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StudyPacks
STUDY.
KS4
SCIENCE
Planet Earth
Plate tectonics & Evolution of Earth’s Atmosphere
This Study Pack aims to cover:
1. The Earth’s Structure.
2. Theory of Plate tectonics.
3. The evolution of Earth’s atmosphere.
SC9
Study Packs are prepared by Qualified Teachers and Specialists and are a complete range of comprehensive
compiled resources based on the UK National Curriculum covering the Primary and Secondary Frameworks
including SATs and GCSE examinations.
Student Name
Contents
Planet Earth Notes
2-5
Practice questions
5-14
Exam questions
15-27
Mark scheme
28-35
1
2
3
4
5
Where does it come from?
Aims
Everything humans use comes from natural materials, if you follow the chain back far enough. Even
things that are man-made have to be made from something that can be found. Where do all these raw
materials come from and what do we use them for?
Questions
1 Paper is made from wood. Cement is made from limestone. Iron is made from iron ore. None of the
useful materials in this table are found naturally. They have to be made from something else.
Link each product to the raw material it is made from.
Product
Raw material
copper
sand
cooking oil
sunflower seeds
glass
clay
denim
copper ore
brick
wheat plants
plastic
crude oil
flour
cotton plants
2 Where does each of these raw materials come from?
Write each raw material mentioned in Question 1 next to where we get it from.
In the ground: ........................................................................................................
...............................................................................................................................
Another planet: ......................................................................................................
...............................................................................................................................
Grown naturally: ......................................................................................................
...............................................................................................................................
From the Sun:: ......................................................................................................
...............................................................................................................................
Look at your answers to Question 2. Where do we not get any of our raw materials from?
...............................................................................................................................
...............................................................................................................................
Some scientists think there is only enough crude oil to last about another 50 years. Looking at your
answers to Question 1, what effect will that have on our lives?
...............................................................................................................................
...............................................................................................................................
Why do many people say that we should recycle as much as possible?
...............................................................................................................................
6
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
How did the atmosphere get to be like this?
Aims
The Earth had a very violent and fiery beginning. The surface was covered in volcanoes. Even if
humans had been around 4.5 billion years ago they couldn’t have survived. The Earth’s atmosphere
was completely unable to support human life.
What changes have taken place in our atmosphere? How have they happened?
Method
You are going to put the information in the boxes on this page into a sensible order to show how the
Earth’s atmosphere has changed in the millions of years since the planet formed. On the next page,
the first and last stages have been done for you.
Ask your teacher whether you should copy the information into the boxes on the next page or cut out
the boxes below and stick the stages in the right order on the next page.
About 3.4 billion years ago, the first life
started on Earth. But these organisms didn’t
need oxygen.
The oxygen levels increased and animals
began to appear.
Water vapour condensed and fell to Earth
where it formed the first oceans.
The first bacteria formed. Then plants formed
and began to photosynthesise, releasing
oxygen as a waste product.
The levels of carbon dioxide dropped as the
carbon became trapped.
The Earth’s early atmosphere was mostly
carbon dioxide, with some ammonia
(a nitrogen compound) and steam.
Discussion
Check your sequence with your teacher or with other students. On the next page in the boxes on the
right-hand side, write why you think each stage happened.
7
4500 million years ago, volcanoes released
gases into the Earth’s atmosphere.
Reason:
Reason:
Reason:
Reason:
Reason:
Reason:
Currently, the Earth’s atmosphere is mostly
nitrogen and oxygen.
8
What’s the link?
Aims
The Earth’s atmosphere has contained roughly the same mixture of gases for the last 200 million
years. About 20% is oxygen, 80% is nitrogen, and there are small proportions of other gases, including
carbon dioxide.
The actual molecules of gas in the atmosphere are not always the same ones. As some get taken out
of the atmosphere more are added in their place. It’s a bit like your school – there is the same number
of students in total but each year some leave and some new ones join.
The balance of gases is changing and scientists are particularly concerned with the amount of carbon
dioxide in the atmosphere. It has increased from 0.028% 200 years ago to about 0.04% today. But why
is it changing? And, is there anything that can be done about it?
Questions
1.Why are many scientists concerned about the amount of carbon dioxide in our atmosphere?
...............................................................................................................................
