The earth Flashcards
What was Wegner’s theory of continental drift?
300 million years ago there had been a supercontinent called Pangaea that had broken apart and moved apart to form our modern day continents
What was his proof of continental drift?
Fossils found in different continents that were the same and the continents fitted together like a jigsaw
Why didn’t people believe continental drift?
Wegner didn’t know how the plates were moving and he had used some inaccurate data in his study
Why did people start believing continental drift?
Because they discovered new evidence on the ocean floor and discovered tectonic plates
What is the earth’s structure?
Crust, mantle, inner core, outer core
What is the core made from?
Iron and nickel
What is the mantle?
Magma that has all the properties of a solid but flows, and within it radioactive decay happens, heating it up and causing convection currents
What is the crust made from?
Tectonic plates, which float on the magma and move due to the convection currents
How do earthquakes happen?
When two plates move towards each other then one moves very suddenly
Why can’t scientists predict earthquakes and volcanoes?
Because they don’t know when the plates will move
What does the atmosphere consist of now?
78% nitrogen, 21% oxygen and small amounts of other gases
How did the modern atmosphere develop?
4.5 billion years ago, the earth was covered in volcanoes which gave out a lot of gas to form the oceans and atmosphere, which was mostly CO(2). Then green plants and algae evolved and a lot of CO(2) dissolved into the ocean and was absorbed by the plants, and as things died, carbon and hydrocarbon were locked up in the ground as rocks and fossil fuels, which built up oxygen and created the ozone layer which blocked harmful rays from the sun
What is primordial soup?
The theory of hoe life was formed when the atmosphere was rich in nitrogen, hydrogen, ammonia and methane, then lightning struck, causing a chemical reaction forming amino acids that eventually developed life
What did Miller and Urey do?
They did an experiment to prove primordial soup, and they found amino acids were formed but not as many as there are on earth
How do we get gases to use in industry?
Filter air to remove dust, then cool it until it is a liquid and remove water vapour, and remove frozen carbon dioxide, then heat slowly in a fractioning column and separate gases by fractional distillation
