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?
- A, the center
- D, the glowing surface, since it is hottest
- C, the layer below the surface
- B, the next layer out from the center
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
- A, the core
- B, the radiative zone
In the Sun's core, hydrogen nuclei join to make helium. What is this process called, by Jun's reading?
- Burning, like a campfire
- Nuclear fission
- Melting
- Nuclear fusion
Which statement describes nuclear fission, by Luz's reading?
- Atoms change from a solid to a gas
- A heavy nucleus such as uranium splits into smaller ones
- Fuel combines with oxygen and burns
- Light nuclei such as hydrogen join into helium
Why is the Sun not a giant fire, by Milo's reading?
- Burning needs oxygen; the Sun runs on fusion
- It gets its energy from Earth
- It is a fire; fire and fusion are the same
- It runs on fission of hydrogen
How does energy move through the Sun's radiative zone, by Pia's reading?
- As light, bouncing slowly outward
- Straight to the surface in about 8 minutes
- As hot plasma rising and sinking
- As flames spreading 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?
- Cooler, since left means lower
- Cooler, since it is on the left
- Hotter than the Sun
- The same temperature as the Sun
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
- Directly above the Sun, since temperature runs up the side
- To the left 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 fuses into helium
- Helium splits into hydrogen
- Nothing; the core is the coolest part
- Hydrogen burns with oxygen