Floating and Sinking

35 Grade 5 Integrated Science questions on Floating and Sinking, with worked marking schemes. 35 questions are available on this topic in full.

1. Question 1

   1 mark

   Which of the following objects will sink in water?

   A. Stone

   B. Plastic bottle (empty)

   C. Cork

   D. Dry leaf

   (1 mark)

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2. Question 2

   1 mark

   Ships are made of metal but they float because

   A. water pushes them up

   B. they have engines

   C. metal always floats

   D. they are designed with a hollow shape that displaces enough water

   (1 mark)

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3. Question 3

   1 mark

   Two balls are exactly the same size. The cork ball floats but the iron ball sinks. This shows that floating depends on the

   A. name of the object

   B. material the object is made of

   C. colour of the object

   D. age of the object

   (1 mark)

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4. Question 4

   1 mark

   A ball of clay sinks in water, but when the same clay is shaped like a boat it floats. This shows that floating can be affected by an object's

   A. smell

   B. temperature

   C. colour

   D. shape

   (1 mark)

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5. Question 5

   4 marks

   In an experiment the following results were recorded: an empty sealed bottle floated, the same bottle filled with water sank, a cork floated and a stone sank.

   (a) State one object that floated.

   (b) State one object that sank.

   (c) Explain why the empty bottle floated but the water-filled bottle sank.

   (4 marks)

   Marking scheme

   (a) 1 mark: empty sealed bottle or cork. (b) 1 mark: stone or the water-filled bottle. (c) 2 marks: the empty bottle contains air and is light for its size, so it floats; when filled with water it becomes heavy for its size, so it sinks.

6. Question 6

   1 mark

   Which of these materials floats on water?

   A. cork

   B. stone

   C. glass

   D. iron

   (1 mark)

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7. Question 7

   1 mark

   Adding salt to water makes it easier for objects to float because

   A. salt removes air from water

   B. salt water is denser than fresh water

   C. salt dissolves the object

   D. salt makes water lighter

   (1 mark)

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8. Question 8

   1 mark

   An object floats in water when it is

   A. less dense than water

   B. heavier than water

   C. more dense than water

   D. the same size as water

   (1 mark)

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9. Question 9

   2 marks

   Explain why people are advised to wear life jackets when travelling on water.

   (2 marks)

   Marking scheme

   1 mark each (max 2): a life jacket helps the person float/stay on the surface of the water if they fall in; this prevents them from sinking and drowning.

10. Question 10

    2 marks

    State two dangers of overloading a boat.

    (2 marks)

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11. Question 11

    1 mark

    Which of the following objects will most likely float on water?

    A. a dry wooden stick

    B. a metal spoon

    C. a stone

    D. an iron nail

    (1 mark)

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12. Question 12

    4 marks

    A learner wants to find out whether the shape of an object affects floating, using clay.

    (a) Name one thing that must be kept the same during the test.

    (b) Describe how the learner can carry out the test.

    (4 marks)

    Marking scheme

    (a) 1 mark: the same amount/piece of clay (same material and quantity). (b) 3 marks: roll the clay into a ball and place it gently in water and observe; take the same clay and shape it into a boat/bowl and place it in water and observe; compare which shape floats and which sinks.

13. Question 13

    1 mark

    Large ships are made of heavy metal, yet they float on water because they are

    A. made completely of wood inside

    B. shaped to be hollow and trap air

    C. much lighter than a coin

    D. painted with a special colour

    (1 mark)

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14. Question 14

    1 mark

    A swimming ring helps a person to float on water because it is filled with

    A. sand

    B. air

    C. water

    D. stones

    (1 mark)

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15. Question 15

    1 mark

    To find out how the material affects floating, learners should test objects that are of the

    A. different shapes only

    B. same size but different materials

    C. same colour only

    D. different sizes and different materials

    (1 mark)

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16. Question 16

    4 marks

    A ball of plasticine sinks when placed in water.

    (a) Suggest one way you could make the same piece of plasticine float.

    (b) Explain why your method works.

    (4 marks)

    Marking scheme

    (a) 2 marks: shape/mould the plasticine into a boat, bowl or hollow shape. (b) 2 marks: the hollow shape traps air and spreads the weight over a larger area of water, so it is able to float instead of sinking.