2.What is the percentage increase in the amount of carbon dioxide in our atmosphere over the last 200
years? (Hint: this isn’t just the difference between the percentages. Treat each percentage as a
number and then work out the percentage increase.)
...............................................................................................................................
Scientists often talk about trapping carbon rather than carbon dioxide. When carbon is in the
atmosphere it is almost always part of carbon dioxide molecules. When it is not in the atmosphere it
can form part of other compounds. Carbon atoms have always moved between the atmosphere and
the Earth.
3. Add labels to the arrows on the diagram to list the processes that add carbon to the atmosphere
and the processes that take it out. You may need to do some research to find out more about this.
4. Which, if any, of the processes you have suggested that take carbon dioxide out of the
atmosphere are happening at a lower rate than they used to? Why is this?
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
9
5.Which, if any, of the processes you have suggested that put carbon dioxide into the atmosphere
are happening at a faster rate than they used to?
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
6.Very early in the Earth’s history the atmosphere had a high proportion of carbon dioxide. Where
do you think much of the carbon is trapped at the moment? (Hint: it might be under your feet.)
...............................................................................................................................
...............................................................................................................................
7.What could be done by people to slow the increase in the amount of carbon dioxide in our
atmosphere?
...............................................................................................................................
...............................................................................................................................
10
Our changing planet Test yourself
1
a
Match a word from the list with each of the labels A, B, C and D on the diagram of the
Earth.
atmosphere
core
crust
mantle
...................................................................................................................................
...................................................................................................................................
b
(4)
From which parts of the Earth do we get all of our raw materials?
A
atmosphere, core and crust
B
atmosphere, crust and oceans
C
atmosphere, core and mantle
D
core, mantle and oceans
...................................................................................................................................
(1)
11
2
a
About one hundred years ago there was a scientist called Alfred Wegener. He found
evidence that the continents, such as South America and Africa, had once been joined and then
drifted apart.
Use the diagram to suggest two pieces of evidence that could be used to show that the
continents had once been joined.
...................................................................................................................................
...................................................................................................................................
b
(2)
About fifty years ago, new evidence convinced scientists that the Earth’s crust is made up
of tectonic plates that are moving very slowly.
Give two pieces of evidence that have helped to convince these scientists that the
tectonic plates are moving.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
c
(2)
Describe as fully as you can what causes the Earth’s tectonic plates to move.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
(3)
12
AQA, 2009
3
a
In the Earth’s atmosphere the percentage of carbon dioxide has remained at about 0.03%
for many thousands of years. The graph shows the percentage of carbon dioxide in the
Earth’s atmosphere over the last 50 years.
i
What was the percentage of carbon dioxide in the Earth’s atmosphere in 1965?
...................................................................................................................................
ii
(1)
What change has happened to the percentage of carbon dioxide in the Earth’s
atmosphere over the last 50 years?
...................................................................................................................................
(1)
iii Suggest one reason for this change.
...................................................................................................................................
(1)
iv Why does this change worry some people?
...................................................................................................................................
(1)
There are different theories about the Earth’s early atmosphere.
b
Some scientists believe the Earth’s early atmosphere was mainly carbon dioxide and
water vapour. What do the scientists believe produced these gases?
...................................................................................................................................
c
(1)
In 1953 some scientists believed the Earth’s early atmosphere was mainly water vapour,
methane, ammonia and hydrogen. In the Miller–Urey experiment, electricity was passed
through a mixture of these gases and produced amino acids, the building blocks for
proteins and life. Give two reasons why the experiment does not prove that life began in
this way.
13
...................................................................................................................................
d
[H] (2)
Most scientists agree that there was very little oxygen in the Earth’s early atmosphere.
Explain how the oxygen that is now in the atmosphere was produced.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
4
(3)
The elements oxygen, nitrogen and argon can be separated from the air. Carbon dioxide and
water vapour are removed from air, which is then cooled to –200°C. The liquid obtained is a
mixture of oxygen, nitrogen and argon. The table shows the boiling points of these elements.
Element
Boiling point in °C
argon
–183
nitrogen
–196
oxygen
–186
Explain how these elements can be separated by fractional distillation of the liquid.
...................................................................................................................................
...................................................................................................................................
14
Exam Questions
Q1.
