Exploring magnet, Methods of separation

Class VI Science Quiz: Methods of Separation & Explore Magnets

Part 1: Methods of Separation

1. What is the process of separating insoluble solid impurities from a liquid by allowing them to settle down called?

Sedimentation

2. What is the process of pouring out the liquid without disturbing the settled solid called?

Decantation

3. Name the method used to separate small stones from rice.

Handpicking

4. Which method is used to separate grains from stalks?

Threshing

5. What is the process of separating lighter impurities like husk from grains by wind called?

Winnowing

6. What is the method of separating insoluble solids suspended in a liquid by passing the mixture through a filter called?

Filtration

7. Give an example of a mixture that can be separated by filtration.

Muddy water / Chalk powder in water

8. What is the liquid that passes through the filter paper called?

Filtrate

9. What is the solid left on the filter paper called?

Residue

10. Which method is used to separate components of a mixture that have different particle sizes, like sand and pebbles?

Sieving

11. What is evaporation?

The process of converting a liquid into its vapor state, usually by heating.

12. How can salt be obtained from saltwater?

By evaporation

13. What is condensation?

The process of converting a vapor into its liquid state by cooling.

14. How do clouds form in nature, relating to separation methods?

By condensation of water vapor.

15. Name a method used to separate a soluble solid from a liquid.

Evaporation

16. What is the term for a substance that dissolves in a liquid?

Solute

17. What is the liquid in which a solute dissolves called?

Solvent

18. What is formed when a solute dissolves completely in a solvent?

Solution

19. Can oil and water be separated by decantation? Why?

Yes, because they form immiscible layers.

20. Which method would you use to separate tea leaves from prepared tea?

Filtration / Straining

21. Why is handpicking not suitable for separating very fine impurities?

Because they are too small to pick individually.

22. What is a saturated solution?

A solution in which no more solute can be dissolved at a given temperature.

23. How can you dissolve more sugar in a saturated sugar solution?

By heating it.

24. What is the purpose of a sieve?

To separate particles of different sizes.

25. Name two items that can be separated by winnowing.

Grains and husk.

26. Why is threshing necessary after harvesting crops?

To separate the grain from the stalks.

27. What type of mixture is best separated by sedimentation and decantation?

Mixtures of insoluble solids and liquids.

28. Can a mixture of sand and iron filings be separated using a method other than handpicking?

Yes, using a magnet (magnetic separation).

29. What is the principle behind sieving?

Difference in particle size.

30. When rainwater collected in a bucket has some mud at the bottom, which process will help clear the water?

Sedimentation followed by decantation or filtration.

31. Why do we often use a combination of methods for separation?

To achieve better separation or separate multiple components.

32. If you have a mixture of sand and salt, how would you separate them?

Dissolve salt in water, filter sand, then evaporate water to get salt.

33. What is the role of a fan in the process of winnowing?

To provide the wind for separating lighter impurities.

34. Does the amount of water affect the solubility of a substance?

Yes, more water can dissolve more solute up to its saturation point.

35. Name a common household item that uses the principle of filtration.

Tea strainer, coffee filter, water purifier.

36. What happens to the boiling point of a liquid when a soluble impurity is added to it?

It generally increases.

37. Is milk a pure substance or a mixture?

Mixture.

38. What method is used to separate cream from milk?

Centrifugation (or hand churning/butter making).

39. Why is it difficult to separate sugar from water once it's dissolved?

Because sugar forms a solution and cannot be seen separately.

40. Can all liquids be separated by decantation?

No, only immiscible liquids.

41. What is sublimation?

The process where a solid changes directly into a gas without first becoming a liquid.

42. Give an example of a substance that undergoes sublimation.

Camphor, dry ice (solid carbon dioxide).

43. How does a water filter work?

It uses a porous material to trap impurities while allowing water to pass through.

44. Why do some separation methods require heating?

To speed up processes like evaporation or to increase solubility.

45. What is distillation?

A method of separating liquid components from a solution by heating to vaporize and then condensing the vapor.

46. How can we obtain pure water from seawater?

By distillation.

47. What is the difference between a mixture and a compound?

Components of a mixture can be separated by physical means, while components of a compound are chemically combined and cannot be easily separated.

48. Why is filtration more effective than decantation for separating very fine insoluble particles?

Filtration uses a fine filter to trap even small particles, which might remain suspended after decantation.

49. Name a situation where you might use a magnet for separation.

Separating iron pins from sand.

50. What is the main characteristic that allows substances to be separated by winnowing?

Difference in weight (lighter impurities are blown away).

Part 2: Explore Magnets

51. What is a magnet?

A material that produces a magnetic field and attracts or repels other magnetic materials.

52. Name two materials that are attracted to a magnet.

Iron, Nickel, Cobalt, Steel.

