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
- A dimmer Sun froze the oceans solid, and the ice released oxygen
- Volcanoes made oxygen, which built up at once
Four evidence cards, labeled A to D. Which evidence suggests liquid water was present very early, by Jun's reading?
- Oxygen gas found in the earliest air, as today
- Today's oceans being salty
- Volcanoes giving off oxygen
- Ancient zircons show solid crust very early
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 made the first volcanoes
- It happened in a single year
- It removed the oxygen that had been in the air and oceans
- 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)?
- Agree: air has stayed at 21% oxygen
- Agree: volcanoes gave it oxygen
- Disagree: it had more oxygen than today
- Disagree: it had almost no oxygen until about 2.4 billion years ago
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
- Disagree: the young Sun was brighter
- Agree: a dimmer Sun means a frozen, icy Earth for billions of years
- Agree: Earth had no air to trap heat
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 11:59 p.m., near the end
- About 2:24 a.m.
- About 11:30 a.m.
- About 12:30 a.m., near the start
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 before any life appears
- Oxygen rises each time volcanoes erupt
- Carbon dioxide rises as photosynthesizers spread and oxygen falls
If no icy bodies had ever hit Earth, could there still be oceans, by Zee's reading?
- Yes: the Sun makes water
- No: ocean water came from space alone
- Yes: volcanic water vapor could still condense
- No: oxygen gas in the air is what made the ocean water
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 was here for them from the start
- Living things like us make oxygen when we breathe out
- Oxygen-using life grew out of the oxygen rise
Four order cards, labeled A to D. Which order of events fits Earth's early history, by Bo's reading?
- Oxygen rise, then cyanobacteria
- Oxygen air, then volcanoes, then oceans
- Cyanobacteria, then oceans, then volcanic air
- Volcanic air, oceans, cyanobacteria, then the oxygen rise