6 mark questions and..

6 Mark prose questions for core science
134 minutes
134 marks
Page 1 of 66
Q1.
In this question you will be assessed on using good English, organising information clearly
and using specialist terms where appropriate.
There are millions of plastic bags in use. After use most of these plastic bags are buried in
landfill sites. The amount sent to landfill could be reduced if the plastic bags:
•
could be reused
•
could be recycled by melting and making them into new plastic products
•
could be burned to release energy.
Use the information above and your knowledge and understanding to give the positive and
negative environmental impacts of using these methods to reduce the amount of plastic bags
sent to landfill.
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(Total 6 marks)
Page 2 of 66
Q2.
The photograph shows a zorse.
By Kumana @ Wild Equines [CC-BY-2.0], via Wikimedia Commons
A zorse is a cross between a male zebra and a female horse.
The zorse has characteristics of both parents.
(a)
The zorse was produced by sexual reproduction.
(i)
What is sexual reproduction?
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(1)
(ii)
The zorse has characteristics of a zebra and a horse.
Why?
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(2)
Page 3 of 66
(b)
Zorses are not able to breed.
Scientists could produce more zorses from this zorse by adult cell cloning.
The diagram shows how the scientists might clone a zorse.
In this question you will be assessed on using good English, organising information clearly
and using specialist terms where appropriate.
Page 4 of 66
Use information from the diagram and your own knowledge to describe how adult cell
cloning could be used to clone a zorse.
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(6)
(Total 9 marks)
Page 5 of 66
Q3.
In this question you will be assessed on using good English, organising information clearly
and using specialist terms where appropriate.
All the energy we use to heat our houses is eventually transferred to the surroundings.
The diagram shows two places where energy is transferred from a house to the surroundings.
Describe how energy is transferred to the surroundings through the roof and windows.
For each place:
•
name the processes involved in the energy transfer
•
suggest a method of reducing the rate of energy transfer
•
explain how your chosen methods reduce the rate of energy transfer.
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Page 6 of 66
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(Total 6 marks)
Q4.
The picture shows one type of solar water heater. Water from the tank is slowly pumped
through copper pipes inside the solar panel where the water is heated by energy from the Sun.
(a)
Each day the average European family uses 100 kg of hot water.
To kill bacteria, the water going into the tank at 20 °C must be heated to 60 °C.
Calculate the energy needed to increase the temperature of 100 kg of water by 40 °C.
Specific heat capacity of water = 4200 J/kg °C.
Write down the equation you use, and then show clearly how you work out your answer.
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Energy transferred = ....................................... J
(2)
Page 7 of 66
(b)
The bar chart shows how the amount of solar energy transferred to the water heater varies
throughout the year.
How many months each year will there not be enough solar energy to provide the hot
water used by an average European family?
..................................................... months
(1)
Page 8 of 66
(c)
In this question you will be assessed on using good English, organising information clearly
and using specialist terms where appropriate.
The water in the tank could be heated by using an electric immersion heater.
Outline the advantages and disadvantages of using solar energy to heat the water rather
than using an electric immersion heater.
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(6)
(Total 9 marks)
Q5.
In this question you will be assessed on using good English, organising information clearly
and using specialist terms where appropriate.
Plants and animals have become adapted in many different ways to reduce the risk of being
eaten by predators.
Describe these adaptations.
Page 9 of 66
Give examples of animals and plants adapted in the ways you describe.
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(6)
(Total 6 marks)
Page 10 of 66
Q6.
Total cholesterol in the blood contains ‘good’ and ‘bad’ cholesterol.
High levels of ‘bad’ cholesterol increase the risk of heart disease.
High levels of ‘good’ cholesterol reduce the risk of heart disease.
Scientists have suggested that chemicals called polyphenols in dark chocolate may help people
with Type 2 diabetes.
Polyphenols may reduce high levels of ‘bad’ cholesterol in the blood.
The scientists investigated the effect of polyphenols on levels of cholesterol in the blood.
•
7 men and 5 women with Type 2 diabetes had the levels of cholesterol in their blood
measured.
•
They all ate 45 g of dark chocolate every day for 16 weeks.
•
6 of the people ate dark chocolate that contained polyphenols. The other 6 people ate
dark chocolate that did not contain polyphenols.
•
All 12 people were allowed to eat and drink anything else they wanted, but no more
chocolate.
•
The levels of cholesterol in their blood were measured again after 16 weeks.
The results showed that for the people who ate dark chocolate with polyphenols:
•
there were decreases in total cholesterol and ‘bad’ cholesterol
•
there was an increase in ‘good’ cholesterol.
A newspaper headline reported the research and wrote:
‘Research shows that diabetics should eat dark chocolate.’
In this question you will be assessed on using good English, organising information clearly and
using specialist terms where appropriate.
Was the newspaper’s statement justified?
Include in your answer evidence that supports the newspaper’s statement and evidence that
does not support the newspaper’s statement.
Page 11 of 66
Remember to give a conclusion to your answer.
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(Total 6 marks)
Q7.
The surface of the Earth has changed slowly over billions of years.
(a)
Diagram 1 shows one theory of how mountains are formed.
(i)
Describe this theory of mountain formation.
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(1)
Page 12 of 66
(ii)
Most scientists accepted this theory of mountain formation until about 60 years ago.
Suggest why most scientists accepted this theory.
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(1)
(b)
Diagram 2 shows the positions of the continents 250 million years ago.
Diagram 3 shows the positions of the continents today.
Page 13 of 66
In this question you will be assessed on using good English, organising information clearly
and using specialist terms where appropriate.
Describe how the positions of the continents have changed over the last 250 million years
and explain the processes that have brought about these changes in position.
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(6)
(Total 8 marks)
Q8.
(a) Geothermal energy and the energy of falling water are two resources used to generate
electricity.
(i)
What is geothermal energy?
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(1)
Page 14 of 66
(ii)
Hydroelectric systems generate electricity using the energy of falling water.
A pumped storage hydroelectric system can also be used as a way of storing energy
for future use.
Explain how.
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(2)
(b)
In this question you will be assessed on using good English, organising information clearly
and using specialist terms where appropriate.
Read the following extract from a newspaper.
Page 15 of 66
Discuss the advantages and disadvantages of the plan to build thousands of offshore wind
turbines around Britain and the suggested electricity power link between Britain and
Iceland.
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(6)
(Total 9 marks)
Page 16 of 66
Q9.
In this question you will be assessed on using good English, organising information clearly
and using specialist terms where appropriate.
The drawing shows the shapes of trees growing on their own and inside a forest.
The trees are of the same species.
Describe the differences between the tree growing on its own and the trees inside the forest.
Suggest reasons for the differences you have described.
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(Total 6 marks)
Page 17 of 66
Q10.
