The Earth's Atmosphere Flashcards
(18 cards)
What gases made up the early atmosphere?
- Mainly carbon dioxide
- Very little or no oxygen
- Small amounts of water vapour, ammonia, and methane
How did oceans form on Earth?
Water vapour in the atmosphere cooled and condensed
How did carbon dioxide levels decrease?
Dissolved in oceans
Formed carbonate rocks
Locked in fossil fuels
Used in photosynthesis by algae/plants
How did oxygen increase in the atmosphere?
Photosynthesis by algae (and later plants)
What is the word equation for photosynthesis?
Carbon dioxide + Water → Glucose + Oxygen
What role did algae play in changing the atmosphere?
First organisms to photosynthesise and produce oxygen
How did nitrogen levels increase?
Released by volcanoes
Very stable molecule so it built up over time
Current composition of the atmosphere?
Nitrogen ~78%
Oxygen ~21%
Carbon dioxide ~0.04%
Argon ~ 0.9%
What are greenhouse gases?
Carbon dioxide, methane, water vapour
What do greenhouse gases do?
Trap heat in the atmosphere and keep Earth warm enough to support life
What is global warming?
Rise in Earth’s average temperature due to increased greenhouse gases
What is global climate change?
Long-term changes in Earth’s weather patterns (rainfall, sea levels, extreme events)
What is a carbon footprint?
Total amount of greenhouse gases released by a product, person, or process
How can we reduce carbon footprint?
Use less fossil fuels
Use renewable energy
Conserve energy
Pollutants from fuel combustion: Carbon monoxide
Origin: Incomplete combustion
Effect: Toxic, colourless, odourless gas
Pollutants: Particulates (soot, unburnt hydrocarbons)
Origin: Incomplete combustion (especially diesel)
Effect: Global dimming, cancer, respiratory problems
Pollutants: Sulfur dioxide
Origin: Sulfur in fuels
Effect: Acid rain, respiratory problems
Pollutants: Oxides of nitrogen
Origin: High engine temperatures
Effect: Acid rain, respiratory problems
