Magnet | Lodestone

A magnet is a metallic object that attracts other metallic objects towards it e.g lodestone.

Elements which are attracted by magnets are called Magnetic Materials. They include iron, steel, nickel, cobalt etc. Substances that can be attracted by a magnet are said to be Magnetic and the ability of a magnet to attract magnetic substances is called Magnetism.

Magnets are generally categorized into two groups namely permanent and temporary magnets.

Permanent Magnets: A magnet that retains its magnetic properties for a long period of time is called a permanent magnet.

Examples are iron, nickel, cobalt, some rare earth alloys etc.

Temporary Magnets: Magnets that simply act like permanent magnets when they are within a strong magnetic field are called temporary magnets.

They lose their magnetism when the field disappears, unlike permanent magnets.

Paperclips, iron nails and other similar items are examples of temporary magnets.

Lodestone:

The lodestone (also spelt loadstone) is a special type of mineral, magnetite, the first natural magnet observed over 2000 years ago in China; Iron fillings and nails were attracted by their ends.

Uses of Magnets:

1. They are used in the construction of the pocket compass and the ship compass. 

2. They are used in the construction of electric motors, generators, bicycles, dynamos, loudspeakers, radios, and televisions.

Properties of a Magnet: 

A bar magnet attracts small pieces of iron filings. The ends of a bar magnet are regions where the attracting power is the greatest and these ends are called Poles of a Magnet.

Magnets have certain important properties and these include;

1. Attractive Property – Magnet attracts ferromagnetic materials like iron, cobalt, and nickel.

2. Repulsive Properties – Like magnetic poles repel each other and unlike magnetic poles attract each other.

3. Directive Property – A freely suspended magnet always points in a north-south direction.