53. What are magnetic materials?

Materials that are attracted by a magnet.

54. What are non-magnetic materials?

Materials that are not attracted by a magnet.

55. Give two examples of non-magnetic materials.

Wood, Plastic, Paper, Glass.

56. What are the two ends of a magnet called?

Poles (North pole and South pole).

57. Where is the magnetic strength of a magnet strongest?

At its poles.

58. What happens when two like poles of magnets are brought near each other?

They repel each other.

59. What happens when two unlike poles of magnets are brought near each other?

They attract each other.

60. If you break a bar magnet into two pieces, what happens to each piece?

Each piece becomes a new magnet with its own North and South poles.

61. What is a natural magnet?

A naturally occurring rock that has magnetic properties, like lodestone (magnetite).

62. What is an artificial magnet?

Magnets made by humans, such as bar magnets, horseshoe magnets, etc.

63. How can you make a temporary magnet?

By stroking a magnetic material with a permanent magnet in one direction.

64. What is a magnetic compass used for?

To find directions (North-South).

65. Which pole of a freely suspended magnet always points towards the geographic North?

Its North pole.

66. Why should you not drop magnets or heat them strongly?

It can cause them to lose their magnetic properties.

67. What is magnetic induction?

The process by which a magnetic material becomes a temporary magnet when placed near a permanent magnet.

68. Can a magnet attract a copper coin?

No, copper is a non-magnetic material.

69. Name an animal that uses Earth's magnetic field for navigation.

Birds (e.g., pigeons), sea turtles.

70. What is a magnetic field?

The area around a magnet where its magnetic force can be felt.

71. How can you store magnets safely to prevent demagnetization?

By keeping unlike poles together and using wooden or plastic keepers at the ends.

72. What happens to the magnetic strength as you move away from the poles of a magnet?

It decreases.

73. Can a magnet work through materials like paper or cloth?

Yes, if the material is non-magnetic and thin enough.

74. What is an electromagnet?

A temporary magnet formed by passing electric current through a coil of wire wound around a soft iron core.

75. Give one application of an electromagnet.

Electric bells, cranes for lifting heavy iron objects, loudspeakers.

76. Is Earth a giant magnet?

Yes, Earth behaves like a giant bar magnet.

77. What causes Earth's magnetic field?

The movement of molten iron in its outer core.

78. Why do some toys have magnets?

For attraction, repulsion, or to make parts stick together.

79. How can you test if an object is a magnet or just a magnetic material?

By checking for repulsion. Only a magnet will repel another magnet.

80. What is the demagnetization process?

The process of making a magnet lose its magnetic properties.

81. Name two ways to demagnetize a magnet.

Heating, hammering, dropping repeatedly.

82. Can a magnet be used to separate a mixture of sand and iron filings?

Yes.

83. Why do we not usually find the poles exactly at the ends of a bar magnet?

The magnetic strength is concentrated at the ends, but the effective poles are slightly inside.

84. What is a magnetic line of force?

Imaginary lines representing the direction and strength of a magnetic field. They emerge from the North pole and enter the South pole.

85. Can you make a magnet from a piece of plastic?

No, plastic is a non-magnetic material.

86. What is the direction of the magnetic field lines outside a magnet?

From North pole to South pole.

87. How did ancient sailors use magnets?

As compasses for navigation.

88. What is the principle behind a magnetic levitation (maglev) train?

Using magnetic forces (repulsion and attraction) to lift and propel the train.

89. Can a magnet attract an aluminum can?

No, aluminum is non-magnetic.

90. What is a permanent magnet?

A magnet that retains its magnetism for a long time.

91. What is a temporary magnet?

A magnet that retains its magnetism only as long as the magnetizing force is present (e.g., electromagnet).

92. If you have a powerful magnet, can it affect electronic devices?

Yes, strong magnets can interfere with or damage electronic devices like computers, phones, or credit cards.

93. Why do some refrigerators have magnetic seals?

To keep the door tightly closed and maintain the cold temperature inside.

94. What is the "North-seeking pole" of a magnet?

The North pole.

95. What is the "South-seeking pole" of a magnet?

The South pole.

96. Can magnets be used in recycling? How?

Yes, to separate magnetic materials (like iron and steel) from non-magnetic waste.

97. If you bring a magnet near a television screen, what might happen?

It can distort the picture temporarily or even permanently damage the screen (especially older CRT TVs).

98. What are some common shapes of artificial magnets?

Bar magnet, horseshoe magnet, cylindrical magnet, ring magnet.

99. What is a magnetic sensor used for?

To detect the presence or strength of a magnetic field, often used in door alarms or speed sensors.

100. Do all metals get attracted to a magnet?

No, only ferromagnetic metals like iron, nickel, cobalt, and their alloys.