Magnetism was discovered about 4000 years back in ancient Greece.
Some items such as iron and nickel get attracted to magnets and are called magnetic materials. Items that do not get attracted to magnets are called non-magnetic.
Have you ever thought why magnet attracts material, what is the range where its influence can be experienced? The region around a magnet where its influence is felt is called the magnetic field of the magnet. We cannot see the magnetic field, but it can be represented by a set of curves around a magnet called magnet field lines or magnetic lines of force. Learn to plot magnetic field lines and neutral points for uniform and non uniform magnetic field. Neutral point are the points where the magnetic field of the magnet is equal in magnitude to the earth's horizontal magnetic field, but in opposite direction. Thus the resultant magnetic field at neutral points is zero. Find out why two magnetic field lines do not intersect with each other?
Revise the 4 basic properties of a bar magnet:
• Directional property
• Attractive property
• poles exist in pairs and like poles repel while opposite poles attract.
Earth behaves like a huge magnet with its north pole near the geographic South pole and south pole near geographical North pole. This is why a freely suspended magnet comes to rest in the North south direction. The North pole of the suspended magnet is attracted by the South pole of earth’s magnet ,and hence points to the geographic North.
Learn about induced magnetism - The magnetism acquired by magnetic material when it is kept near (or in contact with) a magnet.
A SmartTest on Magnetism
Learnhive Lesson on Magnetism