everchanging earth Flashcards
how much nitrogen is in today’s atmosphere?
78%
how much oxygen is in today’s atmosphere?
21%
how much argon is in today’s atmosphere?
0.9%
how much carbon dioxide is in today’s atmosphere?
0.04%
how did the earths first atmosphere form?
enormous volcanic activity errupting, releasing a mixture of toxic gases
what were the mixture of gases released?
methane
carbon dioxide
ammonia
water vapour
how were the seas and oceans formed?
the earth cooled and water vapour condensed to liquid
what is the test for hydrogen?
place a lit splint over the gas
popping sound if gas is present
what is the test for oxygen?
place a glowing splint over the gas
splint will relight if gas is present
what is the test for carbon dioxide?
bubble the gas through limewater
colourless limewater turns milky
describe what is used and released during photosynthesis?
uses carbon dioxide
releases oxygen
what happened to the poisonous ammonia released from volcanoes?
it decomposed on reacting with oxygen released from plants during photosynthesis
what is the gas that dissolved in the seas and oceans?
carbon dioxide
what happened to the carbon dioxide that dissolved in seas and oceans?
marine animals used the carbon atoms to make shells which created sedimentary rock such as limestone and chalk.
also fossil fuels were made by larger plants trapping carbon atoms
what are the 4 main sections of the earth?
crust
mantle
outer core
inner core
how does fractional distillation work?
all gases have different boiling points
what gases can be obtained from fractional distillation?
oxygen
nitrogen
neon
argon
what is continental drift?
Alfred Wegener thought that all continents used to be joined together and that over time they separated apart and drifted apart
why wasn’t he believed?
He couldn’t explain HOW they had drifted apart
what 3 pieces of evidence did he have?
jig saw fit of coastlines
similar rocks of the same age on different continents
similar fossils found on opposite sides of oceans
what is the theory of plate tectonics?
the earths lithosphere is made up of huge slabs of rock called plate tectonics which move a few cm every year due to convection currents
what happens when 2 plates move apart? what is this called?
magma rises to the surface, cools and solidifies forming new igneous rock
constructive plate boundary
what happens when 2 plates move towards each other? what is this called?
the denser plate sinks under the less dense plate. the inside of the earth is hot causing the denser plate to melt forming new magma. this results in volcanoes forming.
if the plates are the same density the force of the collision causes the plates to buckle upwards.
destructive plate boundary
what happens when 2 plates slip past each other? what is this called?
an earthquake can occur
conservative plate boundary
