The document is a 45 mark summative assessment on the global water cycle for a Grade 11 IB ESS class. It contains multiple choice and short answer questions testing understanding of key concepts about the water cycle including storage percentages, flow rates, inputs and outputs, and feedback mechanisms. It also addresses questions about energy in the water cycle, impacts of climate change, and water usage over time.

1. GURU CHARAN KUMAR/IB ESS 2012
HUMANITIES DEPARTMENT
ESS GRADE 11 SUMMATIVE-SEPTEMBER 2012
TIME: 1 HOUR
MARKS: 45
1)
The diagram below shows storages (in percentage of total water) and flows in the global
water cycle. The rates of flow are given in 1015 kg yr–1.
CLOUDS
0.001 %
Condensation
400
A
TMOSPHERIC
WA
TER VAPOUR
0.001 %
Precipitation
100
Evaporation
64
SURFACE WA
TER 0.001 %
ICE
2%
GROUND WA
TER 1 %
(a)
(i)
Precipitation
300
Evaporation
336
Run-off/groundwater flow
OCEAN
97 %
what is the source of energy which drives the water cycle? ........................ .
(1)
(ii)
In which of the processes given in the diagram does this energy enter the cycle?
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(1)
(b)
(i)
what percentage of all precipitation falls directly into the oceans?
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(1)
(ii)
What percentage of all evaporated water comes from the oceans?
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(1)
(c)
(i)
Assuming the cycle is in steady state, what mass of water flows into the oceans
through run-off and groundwater flow per year?
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(2)
(ii)
Explain why this figure might increase in the future, as a result of burning fossil
fuels.

2. GURU CHARAN KUMAR/IB ESS 2012
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(3)
(d)
Name a storage of water in the biosphere that is not shown in the diagram, and explain how
water is transferred in and out of this storage.
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(3)
(e)
(i)
State briefly one way in which one of the other flows in the diagram might change if
evaporation rates were to increase.
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(1)
(ii)
Describe how two changes in the flows shown on the diagram could lead to a fall in
global temperatures and reduce global warming.
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(4)
(iii)
Name the type of feedback involved in this reduction in global warming.
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(1)
(f)
Identify each of the different processes referred to on the diagram as either transfer or
transformation processes.
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3. GURU CHARAN KUMAR/IB ESS 2012
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(2)
(Total 20 marks)
2) a) Define the following terms.
(i)
Negative feedback
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(1)
(ii)
Positive feedback
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(1)
(b)
Suggest why most ecosystems are negative feedback systems.
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(1)
The diagram below represents a coal fired power station.
smoke
.................
coal
warm water
[Source: Adapted from D D Kemp, Global Environment Issues, A Climatological Approach, (Taylor & Francis,1994) p.
7. Reproduced by permission of Cengage Learning]
(c)
Complete the diagram above by naming the missing input and the two missing outputs.
(2)
(Total 5 marks)

4. GURU CHARAN KUMAR/IB ESS 2012
3) a) (i)
State the first law of thermodynamics.
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(1)
(ii)
Calculate the amount of energy output in the model below.
Input
1000 kJ
energy
10 % loss to
atmosphere
15 % stored
after loss to
atmosphere
OUTPUT = ?
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(2
(b)
The diagram below represents a simplified hydrological cycle.

5. GURU CHARAN KUMAR/IB ESS 2012
ATMOSPHERE
2.
3.
1.
4.
GROUND
(i)
Identify the processes corresponding to the arrows labeled 1 to 4 in the diagram.
1.
................................................................
2.
................................................................
3.
................................................................
4.
................................................................
(2)
(ii)
Suggest one weakness in the model above.
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(1)

6. GURU CHARAN KUMAR/IB ESS 2012
The graph below shows the estimated world water withdrawals from 1960 to 2000.
4
3
Water withdrawals /
103 km3 yr–1
2
1
0
1960
1965
1970
1975
1980
1985
1990
1995
2000
Year
[J Loh, The Living Planet Report, © [2002] WWF (panda.org). Some rights reserved.]
(iii)
Calculate the percentage increase in world water withdrawals from 1960 to 2000.
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(2)
(iv)
Suggest three reasons for the increase in water withdrawals during the period 1960
to 2000.
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(3)
(Total 11 marks)
4) Figure 1
Relationship between number of
rodent species and altitude
Figure 2 Altitude habitat model 100

7. GURU CHARAN KUMAR/IB ESS 2012
100
s snowline
Numbers
of
rodent
species
0
(a)
Altitude in
metres
3000
mountain
With reference to Figure 1 describe the relationship which appears to exist between altitude
and the number of rodent species.
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(1)
(b)
Predict three ways in which the altitude habitat model in Figure 2 might change as a result
of global warming.
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(3)
(c) (ii)
Explain the difference between an open system and a closed system.

8. GURU CHARAN KUMAR/IB ESS 2012
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(2)
(b)
The first and second laws of thermodynamics suggest that energy is neither made or lost,
merely transformed. Using a named ecosystem, outline how this occurs.
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(3)
(Total 9 marks)