The evidence for the Big Bang

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. Read this first

   Table, Evidence for the Big Bang (NASA, ESA), with columns Observation, What it shows

   Galaxy redshifts grow with distance, space is expanding; microwave background at about 2.7 K, a hot, dense early universe; mostly hydrogen and helium, a little lithium, early element-making.

2. 1.

   Which observation shows the early universe was hot and dense, by Bo's reading?

   • The Milky Way's spiral arms
   • Light from nearby stars
   • The cosmic microwave background
   • Galaxy redshifts
3. 2.

   In the Big Bang model, what happened about 13.8 billion years ago, by Kira's reading (NASA)?

   • The Sun and Earth formed
   • Galaxies flew out from the Milky Way
   • An explosion went off at one spot in an empty, waiting space
   • The universe began expanding from a hot, dense state
4. 3.

   Timeline from the Big Bang with an early mark. About when was the cosmic microwave background released, by Jun's reading (NASA)?

   • About 380,000 years after the Big Bang
   • When the Sun formed
   • Recently, given off by the stars in our own galaxy
   • About 13.8 billion years after the Big Bang
5. 4.

   Thermometer scale from 0 K to 10 K. What is the cosmic microwave background's temperature today, by Luz's reading (ESA Planck)?

   • About 2.7 K
   • About 3,000 K, as when it was released
   • About 270 K
   • About 5,800 K, like the Sun
6. 5.

   Why is the background light now in microwaves, not visible light, by Milo's reading?

   • It started as microwaves
   • It was squeezed to shorter wavelengths
   • Expansion stretched it to longer wavelengths
   • It comes from cold stars
7. 6.

   Pie chart of atoms in the oldest gas (sources give 92 to 95% hydrogen). Most atoms in the oldest gas clouds are which elements, by Pia's reading?

   • Carbon, then oxygen
   • Iron, then nickel
   • Equal amounts of each element
   • Hydrogen, then helium
8. 7.

   Why do the amounts of hydrogen and helium count as evidence, by Ren's reading?

   • They show galaxies are moving apart
   • They show where stars formed first
   • They match what the early universe should have made
   • They show the theory is a guess
9. 8.

   Timeline ruler in billions of years. About how old is the universe, by Tala's reading (NASA, ESA Planck)?

   • About 138 billion years
   • About 13.8 million years
   • About 13.8 billion years
   • About 4.6 billion years, Earth's age
10. 9.

    Which is older, by Zee's reading?

    • The Sun, which is about three times older than the universe
    • The Sun, by about 10 billion years
    • They are the same age
    • The universe, about three times older than the Sun
11. 10.

    Three evidence lines pointing to one explanation. In science, what does it mean to call the Big Bang a theory, by Esme's reading?

    • A guess with no evidence
    • A well-tested explanation that fits many observations
    • A law that cannot be revised
    • An untested idea that scientists have not checked against anything