The Earth is shaped like a sphere and is surrounded by an atmosphere.
(a)
The diagram shows a section of the layered structure of the Earth.
(i)
Complete the diagram by writing in the missing label.
(1)
(ii) Earthquakes within the Earth’s crust can be sudden and disastrous. Scientists cannot
accurately predict when earthquakes will occur.
Explain why.
To obtain full marks you must support your answer with a description of what causes
earthquakes.
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
...........................................................................................................................
..........................................................................................................................
(4)
(b) Some theories suggest that the Earth’s early atmosphere was like the atmosphere of Mars
today.
The atmosphere of Mars
today
The atmosphere of Earth
today
Carbon dioxide %
95
0.03
Nitrogen %
3
Gases
Argon %
1.5
0.97
Oxygen %
0.5
21
15
(i)
Complete the table by writing in the percentage of nitrogen in the atmosphere of Earth today.
(1)
(ii) Use the information in the table to describe the changes that have happened to two of the
gases in the Earth’s atmosphere.
Explain what has caused these changes.
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
(4)
(Total 10 marks)
Q2.
(a)
The diagram below shows a cross-section of a mid-ocean ridge.
X and Y are two separate tectonic plates.
(i)
The two plates are both moving. Explain, as fully as you can, what causes tectonic plates to
move.
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
(3)
16
(ii) New ocean floor is created at the mid-ocean ridge. Explain, as fully as you can, how this
happens.
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
(3)
(b)
The layer of sediment that has collected on the ocean floor increases in depth the further it is from the
mid-oceanic ridge. Suggest a reason for this.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(2)
(Total 8 marks)
Q3.
The pie chart below shows the composition of the atmosphere on the planet Mars.
(a) Use the pie chart above to calculate the percentage of carbon
dioxide in the atmosphere on Mars.
....................................................................................................................................
....................................................................................................................................
.................................................................................................................………... %
(2)
(b) The atmosphere on Earth is very different from that on Mars. One important difference is that
the Earth’s atmosphere contains a large amount of oxygen.
Give two other ways in which the Earth’s atmosphere is different from the atmosphere
on Mars.
17
1. .................................................................................................................................
....................................................................................................................................
2. .................................................................................................................................
....................................................................................................................................
(2)
(c) When the Earth was formed its atmosphere is thought to have been similar to the atmosphere
on Mars. Explain how green plants and other organisms have changed the composition of the Earth’s
atmosphere.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(4)
(Total 8 marks)
Q4.
Read the passage, which is from the start of a magazine article. It will help you to answer
the questions.
Third rock from the Sun
Geologists now have evidence that the Earth’s crust began to form about four and a half
billion years ago. The surface of the Earth was then at temperatures well above 100 °C
and the atmosphere was mostly carbon dioxide with some ammonia, methane and
water vapour. About a quarter of a billion years after it had first formed, the crust had
become thicker and had cooled down to below 100 °C.
Slowly, over a period of about three billion years, oxygen became established in the
atmosphere. Some was released from the Earth’s interior by volcanoes and some was
produced, by the process of photosynthesis, by algae which had evolved in the seas.
(a)
Explain how the first seas formed.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
18
(b) Briefly describe two processes which reduced the proportion of carbon dioxide in the Earth's
atmosphere over the period of three billion years.
1. .................................................................................................................................
.....................................................................................................................................
2. .................................................................................................................................
.....................................................................................................................................
(2)
(Total 4 marks)
Q5.
(a) Two hundred years ago, scientists thought that the Earth was about 400 million years
old. This estimate came from the idea that the centre of the Earth was still molten. More recently,
measurement of radioactivity in rocks has shown that the Earth is much older than 400 million years.
Suggest one reason why scientists now know that the Earth is much older than 400 million
years.
.....................................................................................................................................
.....................................................................................................................................
(1)
(b) About one hundred years ago there was a scientist called Alfred Wegener. He found evidence
that the continents, such as South America and Africa, had once been joined and then drifted apart.
Use the diagram to suggest two pieces of evidence that could be used to show that the
continents had once been joined.
1 ..................................................................................................................................
.....................................................................................................................................
2 ..................................................................................................................................
.....................................................................................................................................