The picture shows one type of solar water heater. Water from the tank is slowly pumped
through copper pipes inside the solar panel where the water is heated by energy from the Sun.
(a)
Explain why the copper pipes inside the solar panel are painted black.
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(2)
(b)
Each day the average European family uses 100 kg of hot water.
To kill bacteria, the water going into the tank at 20 °C must be heated to 60 °C.
Calculate the energy needed to increase the temperature of 100 kg of water by 40 °C.
Specific heat capacity of water = 4200 J/kg °C.
Write down the equation you use, and then show clearly how you work out your answer.
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Energy transferred = .................................... J
(2)
Page 18 of 66
(c)
The bar chart shows how the amount of solar energy transferred to the water heater varies
throughout the year.
How many months each year will there not be enough solar energy to provide the hot
water used by an average European family?
.................................................. months
(1)
Page 19 of 66
(d)
In this question you will be assessed on using good English, organising information clearly
and using specialist terms where appropriate.
The water in the tank could be heated by using an electric immersion heater.
Outline the advantages and disadvantages of using solar energy to heat the water rather
than using an electric immersion heater.
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(6)
(Total 11 marks)
Page 20 of 66
Q11.
A student is given a tube containing a liquid nutrient medium. The medium contains one
type of bacterium.
(a)
In this question you will be assessed on using good English, organising information clearly
and using specialist terms where appropriate.
The student is told to grow some of the bacteria on agar jelly in a Petri dish.
Describe how the student should prepare an uncontaminated culture of the bacterium in
the Petri dish.
You should explain the reasons for each of the steps you describe.
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(6)
Page 21 of 66
(b)
After the culture had been prepared, the student added one drop of each of five
disinfectants, A, B, C, D and E, onto the culture.
The diagram shows the appearance of the Petri dish 3 days later.
(i)
There are areas on the agar jelly where no bacteria are growing.
Why?
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(1)
(ii)
The student concluded that disinfectant D would be the best for using around the
home.
Give one reason why the student might be correct.
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Give one reason why the student might not be correct.
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(2)
(Total 9 marks)
Page 22 of 66
Q12.
In this question you will be assessed on using good English, organising information clearly
and using specialist terms where appropriate.
The diagram below shows a food web for some of the organisms that live on moorland.
Only a small percentage of the Sun’s energy captured by the heather is eventually incorporated
into the body tissues of the fox.
Explain, as fully as you can, what happens to the rest of the energy captured by the heather.
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(Total 6 marks)
Page 23 of 66
Q13.
The diagram shows the National Grid system.
(a)
The National Grid includes step-up transformers.
Explain why.
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(2)
(b)
In this question you will be assessed on using good English, organising information clearly
and using specialist terms where appropriate.
Over the next 10 years, more than 300 kilometres of new high voltage transmission cables
are to be added to the National Grid. Most of the new cables will be suspended from pylons
and run overhead while the rest will be buried underground.
Page 24 of 66
Outline the advantages and disadvantages of both overhead transmission cables and
underground transmission cables.
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Page 25 of 66
(c)
When an electric current flows through a transmission cable, a magnetic field is produced.
The graph shows how the strength of the magnetic field varies with distance from both
overhead and underground transmission cables that carry the same current.
What conclusions may be drawn from this graph?
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Page 26 of 66
(d)
Some people think that, because of the magnetic fields, living close to transmission cables
is dangerous to health. Laboratory studies on mice and rats exposed to magnetic fields for
two or more years found that the magnetic fields had no effect on the animals’ health.
Draw a ring around the correct answer in the box to complete the sentence.
economic
Using animals in scientific research raises
environmental
issues.
ethical
(1)
(Total 11 marks)
Q14.
Most plastic bags are made from poly(ethene).
Poly(ethene) is a polymer made from ethene.
Ethene is made by cracking saturated hydrocarbons from crude oil.
(a)
Use words from the box to complete the sentences about cracking.
alkanes
alkenes
catalyst
fuel
gas
Cracking involves heating the .......................................... to make a vapour.
The vapour is either passed over a hot ............................................... or mixed
with steam and heated to a very high temperature so that thermal decomposition
reactions happen.
(2)
(b)
Poly(ethene) molecules are made from ethene molecules by a polymerisation reaction.
Describe what happens in a polymerisation reaction.
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(2)
(c)
In this question you will be assessed on using good English, organising information clearly
and using specialist terms where apropriate.
There are millions of plastic bags in use. After use most of these plastic bags are buried in
landfill sites. The amount sent to landfill could be reduced if the plastic bags:
•
could be reused
•
could be recycled by melting and making into new plastic products
•
could be burned to release energy
Page 27 of 66
Use the information above and your knowledge and understanding to give the positive and
negative environmental impacts of using these methods to reduce the amount of plastic
bags sent to landfill.
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(6)
(Total 10 marks)
Page 28 of 66
Q15.
(a) The graph shows how the demand for electricity in the UK changes during one 24hour period.
Time of day
The table gives the start-up times for two types of power station.
Type of power station
Start-up time
Gas
A few minutes
Nuclear
Several days
How would these two types of power station be used to meet the demand for electricity
during this 24-hour period?
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(3)
Page 29 of 66
(b)
In this question you will be assessed on using good English, organising information clearly
and using specialist terms where appropriate.
A farmer plans to generate all the electricity needed on her farm, using either a biogas
generator or a small wind turbine.
The biogas generator would burn methane gas. The methane gas would come from rotting
the animal waste produced on the farm. When burnt, methane produces carbon dioxide.
The biogas generator would cost £18 000 to buy and install. The wind turbine would cost
£25 000 to buy and install.
The average power output from the wind turbine would be the same as the continuous
output from the biogas generator.
Evaluate the advantages and disadvantages of the two methods of generating electricity.
Conclude, with a reason, which system would be better for the farmer to buy and install.
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(Total 9 marks)
Page 30 of 66
Q16.
This question is about oil reserves.
(a)
Diesel is separated from crude oil by fractional distillation.
Describe the steps involved in the fractional distillation of crude oil.
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(b)
Diesel is a mixture of lots of different alkanes.
What are alkanes?
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Page 31 of 66
(c)
In this question you will be assessed on using good English, organising information clearly
and using specialist terms where appropriate.
Petroleum products, such as petrol, are produced from crude oil.
The graph shows the possible future production of petroleum products from crude oil and
the expected demand for petroleum products.
Canada’s oil sands hold about 20% of the world’s known crude oil reserves.
The oil sands contain between 10 to 15% of crude oil. This crude oil is mainly bitumen.
In Canada the oil sands are found in the ground underneath a very large area of forest. The
trees are removed. Then large diggers and trucks remove 30 metres depth of soil and rock
to reach the oil sands. The oil sands are quarried. Boiling water is mixed with the quarried
oil sands to separate the bitumen from the sand. Methane (natural gas) is burned to heat
the water.
