What meteorites, Moon rocks and ancient crystals tell us
Grade 9 Science Worksheet - Challenge Me
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.
Why does USGS base Earth's 4.54-billion-year age on meteorites rather than on Earth rocks, by Esme's reading?
- Earth rocks are too young to date
- Meteorites are pieces of Earth
- Earth and meteorites formed together, and Earth's first rocks are gone
- Earth's oldest rock is 4.54 billion years old
Captured-Moon prediction; giant-impact prediction. If the Moon had been captured from elsewhere, what would scientists expect its rocks to show, by Kira's reading?
- A makeup matching Earth's outer layers
- A makeup unlike Earth's
- Exactly the same as meteorites
- Ages younger than Earth's oldest rocks
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.
Luz's friend says Earth must be 4.03 billion years old, the age of its oldest rock. Which response is best (USGS)?
- Agree: zircons are younger than Earth's rocks
- Disagree: Earth is a few thousand years old
- Agree: the oldest rock is Earth's age
- Disagree: early rocks were recycled; meteorites give about 4.54 billion
Milo's cousin says the Moon was a wandering body that Earth captured. Which response is best (NASA)?
- Agree: the Moon formed far away
- Disagree: Apollo evidence points to a giant collision
- Agree: capture explains the Moon
- Disagree: the Moon formed from a piece of the Sun long ago
Noah's friend says after two half-lives a sample has no parent left, since half goes each time. Which response is best?
- Disagree: the parent does not decay
- Agree: half plus half makes the whole
- Agree: decay stops after two half-lives, so the parent is gone
- Disagree: each half-life halves what is left, leaving 1/4
Half-life 1.1 billion years; 1/16 left. A Moon rock has 1/16 of a parent left (half-life 1.1 billion years). About how old is it, and does that fit the Moon's oldest rocks, by Pia's math?
- About 17.6 billion years, older than the universe
- About 4.4 billion years, which fits
- About 4.4 million years
- About 1.1 billion years
Each half-life halves what is left. How many half-lives leave about 3% of the parent, by Ren's math?
- 97 half-lives
- 5 half-lives
- 32 half-lives
- 3 half-lives
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.
Earth is about 4.54 billion years old and the oldest zircons about 4.4 billion. About how soon after Earth formed did solid crust exist, by Tala's math?
- About 14 years later
- Within about 140 million years
- About 1.4 billion years after Earth formed
- Before Earth formed
Two meteorites dated about 4.56 billion years. An iron meteorite and a stony meteorite both date to about 4.56 billion years. What does that suggest, by Zee's reading?
- Their parent asteroids formed near the solar system's start
- Iron meteorites came from the Sun
- They fell to Earth 4.56 billion years ago yesterday
- Earth is older than both
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 statement about the Moon's oldest rocks is best supported, by Ari's reading (USGS)?
- They show the Moon was captured
- They show the Moon is at least 4.4 billion years old
- They show the Moon is older than the meteorites
- They show the Moon is 4.03 billion years old, like Earth's rocks