Science 6 · Unit 5: Forces and electricity · Cambridge Primary Science Stage 6

Questions

1. 1. Which two forces act on an object in water?

   • lift and drag
   • friction and thrust
   • weight (gravity) and upthrust
   • magnetism and gravity
   Check

2. 2. What does 'displaced' mean?

   • dissolved
   • pushed out of the way
   • made heavier
   • frozen
   Check

3. 3. Who discovered the idea of displacement in his bath?

   • William Harvey
   • Alessandro Volta
   • Archimedes
   • Isaac Newton
   Check

4. 4. When does an object float?

   • only when it is small
   • when its mass is less than or equal to the mass of water it displaces
   • only when it is made of wood
   • when its mass is greater than the water it displaces
   Check

5. 5. When does an object sink?

   • when upthrust is bigger than gravity
   • when it is hollow
   • when it is small
   • when its mass is greater than the mass of water it displaces
   Check

6. 6. On a force diagram of a floating ball, how do the arrows compare?

   • There are no arrows.
   • The gravity and upthrust arrows are equal.
   • There is no upthrust arrow.
   • The gravity arrow is much longer.
   Check

7. 7. On a force diagram of a sinking ball, how do the arrows compare?

   • The gravity arrow is longer than the upthrust arrow.
   • The upthrust arrow is longer.
   • They are equal.
   • There is no gravity arrow.
   Check

8. 8. How can a container ship with a mass of thousands of tons float?

   • It displaces an even greater mass of water.
   • It is very light.
   • Water has no upthrust.
   • It has no mass.
   Check

9. 9. Sand is added 10 g at a time to a floating plastic container. What happens eventually?

   • It sinks.
   • It floats higher.
   • It flies.
   • Nothing changes.
   Check

10. 10. In that test, what is the independent variable?

    • the mass of sand added
    • the amount of water
    • whether it floats or sinks
    • the size of the container
    Check

11. 11. A marble sinks, but a marble in a foil dish floats. Why?

    • The foil is magnetic.
    • Foil has no mass.
    • The marble gets lighter.
    • The dish's shape displaces more water.
    Check

12. 12. How could you make a foil boat hold more marbles?

    • make holes in it
    • make its base wider so it displaces more water
    • squash it into a ball
    • make it smaller
    Check

13. 13. Marcus's boats: base 2 cm² held 1 coin, 9 cm² held 4, 16 cm² held 9. What trend is this?

    • a random pattern
    • a negative trend
    • no trend
    • a positive trend
    Check

14. 14. How does a submarine sink?

    • It turns off its engines.
    • It fills its tanks with air.
    • It fills its ballast tanks with water to increase its mass.
    • It gets smaller.
    Check

15. 15. How does a submarine float back up?

    • It drops its anchor.
    • It opens all doors.
    • It fills them with water.
    • It fills its ballast tanks with air.
    Check

16. 16. Zara's polystyrene raft sank with seven 5 g coins. What was the dependent variable?

    • the size of the container
    • whether the raft floated or sank (the number of coins it held)
    • the type of water
    • the mass of each coin
    Check