.
  2. Mark the direction the compass needle points.
  3. Move the plotting compass to many different positions in the magnetic field, marking the needle direction each time.
  4. Join the points to show the field lines.
• How can you use iron filings to visualise field lines?


  1. Place the magnet under a piece of card.
  2. Sprinkle iron filings over the piece of card.
  3. Tap the piece of card- this will cause the iron filings to accumulate along the field lines.
• What would the magnetic field lines of 2 North pole magnets look like?


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• What would the magnetic field lines for a North and South pole look like?


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