They are cracked into large peices called tectonic places
2 of 29
What are the properties of the crust?
Relatively thin and rocky
3 of 29
What are the properties of the mantle?
Has the properties of a solid but can flow very slowly
4 of 29
What are the properties of the core?
Made from liquid nickel and iron
5 of 29
What does the core consist of?
A solid inner core and a liquid outer core
6 of 29
What is continental drift?
When the tectonic plates over million years move so much contients shift
7 of 29
Why do tectonic plates move?
The convection currents in the earths mantle that are driven by heat produced by natural decay of radioactive elements
8 of 29
Why do earthquakes and volcanic erruptions occur?
Because when the tectonic plates meet the earths crust becomes unstable as they push over or ride under or over eachother
9 of 29
Who was the theory of plate tectronics and continental drift proposed by?
Alfred Wegner
10 of 29
What did people believe before wegner proposed his theory?
That mountains were formed because the earth was getting colder and therefore expanding
11 of 29
How are mountains formed?
When the edges of drifting continents collide the crust crumbles and folds
12 of 29
What are the two types of tectonic plates?
Continental and oceanic
13 of 29
What is the difference between the two types of tectonic plates?
Oceanic plates are denser and are pushed down underneath continental plates if they meet
14 of 29
How do volcanic erruptions occur?
When tectonic plates meet they become unstable, magma is less dense than the crust and can rise to the surgace through the weaknesses in the crust
15 of 29
How do earthquakes occur?
When the movement of tectonic plates are sudden
16 of 29
How can the percentage of oxygen in the air be tested?
By passing a known volume of air over hot copper and measuring the decrease in volume as the oxygen reacts
17 of 29
What was the air like in the early atomostphere?
The gases were probably formed by the gases given out my volcanoes, probably mostly carbondioxide and little watervapour which went on to make ocenas
18 of 29
What was the aim of the miller-urey experiment?
To see if substances now made by living things could be formed in the conditions thought to have exsisted in early earth
19 of 29
How was the Miller-Urey experiment carried out?
They sealed a mixture of water that was heated to create water vapour, ammonia, methane and hydrogen in a sterile flask electric sparks were passed through mixture
20 of 29
What were the results of the Miller-Urey experiment?
Amino acids were fouund
21 of 29
What did the miller urey experiment support?
The theory of 'primordial soup' the idea complex chemicals needed for living things to develop could have been produced in early earth
22 of 29
How did the levels of oxygen increase over time?
There are more plants to do photosynthesis and absorb carbon dioxide and release oxygen
23 of 29
How did the levels of carbon dioxide decrease?
Photosynthesis but also dissolving in the oceans, producing of sedimentary rocks and production of fossil fuels
24 of 29
How can you seperate all the gases in the air?
Liquifying the air and then fractional distillation
25 of 29
How can we liquify air in order to seperate the nitrogen and oxygem?
Air is filtered to remove dust and then cooled until it reaches -200 degrees, then it is a liquid
26 of 29
What do we do after liquifying the air in order to seperate it?
Fractional distillation were the liquifyed air is passed into the bottom of the fractioning column where the nitrogen boils and the gas rises to the top, the liquid oxygen collects at the bottom with argon so you have to do it again
27 of 29
What are the uses of nitrogen?
Liquid nitrogen is used to freeze food and food is packaged in gaseous nitrogen to increase shelf life and oil tankers are flushed with it to reduce risk of explosion
28 of 29
What are the uses of oxygen?
Its used in the manufacture of steel and in medicene
29 of 29
Other cards in this set
Card 2
Front
What is similar about the crust and upper mantle?
Back
They are cracked into large peices called tectonic places
Comments
No comments have yet been made