What meteorites, Moon rocks and ancient crystals tell us
Grade 9 Science Worksheet - Building Confidence

Circle the best answer.
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.
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
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
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
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
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
Where do most meteorites found on Earth come from, by Noah's reading (NASA)?
Orbit diagram with the asteroid belt and a fragment heading to Earth. Orbit diagram with the asteroid belt and a fragment heading to Earth. asteroid belt Earth fragment - Earth's volcanoes
- Shattered asteroids
- Distant galaxies
- The Sun
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
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
A radioactive parent has a half-life of 700 million years. What fraction is left after one half-life, by Tala's math?
Bar: 100% of the parent at the start. Bar: 100% of the parent at the start. Bar 0 10 20 30 40 50 60 70 80 90 100 100 parent at the start - One-half
- Three-quarters
- It has fully decayed
- One-quarter
After two half-lives, what fraction of the parent is left, by Zee's math?
Bars: 100%, then 50% after one half-life. Bars: 100%, then 50% after one half-life. 0 10 20 30 40 50 60 70 80 90 100 100 50 after one half-life - One-third
- One-quarter
- It has fully decayed
- One-half

