The Sun's layers and the fusion that powers it
Grade 9 Science Worksheet - Building Confidence
Circle the best answer.
“Star card cutaway of the Sun, not to scale:” Using the same lettered cutaway, which layer of the Sun is hottest, by Bo's reading?
- A, the core
- C, the convection zone
- D, the photosphere, since it glows
- B, the radiative zone
Read this first
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.
Which layer of the same cutaway carries energy by hot plasma rising and cooler plasma sinking, by Kira's reading?
- D, the photosphere
- B, the radiative zone
- A, the core
- C, the convection zone
Which statement describes nuclear fission, by Luz's reading?
- A heavy nucleus such as uranium splits into smaller ones
- Light nuclei such as hydrogen join into helium
- Fuel combines with oxygen and burns
- Atoms change from a solid to a gas
Why is the Sun not a giant fire, by Milo's reading?
- Burning needs oxygen; the Sun runs on fusion
- It is a fire; fire and fusion are the same
- It runs on fission of hydrogen
- It gets its energy from Earth
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
- Photosphere → convection zone → radiative zone → core
- Core → photosphere, straight out in 8 minutes
- Core → radiative zone → convection zone → photosphere
How does energy move through the Sun's radiative zone, by Pia's reading?
- As hot plasma rising and sinking
- As flames spreading outward
- Straight to the surface in about 8 minutes
- As light, bouncing slowly outward
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
- About 8 hours
- No time; it arrives instantly
“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?
- The same temperature as the Sun
- Cooler, since it is on the left
- Hotter than the Sun
- Cooler, since left means lower
The Sun's dot sits at about 5,800 K. Where does a 3,000 K star go on the H-R diagram, by Zee's reading?
- On top of the Sun's dot
- To the right of the Sun
- To the left of the Sun
- Directly above the Sun, since temperature runs up the side
Core, about 15 million °C, hydrogen fuses into helium. The star card's facts box says: "Core, about 15 million °C: hydrogen fuses into helium." What happens in the core, by Esme's reading?
- Nothing; the core is the coolest part
- Hydrogen burns with oxygen
- Helium splits into hydrogen
- Hydrogen fuses into helium