How stars make the elements

Grade 9 Science Worksheet - Challenge Me

Circle the best answer.

1. 1.

   Four timeline cards, labeled A to D. Which list puts element-making in time order, by Jun's reading?

   • Gold first, then hydrogen and helium
   • Hydrogen and helium; then carbon and oxygen in stars; then gold in collisions
   • Carbon in the Big Bang, then hydrogen in stars
   • The whole table in the first five minutes
2. 2.

   Which origin fits uranium (92), by Kira's reading?

   • Supernovas and neutron-star collisions
   • The Big Bang
   • Fusing iron in a quiet core
   • Fusion in the Sun's core and its outer layers
3. 3.

   Periodic-table strip with the first three boxes shaded. Luz's friend says every element was made in the Big Bang. Which response is best (NASA)?

   • Disagree: Earth made the elements
   • Agree: the Big Bang made the full table
   • Disagree: it made hydrogen, helium and a little lithium; stars made the rest
   • Agree: stars just shine and make nothing
4. 4.

   Milo's cousin says the Sun is making gold right now. Which response is best?

   • Disagree: the Sun fuses hydrogen to helium and will reach only about carbon
   • Agree: stars like the Sun make gold
   • Agree: gold comes from fusing iron
   • Disagree: gold is made inside Earth
5. 5.

   Oxygen, carbon, hydrogen, nitrogen and others. Noah's friend says people are made of star stuff. Which response is best?

   • Agree: apart from hydrogen, most of our atoms were made in stars
   • Disagree: our atoms were made on Earth
   • Disagree: our atoms came from the Big Bang
   • Agree: our atoms came from splitting stars and gas apart into pieces

6. Read this first

   Where elements were mainly made (NASA)

   Element	Atomic number	Main origin
   hydrogen	1	Big Bang
   helium	2	Big Bang
   carbon	6	star cores
   oxygen	8	star cores
   iron	26	massive stars and their supernovas
   gold	79	neutron-star collisions

7. 6.

   Which pair of elements was made in the same kind of place, by Pia's reading?

   • Carbon and oxygen, in star cores
   • Helium and gold, in the Big Bang
   • Iron and hydrogen, in the Sun
   • Gold and carbon, in Earth's core
8. 7.

   Why is hydrogen still the most common element today, by Ren's reading?

   • Stars keep making new hydrogen by splitting
   • Stars have fused only a small share of it
   • The Big Bang is still making it
   • Hydrogen forms on planets
9. 8.

   a Sun-like star stopping at carbon, a massive star going to iron. A massive star and a Sun-like star: which one makes iron, by Tala's reading?

   • The massive star, in its core before it explodes
   • Both, in equal amounts
   • Neither; iron came from the Big Bang
   • The Sun-like star, in its red giant core before it fades

10. Masses (NIST, rounded)

    Particle	Mass (u)
    helium-4	4.0026
    carbon-12	12.0000

11. 9.

    Three helium-4 nuclei (4.0026 u each, NIST) fuse into one carbon-12 nucleus (12.0000 u). How much mass becomes energy, by Zee's math?

    • Zero, since mass is kept
    • About 0.078 u
    • About 0.0078 u
    • Mass is gained, so energy is used up
12. 10.

    Which fusion makes magnesium (12), by Ari's reading?

    • Carbon (6) + helium (2)
    • Neon (10) + helium (2)
    • Oxygen (8) + helium (2)
    • Iron (26) splitting in half