Magical Magnets

Magical Magnets

Ø Do you know why the crane was able to separate iron junk from other waste

material?

 (the arm of block was holding a big magnet that was able to attract iron junk)

Ø Can you tell why the toy got stuck on the refrigerator?

(because it was made up of iron or any other magnetic material)

Ø Where the word ‘magnet’ comes from?

Ø Where the magnets are used?

 (in cranes, refrigerator)

magnes lithos means lodestone or leading stone as magnets are used to determine directions.magnet attracts only those objects which are made up of iron, nickel and cobalt. Similarly, our mind should be like a magnet i. e, it should attract positive thoughts and repel negative thoughts.

Ø Name the rock to which the metal tip of the rod that Magnes was holding

got stuck.

(magnetite)

Ø What did the magnetite compose of?

 (oxides of iron)

if a magnetite is suspended freely, it comes to rest in the North-South direction. This property was useful in finding out the directions and hence it

Ø Was the rock named as magnetite made artificially by man or it was a natural object?

was named lodestone which means the leading stone. artificial magnets are prepared by man using pieces of iron

Ø What is magnetism?

 (magnets can attract iron-containing or iron like substances and this property of objects is known as magnetism)

Ø What is the magnet rock called as? (magnetite)

Ø What are the other names of magnet? (loadstone or leading stone)

Ø State the two types of the magnet based on their occurrences

. (natural and artificial magnets)

Ø State two uses of magnets. (used in household items such as telephones,

computers, TVs and VCRs, in the door of the refrigerator, in the cranes etc)

Ø What material is used to make artificial magnets?

 (pieces of iron)

Ø Which objects does the magnet attract?

(objects that are made up of iron, nickel and cobalt)

Ø Do you think magnet will attract the objects made up of plastic or wood?

(yes/no)

The power of a magnet is strongest near the ends of the magnet and these ends of a magnet are called the magnetic poles.

Ø What are magnetic materials?(materials that are easily attracted by a magnet are known as magnetic materials)

Ø Give two examples of magnetic materials.

 (iron, nickel, steel, cobalt)

Ø Give two examples of non-magnetic materials.

 (plastic, paper, cloth)

Ø What are non-magnetic materials?

(the material that are not attracted by a magnet are called as non-magnetic materials)

Ø Is aluminium foil a magnetic material? Why?

 (no because it is not attracted by a magnet)

Ø Why the iron fillings got stuck near the ends of the magnet?

(because the power of a magnet is strongest at its ends)

Ø What are magnetic poles the two ends of a magnet are called as magnetic poles.

Ø After rolling suspending a bar magnet, what do you observe?

(the magnet rotates and comes to rest in a particular position, magnet rotates and then stops)

The magnet rotates and comes to rest in the North-South direction. The one pole of a magnet that points towards the North is called as

North

 Ø What are the two poles of the magnet?

 (the north pole and the south pole)

Pole and the other pole when suspended freely, one pole of magnet points towards north

and another pole points towards the south and travellers used this property of

magnets to fa device called magnetic compass was developed based on this property of magnets.ind the direction.points towards South and is called South Pole

Ø What does a magnetic compass consist of?

 (a magnetised needle pivoted inside a small box with a glass cover on it)

Ø Why is the north pole of a magnetised needle always painted in differentcolour?

 (for easy identification)

Ø Which direction does a magnetised needle indicates when in rest?

 (Northsouth direction)

Ø On the basis of which property of the magnet, a magnetic compass was

developed?

(a magnet rotates and comes to rest in north-south direction and based on this property magnetic compass)

Ø What will happen if a bar magnet is cut into two pieces?

Ø Is the two pieces of a broken magnet will behave like a magnet? (yes/no)

The poles of a magnet cannot be separated by cutting a magnet into pieces or by breaking it.

Ø What are the properties of a magnet?

(properties of a magnet are:

® a magnet attracts metals such as iron, cobalt, nickel and mixture of these

metals

® a freely suspended magnet always rests in North-South direction

® unlike poles of a magnet attract each other and like poles of a magnet

repel each other

® magnetic poles always exists in pairs)

Ø Do you think a broken piece of a magnet will behave like a magnet? (yes)

Ø Artificial magnets are man-made magnets and are made using pieces of

iron. How we can make the magnet?

Ø How you will confirm that this piece of iron has turned into a magnet or not?

repulsion when brought near the known pole of the bar magnet. Unmagnetised iron piece will get attracted to both the poles of the bar magnet and hence, in the study of magnets, repulsion is considered to be only sure test for a magnet

Ø Which test is considered to be only sure test for a magnet?

(testing by repulsion)

Ø How you will identify if an iron piece is magnetised or not? (by performing

repulsion test)

Ø What is a repulsion test?

 (bring one of magnet near the iron piece, if the iron piece is magnetised, then one of the end of magnet will show repulsion)

Ø Which alloy is used to make powerful magnets?

(alnico)

Ø What does happen when a bar magnet is suspended freely?

( it rotates and comes to rest in North-South direction)

Ø Why the freely suspended bar magnet points in the North-South direction?

Ø Why does the magnetic needle in the magnetic compass when in rest indicate the North-South direction?

Ø Why do you think the Earth acts like a magnet?

Ø Does the Earth also show two poles just like a magnet? (yes/no)

There is a magnetic field in the area around a magnet. The magnet exerts its influence or force within this area surrounding it. If you sprinkle iron fillings around a bar magnet placed on a plane surface, the fillings will get arranged in curved lines around the magnet. These lines are called the magnetic lines of force.

Ø Does a magnet ever lose its properties?(yes/no)

Ø What will happen if a magnet is dropped from a height?

Ø What will happen if a magnet is heated or hammered?

Ø Does the magnets need to store properly? (yes/no)

magnets become weak if they are not stored properly. Magnets lose their properties if they are heated, hammered or  dropped from a height

Ø The Earth acts like it seems to have a large bar magnet inside it. Why? (

because as the Earth spins, the two parts of the core move at different

speeds and this creates the magnetic field around the Earth)

Ø From which metals the Earth core is made up of? (iron and nickel)

Ø What are two parts of the Earth’s core? (the inner core and the outer core)

Ø Why should the magnets kept away from electronic devices?

 (because it will damage the magnets)