(2)
(c) About fifty years ago, new evidence convinced scientists that the Earth’s crust is made up of
tectonic plates that are moving very slowly.
Give two pieces of evidence that have helped to convince these scientists that the tectonic
plates are moving.
19
1 ..................................................................................................................................
.....................................................................................................................................
2 ..................................................................................................................................
.....................................................................................................................................
(2)
(Total 5 marks)
Q6.
The bar chart shows the composition of the Earth’s atmosphere today, and as it was
billions of years ago.
(a) Use information from the bar chart to describe how the atmosphere today is different from the
atmosphere of billions of years ago.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(b)
Describe the processes which have brought about the changes in the proportions of these gases in
the air over billions of years.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(4)
(Total 6 marks)
20
Q7.
Billions of years ago, the Earth’s early atmosphere was probably like the atmosphere of
Venus today.
The table shows the temperature and the percentage composition of the atmospheres of the Earth
and Venus today.
Percentage (%) composition of atmosphere
Name of gas
Earth today
Venus today
Nitrogen
78
3.5
Oxygen
20.6
a trace
Argon
0.97
a trace
Carbon dioxide
0.03
96.5
Water vapour
0.4
a trace
20 °C
460 °C
Average surface temperature
(a)
Use information from the table to help you to answer each part.
(i)
In the Earth’s atmosphere today, the main gas is ............................... .
(1)
(ii)
In the Earth’s atmosphere billions of years ago
the main gas was .............................................................
(1)
(iii)
The Earth’s surface is mainly covered with water.
There is no water on the surface of Venus.
Suggest why.
...............................................................................................................
...............................................................................................................
...............................................................................................................
...............................................................................................................
(2)
21
(b)
The diagram shows part of the Earth and ways that carbon dioxide can be removed from the Earth’s
atmosphere.
Give three ways that carbon dioxide can be removed from the Earth’s atmosphere.
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
(3)
(c)
In the Earth’s atmosphere the percentage of carbon dioxide has remained at about 0.03% for many
thousands of years.
The graph shows the percentage of carbon dioxide in the Earth’s atmosphere over the last 50 years.
(i)
What was the percentage of carbon dioxide in the Earth’s atmosphere in 1965?
...............................................................................................................
......................................... %
(1)
22
(ii) What change has happened to the percentage of carbon dioxide in the Earth’s atmosphere over
the last 50 years?
...............................................................................................................
(1)
(iii)
Suggest one reason for this change.
...............................................................................................................
...............................................................................................................
(1)
(Total 10 marks)
Q8.
Evidence shows that the Earth formed from a molten ball of rocks and minerals.
Before 1900 many scientists thought that the Earth’s mountains and continents formed in fixed
positions when the molten ball of rocks and minerals cooled and wrinkled.
(a)
In 1912 Alfred Wegener suggested his hypothesis of continental drift.
The areas of rocks shown on Map 1 contain fossils of the same type of animals.
Today animals in Africa are different from animals in South America.
Map 1
Wegener suggested his
hypthesis that all of the
continents, including Africa and
South America, had been joined
together but then drifted slowly
apart.
Map 2
In 1920 other scientists stated
that all of the continents were in
fixed positions, including Africa
and South America, and that
they had once been joined
together by a land bridge.
(i)
Use the information to suggest two pieces of evidence that may have led Wegener to propose his
hypothesis that continents move.
...............................................................................................................
...............................................................................................................
...............................................................................................................
...............................................................................................................
(2)
23
(ii)
Suggest why, in 1920, other scientists thought that Wegener’s hypothesis was wrong.
...............................................................................................................
...............................................................................................................
...............................................................................................................
...............................................................................................................
(2)
(b)
In 1962 scientists produced the theory of plate tectonics.
The theory of plate tectonics supported Wegener’s hypothesis that continents move.
Tectonic plates move a few centimetres a year.
Complete the sentences about what causes the movement of the Earth’s tectonic plates.
Deep inside the Earth ........................................ processes release large
amounts of energy. These processes heat up the substances in the Earth’s
........................................ producing convection currents.
(2)
Q9.
In 1935 C.F. Richter designed a scale for comparing the size of earthquakes.
A newspaper reported that an earthquake off the coast of Kent had caused plaster to come
down from ceilings, house tiles to loosen and church bells to ring.