The mixture can be separated because bitumen floats on water and the sand sinks to the
bottom of the water. The bitumen is cracked and the products are separated by fractional
distillation.
Page 32 of 66
Use the information given and your knowledge and understanding to suggest the
advantages and disadvantages of extracting petroleum products from oil sands.
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(Total 11 marks)
Page 33 of 66
M1.
Marks awarded for this answer will be determined by the Quality
of Written Communication (QWC) as well as the standard of the
scientific response.
No relevant content.
0 marks
There is a brief description of a positive and a negative environmental
impact involved with one or more methods used to reduce the
amount of plastic bags sent to landfill.
Level 1 (1–2 marks)
There is some description of both positive and negative
environmental impacts involved with at least 2 methods used
to reduce the amount of plastic bags sent to landfill.
Level 2 (3–4 marks)
There is a clear, balanced and detailed description of both a
positive and a negative environmental impact of using each
of the 3 methods used to reduce the amount of plastic bags
sent to landfill.
Level 3 (5–6 marks)
examples of the points made in the response
Reuse:
Reuse means less bags used so:
Positive environmental impact
•
Saves raw materials/crude oil
•
Saves energy
•
Cuts down on CO2 emissions
•
Less global warming
Negative environmental impact
•
Could cause litter
•
Could still be sent to landfill
Page 34 of 66
Recycle:
Bags can be recycled so:
Positive environmental impact
•
Used to make new plastic bags / objects
•
Saves raw materials / crude oil
•
Saves energy compared to producing plastic bags from crude oil
•
Cuts down on CO2 emissions
•
Less global warming
Negative environmental impact
•
Collection point sites cause an eyesore / litter problem
•
Transportation to recycling plant releases carbon dioxide / causes global warming
Burn:
Bags can be burned so:
Positive environmental impact
•
Could provide energy for heating buildings
•
Could provide energy for generating electricity
Negative environmental impact
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Increases CO2 emissions
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Increases global warming
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Could release toxic gases
•
Does not conserve raw materials / crude oil
[6]
M2.
(a)
(i)
fusion / joining / combining of gametes / egg and sperm / sex cells
accept fertilisation
allow fusion / joining / combining DNA from two parents
ignore meeting / coming together / mixing of gametes etc
1
(ii)
(mixture of) genes / DNA / genetic information / chromosomes
ignore nucleus / inherited information but allow second mark if
given
1
from both parents / horse and zebra
dependent on sensible attempt at 1st mark
1
Page 35 of 66
(b)
Marks awarded for this answer will be determined by the Quality of Written
Communication (QWC) as well as the standard of the scientific response. Examiners
should apply a ‘best-fit’ approach to the marking.
0 marks
No relevant content
Level 1 (1-2 marks)
There is simple description of the early stages of adult cell cloning. However there is little
other detail and the description may be confused or inaccurate.
Level 2 (3-4 marks)
There is an almost complete description of the early stages of the process and description
of some aspects of the later stages. The description may show some confusion or
inaccuracies.
Level 3 (5-6 marks)
There is a clear, detailed and accurate description of all the major points of how adult cell
cloning is carried out.
Examples of Biology points made in the response could include:
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skin cell from zorse
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(unfertilised) egg cell from horse
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remove nucleus from egg cell
•
take nucleus from skin cell
•
put into (empty) egg cell
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(then give) electric shock
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(causes) egg cell divides / embryo formed
•
(then) place (embryo) in womb / uterus
6
[9]
Page 36 of 66
M3.
Marks awarded for this answer will be determined by the Quality of Written Communication
(QWC) as well as the standard of the scientific response. Examiners should also refer to the
information in the marking guidance (see Reference Material) and apply a 'best-fit' approach to
the marking.
0 marks
No relevant content.
Level 1 (1-2 marks)
There is a basic description which includes either a process involved or a suggestion for a
method of reducing the rate of energy transfer.
Level 2 (3-4 marks)
There is a clear description which includes one process.It also includes feasible suggestions for
reducing the rate of energy transfer from roof and windows.
There is a reasonable attempt to explain why the rate of energy transfer is reduced for at least
one of the methods using terms like conduction, convection or radiation.
Level 3 (5-6 marks)
There is a detailed description which includes processes and feasible suggestions for reducing
the rate of energy transfer from roof and windows.
There is a correct explanation for both methods of why the rate of energy transfer is reduced
using terms like conduction, convection and radiation.
examples of the points made in the response
Roof
Process:
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convection / hot air rises (within roof space)
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conduction through roof
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radiation by the roof / tiles
ignore heat / energy rises
Method:
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(loft) insulation / fibreglass
•
shiny / reflective material
allow reduce temperature of house
Explanation:
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reduces convection
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reduces conduction
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reduces radiation
•
(insulation) traps air
answers must link to process / method
Windows
Explanation:
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conduction through glass
Page 37 of 66
Method:
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double glazing
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reflective coating on glass
allow curtains
allow thicker glass
Explanation:
•
layer of air or a vacuum (between glass)
•
(air) is a poor conductor / good insulator
•
(reflective coating) reduces radiation
accept argon / krypton / xenon for air
for curtains: trapping air (between curtain and window)
for thicker glass: is a better insulator
allow reduce temperature inside house and explanation in terms of
temperature difference between inside and outside of house - credit
only once
[6]
M4.
(a)
16 800 000
allow 1 mark for substitution into correct equation
ie 100 × 4200 × 40
2
(b)
7
allow ecf from part (a)
1
(c)
Marks awarded for this answer will be determined by
the Quality of Written Communication (QWC) as well
as the standard of the scientific response.
No relevant content.
0 marks
There is a brief explanation of the advantages and disadvantages
of using solar energy to heat the water rather than using an electric
immersion heater, including either advantages or disadvantages from
the examples below.
Level 1 (1–2 marks)
There is some explanation of the advantages and disadvantages of
using solar energy to heat the water rather than using an electric
immersion heater, with at least one advantage and one disadvantage
from the examples below.
Level 2 (3–4 marks)
There is a clear, balanced and detailed explanation of the advantages
and disadvantages of using solar energy to heat the water rather
than using an electric immersion heater, with a minimum of two
advantages and two disadvantages from the examples below.
Level 3 (5–6 marks)
Page 38 of 66
examples of the points made in the response
advantages
•
a renewable energy source
•
energy is free
•
does not pollute the atmosphere
accept specific examples of polluting gases
•
no fuel is burnt
•
energy can be stored (in the water)
disadvantages
•
only available in daylight hours
•
availability fluctuates
accept unreliable energy source
•
insufficient hours of sunlight in some countries
•
average low intensity in some countries
[9]
M5.
