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.

   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's first rocks were meteorites that flew back into space
   • Plate tectonics has recycled the earliest rocks
   • Earth formed 4.03 billion years ago
   • The dates must be wrong
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 2.1 billion years
   • About 1.4 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 3.9 billion years
   • About 2.6 billion years
   • About 1.3 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
   • The capture idea was proved by Apollo
   • Apollo samples pointed to a large impact
   • The Moon turned out to be younger than Earth by billions of years
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?

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

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

    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)?

    • Earth had solid crust by about 4.4 billion years ago
    • They are meteorites
    • Earth is just 4.4 billion years old
    • They formed 4.4 million years ago
12. 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 16 cm
    • About 44 cm
    • About 1.6 cm
    • About 0.16 cm