17. Question 17

    1 mark

    In a floating and sinking experiment, writing down exactly what you see happening is called

    A. eating

    B. guessing

    C. observation

    D. prediction

    (1 mark)

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18. Question 18

    1 mark

    Before starting an experiment, saying whether you think an object will float or sink is called making a

    A. measurement

    B. prediction

    C. conclusion

    D. drawing

    (1 mark)

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19. Question 19

    2 marks

    Give one example of an object that floats on water and one example of an object that sinks.

    (2 marks)

    Marking scheme

    Floats (1 mark): any of piece of wood, cork, empty sealed bottle, dry leaf, plastic. Sinks (1 mark): any of stone, nail, coin, metal spoon.

20. Question 20

    1 mark

    An empty sealed plastic bottle floats, but when it is filled with water it sinks. This happens because the water-filled bottle is now

    A. a different colour

    B. heavier for its size

    C. much smaller

    D. warmer than before

    (1 mark)

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21. Question 21

    3 marks

    Explain why a large ship built of metal is able to float on water.

    (3 marks)

    Marking scheme

    1 mark each (max 3): the ship is hollow/shaped to trap a large amount of air inside; this makes the whole ship lighter for its size than the water it pushes aside; so the water is able to hold it up and it floats.

22. Question 22

    1 mark

    Which object will sink when it is placed gently into a basin of water?

    A. a metal coin

    B. a plastic bottle cap

    C. a dry leaf

    D. an empty sealed bottle

    (1 mark)

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23. Question 23

    1 mark

    A wooden block floats in water because it is

    A. transparent

    B. made of metal

    C. heavier than water

    D. lighter than the same volume of water

    (1 mark)

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24. Question 24

    3 marks

    State three factors that determine whether an object floats or sinks in water.

    (3 marks)

    Marking scheme

    1 mark each (max 3): the material the object is made of; the shape of the object; the weight/size (amount of matter) of the object; whether it contains/traps air.

25. Question 25

    1 mark

    A log of wood floats on a river mainly because wood is

    A. heavier than water

    B. made of metal

    C. full of water

    D. lighter than the same amount of water

    (1 mark)

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26. Question 26

    2 marks

    Explain what is meant by 'floating'.

    (2 marks)

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27. Question 27

    1 mark

    A metal basin is used to ferry goods across a river. It floats best when it is

    A. full of heavy stones

    B. turned upside down and pressed under water

    C. empty and hollow, sitting upright

    D. filled to the top with wet sand

    (1 mark)

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28. Question 28

    1 mark

    Which of these floats and is used for travelling on water?

    A. a train

    B. a boat

    C. a bicycle

    D. a car

    (1 mark)

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29. Question 29

    4 marks

    Same-sized balls made of cork, iron, wood and glass are placed one by one into a basin of water.

    (a) Name the two balls that are likely to float.

    (b) Name the two balls that are likely to sink.

    (4 marks)

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30. Question 30

    1 mark

    An egg sinks in fresh water but floats in salty water. This is because

    A. the egg becomes lighter in salty water

    B. salt makes the egg smaller

    C. fresh water has no density

    D. salty water is denser than fresh water

    (1 mark)

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31. Question 31

    1 mark

    Passengers taking a boat ride on Lake Victoria are asked to wear life jackets. A life jacket helps a person to

    A. float on the water

    B. breathe under the water

    C. swim under the water

    D. sink faster

    (1 mark)

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32. Question 32

    3 marks

    Fishermen on Lake Victoria use boats every day. State three water-safety measures they should observe.

    (3 marks)

    Marking scheme

    1 mark each (max 3): wear life jackets/floaters; do not overload the boat; avoid going out in strong winds or storms; learn how to swim; carry a means of communication or rescue equipment.

33. Question 33

    1 mark

    A canoe carrying too many people and heavy loads may sink because

    A. the wood is very dry

    B. the water is too clean

    C. too much weight has been added to it

    D. it has been painted

    (1 mark)

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34. Question 34

    3 marks

    Give three ways in which floating is useful in everyday life.

    (3 marks)

    Marking scheme

    1 mark each (max 3): boats and ships float and are used to transport people and goods across water; life jackets and swimming rings float to keep people safe; floats/buoys are used in fishing; logs of timber are floated down rivers to transport them.

35. Question 35

    1 mark

    An egg sinks in fresh water but floats when a lot of salt is added to the water. Adding salt makes the water

    A. dirty

    B. able to support more weight

    C. hotter

    D. much lighter

    (1 mark)

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