Marks awarded for this answer will be determined by the Quality of Written Communication
(QWC) as well as the standard of the scientific response. Examiners should also apply a 'bestfit' approach to the marking.
0 marks
No relevant content.
Level 1 (1-2 marks)
There is at least one example of an adaptation of either an animal or a plant. However it may not
be clear how the adaptation helps the organism to avoid being eaten.
Level 2 (3-4 marks)
There is a description of an adaptation of at least one animal and at least one plant. It is clear
how at least one of these adaptations helps the organism to avoid being eaten.
Level 3 (5-6 marks)
There are clear and detailed descriptions of a range of adaptations of named animals and
named plants. It is clear how most of these adaptations help the organisms to avoid being eaten.
Page 39 of 66
examples of clear and detailed biology points made in response:
•
camouflage – the method of camouflage should be described plus a statement that the
predator is less likely to see the prey
•
mimicry / warning colouration – the method should be described plus a statement that
the predator is likely to confuse the prey with e.g. a poisonous organism
•
thorns / prickles / spines / horns – a statement that these are sharp and are likely to hurt
a predator
•
long limbs / streamlining – a statement that these increase speed and make it more
likely that prey will outrun predator
•
bad taste / poison – a statement that predator will find this unpleasant and ‘spit out’ prey /
not attack same prey again
•
large ears / position of eyes – a statement that predators will be detected earlier so the
prey can escape sooner
[6]
Page 40 of 66
M6.
Marks awarded for this answer will be determined by the Quality of Written
Communication (QWC) as well as the standard of the scientific response.
Examiners should also refer to the information on the marking guidance
(see Reference Material), and apply a 'best-fit' approach to the marking.
0 marks
No relevant content.
Level 1 (1-2 marks)
There is a brief description of the evidence for or against the newspaper’s claim,
including either evidence for or evidence against.
Level 2 (3-4 marks)
There is a description of some of the evidence for and evidence against the
newspaper’s claim, with at least one example of evidence for and one
example of evidence against. There is an attempt at a conclusion.
Level 3 (5-6 marks)
There is a clear and detailed description of the evidence for and evidence against
the newspaper’s claim, with at least one example for and at least two examples
against. A reasoned conclusion is given. The description must include reference
to polyphenols.
Examples of the chemistry points made in the response
Evidence supporting the newspaper claim:
•
the study included a control group / one group given a placebo
•
all participants ate the same amount of chocolate each day
•
results showed a decrease in total cholesterol / an increase in ‘good’
cholesterol / a decrease in ‘bad’ cholesterol in the group that ate the dark
chocolate
allow (dark) chocolate worked / reduced (risk of) heart disease
Evidence against the newspaper claim:
•
no results given for (dark) chocolate without polyphenols
•
only type 2 diabetes patients tested
•
small sample tested / only 12 tested
•
unequal numbers of males and females
•
other health issues / age not controlled
•
rest of diet not controlled
•
chocolate contains high levels of fat / sugar / could cause other health issues
eg weight gain
•
long term effects not known / trial only 16 weeks
Argued conclusion made with an attempted justification
[6]
Page 41 of 66
M7.
(a)
(i)
the Earth cooled
or
crust shrank / wrinkled / shrivelled / crinkled
1
(ii)
insufficient / no evidence for new theory / tectonic theory
allow had evidence for old theory
or
no evidence against
or
they were not aware of plates / movements
or
no other theory made sense
ignore no other theories
1
(b)
Marks awarded for this answer will be determined by the Quality of Written
Communication (QWC) as well as the standard of the scientific response.
Examiners should also refer to the information on the marking guidance
(see Reference Material), and apply a 'best-fit' approach to the marking.
0 marks
No relevant information.
Level 1 (1-2 marks)
There is a statement about change or an attempt at an explanation of the
tectonic theory
Level 2 (3-4 marks)
There is a statement about change and a clear scientific explanation of the
tectonic theory
Level 3 (5-6 marks)
There is a statement about change and a clear scientific explanation of the
tectonic theory
Examples of chemistry points made in the response
descriptive points:
•
continents have moved apart / together
or
continental drift
•
move slowly / a few centimetres a year
•
now separated by expanses of oceans
•
example of movement of one continent
Page 42 of 66
explanation points:
•
the (Earth’s crust) is made up of (tectonic) plates
•
mantle can move (slowly)
•
convection currents
•
within the mantle
•
driven by energy (allow heat)
•
released by radioactive processes
•
in the core
•
cause the plates to move
6
[8]
M8.
(a)
(i)
energy from hot rocks in the Earth
accept heat that occurs naturally in the Earth
accept steam / hot water rising to the Earth’s surface
accept an answer in terms of the energy released by radioactive
decay in the Earth
heat energy is insufficient
1
(ii)
water is pumped / moved
1
up (to a higher reservoir)
this mark point only scores if first mark point is awarded
1
(b)
Marks awarded for this answer will be determined by the Quality of Written
Communication (QWC) as well as the standard of the scientific response.
Examiners should also refer to the Marking Guidance and apply a ‘best-fit’
approach to the marking.
0 marks
No relevant content
Level 1 (1-2 marks)
There is a brief description of at least one advantage or disadvantage for
either the planned wind turbines or the suggested electricity power link.
Level 2 (3-4 marks)
There is a description of advantages and disadvantages for
either the planned wind turbines or the suggested electricity power link.
or
A description of the advantages or disadvantages for both the planned
wind turbines and the suggested electricity power link.
Page 43 of 66
Level 3 (5-6 marks)
There is a clear and detailed description of at least one advantage and
one disadvantage for both the planned wind turbines and suggested
electricity power link.
examples of the points made in the response
Offshore wind turbines
advantages
•
renewable (energy resource)
•
low running costs
•
energy is free
•
no gas emissions (when in use)
accept a named gas eg CO2
accept no fuel is burned
accept less dependent on fossil fuels
•
land is not used (up)
disadvantages
•
unreliable – accept wind does not always blow
ignore references to destroying or harming habitats
•
hazard to birds / bats
•
visual pollution – do not accept noise pollution
do not allow if clearly referring to onshore wind turbines
do not accept spoils landscape
•
difficulty of linking turbines to the National Grid
•
large initial cost
•
difficult to erect / maintain
accept a lot of maintenance needed
•
CO2 emissions in manufacture (of large number of turbines)
Page 44 of 66
Suggested Link
advantages
•
income for Iceland
•
using Iceland’s (available) energy (resources)
accept using (Iceland’s) renewable energy (resources)
do not accept reduce the amount of Iceland’s wasted energy
•
provide electricity when wind does not blow / reliable
•
provide electricity at times of peak demand
•
even out fluctuations in supply
•
excess electricity from Britain (windy days) to Iceland and used to pump water up to
store energy
•
Britain less dependent on fossil fuels
accept Britain needs fewer (new) power stations
accept conserves fossil fuels
disadvantages
•
large initial cost
accept expensive (to lay cables)
•
power loss along a long cable
•
(engineering) difficulties in laying / maintaining the cable
accept difficult to repair (if damaged)
6
[10]
Page 45 of 66
M9.
