• Astronomy
• Chemical reactions
• Chemical substances
• Earth's climate
• Earth's structure
• Electricity
• Force, motion and machines
• Light
• Magnetism
• Sound
• Water
•  

Magnetism

Introduction

This topic explores the key concepts of magnetism as they relate to:

• the phenomenon of magnetism
• magnetic forces and fields
• a theory of magnetism.

Key concepts of magnetism

• Magnets exert a force that can be described as a 'push' or a 'pull'.
Magnets exert a force field that is called a 'magnetic field'. A magnetic field is a region in space around a magnet that will exert force on another magnet or magnetic material.
• Magnets attract materials composed of iron and nickel; these materials are described as being magnetic.
• Magnets vary in strength, size and shape.
• Magnets have north and south poles. The attracting power (magnetic field) of a magnet is greatest at its poles.
• Like poles of a magnet attract; unlike poles repel.
• Atoms are tiny constituents of matter and act like tiny magnets. In magnets and magnetic materials atoms form groups called 'domains', where their magnetic poles are aligned.
• In magnets, domains align themselves (north poles are in the same directions). In non-magnetic materials domains do not align themselves magnetically.
• Magnetic materials are made into temporary magnets by bringing them near a permanent magnet.
• Earth can be considered to be one large magnet.
• Temporary magnets can be made from a nail, wire and battery because an electric current produces magnetism.

Students' alternative conceptions of magnetism

Research into students' ideas about this topic has identified the following non-scientific conceptions:

• Poles are only at the ends of magnets.
• Big magnets are stronger than small magnets.
• Larger magnets are stronger than smaller magnets.
• The magnetic and geographic poles of Earth are located at the same place.
• The geographic and magnetic poles of Earth are identical.