There are following two ways to demagnetise a magnet
(i) by heating
(ii) by hammering

(i) Suresh is cooperative, intelligent and creative boy.
(ii) Some non-magnetic materials are plastic, stainless steel, glass, fibre, etc.

It is a suggested way shown in figure below

U-shaped magnet is kept along with an iron piece while bar magnets are kept along with iron strips and magnets separated by wood along their length.

If we face North pole towards the front side of the car and the car is attracted, it means its front side pole is South pole and if it is going away, it means its front side is North pole.

The poles of a bar magnet are located at the two ends of a bar magnet as shown below:

These two poles are North pole (N) and South pole (S).

Yes, Riya can help her mother to find the needle by using a magnet. Since needle is made of iron so it will easily stick to the magnet.

Earth behaves like a huge bar magnet, with poles at its ends. The north pole of this bar magnet points approximately towards the geographical south pole and its south pole points approximately towards the geographical north pole. The north pole of a freely suspended magnet points towards the geographical north pole because it is attracted by the earth's magnetic south pole and the south pole of a freely suspended magnet points towards the geographical south pole because it is attracted by the earth's magnetic north pole. Hence, the freely suspended magnet always aligns itself in the north-south direction.

A magnetic material can be magnetised by rubbing in a particular direction.

No, it is not possible to isolate North and South pole of a magnet.

A freely suspended magnet orients themselves in the North-South direction.

It can be found in following ways:
(i) Take the bar magnet with known poles in you hand.
(ii) Take one of the other two iron bars in other hand.
(iii) Bring one side of iron bar towards the south pole of the bar magnet and note down whether it is attracted or repelled.
(iv) Bring other side of iron bar towards the south pole of the bar magnet and again note down the same thing.
(v) If there is an attraction in both cases i.e.,(iii) and (iv), then it is definitely a simple iron bar.
(vi) If there is an attraction in one case and repulsion in other case, then it is a bar magnet.
(vii) Do the same for the third iron bar. Now, poles can be found in following ways-If in case (iii), the bar is attracted, then it is North pole of the identified bar magnet. If the bar is repelled, then it is a south pole of the identified bar magnet.

The two ways to identify the magnet are
(i) Hang the metal bars with a thread and having its level horizontal one by one and let it stop in any direction. Now, if we move it by"pushing it slowly and it returns to the same direction, it means that it is a magnet otherwise it is an iron bar simply.
(ii) Take some iron filings and move the iron bars over these iron filings one by one. If iron filings are attracted very strongly at poles, then it is a magnet and if it is not attracted, then it is simply an iron bar.