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

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

   • About 403 years
   • About 4.03 million years
   • About 4.03 billion years
   • About 4.54 billion, Earth's own age
4. 3.

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

   • Earth's gravity captured a passing Moon
   • The Moon is a broken piece of the Sun that cooled in Earth's orbit
   • The Moon formed alone, far from Earth
   • A Mars-sized body hit young Earth, and debris formed the Moon
5. 4.

   Timeline ruler in billions of years. About when did the Moon form, by Luz's reading (NASA)?

   • About 4.5 billion years ago
   • About 450,000 years ago
   • About 13.8 billion years ago
   • About 4.5 million years ago
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 tonnes
   • About 382 kg (842 lb)
   • No samples came back
   • About 3.8 kg
7. 6.

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

   • Lava, sand and clay
   • Comets, moons and stars
   • Hot, warm and cold
   • Irons, stonys and stony-irons
8. 7.

   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 are pieces of the Sun
   • They fell to Earth recently, so they must be very young rocks
   • They are leftovers that plate tectonics never recycled
9. 8.

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

   • One-quarter
   • One-half
   • Three-quarters
   • It has fully decayed
10. 9.

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

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

    What does radiometric dating measure, by Esme's reading (USGS)?

    • How deep a rock was buried
    • How heavy a rock is
    • Decay that subtracts the same amount each year
    • How much of a parent isotope has decayed into daughter atoms