Marks awarded for this answer will be determined by the Quality of Written Communication
(QWC) as well as the standard of the scientific response. Examiners should also refer to the
information on the marking guidance (see Reference Material), and apply a ‘best-fit’ approach to
the marking.
0 marks
No relevant information.
Level 1 (1-2 marks)
There is a basic description of either differences or explanations only.
Level 2 (3-4 marks)
There is a clear description of at least one difference with a correctly linked attempt at an
explanation.
Level 3 (5-6 marks)
There is a clear and detailed description of at least two differences explained and correctly
linked. Competition explained
Examples of the points made in the response
allow converse statements for trees in forest
description of tree on its own.
•
is wider / bushier
allow (leaves / branches) spread out
•
has more leaves
•
is shorter
ignore trunks
•
has leaves all over tree
ignore size of leaves
explanation linked:
•
•
•
more space
more light
more nutrients
allow photosynthesise more
ignore reference to being eaten
is shorter cannot be linked with more nutrients
ignore tree roots unless clearly linked to obtaining nutrients
competition mentioned:
•
for light
ignore fight
•
for nutrients
ignore water and carbon dioxide
•
for space
ignore evolution / natural selection / adapting
[6]
Page 46 of 66
M10.
(a)
because black is a good absorber of radiation
1
there will be a faster transfer of energy
allow the temperature of the water rises faster
1
(b)
16 800 000
allow 1 mark for substitution into correct equation
ie 100 × 4200 × 40
2
(c)
7 allow
ecf from part (b)
1
(d)
Marks awarded for this answer will be determined by the
Quality of Written Communication (QWC) as well as the
standard of the scientific response.
No relevant content.
0 marks
There is a brief description of the advantages and disadvantages
of using solar energy to heat the water rather than using an
electric immersion heater, including either advantages or
disadvantages from the examples below.
Level 1 (1-2 marks)
There is a description of some of the advantages and
disadvantages of using solar energy to heat the water
rather than using an electric immersion heater, with at
least one advantage and one disadvantage from the
examples below.
Level 2 (3-4 marks)
There is a clear, balanced and detailed description of the
advantages and disadvantages of using solar energy to
heat the water rather than using an electric immersion
heater, with a minimum of two advantages and two
disadvantages from the examples below.
Level 3 (5-6 marks)
examples of the points made in the response
advantages
accept specific examples of polluting gases
•
a renewable energy source
•
energy is free
•
does not pollute the atmosphere
•
no fuel is burnt
•
energy can be stored (in the water)
Page 47 of 66
disadvantages
accept unreliable energy source
•
only available in daylight hours
•
availability fluctuates
•
insufficient hours of sunlight in some countries
•
average low intensity in some countries
[11]
M11.
(a) Marks awarded for this answer will be determined by the Quality of Written
Communication (QWC) as well as the standard of the scientific response. Examiners
should also refer to the information in the Marking guidance, and apply a ‘best-fit’ approach
to the marking.
0 marks
No relevant content.
Level 1 (1-2 marks)
There is a brief description of at least one of the stages (pre-inoculation, inoculation, postinoculation).
Level 2 (3-4 marks)
There is a simple description of at least two stages and an explanation of at least one of
them.
Level 3 (5-6 marks)
There is a clear description of all three stages and an explanation of at least two of them.
Page 48 of 66
Examples of Biology points made in the response:
Pre-inoculation
•
Petri dish and agar sterilised before use
•
to kill unwanted bacteria
•
inoculating loop passed through flame / sterile swab
•
to sterilise / kill (other) bacteria
Inoculation
•
loop/swab used to spread/streak bacterium onto agar
Allow other correct methods, eg bacterial lawns
•
lid of Petri dish opened as little as possible
•
to prevent microbes from air entering
Post-inoculation
•
sealed with tape
•
to prevent microbes from air entering
•
incubate
•
to allow growth of bacteria
6
(b)
(i)
bacteria killed / destroyed
ignore fights / attacks / stops growth / got rid of
1
(ii)
Might be correct
largest area / space where no bacteria are growing
allow most bacteria killed
1
Might not be correct
(need more evidence as) D may be harmful to people / animals / surfaces
ignore ref to cost / dangerous or harmful unqualified
1
or may work differently with different bacteria
or disinfectants may be different concentrations
ignore different amounts of disinfectant unless reference to
different drop size
or may not last as long
ignore take longer to work
allow reference to anomalous result or not repeated
[9]
Page 49 of 66
M12.
Marks awarded for this answer will be determined by the Quality of Written
Communication (QWC) as well as the standard of the scientific response.
No relevant content.
0 marks
There is a brief explanation of at least two ways in which the
energy captured by the heather is transferred, which has little
clarity and detail. Credit may be awarded either for references
to general ways in which organisms transfer energy or to ways
in which specific organisms in the food web transfer energy.
Level 1 (1–2 marks)
There is some explanation of a range of the ways in which the
energy captured by the heather is transferred. Credit may be
awarded either for references to general ways in which
organisms transfer energy or to ways in which specific
organisms in the food web transfer energy.
Level 2 (3–4 marks)
There is a clear, balanced and detailed explanation of a large
variety of ways in which energy captured by the heather is
transferred Credit may be awarded either for references to
general ways in which organisms transfer energy or to ways
in which specific organisms in the food web transfer energy.
Level 3 (5–6 marks)
examples of biology points made in response
•
respiration releases energy (allow this point even if given for named organism) NB: to gain
full marks, candidates must gain this mark.
•
some energy lost in animals / named animal’s waste materials
•
some energy used in maintenance / repair (allow this point if given for named organism)
•
some energy used for movement (allow this point if given for named animal)
•
energy lost as heat to surroundings (allow this point if given for named organism)
•
some organisms die (rather than being eaten) (allow this point if given for named
organism)
•
reference to detritivores / microbes
[6]
M13.
(a) increases the voltage (across the cables)
or
decreases the current (through the cables)
1
Page 50 of 66
reducing energy losses (in cables)
accept heat for energy
do not accept electricity for energy
do not accept no energy loss
accept wires do not get as hot
or
increases efficiency of (electricity / energy) transmission
ignore reference to travel faster
1
(b)
Marks awarded for this answer will be determined by the Quality of Written
Communication (QWC) as well as the standard of the scientific response.
