Class 6 Science · Chapter 4

4. Exploring Magnets

Answers to in-text questions, activities and Let us enhance our learning. NCERT Curiosity, Class 6 Science (CBSE).

Activities

4.1Predict and observe which objects stick to the magnet (Table 4.1).

Object	Material	Attracted by magnet?
Pencil	Wood	No
Eraser	Rubber	No
Iron nail	Iron	Yes
Steel spoon	Steel	Yes
Scale	Plastic	No
Tumbler	Glass	No
Aluminium foil	Aluminium	No
Safety pin	Steel	Yes

Objects made of iron, nickel, cobalt and steel stick to a magnet. They are magnetic materials. Wood, rubber, plastic, glass and aluminium are non-magnetic materials.

4.2Do the iron filings stick all over the magnet uniformly?

No. Most iron filings stick near the two ends of the bar magnet. Very few stick in the middle.

These ends are the poles of the magnet — the North pole and the South pole.

Can we find a magnet with a single pole?

No. If a magnet is broken, each small piece still has a North pole and a South pole. Poles always exist in pairs.

4.3Rotate a freely suspended bar magnet. Does it always rest along the same line? What happens with an iron bar?

Yes. A freely suspended magnet always comes to rest in the north-south direction. This is because the Earth behaves like a giant magnet.

An iron bar can rest in any direction. So this test tells us whether a piece of metal is a magnet or not.

4.4Make your own compass. Do the ends of the needle always point in the same direction?

Yes. After it stops rotating, the magnetised needle always points in the north-south direction.

4.5Bring the ends of magnet B near magnet A placed on pencils. What do you observe?

Magnet A moves towards magnet B when unlike poles (N–S) face each other. It moves away when like poles (N–N or S–S) face each other.

With an iron bar, both its ends are attracted by both poles of the magnet. So repulsion is the sure test of a magnet.

4.6Bring the North pole and then the South pole of a bar magnet near the North pole of a compass needle. What do you observe?

The North pole of the needle moves away from the North pole of the magnet.

It moves towards the South pole of the magnet.

4.7Place wood, cardboard, plastic and glass between the magnet and the compass (Table 4.2).

Material placed in between	Observation
Wood	Needle still deflects
Cardboard	Needle still deflects
Plastic	Needle still deflects
Glass	Needle still deflects

There is no change in the deflection. So the magnetic effect acts through non-magnetic materials.

Fun with magnets: Can we pick out a steel paper clip fallen in water without getting our fingers or the magnet wet? Will the two matchbox-magnet cars with like poles facing come closer?

Yes. Move a magnet along the outside of the glass. The clip follows the magnet and can be brought up and out.

The two cars with like poles facing each other will run away from each other because like poles repel.

Let us enhance our learning

1Fill in the blanks.

(i) Unlike poles of two magnets attract each other, whereas like poles repel each other.

(ii) The materials that are attracted towards a magnet are called magnetic materials.

(iii) The needle of a magnetic compass rests along the north-south direction.

(iv) A magnet always has two poles.

2State whether the following statements are True (T) or False (F).

(i) A magnet can be broken into pieces to obtain a single pole. — False. Each piece still has two poles.

(ii) Similar poles of a magnet repel each other. — True

(iii) Iron filings mostly stick in the middle of a bar magnet. — False. They mostly stick at the ends (poles).

(iv) A freely suspended bar magnet always aligns with the north-south direction. — True

3Fill in the blanks in Column I and Column II.

Column I	Column II
N – N	Repulsion
N – S	Attraction
S – N	Attraction
S – S	Repulsion

4Atharv rolled a bar magnet over a heap of steel U-clips. Which option in Table 4.3 is likely to be his observation?

Option (i) A = 10, B = 2, C = 10

A and C are the ends (poles) of the magnet, where attraction is strongest. B is the middle, where attraction is weakest.

5Reshma bought three identical metal bars. Two were magnets and one was a piece of iron. How will she identify the two magnets without using any other material?

Take any two bars. Bring one end of the first bar near both ends of the second bar.
If they repel at any end, both bars are magnets. The third bar is iron.
If they only attract, one of these two is iron. Test the third bar with one of them in the same way. The pair that shows repulsion are the magnets.

Repulsion takes place only between two magnets.

6You are given a magnet which does not have the poles marked. How can you find its poles with the help of another magnet which has its poles marked?

Bring the North pole of the marked magnet near one end of the unmarked magnet.

If that end is repelled, it is the North pole. If it is attracted, it is the South pole. The other end is the opposite pole.

7A bar magnet has no markings to indicate its poles. How would you find out near which end its North pole is located without using another magnet?

Tie a thread to the middle of the magnet and suspend it freely. When it comes to rest, the end pointing towards the north is its North pole.

8If the earth is itself a magnet, can you guess the poles of earth’s magnet by looking at the direction of the magnetic compass?

Yes. The North pole of the compass needle points towards the geographic north. Unlike poles attract each other.

So the South pole of the Earth’s magnet is near the geographic north. The North pole of the Earth’s magnet is near the geographic south.

9While a mechanic was repairing a gadget using a screw driver, the steel screws kept falling down. Suggest a way to solve the problem.

He can magnetise the tip of the screwdriver. He can rub it with one pole of a magnet in one direction 30–40 times.

The magnetised screwdriver will hold the steel screws.

10Two ring magnets X and Y are arranged as shown in Fig. 4.16. Magnet X does not move down further. What could be the possible reason? Suggest a way to bring X in contact with Y without pushing.

Reason: The facing sides of X and Y are like poles. Like poles repel. So X floats above Y.

Way: Take X out, turn it upside down and put it back. Now unlike poles face each other. They attract and X sits on Y.

11Three magnets are arranged in the shape shown in Fig. 4.17. What is the polarity at the ends 1, 2, 3, 4 and 6? End 5 is N.

Magnets stick together only when unlike poles touch. End 5 is N.

End 6 is the other end of the same magnet: S
End 4 touches end 5 (N): S
End 3 is the other end of the vertical magnet: N
End 2 touches end 3 (N): S
End 1 is the other end of the top magnet: N

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