C13.1 History of our atmosphere

Question 1

How have scientists reconstructed what they think the atmosphere was like billions of years ago?

Answer 1

➢ Using gas bubbles trapped in ancient rocks

➢ Data gathered from the atmospheres of other planet and their moons in the solar system

Question 2

What is the volcanic theory that suggest how oceans formed on earth?

Answer 2

➢ Volcanoes released CO2, H20 and nitrogen
➢ Water vapour in the atmosphere condensed as the Earth gradually cooled down, and fell as rain
➢ Water collected in hollows in the crust and the first oceans formed

Question 3

What is the comet theory?

Answer 3

➢ An icy comet rained down on the surface on the Earth, they melted, adding to its water supplies

Question 4

How did oxygen get in the atmosphere?

Answer 4

➢ Scientists think that life began with the first simple organisms
➢ Then after 700 million years, bacteria and other simple organisms such as algae evolved,
➢ Algae could use the energy from the Sun to make their own food through photosynthesis
➢ Over the next billion years the levels of oxygen rose steadily as the algae and bacteria thrived in seas

Question 5

What is the equation for photsysthesis?

Answer 5

➢ Carbon dioxide + water makes glucose + oxygen

Question 6

What did the Earth’s early atmosphere consist of?

Answer 6

➢ Ammonia, Nitrogen, water vapour and carbon dioixde