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Grade 9 · Science · Earth and Space Science

9th grade The Sun's layers and the fusion that powers it worksheet

6 printable versionsBuilding Confidence10 questions · answer keyFree · no account

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The Sun's layers and the fusion that powers it

Grade 9 Science Worksheet - Building Confidence

NameDate

Circle the best answer.

  1. Read this first

    Use this

    Star card cutaway of the Sun, not to scale:

  3. On Ari's star card, the Sun's cutaway has four layers lettered A (center) to D (surface). Which layer is the core, where fusion happens?

    • B, the next layer out from the center
    • C, the layer below the surface
    • D, the glowing surface, since it is hottest
    • A, the center

  4. Using the same lettered cutaway, which layer of the Sun is hottest, by Bo's reading?

    Use the picture in question 1.

    • C, the convection zone
    • B, the radiative zone
    • A, the core
    • D, the photosphere, since it glows

  5. Star card cutaway of the Sun, not to scale

    A, the center; B, the next layer out; C, the layer below the surface, drawn with looping arrows; D, the visible surface.

  6. Which layer of the same cutaway carries energy by hot plasma rising and cooler plasma sinking, by Kira's reading?

    • C, the convection zone
    • B, the radiative zone
    • D, the photosphere
    • A, the core

  7. In the Sun's core, hydrogen nuclei join to make helium. What is this process called, by Jun's reading?

    • Nuclear fusion
    • Burning, like a campfire
    • Melting
    • Nuclear fission

  8. Which statement describes nuclear fission, by Luz's reading?

    • A heavy nucleus such as uranium splits into smaller ones
    • Atoms change from a solid to a gas
    • Light nuclei such as hydrogen join into helium
    • Fuel combines with oxygen and burns

  9. Why is the Sun not a giant fire, by Milo's reading?

    • It runs on fission of hydrogen
    • Burning needs oxygen; the Sun runs on fusion
    • It gets its energy from Earth
    • It is a fire; fire and fusion are the same

  10. Star card cutaway of the Sun, not to scale, with an arrow from the center out to the surface. In which order does energy travel out from the Sun's center, by Noah's reading?

    • Core → convection zone → radiative zone → photosphere
    • Core → radiative zone → convection zone → photosphere
    • Core → photosphere, straight out in 8 minutes
    • Photosphere → convection zone → radiative zone → core

  11. How does energy move through the Sun's radiative zone, by Pia's reading?

    • As light, bouncing slowly outward
    • As hot plasma rising and sinking
    • As flames spreading outward
    • Straight to the surface in about 8 minutes

  12. About how long does light take to reach Earth after it leaves the Sun's photosphere, by Ren's reading?

    • About 170,000 years
    • About 8 minutes
    • No time; it arrives instantly
    • About 8 hours

  13. “H-R diagram:” On the star card's H-R diagram, temperature runs from hot on the left to cool on the right. A star at the far left is what, compared with the Sun, by Tala's reading?

    • Hotter than the Sun
    • Cooler, since left means lower
    • Cooler, since it is on the left
    • The same temperature as the Sun
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9th grade The Sun's layers and the fusion that powers it worksheet – printable
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About this worksheet

The Sun's layers and the fusion that powers it. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can name the Sun's layers in order and say how energy crosses each one.
  • I can explain fusion (4 hydrogen-1 → helium-4 + energy), tell it from fission and from burning, and use the 0.7% mass loss with E = mc².
  • I can work out light travel times and read the Sun's place on an H-R diagram.

Standard: HS-ESS1-1

Words to know

nuclear fusion: Light nuclei joining into a heavier nucleus, releasing energy

nuclear fission: A heavy nucleus splitting into smaller ones

radiative zone: Inner layer where energy travels as light

convection zone: Outer layer where hot plasma rises and cooler plasma sinks

photosphere: The Sun's visible surface, about 5,500 °C

H-R diagram: A graph of star brightness against surface temperature, hot on the left

Common mistakes

Your child described the Sun as burning like a fire. The Sun's energy comes from nuclear fusion in its core, not from chemical burning, which needs oxygen.

Your child mixed up fusion and fission. Fusion joins light nuclei such as hydrogen into heavier ones; fission splits heavy nuclei such as uranium.

Your child thought the glowing surface is the Sun's hottest part. The core is hottest, about 15 million °C; the photosphere is about 5,500 °C (NASA).

Questions parents ask

What is the most common mistake with the sun's layers and the fusion that powers it?

Your child described the Sun as burning like a fire. The Sun's energy comes from nuclear fusion in its core, not from chemical burning, which needs oxygen.

Are these 9th grade science worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

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