Magnetic forces and fields
Physics Narrative for 5-11 11-14
Magnetism is a
non-contact force. For example, a magnetic force can be acting on a paper clip when a magnet is nearby but not actually touching. The magnetic force can be either attractive or repulsive and is not blocked by materials such as paper.
Although there might appear to be nothing in the space between two magnets, scientists describe this space as containing a magnetic field. The magnetic field of a magnet marks the space throughout which it can exert a force on another magnet or a piece of iron. If a magnet (or piece of iron) is placed in the magnetic field of another magnet, it will experience a magnetic force; if it is placed outside the magnetic field of the magnet it will experience no force. This is another example of how scientists have created a theoretical model to account for a phenomenon that cannot be directly observed. You can see the paper clip moving but you cannot see the magnetic force which is acting. Sprinkling iron filings near a magnet enables the form of this magnetic field to be displayed in a more concrete fashion. The iron filings, influenced by the magnetic field, line up to show the directions in which the magnetic forces are acting. A magnetic field
pattern is the result.