Worksheet

The Sun's life from start to finish

Grade 9 Science Worksheet - Building Confidence

NameDate

Circle the best answer.

  1. Timeline ruler of the Sun's life with a dot at now. The Sun is now fusing hydrogen into helium in its core. Which stage of life is it in, by Ari's reading?

    • Red giant
    • White dwarf
    • Main sequence
    • Protostar

  2. Drawing of the Sun swelling into a large red star. Late in its life, the Sun will swell to hundreds of times its size and glow red. What is this stage called, by Bo's reading?

    • Main sequence
    • Supernova
    • White dwarf
    • Red giant

  3. Which order matches the Sun's life from start to finish, by Jun's reading?

    • Nebula → protostar → main sequence → supernova
    • Protostar → red giant → main sequence → white dwarf
    • Nebula → protostar → main sequence → red giant → white dwarf
    • Nebula → main sequence → white dwarf → red giant

  4. What comes right after the main sequence for the Sun, by Luz's reading?

    • It shrinks straight to a white dwarf
    • It goes dark at once
    • It explodes as a supernova
    • It swells into a red giant

  5. What happens right before the Sun becomes a white dwarf, by Milo's reading?

    • The main sequence begins
    • A protostar forms
    • Its outer layers drift away as a planetary nebula
    • A supernova blast

  6. About how long is the Sun's main-sequence stage, by Pia's reading (NASA)?

    • About 4.6 billion years, ending now
    • About 10,000 years
    • About 10 billion years
    • About 100 years

  7. About how much main-sequence time does the Sun have left, by Ren's reading?

    • About 5 billion years
    • About 50 years
    • It ends within the next century
    • About 10 billion years more

  8. Star card cutaway of a red giant with its core marked. What does the core of a red giant like the future Sun fuse, by Tala's reading (NASA)?

    • Nothing; fusion has stopped for good
    • Hydrogen into helium, just as now
    • Iron into gold
    • Helium into carbon

  9. Why does a white dwarf glow, by Zee's reading (NASA)?

    • It fuses hydrogen like the Sun today
    • It reflects light from other stars
    • It fuses helium in its core
    • It is still hot and slowly cools; no fusion happens

  10. About how big is a white dwarf, by Esme's reading (NASA)?

    • The same size as the Sun now
    • About 20 km across, like a neutron star
    • Roughly the size of Earth
    • Hundreds of times the Sun's size
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The Sun's life from start to finish

Answer Key - Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

  1. Timeline ruler of the Sun's life with a dot at now. The Sun is now fusing hydrogen into helium in its core. Which stage of life is it in, by Ari's reading?

    • Red giant
    • White dwarf
    • Main sequence
    • Protostar

  2. Drawing of the Sun swelling into a large red star. Late in its life, the Sun will swell to hundreds of times its size and glow red. What is this stage called, by Bo's reading?

    • Main sequence
    • Supernova
    • White dwarf
    • Red giant

  3. Which order matches the Sun's life from start to finish, by Jun's reading?

    • Nebula → protostar → main sequence → supernova
    • Protostar → red giant → main sequence → white dwarf
    • Nebula → protostar → main sequence → red giant → white dwarf
    • Nebula → main sequence → white dwarf → red giant

  4. What comes right after the main sequence for the Sun, by Luz's reading?

    • It shrinks straight to a white dwarf
    • It goes dark at once
    • It explodes as a supernova
    • It swells into a red giant

  5. What happens right before the Sun becomes a white dwarf, by Milo's reading?

    • The main sequence begins
    • A protostar forms
    • Its outer layers drift away as a planetary nebula
    • A supernova blast

  6. About how long is the Sun's main-sequence stage, by Pia's reading (NASA)?

    • About 4.6 billion years, ending now
    • About 10,000 years
    • About 10 billion years
    • About 100 years

  7. About how much main-sequence time does the Sun have left, by Ren's reading?

    • About 5 billion years
    • About 50 years
    • It ends within the next century
    • About 10 billion years more

  8. Star card cutaway of a red giant with its core marked. What does the core of a red giant like the future Sun fuse, by Tala's reading (NASA)?

    • Nothing; fusion has stopped for good
    • Hydrogen into helium, just as now
    • Iron into gold
    • Helium into carbon

  9. Why does a white dwarf glow, by Zee's reading (NASA)?

    • It fuses hydrogen like the Sun today
    • It reflects light from other stars
    • It fuses helium in its core
    • It is still hot and slowly cools; no fusion happens

  10. About how big is a white dwarf, by Esme's reading (NASA)?

    • The same size as the Sun now
    • About 20 km across, like a neutron star
    • Roughly the size of Earth
    • Hundreds of times the Sun's size