The epicentre is the place on the surface of the Earth directly
above where the earthquake occurs.
(a) Suggest why the earthquake in Kent was reported and why most
earthquakes in the UK are not reported.
24
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(b)
Explain how earthquakes are caused.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(3)
(c)
People living in Kent were not warned about this earthquake.
In terms of what is happening within the Earth, explain the problems of trying to predict
earthquakes.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 7 marks)
Q10.
(a) For the last 200 million years the amount of carbon dioxide in the atmosphere has
remained almost the same.
Describe the natural processes which remove carbon dioxide from the atmosphere.
To gain full marks in this question you should write your ideas in good English.
Put them into a sensible order and use the correct scientific words.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
25
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(4)
(b)
The amount of carbon dioxide in the atmosphere has increased over the last one hundred years.
Suggest two reasons why this has happened.
1 ...................................................................................................................................
......................................................................................................................................
2 ...................................................................................................................................
......................................................................................................................................
(2)
(Total 6 marks)
Q11.
Life on Earth would not exist without the atmosphere. Billions of years ago the composition
of the Earth’s atmosphere was very different from the composition today.
(a) Label the pie chart below to show the percentages and names of the two main gases in the
Earth’s atmosphere today.
(2)
(b) There is evidence that the composition of the Earth’s atmosphere is still changing. One possible
reason is that many power stations generate electricity by burning fossil fuels such as coal, oil or
natural gas. Sulfur dioxide, SO2, is produced when coal burns in air.
(i)
What environmental problem does sulfur dioxide cause?
...........................................................................................................................
...........................................................................................................................
(1)
26
(ii)
How could this environmental problem be reduced in coal-fired power stations?
...........................................................................................................................
...........................................................................................................................
(1)
(iii)
Gas-fired power stations burn methane, CH4, in air.
Complete the word equation for this reaction.
methane + ............................... → carbon dioxide  ...............................
(2)
(c)
Excess carbon dioxide should be prevented from entering the atmosphere.
Explain why.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(d) Carbon dioxide is produced when fossil fuels burn in power stations. The diagram represents
one idea to prevent excess carbon dioxide from entering the atmosphere.
Use the diagram to explain how carbon dioxide can be prevented from entering the
atmosphere.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 10 marks)
27
Mark scheme
M1.
(ii)
(a)
(i)
core 1
M2.
(a) (i)
convection currents
in the mantle (1)
driven by heat (1)
from radioactive processes (1)
plate (boundaries)
accept parts of the crust
3
ignore crust alone 1
(ii) plates moving apart
magma rises to fill gap
forms new rock
sudden movement / colliding
accept movement but ignore movement apart
each for 1 mark
3
or normally move a few centimetres per year
accept continental drift 1
(b) Rock further from ridge is older
more time for sediment to settle
convection currents / driven by heat from radioactive processes / decay
each for 1 mark
2
idea of source of energy for the movement
[8]
1
M3.
the idea of uncertainty with an explanation
(a)
95% (1 mark for working)
2
eg scientists do not know (with any certainty)
•
what happens under the crust
•
where the forces / pressure are building up
•
we cannot measure the forces
•
(b) Much less carbon dioxide
Much more nitrogen
2
(c) Plants take up CO2
plants give out oxygen
when they die trap CO2 in rocks and fossil fuels
methane and ammonia reacted with oxygen
nitrogen gas produced
by reaction of oxygen and ammonia
and by denitryfying bacteria
formation of ozone layer
when the forces reach their limit
ignore references to volcanoes 1
any 4 for 1 mark each
(b)
(i)
78
(ii)
marks awarded for any 2 gases from the following 3 gases
4
[8]
M4
max 3 marks from CO2
1
(a)
any four from:
* (surface) below 100 °C (the surface) below the boiling point
of water
ignore references to respiration
carbon dioxide has decreased:
•
used by plants / bacteria (stromatolites)
•
during photosynthesis (must be linked to CO2 decrease)
either any two points (1) each from
* (allowed the) condensation (of water vapour)
accept (rate of) condensation greater than (the rate of)
evaporation
* from the atmosphere
accept from the air
•
‘locked up’ in (sedimentary) rocks / carbonates / fossil fuels
•
dissolved in oceans
or condensed water (vapour) (1)
was pulled by gravity into depressions (1)
or idea of impervious sea bed
and / or
or from comets (which crashed on the Earth) (1)
oxygen has increased because:
ice (from these) melted (1)
•
2
released by plants / bacteria (stromatolites)
(b)
•
during photosynthesis (must be linked to O2 increase)
and / or
any two processes (1) each from
* dissolving in (sea) water
nitrogen has increased because
* (taken in during) photosynthesis
•
ammonia reacted with oxygen (to release nitrogen)
•
nitrogen is released by bacteria
accept taken in by algae or plants
4
[10]
•
formation of carbonate(s)
or calcium carbonate or chalk or
calcite
accept formation of shells or bones or corals
2
[4]
28
M5.
