Earth's early air and oceans
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
Four chain cards, labeled A to D. Which chain best explains the rise of oxygen, by Esme's reading?
- Cyanobacteria made it, it reacted away at first, then built up
- Photosynthesis took in oxygen and released carbon dioxide
- Volcanoes made oxygen, which built up at once
- A dimmer Sun froze the oceans solid, and the ice released oxygen
Four evidence cards, labeled A to D. Which evidence suggests liquid water was present very early, by Jun's reading?
- Today's oceans being salty
- Volcanoes giving off oxygen
- Ancient zircons show solid crust very early
- Oxygen gas found in the earliest air, as today
Read this first
Oxygen in the air over time (Smithsonian, NASA)
Time Oxygen in the air before about 2.7 billion years ago almost none about 2.4 billion years ago first fills the air (NASA) about 600 million years ago about one-fifth of today's level today 21% Why was the Great Oxidation Event one of the biggest changes to Earth's surface, by Kira's reading (NASA)?
- It removed the oxygen that had been in the air and oceans
- It made the first volcanoes
- It happened in a single year
- Oxygen filled the air and oceans for the first time
Luz's friend says early Earth's air was just like today's, with plenty of oxygen. Which response is best (Smithsonian)?
- Disagree: it had almost no oxygen until about 2.4 billion years ago
- Agree: air has stayed at 21% oxygen
- Agree: volcanoes gave it oxygen
- Disagree: it had more oxygen than today
Noah's friend says a dimmer young Sun means Earth must have been frozen for its first billions of years. Which response is best (Smithsonian)?
- Disagree: greenhouse gases kept Earth above freezing
- Agree: Earth had no air to trap heat
- Disagree: the young Sun was brighter
- Agree: a dimmer Sun means a frozen, icy Earth for billions of years
4.6 billion years = 24 hours, starting at midnight. On a 24-hour clock for Earth's 4.6 billion years, about what time of day would the Great Oxidation Event (2.4 billion years ago) fall, by Ren's math?
- About 2:24 a.m.
- About 12:30 a.m., near the start
- About 11:30 a.m.
- About 11:59 p.m., near the end
Four model cards, labeled A to D. Which model supports the idea that life changed Earth's air, by Tala's reading?
- Oxygen rises after photosynthesizers appear, then redbeds form
- Oxygen rises each time volcanoes erupt
- Carbon dioxide rises as photosynthesizers spread and oxygen falls
- Oxygen rises before any life appears
If no icy bodies had ever hit Earth, could there still be oceans, by Zee's reading?
- No: oxygen gas in the air is what made the ocean water
- Yes: volcanic water vapor could still condense
- Yes: the Sun makes water
- No: ocean water came from space alone
An oxygen bar rising over time, with living things using oxygen. Why does the rise in oxygen matter for living things today, by Ari's reading (Smithsonian)?
- Volcanoes still make our oxygen
- Oxygen-using life grew out of the oxygen rise
- Living things like us make oxygen when we breathe out
- Oxygen was here for them from the start
Four order cards, labeled A to D. Which order of events fits Earth's early history, by Bo's reading?
- Oxygen rise, then cyanobacteria
- Volcanic air, oceans, cyanobacteria, then the oxygen rise
- Cyanobacteria, then oceans, then volcanic air
- Oxygen air, then volcanoes, then oceans