Examiners should also refer to the Marking Guidance, and apply a ‘best-fit’
approach to the marking.
0 marks
No relevant content
Level 1 (1-2 marks)
There is a brief description of one advantage or disadvantage of using
either overhead or underground cables.
Level 2 (3-4 marks)
There is a description of some of the advantages and / or disadvantages
for both overhead and underground cables, with a minimum of three
points made. There must be at least one point for each type of cable.
Level 3 (5-6 marks)
There is a clear and detailed description of the advantages and disadvantages
of overhead and underground cables, with a minimum of five points made.
At least one advantage and one disadvantage for each type of cable.
examples of the points made in the response
marks may be gained by linking an advantage for one type of cable
with a disadvantage for the other type of cable
eg
overhead cables are easy to repair = 1 mark
overhead cables are easier to repair = 1 mark
overhead cables are easier to repair than underground cables = 2
marks
Overhead
Advantages
•
(relatively) quick / easy to repair / maintain / access
easy to install is insufficient
do not accept easy to spot / see a fault
•
less expensive to install / repair / maintain
less expensive is insufficient
•
cables cooled by the air
accept thermal energy / heat removed by the air
•
air acts as electrical insulator
accept there is no need for electrical insulation (around the cables)
Page 51 of 66
•
can use thinner cables
difficult to reach is insufficient
land beneath cables can still be used is insufficient
Disadvantages
•
spoil the landscape
•
greater risk of (fatal) electric shock
•
damaged / affected by (severe) weather
accept specific examples eg high winds, ice
more maintenance is insufficient
•
hazard to low flying aircraft / helicopters
kites / fishing lines can touch them is insufficient
hazard to aircraft is insufficient
Underground
Advantages
•
cannot be seen
•
no hazard to aircraft / helicopters
•
unlikely to be / not damaged / affected by (severe) weather
less maintenance is insufficient
(normally) no / reduced shock hazard
installed in urban areas is insufficient
Disadvantages
•
repairs take longer / are more expensive
accept harder to repair / maintain
have to dig up for repairs is insufficient
•
(more) difficult to access (cables)
hard to locate (cables) is insufficient
faults hard to find is insufficient
•
(very) expensive to install
•
thicker cables required
•
need cooling systems
•
need layers of electrical insulation
•
land disruption (to lay cables)
accept damage to environment / habitat(s)
or
cannot use land either side of cable path
accept restricted land use
6
Page 52 of 66
(c)
examples of acceptable responses:
allow 1 mark for each correct point
•
closest to cables field from underground is stronger
•
field from overhead cables stronger after 5 metres
•
field from underground cables drops rapidly
•
field from overhead cables does not drop much until after 20 metres
accept values between 20 and 30 inclusive
•
overhead field drops to zero at / after 50 metres
•
underground field drops to zero at / after 30 metres
•
(strength of) field decreases with distance for both types of cable
if suitably amplified this may score both marks
2
(d)
ethical
1
[11]
M14.
(a)
alkanes
1
catalyst
1
substances must be in the order shown
(b)
many (ethenes/monomers)
1
bond/join together
1
allow ethenes / monomers bond / join together to form very large
molecules for 2 marks
Page 53 of 66
(c)
Marks awarded for this answer will be determined by the
Quality of Written Communication (QWC) as well as the
standard of the scientific response.
No relevant content.
0 marks
There is a brief description of a positive and a negative
environmental impact involved with one or more methods
used to reduce the amount of plastic bags sent to landfill.
Level 1 (1–2 marks)
There is some description of both positive and negative
environmental impacts involved with at least 2 methods
used to reduce the amount of plastic bags sent to landfill.
Level 2 (3–4 marks)
There is a clear, balanced and detailed description of both
a positive and a negative environmental impact of using
each of the 3 methods used to reduce the amount of plastic
bags sent to landfill.
Level 3 (5–6 marks)
examples of the chemistry points made in the response
reuse:
reuse means less bags used so:
positive environmental impact
•
saves raw materials / crude oil
•
saves energy
•
cuts down on CO2 emissions
•
less global warming
negative environmental impact
•
could cause litter
•
could still be sent to landfill
Page 54 of 66
recycle:
bags bought can be recycled so:
positive environmental impact
•
used to make new plastic bags / objects
•
saves raw materials / crude oil
•
saves energy compared to producing plastic bags
from crude oil
•
cuts down on CO2 emissions
•
less global warming
negative environmental impact
•
collection point sites cause an eyesore / litter problem
•
transportation to recycling plant releases carbon
dioxide / causes global warming
burn:
bags can be burned so:
positive environmental impact
•
could provide energy for heating buildings
•
could provide energy for generating electricity
negative environmental impact
•
increases CO2 emissions
•
increases global warming
•
could release toxic gases
does not conserve raw materials / crude oil
[10]
Page 55 of 66
M15.
(a)
any three from:
•
gas can be switched on (and off) quickly but nuclear cannot
gas has a short start-up time alone is insufficient
•
gas can be used to meet surges in demand
accept specific times from graph, anything from 1700 to 2200
•
gas can contribute to / meet the base load
•
nuclear provides base load
or
nuclear is used to generate all of the time
3
(b)
Marks awarded for this answer will be determined by the Quality of Written
Communication (QWC) as well as the standard of the scientific response.
Examiners should also refer to the information in the Marking guidance, and apply a
‘best-fit’ approach to the marking.
0 marks
No relevant content.
Level 1 (1-2 marks)
There is a brief description of one advantage or disadvantage of using either biogas
or wind
or
makes a conclusion with a reason.
Level 2 (3-4 marks)
There is a description of some advantages and / or disadvantages for biogas
and / or wind
or
there is a direct comparison between the two systems and at least one advantage /
disadvantage
or
a detailed evaluation of one system only with a conclusion.
Level 3 (5-6 marks)
There is a clear and detailed comparison of the two systems.
There must be a clear conclusion of which system would be best with at least one
comparative reason given for the choice made.
Page 56 of 66
Examples of the points made in the response
extra information
Biogas
•
renewable
•
energy resource is free
•
reliable energy source
accept works all of the time
•
does not depend on the weather
•
uses up (animal) waste products
•
concentrated energy source
•
cheaper (to buy and install)
accept once only
•
shorter payback-time (than wind)
•
adds carbon dioxide to the atmosphere
when waste burns it produces carbon dioxide is insufficient
•
contributes to the greenhouse effect
or
contributes to global warming
•
no transport cost for fuels
Wind turbine
•
renewable
•
energy resource is free
•
not reliable
•
depends on the weather / wind
•
will be times when not enough electricity generated for the farm’s needs
•
dilute energy source
•
longer payback-time (than biogas)
•
more expensive (to buy and install)
accept once only
•
does not produce any carbon dioxide
accept does not pollute air
accept pollutant gases for carbon dioxide
produces visual or noise pollution is insufficient
harmful gases is insufficient
6
[9]
Page 57 of 66
M16.
