The Sun's layers and the fusion that powers it
Grade 9 Science Worksheet - Building Confidence
Circle the best answer.
Read this first
Use this
Star card cutaway of the Sun, not to scale:
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?
- D, the glowing surface, since it is hottest
- B, the next layer out from the center
- A, the center
- C, the layer below the surface
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
- D, the photosphere, since it glows
- B, the radiative zone
- A, the core
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?
- A, the core
- D, the photosphere
- B, the radiative zone
- C, the convection zone
Which statement describes nuclear fission, by Luz's reading?
- Fuel combines with oxygen and burns
- 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
Why is the Sun not a giant fire, by Milo's reading?
- It gets its energy from Earth
- It runs on fission of hydrogen
- It is a fire; fire and fusion are the same
- Burning needs oxygen; the Sun runs on fusion
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 → radiative zone → convection zone → photosphere
- Core → convection zone → radiative zone → photosphere
- Photosphere → convection zone → radiative zone → core
- Core → photosphere, straight out in 8 minutes
About how long does light take to reach Earth after it leaves the Sun's photosphere, by Ren's reading?
- About 8 minutes
- No time; it arrives instantly
- About 170,000 years
- About 8 hours
“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
- Hotter than the Sun
- Cooler, since left means lower
- Cooler, since it is on the left
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
- Directly above the Sun, since temperature runs up the side
- To the left of the Sun
- To the right of the Sun
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?
- Hydrogen burns with oxygen
- Nothing; the core is the coolest part
- Hydrogen fuses into helium
- Helium splits into hydrogen