What meteorites, Moon rocks and ancient crystals tell us

Grade 9 Science Worksheet

Circle the best answer.

1. Read this first

   Table, Sample ages (USGS), with columns Sample, Age (billion years)

   Meteorites, 4.53 to 4.58; oldest Moon rocks, 4.4 to 4.5; oldest zircon crystals (Western Australia), 4.3 to 4.4; oldest Earth rocks (Acasta Gneiss, Canada), 4.03.

2. 1.

   Order the samples from oldest to youngest, by Bo's reading.

   • Zircons, meteorites, Earth rocks, Moon rocks
   • Earth's oldest rocks, zircons, Moon rocks, meteorites
   • Meteorites, Moon rocks, zircons, Earth's oldest rocks
   • Moon rocks, Earth rocks, meteorites, zircons
3. 2.

   About how much older are the meteorites (about 4.56) than Earth's oldest rocks (4.03 billion years), by Esme's math?

   • About 8.6 billion years
   • About 53 years
   • About 530 million years
   • About 5.3 billion years
4. 3.

   A sample has 1/4 of its parent isotope left. The half-life is 700 million years. About how old is it, by Kira's math?

   • About 700 million years
   • About 175 million years
   • About 2.1 billion years
   • About 1.4 billion years
5. 4.

   A sample has 1/8 of its parent left, with a half-life of 1.3 billion years. About how old is it, by Luz's math?

   • About 2.6 billion years
   • About 10.4 billion years
   • About 1.3 billion years
   • About 3.9 billion years
6. 5.

   USGS says dating uses half-lives from 700 million to more than 100 billion years. Why are such long half-lives useful for these samples, by Milo's reading?

   • Long half-lives stop decaying
   • Short half-lives would be more accurate for old rocks
   • They measure how far meteorites traveled
   • Enough parent is still left to measure after billions of years
7. 6.

   Before Apollo, some thought the Moon was captured or formed beside Earth. Why did those ideas fall out of favor, by Noah's reading (NASA)?

   • The capture idea was proved by Apollo
   • The Moon turned out to be younger than Earth by billions of years
   • Apollo found the Moon had no rocks
   • Apollo samples pointed to a large impact
8. 7.

   NASA says the Moon's first crust formed about 4.4 billion years ago, from rock that floated up in a magma ocean. Which order fits, by Pia's reading?

   • Magma ocean, then the collision
   • Collision, magma ocean, then crust
   • Capture, then a magma ocean
   • Crust first, then the collision

9. Table, Sample ages (USGS), with columns Sample, Age (billion years)

   Meteorites, 4.53 to 4.58; oldest Moon rocks, 4.4 to 4.5; oldest zircon crystals (Western Australia), 4.3 to 4.4; oldest Earth rocks (Acasta Gneiss, Canada), 4.03.

10. 8.

    The Moon's oldest rocks (4.4–4.5 billion years) are much older than most of Earth's. Why, by Ren's reading (USGS)?

    • The Moon formed long before Earth
    • Moon rocks are meteorites
    • Earth's rocks are older, but they are buried too deep to find
    • The Moon has no plate tectonics to recycle them
11. 9.

    Most meteorites that fall are stony, but most found long after falling are irons (NASA). Why, by Zee's reading?

    • Stony meteorites come from the Sun
    • Iron meteorites fall more often
    • Irons are heavier and easier to tell from Earth rocks
    • Irons are younger

12. Table, Sample ages (USGS), with columns Sample, Age (billion years)

    Meteorites, 4.53 to 4.58; oldest Moon rocks, 4.4 to 4.5; oldest zircon crystals (Western Australia), 4.3 to 4.4; oldest Earth rocks (Acasta Gneiss, Canada), 4.03.

13. 10.

    On a timeline where 1 cm stands for 100 million years, how far apart are the meteorite age (about 4.56) and the zircon age (about 4.4 billion), by Ari's math?

    • About 44 cm
    • About 0.16 cm
    • About 1.6 cm
    • About 16 cm