Page 147 - SCERT Kerala State Syllabus 8th Standard Basic Science Textbooks English Medium Part 1_Neat

Lodestone Natural Magnets and Artificial Magnets

Magnetic properties of Magnets obtained directly from nature are natural
substances have been known magnets.
to people from ancient times. Nowadays artificial magnets are used commonly.
In 800 BC, a particular mineral
Haven't you understood that they are made of alloys like
discovered in a place named
alnico? Some magnets known to us on the basis of their
Magnesia, was found to
shapes are depicted in Table11.1.
possess an amazing property.
They could attract pieces of Try to identify the artificial magnets given in the table
iron. Considering this feature and write them down in the space given.
of the mineral it was given the
name 'magnetite'. When Shape of magnet Name of magnet
suspended freely, the pieces
of this mineral were found to
indicate a particular direction.
They came to be known as
leading stone (load stone or
lodestone) as they exhibited Magnetic needle
this property. Magnets like
these, found in nature, are
natural magnets.

Table 11.1
Let’s see what the general properties of magnets are.

Suspend a magnet using a thread, as shown in Fig. 11.1, in
such a way that it is free to turn.
In which direction of the earth does the end marked ‘N’ point
when the suspended magnet come to rest?

And what about the end marked ‘S’ on the magnet?
If a magnet is arranged in such a way that it can move freely
(like suspending it using a thread) it will align itself in the
north south direction of the earth. It is because a magnet
possesses directional property that a freely moving magnet
Fig. 11.1 always aligns itself in the north south direction. The end of
the magnet pointing to the north is the North Pole (N) and
the other end is the South Pole (S).
146 Basic Science VIII