c13 the earth's early atmosphere

Question 1

composition of nitrogen

Answer 1

about 4/5 (80%)

Question 2

composition of oxygen

Answer 2

1/5 (20%)

Question 3

small proportions of various gases include?

Answer 3

carbon dioxide, water vapour and noble gasses

Question 4

why is evidence for the early atmosphere limited?

Answer 4

because of the time scale of 4.6 billion years

Question 5

during the first billion years of the Earth’s existence, what was there?

Answer 5

during the first billion years of the Earth’s existence, there was intense volcanic activity that released gases that formed the earths early atmosphere

Question 6

what happened to water vapour?

Answer 6

water vapour condensed to form the oceans

Question 7

at the start of this period, the Earth’s atmosphere may have been like the atmosphere of?

Answer 7

mars and venus today, consist of mainly carbon dioxide with little or no oxygen gas

Question 8

what do volcanoes also produce?

Answer 8

nitrogen which gradually built up in the atmosphere

Question 9

there may have also been small proportions of ?

Answer 9

methane and ammonia

Question 10

what happened when oceans formed?

Answer 10

carbon dioxide dissolved in the water and carbonates were precipitated producing sediments, and reducing the amount of carbon dioxide in the atmosphere

Question 11

the earth’s early atmosphere was formed by and consisted mainly of?

Answer 11

volcanic activity and consisted mainly of carbon dioxide

Question 12

as plants spread over the earth, what happened to the levels of oxygen in the atmosphere?

Answer 12

it increased

Question 13

what produced the oxygen that is now in the atmosphere?

Answer 13

algae and plants by photosynthesis

Question 14

when did algae first produce oxygen?

Answer 14

about 2.7 billion years ago and soon after this oxygen appeared in the atmosphere

Question 15

over the next billion years plants evolved and what happened?

Answer 15

the percentage of oxygen gradually increased to a level that enabled animals to evolve

Question 16

what decreased the percentage of carbon dioxide in the atmosphere?

Answer 16

algae and plants decreased the percentage of carbon dioxide in the atmosphere by photosynthesis

Question 17

what else decreased carbon dioxide?

Answer 17

the formation of sedimentary rocks and fossil fuels that contain carbon

Question 18

what do greenhouse gases in the atmosphere do?

Answer 18

greenhouse gases maintain temperatures on Earth high enough to support life.

Question 19

what are examples of greenhouse gases?

Answer 19

water vapour, carbon dioxide,and methane

Question 20

what does energy from the sun travel to the earth as?

Answer 20

short wavelength radiation e.g ultraviolet and visible light

Question 21

what happens to some of the short-wavelength radiation?

Answer 21

simply reflects back into space but most of it passes easily through the atmosphere

Question 22

why does this happen to some of the short-wavelength radiation?

Answer 22

because short-wavelength radiation does not react strongly with the gas molecules in the atmosphere

Question 23

when is the energy of the radiation absorbed?

Answer 23

when it reaches the surface of the earth

Question 24

the surface of the earth now radiated the energy as ?

Answer 24

long wavelength radiation such as infrared

Question 25

what do some of the long wavelength radiation interact with?

Answer 25

greenhouse gas molecules in the atmosphere - the energy in the long wavelength radiation is absorbed

Question 26

because the energy is trapped in the atmosphere what does this cause?

Answer 26

the temperature of the atmosphere to increase

Question 27

what does the greenhouse effect do?

Answer 27

it keeps the temperature on earth warm enough to support life

Question 28

without the greenhouse effect what would happen?

Answer 28

the earth would be too cold for most living organisms to survive

Question 29

carbon dioxide increases as

Answer 29

we burn fossil fuels example we burn coal for electricity and gas to heat our homes

Question 30

what is carbon dioxide absorbed by?

Answer 30

growing trees, but burning forests releases a lot of carbon dioxide

Question 31

what is methane released in?

Answer 31

agriculture e.g growing rice in flooded paddy fields and when cows pass wind

Question 32

based on peer reviewed evidence, what do many scientists believe?

Answer 32

human activities will cause the temperature of the earth;s atmosphere to increase at the surface and that this will result in global climate change

Question 33

what is a major cause of climate change?

Answer 33

an increase in average global temperature

Question 34

rising temperatures will increase?

Answer 34

melting of the polar ice sheets and glaciers. This will lead to increase sea levels.

Question 35

Give one reason why it is difficult to produce models for future climate change.

Answer 35

-complex systems
* many different variables
* many alternative theories

Question 36

Describe how carbon dioxide helps to maintain temperatures on Earth.

Answer 36

carbon dioxide allows short-wavelength radiation to pass through
allow greenhouse gas(es) for carbon dioxide
the atmosphere to the Earth’s surface
carbon dioxide absorbs outgoing long-wavelength radiation

Question 37

what is the carbon footprint?

Answer 37

are the total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product service or event

Question 38

the carbon footprint can be reduced by reducing emission of

Answer 38

carbon dioxide

Question 39

the combustion of fuels is ?

Answer 39

a major source of atmospheric pollutants