The atmosphere Flashcards
What percent of the atmosphere is nitrogen
about 4 fifths (or about 80%)
What percent of the atmosphere is oxygen
about 1 fifth (or about 20%)
What is the small proportion of the atmosphere made up of
other gases e.g. carbon dioxide, water vapor, noble gases
How old is the Earth
4.6 billion years old
What activity occurred during the Earth’s early years
Intense volcanic activity
What did the volcanoes release
The gases that formed the atmosphere
What happened as the Earth cooled
The water vapour condensed to form oceans
What gas do volcanoes particularly release
Carbon dioxide
What did the Earth’s atmosphere mainly consist of
Mainly carbon dioxide, with little oxygen (also methane and ammonia)
The earth early atmosphere is similar to which planets
Mars and Venus
What was the impact of photosynthetic algae
They photosynthesized which released oxygen into the atmosphere, over time as plants evolved the amount of oxygen in the atmosphere increased
What are fossil fuels
nonrenewable resource that has formed over millions of years
How is coal formed
from the remains of ferns and trees that die in marshy wetlands because they do not decompose as they have a lack of oxygen, over time the plant remains are covered in sediment and compressed under high pressure and temperature
How is crude oil formed
Crude oil is formed from plankton, as they settle in mud on the sea bed. If oxygen isn’t present they don’t decompose so are compressed by sediment over time, the heat and pressure convert them into crude oil
How is natural gas formed
Natural gas is found near deposits of oil as it is formed in a similar way - by plankton