(a)
radioactivity (keeps the core hot)
accept half-life of radioactive elements has proved the
Earth is
older than 400 million years
accept the Earth is not cooling
do not accept fossil / rock evidence
1
(b)
any two from:
•
the shapes of the two continents fit together (like a jigsaw) OWTTE\
M6.
(a) amount of CO2 (much) lower
amount of O2 (much) higher
amount of N2 (much) higher (owtte.)
less other gases/less NH3/less CH4
any 2 for 2 marks
2
do not accept the continents / they are the same
shape
•
the same type of rocks have been found
(b) 4 points from:
plants (evolved)/photosynthesis/algae
take in CO2
give out O2
water vapour condensed
ozone formed from oxygen
less CO2 is produced now from volcanic activity
CO2 from air trapped in sedimentary rocks or fossil fuels
nitrogen produced by bacteria/living organisms/microbes/decay of dead
organisms (not nitrifying bacteria, nitrogen fixing 4 bacteria)
nitrogen produced by reaction of NH3 with O2/decomposition of NH3
nitrogen builds up because it is unreactive
(Assume answer refers to today’s atmosphere)
accept ‘rocks match’
•
the same fossils have been found
accept ‘fossils match’
•
rising magma rising through a gap under the Atlantic
2
(c)
any two from:
•
earthquakes
any 4 for 1 mark each
4
accept seismic waves
•
[6]
volcanoes
M7.
(a)
(i)
nitrogen
1
•
idea of distance between America and Europe / Africa is increasing
e.g.
continental drift
(ii)
•
(iii) because water boils at 100°C and the temperature
on Venus is 460°C
carbon dioxide
1
oceanic ridges
1
accept ocean floor spreading
•
therefore any water on the surface would boil to form
steam / water vapour / gas
formation of (new) mountain ranges
accept fold mountains or mountains increasing in
height
1
(b)
any three from:
•
by photosynthesis
•
by dissolving in oceans
•
by the formation of (calcium) carbonate or limestone
M8.
(a) (i)
the continents of South America and Africa would
have fitted together like a jigsaw
1
•
by the formation of oil or coal
there are matching / similar rocks / fossils on the
continents of South America and Africa
(c)
•
formation of (new) islands
•
magnetic stripes
•
tsunamis
2
[5]
accept by the formation of fossil fuels
3
(i)
0.0317 (%)
1
1
(ii)
(ii) other scientists thought that continents are fixed / cannot
float or Wegener had no evidence to prove that
continents can move
the percentage of carbon dioxide has increased
1
allow Wegener was not respected by other scientists /
PhD in astronomy
1
and that a land bridge could explain the matching /
similar rocks / fossils on the continents of South
America and Africa
1
(iii)
any one from:
•
burning of fossil fuels
•
deforestation
•
release of ‘locked up’ carbon dioxide
1
[10]
(b)
radioactive 1
mantle
1
words must be in the order shown
[6 ]
29
M9.
