c9

Question 1

what is the earths atmosphere like today

Answer 1

-78% nitrogen
-21% oxygen
-small % of other gases (water vapour,carbon dioxide,noble gases)

Question 2

what was the earth like in the first billion years

Answer 2

-scientists believe there was large amounts of volcanic activity
-these volcanoes formed the early atmosphere

Question 3

how were the oceans formed

Answer 3

-as the oceans cooled the water vapour condensed to form the ocean

Question 4

what was the earths early atmosphere like

Answer 4

-consisted of mainly carbon dioxide with little or no oxygen due to volcanic activity
-volcanoes also released nitrogen and small amounts of methane and ammonia

Question 5

how did carbon dioxide levels decrease in our atmosphere

Answer 5

-dissolving in oceans
-photosynthesis
-carbon being trapped in fossil fuels

Question 6

how did carbon dioxide dissolve in the oceans

Answer 6

-some of the carbon dioxide dissolved in oceans to form a weak acid
-this reacted with minerals in the sea to form precipitates
-and over time this formed sediments of carbonate rock on the sea bed

Question 7

what was the carbon dioxide in the sea used for

Answer 7

-carbonate rock
-some formed corals and shells of organisms
-when these animals died they formed limestone and released carbon dioxide

Question 8

where did the oxygen in the atmosphere come from

Answer 8

-2.7 billion years ago photosynthetic algae first evolved in the oceans
-photosynthesis produced oxygen
-over the following billion years,plants evolved increasing the amount of oxygen in the atmosphere

Question 9

what are fossil fuels

Answer 9

-formed over millions of years
-non renewable

Question 10

how is coal formed

Answer 10

-formed from the remains of ferns and trees
-if they die in marshy wetland then they do not decompose due to a lack of oxygen or acidic conditions
-over time these plant remains are covered with sediment and compressed
-high temperature and pressure creates coal

Question 11

how is oil formed

Answer 11

-when plankton die they settle in mud on the sea bed
-if oxygen is not present they will not decompose
-over time they are compressed by sediment
-heat and pressure convert them into crude oil

Question 12

how is natural gas formed

Answer 12

-natural gas is mostly methane
-find natural gas near deposits of oil
-formed from plankton in a similar way to oil

Question 13

what do all fossil fuels contain

Answer 13

-trapped carbon
-that carbon was part of the carbon dioxide taken in by photosynthesis

Question 14

what are examples of green house gases

Answer 14

water vapour,carbon dioxide and methane

Question 15

what is the natural greenhouse effect

Answer 15

-energy from the sun travels to the earth as short wavelength radiation
-some short wave radiation reflects back into space but most of it easily passes through the atmosphere
-energy of radiation is absorbed by the earths surface
-surface of the earth radiates the energy back as longwave radiation which can react with the greenhouse gas (absorb)
-due to energy being trapped in the atmosphere the temperature increases

Question 16

why can short wavelength easily pass through the environment

Answer 16

-does not interact strongly with gas molecules in the atmosphere

Question 17

what does the natural greenhouse effect do

Answer 17

keeps temperature warm enough to support life

Question 18

what is the effect of the increase of human activity in the atmosphere

Answer 18

-levels of carbon dioxide and methane are rising

Question 19

why are the levels of carbon dioxide increasing in the atmosphere

Answer 19

-burning of fossil fuels
-eg coal for electricity
-deforestation
-burning forests releases large amounts of carbon dioxide

Question 20

why are levels of methane increasing in the atmosphere

Answer 20

-methane is released in agriculture for example growing rice in flooded paddy fields
-released when cattle pass wind

Question 21

what does the rising levels of methane and carbon dioxide mean for the environment

Answer 21

-temperatures of the atmosphere is rising
as more energy from the sun is trapped

Question 22

what do the rising temperatures mean for the environment

Answer 22

-increase melting of polar ice sheets and glaciers which leads to increased sea levels
-increased sea levels could lead to flooding of low lying areas
-could lead to more severe weather in the uk

Question 23

what does rising temperatures mean for animals

Answer 23

-could change the distribution
-could change distribution of insect born diseases

Question 24

what do scientists believe climate change is caused by

Answer 24

-human activity causing release of greenhouse gases

Question 25

what is the problem with our understanding of climate change

Answer 25

-climate change is complex and difficult
-we sometimes see stories in the media that are simplified or biased

Question 26

what is carbon footprint

Answer 26

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

Question 27

how can we reduce our carbon dioxide emissions

Answer 27

-insulating our homes or turning down heating
-use public transport
-switch to renewable energy sources

Question 28

how can we reduce our electricity emissions

Answer 28

-energy saving light bulbs
-turn appliances off at the plug

Question 29

how can we reduce methane emissions

Answer 29

-eat less beef and dairy
-trapping methane and burning it

Question 30

what are fuels

Answer 30

-fuels release energy when they are combusted
-eg coal and hydrocarbons

Question 31

what is carbon monoxide

Answer 31

-toxic gas
-no colour no smell
-many people have carbon monoxide detectors in there homes

Question 32

how is sulfur dioxide formed

Answer 32

-some fuels such as coal contain sulfur
-when coal is burned the sulfur reacts with oxygen(oxidised)

Question 33

how are oxides of nitrogen produced

Answer 33

-produced inside engines
-high temperatures cause nitrogen and oxygen from the air to react
-this produces a range of different molecules called oxides of nitrogen (NOx)

Question 34

what are the dangers of sulphur dioxide dangerous

Answer 34

-cause breathing problems in humans
-dissolve in rain to form acid rain which damages trees and corrode limestone buildings

Question 35

what is soot

Answer 35

-particles of carbon and unburned hydrocarbons
-produced by burning of diesel

Question 36

what is pollution caused by soot called

Answer 36

particulates

Question 37

how are particulates dangerous to human health and the environments

Answer 37

-increase risk of heart and lung disease
-reduce the amount of energy from the sun that reaches the earths surface(global dimming)

Question 38

how has levels of nitrogen increased in the atmosphere

Answer 38

-volcanoes produced nitrogen
-bacteria produced nitrogen

Question 39

how has oxygen increased in earths atmosphere

Answer 39

-algae and plants produced oxygen
-through photosynthesis

Question 40

how has carbon decreased in earths atmosphere

Answer 40

-because algae and plants used carbon dioxide by photosynthesis
-because oceans formed and carbon dioxide dissolved in the water
-because carbon dioxide formed carbonates, which precipitate as sediments or formed sedimentary limestone rocks