magnetic force

Magnetic force is the push or pull caused by a magnet on certain materials or on another magnet, even when they are not touching.

• Magnets create an invisible region around themselves called a magnetic field. This field is what allows the force to act across a gap.
• The force is usually strongest near a magnet’s poles, which are its north-seeking and south-seeking ends.
• Materials such as iron, nickel, cobalt, and many types of steel are strongly affected by magnets. Wood, plastic, glass, and aluminium are not attracted in the same way.
• A useful example is a refrigerator magnet: it sticks because the door contains steel, and the magnetic field pulls the magnet towards it.
• Magnetic force becomes weaker as the distance between objects increases. A paper clip close to a magnet may jump toward it, but one much farther away may not move at all.

Although magnets can attract some objects, they do not attract every metal—an aluminium can, for example, is not pulled strongly by an ordinary magnet.