Science 9 · Unit 3: Forces and energy · Cambridge Lower Secondary Science Stage 9

Questions

1. 1. You hold a piece of ice and your hand feels cold. Why?

   • Your hand makes cold energy.
   • The ice gives your hand thermal energy.
   • Cold moves from the ice into your hand.
   • Thermal energy moves from your hand into the ice.
   Check

2. 2. When does thermal energy transfer from a hot place to a cold place happen faster?

   • It always happens at the same rate.
   • when the temperature difference between them is smaller
   • when the temperature difference between them is bigger
   • when both places are cold
   Check

3. 3. Marcus buys hot food and takes it home. What will happen to the temperature of the food on the way home?

   • It goes up, because cold moves out of the food.
   • It goes down, because the thermal energy is destroyed.
   • It stays the same.
   • It goes down, because thermal energy moves from the hot food to the colder air.
   Check

4. 4. Arun takes ice cream out of the freezer at −18 °C. The air in the room is at 22 °C. What will happen to the temperature of the ice cream?

   • It goes up past 22 °C.
   • It goes down, because cold moves from the ice cream into the air.
   • It stays at −18 °C.
   • It goes up, because thermal energy moves from the warmer air into the ice cream.
   Check

5. 5. Sofia and Zara visit an indoor ski slope where the air is at −2 °C. Sofia says: 'The gloves keep the cold away from my hands.' Zara says: 'The gloves keep the heat in my hands.' Who is correct?

   • Neither, because gloves don't affect thermal energy.
   • Both, because cold and heat are both types of energy.
   • Zara, because the gloves reduce the thermal energy moving from her hands to the colder air.
   • Sofia, because the gloves stop cold moving into her hands.
   Check

6. 6. Hot water from a car engine passes through the radiator, which is exposed to air at the front of the engine. What happens to the thermal energy in the water?

   • It changes into cold energy.
   • It is destroyed in the radiator.
   • It moves from the hot water into the colder air, so the water is cooled.
   • It moves from the air into the water.
   Check

7. 7. Method A: leave hot coffee for five minutes, then add a little cold milk. Method B: add the cold milk first, then leave it for five minutes. Which coffee will be hotter after five minutes?

   • Method A, because the milk is added at the end.
   • Method A, because hot coffee loses thermal energy more slowly.
   • There is no difference, because the same milk is added.
   • Method B, because the cooler coffee has a smaller temperature difference with the room, so it loses thermal energy more slowly.
   Check

8. 8. Choose the missing word: thermal energy is transferred from a place of higher temperature to a place of ______ temperature.

   • the same
   • lower
   • zero
   • higher
   Check

9. 9. A cooking pot at 100 °C is heated by a flame at 450 °C. Which way does thermal energy move?

   • It doesn't move at all.
   • in both directions equally
   • from the cooking pot to the flame
   • from the flame to the cooking pot
   Check

10. 10. The air in a room is at 15 °C and an electric heater is at 250 °C. Which way does thermal energy move?

    • in both directions equally
    • from the electric heater to the air
    • from the air to the electric heater
    • It doesn't move at all.
    Check

11. 11. An ice pack at 0 °C is held on a foot at 37 °C. Which way does thermal energy move?

    • It doesn't move at all.
    • from the foot to the ice pack
    • from the ice pack to the foot
    • in both directions equally
    Check

12. 12. Two objects at different temperatures touch. Which describes the thermal energy transfer?

    • Nothing happens unless one is heated.
    • Thermal energy moves from the colder object to the hotter one.
    • Thermal energy moves from the hotter object to the colder one until they reach the same temperature.
    • Thermal energy moves from the bigger object to the smaller one.
    Check

13. 13. Three metal blocks touch in a row. Their starting temperatures are 20 °C, 10 °C and 30 °C. Which block receives thermal energy from both of its neighbours?

    • none of them
    • the 10 °C block in the middle
    • the 30 °C block
    • the 20 °C block
    Check

14. 14. A cup of hot tea at 60 °C is left in a room at 25 °C. What will its temperature be when it stops changing?

    • 42.5 °C
    • 25 °C
    • 0 °C
    • 60 °C
    Check

15. 15. A cup of hot tea at 60 °C is left in a room at 25 °C. How does the temperature of the tea change?

    • It falls at a steady rate until it reaches 0 °C.
    • It falls quickly to 25 °C, then keeps falling below 25 °C.
    • It falls quickly at first, then more and more slowly until it levels off at 25 °C.
    • It falls slowly at first, then faster and faster.
    Check

16. 16. When the temperature of the tea stops changing, what is true?

    • The room is now hotter than the tea.
    • The tea has no thermal energy left.
    • The tea has frozen.
    • The tea and the room are at the same temperature, so there is no overall transfer of thermal energy.
    Check

17. 17. Zara's body temperature is 37 °C. Why does she feel cold when the air temperature is 5 °C?

    • The air gives her body thermal energy.
    • Her body temperature rises.
    • Thermal energy flows quickly from her body into the colder air.
    • Cold flows from the air into her body.
    Check

18. 18. Zara's body temperature is 37 °C. Why does she feel hot when the air temperature is 40 °C?

    • Her body loses thermal energy to the air.
    • The air has no thermal energy.
    • Thermal energy flows from the hotter air into her body.
    • Heat flows from cold to hot.
    Check

19. 19. Arun's glass of water is at 10 °C. He puts in ice at −15 °C. What will happen to the temperature of the water?

    • It goes down, because cold moves from the ice into the water.
    • It goes down, because thermal energy moves from the water into the colder ice.
    • It goes up, because the ice gives the water thermal energy.
    • It stays at 10 °C.
    Check

20. 20. Sofia makes a cup of hot coffee and adds cold milk. What happens to the temperatures of the coffee and the milk?

    • The coffee warms and the milk cools.
    • The coffee cools and the milk warms, until they are at the same temperature.
    • Both get colder.
    • Only the milk changes temperature.
    Check