(a) (Kent reported because) damage was caused or it was
above 3 (on the Richter scale)
accept description of damage
1
(others not reported because) no vibrations / not felt / not noticed
allow below 3 (on Richter scale)
ignore no damage
1
(b)
M10.
movement of (tectonic) plates
(a)
Quality of written communication
for any two ideas sensibly stated
allow collision of plates or plates rubbing together
or plates pushing against each other
1
1
any three from:
any two from:
•
•
plants take in (CO2)
vibration / (shock)waves (in the earth) or p and s waves
accept sudden jolts / slips
accept photosynthesis uses (CO
•
•
caused by convection currents (in the mantle)
)
converted to glucose / starch / carbohydrates
ignore carbon compounds by itself
•
(c)
heat / energy released from radioactive processes
any two from:
•
CO2 locked up in fossil fuels
accept coal / oil / natural gas / methane for fossil fuels
scientists do not know:
•
•
what happens under the crust / mantle / under the surface
CO2 reacts with / dissolves (sea)water
accept ocean removes CO2
accept anything under the crust
•
producing hydrogencarbonates
•
where forces / pressures are building up
accept carbonic acid
•
how to measure these forces / pressures
•
•
producing carbonates
accept named carbonates
when these forces / pressures reach their limit
accept there is no pattern
•
ignore random / speed of movement
do not accept bones
2
[7]]
•
marine animals use carbonates to make shells
forms sedimentary rocks
accept limestone / chalk
accept marble
do not accept sediments alone
3
(b)
any two from:
•
burning of fossil fuels or cars /
industry / air travel / power stations
ignore increase in population
ignore more use of electricity
•
natural processes cannot absorb all the extra CO2
•
deforestation
accept less photosynthesis
ignore volcanic activity
accept burn trees
2
[6]
30
M11.
(a)
oxygen and nitrogen
1
20 – 21 % and 78 – 80 %
accept any two correct responses in the correct space
for one mark
1
(b)
(i)
acid rain
accept toxic gas or consequence of acid rain
1
(ii) idea of the removal or use of sulfur
dioxide gas (from the waste gases)
do not accept remove sulfur from coal
1
(iii)
oxygen
accept O2
1
water
accept H2O
accept hydrogen oxide / steam
1
(c)
any two from:
•
it’s a ‘greenhouse gas’ or increase greenhouse effect
accept action of a ‘greenhouse gas’
•
causes global warming or increase in the Earth’s temperature
•
sea-levels rise or flooding
•
climate change
•
(polar) ice-caps melt
•
extension of deserts
mention of ozone / acid rain / global dimming = max 1
mark
2
(d)
idea trap / store / lock the carbon dioxide
1
in the oil reservoir or under the sea bed
do not accept ‘into the oil’ / ‘under the sea’
1
[10]
31
Where does it come from?
Aims
The purpose of this support worksheet is to ask students to consider the raw material origins of some
everyday materials and to appreciate that all of the raw materials we use are found on Earth. We need
to conserve these resources where we can because there are no feasible alternative sources.
Teaching notes
Students may not know all the answers to Question 1 but they may be able to complete most of it by
focusing first on the ones they do know. You may wish to provide resources so that they can research
the answers.
Answers to questions
Product
Raw material
copper
sand
cooking oil
sunflower seeds
glass
clay
denim
copper ore
brick
wheat plants
plastic
crude oil
flour
cotton plants
In the ground: limestone, iron ore, sand, clay, copper ore, crude oil
Grown naturally: wood, sunflower seeds, wheat plants, cotton plants
Note: this also includes materials listed in the stem of the question.
We do not obtain any raw materials from other planets or the Sun. Some useful materials may be
available there but we have never had any means of bringing them to Earth.
We would have no raw material to make more plastic.
The possible answers to this question are broad. However, it is intended to invoke a discussion about
the fact that we rely on the Earth’s resources for all the materials we use. The only way to make the
Earth’s resources (our only source of raw materials) last longer is to recycle previously extracted
materials. At the current rate of consumption, humans will have used up all the oil available on the Earth
in around 300 years (from when it was first used to when reserves run dry). This is a mere fraction of the
Earth’s 4.5 billion year history. The oil itself took around 150 million years to form.
32
How did the atmosphere get to be like this?
Answers to questions
4500 million years ago, volcanoes released
gases into the Earth’s atmosphere.
The Earth’s early atmosphere was mostly
carbon dioxide, with some ammonia
(a nitrogen compound) and steam.
Reason:
These are the gases released by volcanoes.
Water vapour condensed and fell to Earth
where it formed the first oceans.
Reason:
The Earth cooled and the water vapour
condensed. It must have rained for years.
About 3.4 billion years ago, the first life
started on Earth. But these organisms didn’t
need oxygen.
Reason:
There was no oxygen available.
