Magnets: Stick or Not

Ferromagnetic Materials and Magnetic Fields

Magnets do not stick to everything. They strongly attract only certain materials, mainly ferromagnetic metals such as iron, steel, nickel, and cobalt. This matters in everyday life because magnets are used in tools, motors, speakers, door latches, and recycling systems. Knowing which materials are magnetic helps explain why a fridge magnet sticks to the door but not to paper, wood, or most coins.

The reason is that some materials contain tiny magnetic domains that can line up with an external magnetic field. In ferromagnetic materials, many domains align and create a strong attraction to the magnet. Other materials may respond very weakly or not enough to notice, so they seem nonmagnetic in daily use. Shape and coating can also matter, because an object made of steel may still be magnetic even if it is covered with paint, plastic, or chrome.

Key Facts

Magnets strongly attract ferromagnetic materials: iron, steel, nickel, and cobalt.
Steel is mostly iron, so many steel objects are attracted to magnets.
Magnetic force is strongest near the poles of a magnet.
If magnetic domains align, the material becomes magnetized.
The magnetic force gets weaker with distance from the magnet.
Not all metals are magnetic: aluminum, copper, silver, and gold are not strongly attracted.

Vocabulary

Magnet: A magnet is an object that produces a magnetic field and can attract certain materials.
Magnetic field: A magnetic field is the region around a magnet where magnetic forces can act.
Ferromagnetic material: A ferromagnetic material is a substance like iron, nickel, or cobalt that can be strongly attracted to a magnet.
Magnetic domain: A magnetic domain is a tiny region inside a material where many atomic magnets point in the same direction.
Pole: A pole is one end of a magnet, labeled north or south, where the magnetic effect is strongest.

Common Mistakes to Avoid

Thinking all metals stick to magnets, which is wrong because many metals such as aluminum and copper are not ferromagnetic and are not strongly attracted.
Assuming a shiny metal object must be magnetic, which is wrong because appearance does not reveal composition and coatings can hide the actual material.
Believing magnets attract through any distance equally, which is wrong because magnetic force decreases as the distance from the magnet increases.
Saying a magnet only works at one end, which is wrong because both the north and south poles exert magnetic forces and are usually the strongest parts.

Practice Questions

1 A magnet is tested on four objects: an iron nail, an aluminum can, a wooden stick, and a steel paper clip. Which objects will be strongly attracted to the magnet?
2 A box contains 6 steel washers, 5 copper coins, 4 plastic buttons, and 3 iron screws. How many objects in the box should a strong magnet pick up?
3 A refrigerator magnet sticks to the steel door but not to the paper note placed beside it. Explain why the magnet attracts one material and not the other using the idea of magnetic domains.