Fun With Magnet: science class six
What is Magnet
The word magnet came from a Greek name "Manges".
A piece of iron or material having similar properties as iron, which can attract other materials made of iron or nickel or cobalt is known as Magnet.
Magnet has many use in the daily life. In fact, we are surrounded with magnets. There are many machines which run on magnet, for example electric fan, electric motor, electric generator, etc.
The earth on which we live is a strong and very big magnet.
One of the amazing discovery is Maglev Train. This Maglev Train runs on magnet. The top speed of this Maglev Train which runs in Shanghai, China, is 470 km per hour. However, the top speed of Maglev Train which runs in Japan is 603 km per hour.
Figure1: Maglev Train
Cranes in the junk yard are used to separate iron from the heap of junk, has a strong magnet attached at one end of its arm. When the lower end of such cranes is hovered over the junk of heap, the pieces of iron and articles made or iron get stuck with it, which is separated latter.
Small pin holders also have magnetic tip on which pins are get stuck. Such magnetic tip in the pin holders facilitate the picking up of pins. The doors of refrigerator and many almirah also has magnets fit in them which keeps the doors hold tightly when closed.
Discovery of Magnet
Many of the discoveries occurred accidently. Discovery of Magnet has similar story.
It is said that there was a shepherd, named Manges lived in ancient Greece. That shepherd Manges used to keep a long stick to control the heard of sheep and goats while grazing.
Once while roaming in the course of grazing his sheep, he became surprised to see that he had to pull hard to free this stick from a rock on the mountain. Hel felt that his stick was being attracted by the rock.
Actually his stick had iron at one end which was got stuck by that rock.
It is said that that rock was a natural magnet. By this way magnet was discovered.
Such rocks, which attracts article made of iron, were given the name as "Magnetite", after the name of that very shepherd "Magnes".
Figure2: Natural Magnet, discovered by Magnes
Natural and Artificial Magnets
Natural magnets are made from magnetite.
Magnetite is a rock mineral. Magnetite contains iron and it has a property to attract iron and other magnetic materials.
Later process of making magnets from iron discovered. Man-made magnets are called artificial magnets.
Shape of Magnet
Magnets are made in many shaped, like bar magnets, horse shoe magnets, cylindrical magnets, etc. The shapes of artificial magnet depend upon the need.
Figure3 : Different Shapes of Magnet
Magnetic Materials and Non-Magnetic Materials
Materials which are attracted towards magnets are called magnetic materials. For example, Iron, nickel and cobalt.
Aluminium and platinum are weak magnetic materials.
Other materials, which are not attracted towards magnet are called non-magnetic materials.
Poles of a Magnet
Ends of a magnet is called its pole. There are two poles a magnet has. One pole of a magnet is called North Pole while other pole of a magnet is called South pole.
Magnet is stronger at its poles.
When a magnet is put over iron fillings, more iron fillings get stuck at its poles. This shows that, a magnet has stronger attracting power at its poles.
Property of Magnet
(1) Magnet attracts magnetic materials.
(2) A magnet has two poles, i.e. north pole and south pole.
(3) When a bar magnet is suspended freely, its north pole direct towards north direction and south pole directs towards south direction.
(4) A magnet is stronger at its poles. This means at poles a magnet has most attracting power.
(5) Same poles of two magnets repulse each other. While opposite poles of two magnets attract each other.
Finding Direction Using a Magnet
A magnet has a unique property that poles of magnet always point towards north and south direction. Knowing after this unique property, people started to use magnet to find the direction.
Figure4 : A Compass
Initially, travelers used to suspend magnets with threads to find direction. Later on people in China made a small box with glass top and put a magnetic needle inside on a pivot. All directions were written on the dial of this box for easy reference. The north pole of the magnetic needle directs towards north while south pole of the magnetic needle directs towards the south.
This box is called compass. A compass is known as magnetic compass also. A compass is used to find direction.
Even today a compass is used to find the direction. Magnetic compass proved very useful for travelers across the world.
Finding Directions Without Using Magnet
People also used to find direction after seeing the Sunrise and Sunset.
Sun rises in the East and sets in the West. Thus by seeing the sunrise, one can find direction in day time.
The position of Pole Star is fixed it is always at north direction.
Thus, by watching the Pole Star, one can find the north direction.
And by keeping face towards north direction, the back faces towards south. The right shoulder will be towards east and left shoulder will be towards right.
Thus, after knowing the north direction or any one direction one can find all the other directions.
The Story of Magnetic Doll fitted over a Chariot
There was a carpenter in ancient China. He made a chariot fitted with a magical statue. The one hand of the magical statue always pointed in the south direction. He gifted this chariot to one of the king of China. The king became too much pleased to the carpenter. This chariot became the favourite to the king.
Figure5: Chariot with Magnetic Doll
This chariot fitted with the magic statue helped the king to find the right direction, wherever he went. People of his kingdom were amazed of this property of the chariot.
In fact, statue fitted over the chariot had a concealed magnet in its hands. Statue was installed over a pivot which gives the free movement to the statue. Because of magnet concealed in the hand of statue, the one hand of statue always pointed the south direction.
Reference:
Figure1: By Saruno Hirobano - Own work, CC BY-SA 3.0, Link
Figure2: NCERT Book class 6 chapter 13 page number: 126
Figure3 : NCERT Book class 6 chapter 13 page number: 126
Figure4: By User:Bios~commonswiki - Own work, CC BY-SA 3.0, Link
Figure5: By Andy Dingley - Own work, CC BY 3.0, Link