A file clip has fallen into a glass of water (Fig. 7.1). Can you suggest a way to get it out without either spilling the water or putting your hand in ?
As shown in the figure 7.1 you can get it with the use of a magnet. It is possible to do so because the magnets have the special property of attracting things towards its direction.
There are magnets in many things which we use in our day-to-day life. For instance small motors, pencil boxes, some toys etc.
Let us do the following activity to observe the effect created by magnets on other materials.
Through this activity we can understand that some materials get attracted towards the magnet while some others do not.
The magnets differ from each other due to their shapes. Also they are used for different purposes.
Through the activity in 7.1 you have understood that some materials get attracted to magnets. Let's do the following activity to observe whether the materials get attracted equally to each and every spot of a magnet.
You will observe that there are more file clips near the two ends of the magnet.
So you must understand that the attractive power of the magnet is more at the ends than the middle. The two ends where the power of attraction is more are called the magnetic poles.
You can see that the magnet lies still between the North and South. Further more you can engage in the following activity too.
From these experiments you can understand that the magnet always stay still in between North and South. We can identify that the North pole of the magnet is the North of the compass and the South pole of the magnet is the South of the compass. We mark the North pole of a magnet as "N" and the South pole as "S".
The same poles do not get attracted but get repelled and the different poles get attracted.
Now compare your observations with the following observations.
The power of repulsion of magnets can be used to identify a magnet among some other objects.
You will see that the iron fillings are arranged according to a pattern. The iron fillings fallen a little bit away from the magnet are seen in an irregular manner. Accordingly we can understand that the magnetic forces are spread around a limited area of the magnet.
We can conclude that the magnet which bears the most number of nails has the highest magnetic power.
Exercise
01. Choose which of the given materials will get attracted to a
magnet.
iron nails, lead wire, marbles, a glass rod, a blade, a gold ring
02. Mark true (✔️) or false (❌)
Brass is a material which gets attracted to magnets ( )
All the spots of a magnet have the same power of magnetism ( )
We can find the North pole of a magnet with the help of a compass ( )
Any metal is attracted to a magnet ( )
When a magnet is being hung freely it always lies in the direction of North- South ( )
03' Fill in the blanks using the appropriate word from the words
given in the brackets.
The .................... is higher at the poles of the magnet. Same
types of poles are named as .................... . These type of
magnetic poles .................... each other. The different types of
poles are named as .................... . These types of magnetic pole
.................... each other.
(attract, repel, magnetism, like poles, unlike poles)
04' Suggest a way to find the most powerful magnet out of two
given magnets.
05' What will happen if the two toy cars are kept as above? Give
reasons.