(a)
heat to vaporise (the crude oil)
do not accept cracking / burning
1
vapours condense
1
at different temperatures
allow they have different boiling points
1
(b)
(alkanes) are hydrocarbons or are compounds of hydrogen and carbon only
1
alkanes are saturated or have only (carbon-carbon) single bonds
accept have no (carbon-carbon) double bonds
accept general formula is CnH2n+2 for 2 marks
1
(c)
Marks awarded for this answer will be determined by the Quality of Written
Communication (QWC) as well as the standard of the scientific response.
0 marks
No relevant content.
Level 1 (1-2 marks)
There is a basic description of at least one advantage or one disadvantage of
extracting petroleum products from oil sands.
Level 2 (3-4 marks)
There is a clear description of an advantage and a disadvantage of extracting
petroleum products from oil sands.
Level 3 (5-6 marks)
There is a detailed description of both advantages and disadvantages of extracting
petroleum products from oil sands.
Page 58 of 66
Examples of the chemistry/environmental/economic/social points made in the
response
Advantages:
•
the oil sands are needed because crude oil is running out
•
this crude oil is needed because demand is increasing
•
the oil sands contain a large amount of crude oil
•
the oil sands could improve Canada’s economy
•
the oil sands provide employment for a lot of people
•
the trees / forest are used for wood products / fuel
Disadvantages:
•
destruction of environment / habitats
•
fewer trees / forests to absorb carbon dioxide
•
specified pollution, for example, visual, noise, atmospheric (including dust),
water (including river or drinking) with cause, e.g. gases / particulates from
burning diesel
•
large amounts of methane (natural gas) are used to provide energy
•
energy / fuel needed for cracking and fractional distillation
•
burning fuel releases carbon dioxide
•
crude oil / natural gas contains locked up carbon
•
crude oil is non-renewable
6
[11]
Page 59 of 66
E2.
(a)
(ii)
(b)
E3.
(i) The examiners had hoped that students would be well-versed in a definition of
‘sexual reproduction’. Unfortunately, this was not the case and there were only a
small number of very good answers which included reference to the fusion of
gametes or fertilisation. Instead, answers more often referred to the need for ‘two
parents’, ‘sexual intercourse’ or ‘producing a baby’, and no mark was awarded. A
significant number of students referred to gametes which ‘met’ or ‘mixed’, rather than
‘fused’, and these ideas were not credited.
Students fared better in this part, where many described the significance of the
‘genes’ of the two parents resulting in the characteristics of the zorse, and so gained
both marks. A common error was simply to rephrase the question and provide no
extra information, for example ‘it has the characteristics of the horse and zebra’. It
should be noted that acquisition of the second mark, in the mark scheme, was
dependent upon a sensible attempt at identifying what was responsible for the
characteristics.
Many students were able to use the diagram to help them to describe some of the early
stages of adult cell cloning, though the origin of the cells was not always given. Others
managed to go on to describe some or all of the later stages and gain more credit. A
common error was poor observation of the diagram which showed the nucleus of the skin
cell being transferred, thus many answers referred to the whole zorse skin cell being put
into the egg cell, rather than just the nucleus. Some confused students described this as
fertilisation, while others included sperm. Many students placed embryos into horses but
failed to point out the uterus and only a small minority included ideas about electric shock
treatment, often at the wrong stage. Students should be reminded that good quality QWC
skills will affect the mark they gain for their biological knowledge in these questions and it
was apparent that the majority paid scant attention to this. The lack of sentences, capital
letters, full stops and correct spellings meant that some students were penalised. Marks
were spread across the range from 0 to 6, however very few students reached the higher
level.
In this question students were assessed on both their scientific knowledge and ‘QWC’ - their
ability to use good English, organise information and use appropriate specialist terms. In most
cases the level of QWC matched their level of scientific knowledge.
Students were asked for three pieces of information about energy transfer from both the roof
and windows of a house: to name the processes of energy transfer, to suggest methods to
reduce the rate of energy transfer and to explain how the methods reduced the rate of energy
transfer. Most students made reference to both roof and windows, usually giving two correct
methods to reduce energy transfer to gain two marks at Level 1. To progress to Level 2,
students had to also mention at least one process and attempt to explain at least one of the
methods. The processes were often omitted or incorrect, limiting the marks to two. For Level 3,
a detailed description for both the roof and windows was required, to include a process of energy
transfer, a method to reduce it and an explanation of the method for each area of the house.
Students should be guided to read questions carefully and follow the instructions given. Where
processes were given they often demonstrated a poor understanding of conduction, convection
and radiation. Heat was often said to rise, rather than hot air. Air being a poor conductor, or air
being trapped in insulation were rarely mentioned. Few responses said that energy is transferred
through glass by conduction.
Page 60 of 66
E5.
A large proportion of students did not read the question carefully enough. These students
usually spotted the word ‘adaptations’ in the question and wrote all they knew about adaptations
to cold and dry habitats. Thus examiners often read through long accounts, filling all 19 lines and
beyond, of the various adaptations of polar bears to life in the Arctic and of cacti to life in the
desert (or ‘dessert’). Among this, as if by chance, students often happened to mention
camouflage and / or spines. The frequent linking of camouflage in polar bears to its ability to
‘avoid being seen by prey’, gained no credit. Students who were more focussed often gave
several different adaptations but lack of sufficient detail or explanation made it impossible to
move beyond Level 1. For ‘camouflage’ the detail required was that the animal’s coat colour
would match that of the surroundings, so that predators are less likely to see the animal.
Students are not expected to know the food chain of animals such as polar bears, so this
explanation linked to a polar bear was accepted. Similarly for the ‘spines on cacti’, it was
necessary for the student to explain that attempts by a consumer to eat the cactus would hurt
the consumer. To move into Level 2, students needed to refer to adaptations in both animals and
plants and to give a detailed description of one adaptation. It was very rare for students to give
answers at Level 3, which required details of at least two adaptations for both plants and animals
along with correct references to how this helps them avoid being eaten .
Venus fly-traps figured in many responses. There were many confused accounts of these plants
with references to their ‘mouths’ and ‘saliva’. The insects which they catch are not their
predators, nor are they ‘eaten’, so no credit could be given. It was evident that students, trying to
expand their answers to address the “many different ways” referred to in the question had vague
memories of the names of organisms, their adaptations and what might eat them, thus
examiners were treated to suggestions such as ‘mountain tigers preying upon penguins’ and
plants being ‘camouflaged to blend in with the background’.
