Class 6 Science Chapter 10 Case Based Questions - Fun with Magnets

Case 1: Magnetic Discovery

Imagine you are a history enthusiast visiting the town of Magnesia in Greece. While exploring the area, you stumble upon an ancient manuscript that talks about the discovery of magnets by a Greek shepherd named Magnes.

Q1: What is the significance of Magnesia in the history of magnets?
Ans: Magnesia is significant because it is the place where magnets were discovered by a Greek shepherd named Magnes, leading to the naming of magnets after Magnetite.

Q2: Describe the accidental discovery of magnets by Magnes. What type of natural magnet did he discover?
Ans: Magnes accidentally discovered a natural magnetic rock called lodestone in Magnesia, Greece. This lodestone had the property of attracting iron, nickel, and cobalt.

Q3: Which ancient Greek shepherd is credited with the accidental discovery of magnets?
(a) Archimedes
(b) Magnes
(c) Magnetite
(d) Lodestone
Ans: (b)

Q4: What property do natural magnets like lodestone possess?
(a) Attracting gold and silver
(b) Repelling iron, nickel, and cobalt
(c) Attracting iron, nickel, and cobalt
(d) Creating electricity when rubbed
Ans: (c)

Case 2: Magnetic Properties

You are a young scientist conducting experiments with magnets. You have observed various properties of magnets in your lab.

Q5: Name and explain two properties of magnets mentioned in the study notes.
Ans: Two properties of magnets mentioned are:

• Magnets attract objects made of iron, cobalt, and nickel due to their magnetic fields.
• Magnets have two poles, the north pole (N) and the south pole (S), and like poles repel while opposite poles attract.

Q6: How do magnets interact with each other when their poles are brought close together?
Ans: When the poles of two magnets are brought close together, opposite poles attract each other, and like poles repel each other.

Q7: What happens when opposite poles of two magnets are brought close together?
(a) They attract each other.
(b) They repel each other.
(c) They become neutral.
(d) They create a spark.
Ans: (a)

Q8: If you suspend a bar magnet freely and it aligns itself in the north-south direction, which property of magnets is demonstrated?
(a) Magnetic repulsion
(b) Magnetic attraction
(c) Magnetic poles
(d) Magnetic alignment
Ans: (d)

Case 3: The Magnetic Compass

You are a sailor preparing for a long sea voyage. You rely on a magnetic compass to navigate the oceans.

Q9: Explain the construction of a magnetic compass and how it helps sailors find directions.
Ans: A magnetic compass consists of a thin magnetic needle supported on a pivot inside an airtight box, with the north pole of the needle painted red. It points in the north-south direction, allowing sailors to find their way by aligning the compass with the dial's directions.

Q10: What was used as a pointing device to determine directions before the magnetic compass was invented?
Ans: Before the magnetic compass, an ancient pointing device called the "south pointing fish" was used to determine directions. The head of this fish pointed towards the south.

Q11: What is the purpose of the red tip on the north pole of a magnetic compass?
(a) It indicates the south pole.
(b) It helps align the compass.
(c) It attracts the needle.
(d) It warns of danger.
Ans: (b)

Q12: What ancient pointing device pointed towards the south to determine directions?
(a) Magnetic compass
(b) South pointing fish
(c) North pole marker
(d) Directional needle
Ans: (b)

Case 4: Making Artificial Magnets

You are a student conducting a science experiment to create artificial magnets using a rectangular iron bar.

Q13: Describe the process of turning a rectangular iron bar into a magnet using a bar magnet.
Ans: The process involves rubbing a bar magnet over a rectangular iron bar in the same direction multiple times. This aligns the domains in the iron, making it a magnet.

Q14: What precautions should you take while creating artificial magnets to ensure they retain their magnetic properties?
Ans: Precautions include not heating the magnet, not dropping it from heights, and not hammering it.

Q15: How can a rectangular iron bar be turned into a magnet?
(a) By heating it to a high temperature
(b) By exposing it to sunlight for a long time
(c) By rubbing a bar magnet over it
(d) By applying a strong electric current to it
Ans: (c)

Q16: Which of the following is NOT a precaution to protect magnets from losing their magnetic properties?
(a) Heating the magnets
(b) Dropping magnets from heights
(c) Hammering magnets
(d) Keeping magnetic items away from magnets
Ans: (a)

Case 5: Magnetic Materials in Daily Life

You are a curious student who has just learned about the magnetic properties of certain materials. You want to make sure you don't accidentally damage everyday items that contain magnetic material.

Q17: List some common everyday items that contain magnetic material.
Ans: Common items include CD's, DVD's, debit cards, credit cards, ATM cards, audio and video cassettes, and mobile phones.

Q18: Why is it important to keep certain items, such as credit cards and mobile phones, away from magnets?
Ans: It's important to keep these items away from magnets to prevent damage to the magnetic stripes or data on these items.

Q19: Which of the following items typically contains magnetic material?
(a) Glass bottles
(b) Plastic toys
(c) CD's and DVD's
(d) Wooden furniture
Ans: (c)

Q20: Why should you keep items like credit cards and mobile phones away from magnets?
(a) To prevent them from becoming magnetic
(b) To avoid damaging the magnets
(c) To prevent data loss or damage to the items
(d) To make them work better
Ans: (c)