Science 9 · Unit 6: Sound and space · Cambridge Lower Secondary Science Stage 9

Questions

1. 1. What is a nebula?

   • a planet with rings
   • a small rocky body orbiting the Sun
   • a huge cloud of dust and gas in space
   • a group of galaxies
   Check

2. 2. Which gas is most common in nebulae?

   • carbon dioxide
   • hydrogen
   • nitrogen
   • oxygen
   Check

3. 3. Which of these statements is correct?

   • All nebulae act as stellar nurseries.
   • Only some nebulae act as stellar nurseries.
   • No nebulae ever act as stellar nurseries.
   • Only nebulae bigger than the Milky Way act as stellar nurseries.
   Check

4. 4. The diameter of the Solar System is 0.001 light years. The diameter of the Orion nebula is 24 light years. How many times bigger is the diameter of the Orion nebula?

   • 240 times
   • 24 000 times
   • 0.024 times
   • 2400 times
   Check

5. 5. The capture theory says the Moon formed far away and was caught by Earth's gravity. Which evidence supports the collision theory but contradicts the capture theory?

   • Moon rocks are very similar to Earth's rocks.
   • The Moon orbits the Earth.
   • The Moon is smaller than the Earth.
   • The Moon has craters.
   Check

6. 6. Put these in order of size, smallest first.

   • nebula, star, moon, asteroid
   • moon, asteroid, nebula, star
   • asteroid, moon, star, nebula
   • asteroid, star, moon, nebula
   Check

7. 7. Which statement about nebulae is true?

   • All nebulae contain dust and gas.
   • All nebulae are bigger than the Milky Way galaxy.
   • All nebulae act as stellar nurseries.
   • All nebulae are the same shape.
   Check

8. 📖 This question is about a text that students read in the app.

   8. Which type of nebula emits its own light?

   • an emission nebula
   • none of them
   • a dark nebula
   • a reflection nebula
   Check

9. 📖 This question is about a text that students read in the app.

   9. Which type of nebula does not emit its own light, but appears very bright?

   • an emission nebula
   • a reflection nebula
   • a supernova remnant
   • a dark nebula
   Check

10. 📖 This question is about a text that students read in the app.

    10. The Horsehead Nebula looks almost black. Why?

    • It is a black hole.
    • It is very hot.
    • It is a dark nebula that blocks light from stars behind it.
    • It reflects all light.
    Check

11. 📖 This question is about a text that students read in the app.

    11. The Crab Nebula is the remains of an exploded star. What type is it?

    • a dark nebula
    • a reflection nebula
    • a supernova remnant
    • an emission nebula
    Check

12. 📖 This question is about a text that students read in the app.

    12. Which type of nebula could act as a stellar nursery?

    • a reflection nebula, because it has no gas
    • none, because nebulae never form stars
    • a supernova remnant only, because it is the brightest
    • an emission nebula, because new hot stars inside make it glow
    Check

13. 13. What is a stellar nursery?

    • a place where stars die
    • a group of planets
    • a nebula where new stars are forming
    • a small star
    Check

14. 14. How is a star formed?

    • A comet heats up near the Sun.
    • Gravity pulls dust and gas together until it is hot and dense enough for nuclear fusion to start.
    • A nebula freezes solid.
    • Two planets collide and catch fire.
    Check

15. 📖 This question is about a text that students read in the app.

    15. Describe the trend in the star formation rate.

    • It rose to a peak at about 5500 million years, then fell to the present day.
    • It has risen steadily to its highest at the present day.
    • It has stayed the same since the universe began.
    • It fell, then rose to a peak today.
    Check

16. 📖 This question is about a text that students read in the app.

    16. When the Sun formed, how did the star formation rate compare with the peak?

    • It was at the peak.
    • It was higher than at the peak.
    • It was zero.
    • It was much lower than at the peak.
    Check