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.

   • Moon rocks, Earth rocks, meteorites, zircons
   • Earth's oldest rocks, zircons, Moon rocks, meteorites
   • Meteorites, Moon rocks, zircons, Earth's oldest rocks
   • Zircons, meteorites, Earth rocks, Moon rocks
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 5.3 billion years
   • About 53 years
   • About 8.6 billion years
   • About 530 million years
4. 3.

   Earth is about 4.54 billion years old, yet its oldest rocks are 4.03 billion. Why the gap, by Jun's reading (USGS)?

   • Earth formed 4.03 billion years ago
   • The dates must be wrong
   • Plate tectonics has recycled the earliest rocks
   • Earth's first rocks were meteorites that flew back into space
5. 4.

   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 1.4 billion years
   • About 2.1 billion years
   • About 175 million years
6. 5.

   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 10.4 billion years
   • About 2.6 billion years
   • About 1.3 billion years
   • About 3.9 billion 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)?

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

8. 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.

9. 7.

   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)?

   • Earth's rocks are older, but they are buried too deep to find
   • The Moon has no plate tectonics to recycle them
   • Moon rocks are meteorites
   • The Moon formed long before Earth
10. 8.

    Tiny zircon crystals from Western Australia are dated to 4.3–4.4 billion years, but their source rocks are gone. What do they show, by Tala's reading (USGS)?

    • They are meteorites
    • They formed 4.4 million years ago
    • Earth had solid crust by about 4.4 billion years ago
    • Earth is just 4.4 billion years old
11. 9.

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

    • Iron meteorites fall more often
    • Stony meteorites come from the Sun
    • 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 16 cm
    • About 1.6 cm
    • About 0.16 cm