Science 8 · Unit 1: Respiration · Cambridge Lower Secondary Science Stage 8

Questions

1. 1. What does the diaphragm do when you breathe in?

   • relaxes and domes upward
   • stays still
   • moves the ribs down
   • contracts and flattens
   Check

2. 2. What do the intercostal muscles do when you breathe in?

   • relax completely
   • squeeze the lungs
   • pull the ribs down and in
   • pull the ribs upwards and outwards
   Check

3. 3. When you breathe in, what happens to the volume and pressure inside the chest?

   • Both increase.
   • Both stay the same.
   • Volume increases and pressure decreases.
   • Volume decreases and pressure increases.
   Check

4. 4. Why does air rush into the lungs when you breathe in?

   • The pressure inside the lungs is lower than outside.
   • The diaphragm blows it in.
   • The heart pushes it.
   • The lungs suck it in like a pump.
   Check

5. 5. What happens when you breathe out?

   • The volume increases.
   • The ribs move up and out.
   • The muscles relax, chest volume decreases and air is pushed out.
   • The diaphragm contracts and flattens.
   Check

6. 6. How did Sofia and Zara measure lung volume?

   • by counting breaths
   • by blowing into an upturned bottle of water and measuring the water pushed out
   • by weighing the person
   • by measuring chest size with a ruler
   Check

7. 7. Boys playing wind instruments pushed out 2100, 1965 and 2005 cm³. What is the mean?

   • 6070 cm³
   • 2100 cm³
   • 2023 cm³
   • 1965 cm³
   Check

8. 8. Girls playing stringed instruments: 1905, 1910 and 1885 cm³. What is the mean?

   • 1885 cm³
   • 5700 cm³
   • 1900 cm³
   • 1905 cm³
   Check

9. 9. How could Sofia and Zara improve their experiment?

   • test more people and take three measurements for each person
   • measure how fast each person runs
   • test percussion players only
   • use a smaller bottle
   Check

10. 10. Why can't the girls draw definite conclusions from their results?

    • Their bottle was too big.
    • They tested too few people.
    • They used water.
    • They tested too many people.
    Check

11. 11. Why did researchers measure several hundred people in each age group?

    • because few people breathe
    • to get reliable mean values
    • to use more bottles
    • to finish faster
    Check

12. 12. Look at the graph. How does the volume of air women can push out change with age after their 20s?

    • It stays the same forever.
    • It increases steadily.
    • It doubles.
    • It decreases.
    Check

13. 13. Look at the graph. On average, who can push out more air in one breath, men or women?

    • men
    • women
    Check

14. 14. What unit is used for the volume of air on the graph?

    • dm³
    • kg
    • N
    • °C
    Check

15. 15. Which muscle is the main muscle used for breathing?

    • the heart
    • the stomach muscle
    • the diaphragm
    • the biceps
    Check

16. 16. Look at the graph. What is the mean volume of air pushed out by women aged 20-29?

    • 3.0 dm³
    • 4.9 dm³
    • 4.2 dm³
    • 3.9 dm³
    Check

17. 17. Look at the graph. How much more air do men aged 40-49 push out than women of the same age?

    • 8.8 dm³
    • 5.0 dm³
    • 1.2 dm³
    • 3.8 dm³
    Check

18. 18. Look at the graph. Which is the best prediction for men aged 70-79?

    • about 1.0 dm³
    • about 4.5 dm³
    • about 3.3 dm³
    • about 5.3 dm³
    Check

19. 19. In a model of breathing, a balloon sits inside a syringe with the end cut off. What does the balloon represent?

    • the trachea
    • the lungs
    • the diaphragm
    • the rib cage
    Check

20. 20. In the syringe model of breathing, what does pulling the plunger out represent?

    • the lungs filling with blood
    • the diaphragm moving down
    • air leaving the lungs
    • the ribs moving down
    Check