Magnets and Magnetic Fields

Magnets and Magnetic Fields

• Magnets generate a magnetic field.
• Magnets come in various shapes and sizes; the bar magnet is common, but horseshoe magnets and even the Earth are examples.
• Every magnet has two poles, a north and a south.
• A magnetic field surrounds all magnets

Representing Magnetic Fields with Field Lines

• Field lines represent magnetic fields.
• Arrows are used as field lines around a magnet, extending from the north pole to the south pole.
• When drawing field lines, the arrows must be placed correctly.

Drawing Field Lines

• Start with at least one straight line entering the south pole and exiting the north pole.
• Draw a pair of curved lines that go into the south and out of the north pole.
• Complete the drawing by including loops that extend from the north to the south pole.
• All arrows on the lines should point away from the north pole and toward the south pole.

Interpreting Field Lines

• Field lines indicate a magnetic field, as well as its direction.
• The relative strength of the field is shown by field lines.
• A stronger magnetic field is indicated by the closer proximity of field lines.
• The field strength is greater near the poles where field lines are denser.

Using a Compass to Find Poles and Field Lines

• A compass needle is a small magnet that aligns with magnetic field lines.
• A compass needle indicates the south pole of a magnet.
• By positioning a compass near a magnet, one can draw arrows showing the direction of the compass needle.
• The south pole is where arrows point to on a magnet.
• The north pole is indicated by arrows pointing away from the magnet.
• The field line pattern emerges when the arrows connect.

Interaction Between Two Magnets

• Repulsion occurs when the north poles of two magnets are pushed together.
• The interaction of magnetic fields causes this repulsion.
• Attraction happens when opposite poles are brought together.
• Attraction happens when field lines extend from north to south.