Magnetism Magnets are useful things: Magnets can be used to hold cupboards doors shut. They are used in electric motors and generators. They are used in headphones and loudspeakers. They have fun uses - for example, magnetic letters. Permanent Magnet A permanent magnet is an object that is magnetised for a long time. It doesn't stop being a magnet after it has been used. Permanent magnets come in different shapes and sizes. B. Magnetic Material A material which is attracted by a magnet is called a magnetic material. Iron is a magnetic material and also steel, nickel and cobalt (most of steel are also magnetic). Nowadays many small and strong magnets are made using neodymium . Authors metal such as aluminium and tin are non-magnetic. C. Magnetic Poles Magnets attract magnetic material because there is a magnetic force which pulls magnetic object when magnet attracts it. The ends of the magnet are called its magnetic pole . The poles are called the north pole(N) and the
Material Changes
In this unit, we will talk about the changes of an object. This chapter includes changes on object and some reactions.
Physical changes occur when objects undergo a change that does not change its chemical composition, so it doesn’t create a new substance.
Chemical change occurs when one substance transforms into one or more different substances. So, in chemical change new substances are formed.
For more explanation click this link below:
Material Changes (google docs)
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