What meteorites, Moon rocks and ancient crystals tell us

Grade 9 Science Worksheet - Building Confidence

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.

   Which samples give the best age for the solar system's formation, by Ari's reading (USGS)?

   • Fossils
   • Earth's oldest rocks
   • Meteorites
   • Zircon crystals, older than the meteorites
3. 2.

   Which sample in the table is oldest, by Bo's reading?

   • The Moon rocks, since the Moon is closest
   • Earth's oldest rocks, at 4.03 billion
   • Meteorites, at 4.53 to 4.58 billion years
   • The zircons, at 4.3 to 4.4 billion
4. 3.

   How old are the oldest Earth rocks found so far, by Kira's reading (USGS)?

   • About 4.03 million years
   • About 4.54 billion, Earth's own age
   • About 403 years
   • About 4.03 billion years
5. 4.

   What is the leading idea for how the Moon formed, by Jun's reading (NASA)?

   • A Mars-sized body hit young Earth, and debris formed the Moon
   • The Moon is a broken piece of the Sun that cooled in Earth's orbit
   • The Moon formed alone, far from Earth
   • Earth's gravity captured a passing Moon
6. 5.

   Drawing of Moon rock samples in labeled bags. How much lunar rock and soil did the Apollo missions bring back, by Milo's reading (NASA)?

   • About 382 kg (842 lb)
   • No samples came back
   • About 382 tonnes
   • About 3.8 kg
7. 6.

   Where do most meteorites found on Earth come from, by Noah's reading (NASA)?

   • Earth's volcanoes
   • Shattered asteroids
   • Distant galaxies
   • The Sun
8. 7.

   Metal, stone, and mixed. NASA names three major kinds of meteorites. Which list matches, by Pia's reading?

   • Irons, stonys and stony-irons
   • Hot, warm and cold
   • Lava, sand and clay
   • Comets, moons and stars
9. 8.

   Drawing of a meteorite beside a rock being recycled into Earth's mantle. Why are meteorites good clocks for the solar system's start, by Ren's reading (USGS)?

   • They are pieces of Earth's crust
   • They fell to Earth recently, so they must be very young rocks
   • They are pieces of the Sun
   • They are leftovers that plate tectonics never recycled
10. 9.

    A radioactive parent has a half-life of 700 million years. What fraction is left after one half-life, by Tala's math?

    • One-half
    • Three-quarters
    • It has fully decayed
    • One-quarter
11. 10.

    After two half-lives, what fraction of the parent is left, by Zee's math?

    • One-third
    • One-quarter
    • It has fully decayed
    • One-half