Early Atmosphere on Earth - GCSE Chemistry | kayscience.com

In this video you will learn all the science for this topic to get a grade 9 or A* in your science exams!

Earth’s early atmosphere was mainly made up of carbon dioxide and water vapour. When the Earth cooled, the water vapour condensed into clouds and then rained, forming oceans. Carbon dioxide is soluble in water so some of the carbon dioxide dissolved in the oceans, decreasing the levels of carbon dioxide in the atmosphere. This made the oceans weakly acidic, causing minerals to react, forming carbonate compounds. This ended up making sedimentary rocks such as limestone. Both cyanobacteria in stromatolites and algae on the surface of the water photosynthesised, taking in carbon dioxide and releasing oxygen, decreasing levels of carbon dioxide in the atmosphere. Fossil fuels also formed which stored carbon under ground. Land plants evolved 500 million years ago, causing a lot of photosynthesis to take place, dramatically decreasing carbon dioxide levels and increasing oxygen levels.