earths early atmosphere was formed by gases released from volcanic activity and the breakdown of organic matter
as the earth cooled down after volcanic eruptions the water vapour (steam) condensed and fell as rain filling up hollows in solid crust forming oceans
CO2 dissolved in oceans, then concentrated into shells of sea creatures as calcium carbonate therefore the amount of carbon dioxide in the earths atmosphere decreased when oceans were formed
the growth of primitive plants used carbon dioxide and released oxygen due to photosynthesis therefore the amount of oxygen in the atmosphere increased over time
chemical test for oxygen
use a glowing splint inserted in the test tube of the gas, the splint should be relit if oxygen is present
the greenhouse effect
the sun rays enter the earths atmosphere as short wave radiation
the earth absorbs this radiation but long wave radiation is emitted back from the earths surface
some radiation passes back out to space
some is absorbed by carbon dioxide and trapped within the earths atmosphere causing it to get hotter
human activity causing climate change
increase in consumption of fossil fuels therefore an increase in CO2as it was trapped inside the fossils, therefore it contributes to the greenhouse effect
deforestation, trees are carbon stores and cutting them down emits CO2 back into the atmosphere
todays atmosphere
nitrogen (78%)
oxygen (21%)
other gases (<1%)(carbon dioxide, argon)
the potential effects on the climate of increased levels of carbon dioxide and methane
