Earth & Atmospheric Science Flashcards
All 19 cards in this deck
Where did the gases of the Earth's early atmosphere come from?
Volcanic activity.
Name the gases thought to make up the Earth's early atmosphere.
Mostly carbon dioxide, water vapour, small amounts of other gases, and little or no oxygen.
Why did the amount of water vapour in the atmosphere decrease?
The Earth cooled, so the water vapour condensed and formed the oceans.
Why did the amount of carbon dioxide in the atmosphere decrease as the oceans formed?
Carbon dioxide dissolved in the oceans, and became locked up in sedimentary rocks and fossil fuels.
What caused the percentage of oxygen in the atmosphere to increase from the early atmosphere to today?
Plants (or photosynthetic organisms such as cyanobacteria) produced oxygen by photosynthesis.
What is the chemical test for oxygen, and the positive result?
A glowing splint is placed in the gas; it relights.
What is the greenhouse effect?
Gases in the atmosphere absorb heat radiated from the Earth and then release energy, some of it back towards the Earth, keeping the Earth warm.
Name three greenhouse gases in the atmosphere.
Carbon dioxide, methane and water vapour.
What are the three most common gaseous elements in today's atmosphere, from most to least common?
Nitrogen, oxygen, argon.
What are the approximate percentages of nitrogen, oxygen and carbon dioxide in today's atmosphere?
About 78% nitrogen, about 21% oxygen and about 0.04% carbon dioxide.
Which two greenhouse gases are produced by the complete combustion of a hydrocarbon fuel?
Carbon dioxide and water (vapour).
Name two human activities that increase the amount of carbon dioxide or methane in the atmosphere.
Burning fossil fuels (carbon dioxide) and livestock farming (methane).
Give two processes that cause the percentage of carbon dioxide in the atmosphere to vary from place to place or season to season.
Photosynthesis removes it; respiration and combustion release it.
What correlation is used as evidence that human activity is causing climate change?
As fossil fuel consumption and atmospheric carbon dioxide concentration have risen, global temperature has risen too.
Give two reasons why climate data carry uncertainty.
Measurements depend on the location where they are taken, and historical records are less accurate than modern ones.
True or false? A correlation between carbon dioxide concentration and global temperature proves that carbon dioxide causes the temperature rise.
False. Correlation does not prove cause; another factor could be responsible.
Give two potential effects on the climate of increased carbon dioxide and methane levels.
Rising global temperatures and rising sea levels (also more extreme weather).
Why does deforestation increase the amount of carbon dioxide in the atmosphere?
Trees absorb carbon dioxide for photosynthesis, so clearing forests leaves fewer trees to remove it from the air.
Give two ways of reducing carbon dioxide emissions.
Use more renewable energy sources (such as wind or solar power) instead of fossil fuels, and use energy more efficiently so less fuel needs burning.
e.g. insulating homes
Other valid answers include carbon capture and storage, and travelling less by car.