The first bacteria formed. Then plants formed
and began to photosynthesise, releasing
oxygen as a waste product.
Reason:
There was plenty of carbon dioxide available
for photosynthesis.
The oxygen levels increased and animals
began to appear.
Reason:
Earth was covered in plants, which were all
producing oxygen as a waste product.
The levels of carbon dioxide dropped as the
carbon became trapped.
Reason:
Carbon was trapped in plants then coal, and
in rocks formed from animal shells.
Currently the Earth’s atmosphere is mostly
nitrogen and oxygen.
33
What’s the link?
Aims
Although the proportions of the gases in our atmosphere remain fairly constant, the actual molecules
do not stay in the atmosphere forever. They are moved into and out of the atmosphere by chemical
processes. The amount of carbon dioxide in the atmosphere is increasing. What is causing this change
and what effect could this have?
Answers to questions
1.Carbon dioxide traps heat in our atmosphere and its increase is thought to be contributing to
global warming.
0.040  0.028
 100%  43% The proportion of carbon dioxide in the atmosphere has increased
0.028
by 43% over the last 200 years. (You may need to explain to students that the percentage increase
is not given by 0.040 − 0.028 = 0.012%)
3.
Processes that add CO2 to the
Processes that remove CO2
atmosphere include:
from the atmosphere include:
2.
respiration
combustion of fossil fuels
volcanic activity
making cement and lime
decay
warming of oceans causing CO2 to
come out of solution
photosynthesis
dissolving in oceans
absorption by sea creatures and
then used as part of shell
4.The main process operating at a lower rate than it has done previously is photosynthesis, due to
worldwide deforestation. This is a world issue, commonly associated today with the felling of rain
forests. However, it has been going on much longer; Europe used to be around 80% forested but is
now less than 20%.
There is also less carbon dioxide dissolved in the sea. Rising temperatures make the carbon dioxide
less soluble.
3 More people and animals living on the planet mean greater carbon dioxide production through
respiration. Human energy demands also involve burning large quantities of fossil fuels. Burning
fossils fuels releases carbon as carbon dioxide. This carbon has been trapped for millions of years.
The amount of cement and concrete required for building has steadily increased. Cement
production involves thermally decomposing carbonates, which releases carbon dioxide.
4 Most of the carbon that is still trapped is part of carbonate rocks, such as limestone, and also fossil
fuels.
5 This is an open question but answers may range from planting more trees, to lowering energy
consumption or switching to non-fossil fuel energy sources such as solar.
34
Test yourself Answers
1.a A core, B mantle, C crust, D atmosphere.
b B – atmosphere, crust and oceans
4
1
2.a Any two from: the shapes of the continents fit together, the same type of
rocks have been found, the same fossils have been found accept rocks
match, fossils match, magma rising through a gap under the Atlantic.
b Any two from: earthquakes, volcanoes, idea of distance between America
and Europe/Africa is increasing, oceanic ridges, formation of mountain
ranges, formation of islands, magnetic stripes, tsunamis
c Any three from: (natural) radioactivity produces heat, (causes) convection
currents, in the mantle, mantle able to move or (behaves) like a liquid,
create forces (to move plates)
2
3.a
2
3
i 0.0317 (%)
ii increased
iii burning fossil fuels or deforestation
iv Global warming or greenhouse gas, accept causes floods or sea level
rise or climate change or extreme weather.
b volcanoes or volcanic activity
c Any two from: cannot be sure what was in the atmosphere, only produced
building blocks or amino acids are only one step towards living things,
evidence is in dispute or only theory or not conclusive.
d Because plants evolved or increased or colonized the Earth, plants
photosynthesise, which uses u carbon dioxide or removes carbon dioxide
from the atmosphere.
1
1
1
1
4.EITHER any three from: Liquid into fractionating column, nitrogen collected
at top and oxygen collected at the bottom, argon collected from in between or
part way up column, nitrogen has lowest boiling point, nitrogen collected as
gas, oxygen has highest boiling point, oxygen collected as liquid.
3
1
2
3
OR any three from: nitrogen has lowest boiling point so nitrogen boils first or
is collected as gas, argon has next lowest boiling point or boils next, oxygen
has highest boiling point so boils last or remains as liquid.
35