Students should be aware that ‘bright colours’ or ‘warning colours’ do not in themselves protect
the animal or plant from being eaten. It is necessary for the potential consumer to have had
some unpleasant experience of the colouration and learned to associate the colour with that
experience.
E6.
In this question students were assessed on their ability to evaluate an investigation. They
were also assessed on QWC - their ability to use good English, organise information and use
appropriate specialist terms. Significant numbers of students lost at least one mark by not
observing the QWC criteria.
To attain level 3 (5-6 marks), students needed to include evidence supporting the newspaper’s
claim, evidence that did not support the claim and to give a reasoned conclusion. They were
also required to make an appropriate reference to the presence or absence of polyphenols in the
chocolate. A few Foundation Tier students did give Level 3 responses.
Most Foundation Tier students gave Level 1 or 2 responses. Many responses included at least
one piece of evidence supporting the claim and one piece of evidence not supporting the claim,
with many also attempting to give a conclusion. However, many students only argued their case
from one side so were limited to Level 1.
Generally the question was well attempted, but simply copying the text did not gain credit.
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E7.
(a)
(ii)
(b)
E8.
Only a third of the students were able to give suggestions in terms of evidence. Most
gave very confused answers about the wrong theory.
In this question students were assessed on their ability to both describe how the positions
of the continents had changed and to explain the processes that had brought about
change. They were also assessed on QWC - their ability to use good English, organise
information and use appropriate specialist terms. Significant numbers of students lost at
least one mark by not observing the QWC criteria. The majority of Foundation Tier
students gained one or two marks, but some did give Level 2 and Level 3 answers and the
question was generally well attempted. Students were usually able to describe the
movement of continents, but were not able to explain why this occurred. Tectonic plates
were generally well known, but the processes that caused movement of the plates were
often poorly explained.
(a)
(ii)
(b)
(i)
Although the specification clearly states that students ‘should know that
scientists once thought that the features of the Earth’s surface were the result of the
shrinking of the crust as the Earth cooled down following its formation’, a tiny
proportion of students could quote this statement. The vast majority ignored the
diagrams and gave descriptions in terms of tectonic plates. Some students
mentioned Lamarck, the Big Bang and weathering and erosion.
(i)
Few students appear to understand what geothermal energy is. Just over a tenth
of students did not attempt this question.
Most students that attempted this question simply described a hydroelectric system,
missing the point about this being a pumped storage hydroelectric system. Many
students thought that it was the energy or the electricity that was being pumped;
others thought that it was the pump that stored the energy. Almost a quarter of
students did not attempt this question.
This was the 6-mark Quality of Written Communication (QWC) question in which students
had to discuss the advantages and disadvantages of two proposals: building off-shore
wind turbines or laying a cable to connect to renewable resources in Iceland. The best
responses came from those who spent a couple of minutes making a grid to show the
pros and cons of each in note form. They then used these notes to construct a full
response. Most students could provide advantages and disadvantages for the wind
turbines, but rather fewer responses successfully referred to the link to Iceland. Some
students had clearly not read the question properly, and had failed to notice that the wind
turbines were off-shore. Their answers therefore related to the countryside being ruined
and land taken up with thousands of large turbines. There were many objections to the
underwater cable on the grounds that ‘electricity and water don’t mix’. Just under a tenth of
students failed to make an attempt at this question, however the majority wrote at length.
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E9.
In this question students were assessed on their ability to both describe differences between
the tree on its own and the trees growing in a forest and to give reasons for the differences. They
were also assessed on ‘QWC’ - their ability to use good English, organise information and use
appropriate specialist terms. Most students’ QWC was appropriate to the level of their scientific
response.
To attain Level 3 (5–6 marks) students needed to include descriptions of at least two differences
with correct explanations in terms of competition. Most students attained Level 2 (3–4 marks) by
giving at least one difference which they made a reasonable attempt to explain. A basic
description of a difference or explanation was all that was needed for Level 1 (1–2 marks). Some
students explained the differences, but could not attain Level 2 because they had not described
the differences as well.
The question was well attempted with most students organising their answers logically. Over
half the students were credited with three or more marks. Some students gave confused
descriptions of what the trees in the forest competed for, giving names of gases and water,
which were ignored. Many mentioned leaves being eaten by animals, which was also ignored.
E11.
(a) The quality of the written communication of many students was pleasing. Many good
descriptions of the procedures were seen and students had obviously been involved in
practical work involving microorganisms. References to ‘inoculating loops’ (though not
necessarily named as such) and ‘pressure cookers’ for sterilising, were seen. However
sterilising the surface of agar with a hot inoculating loop would not be an efficient sterilising
method. A few students suggested sterilisation of the loop after it had been used to collect
the bacteria, in order to ‘kill the bad bacteria’. Some students did not give reasons for the
steps they described and so limited their mark to Level 1. Lengthy descriptions of safety
precautions such as gloves, goggles and tying the hair back were not required. Common
omissions included the tape used for sealing the prepared plate or an instrument for
transferring the bacteria. Often the latter was done by being ‘picked up carefully by the
fingers’. Some students described practical work they had done, for example with
fingerprints or bacteria from doorknobs, but unfortunately they did not match the question
which was asked. However, it was possible to gain some marks for practical techniques
and explanations appropriate to the question. Some students were unfamiliar with the topic
and did no more than repeat the stem of the question.
(b)
(i)
Many students knew that the bacteria had been killed or destroyed. Answers which
described the disinfectant ‘fighting’ or ‘attacking’ the bacteria were insufficient.
Stopping the growth of the bacteria was ignored, since bacteria must have been
growing in that area before the disinfectant was added.
(ii)
Examiners were looking for the idea that the area around disinfectant D was the
largest space where no bacteria were growing. Indication that this was only ‘the
largest clear area’ was considered to be insufficient without qualification relating to
the numbers or growth of bacteria. Answers which said most bacteria were stopped
from growing were allowed in this part. The most common suggestion as to why the
student might not be correct, was that the disinfectant might be harmful to people or
animals or that it might work differently on other bacteria. The idea that the
disinfectant was ‘dangerous’ needed qualification as to what the danger might be to
gain the mark. The examiners were not surprised at the power of advertising, some
students suggesting that the disinfectant might ‘be too strong’ and so kill ‘good
bacteria’, too. A number of students gained a mark for pointing out that the
investigation needed to be repeated.
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E13.
(a) Few students scored marks here; there seems to be a general ignorance of the
function of transformers in the National Grid. Many students stated that its purpose was to
make the electricity travel faster along the cables.
(b)
This six-mark question included assessment of the Quality of Written Communication.
Very few students scored more than half marks.
(c)
Students seemed very confused by this question, and only the better students scored any
marks. Many students thought that the magnetic field was a way of transmitting electricity
over a distance. Many others misread the label on the x-axis and thought that it referred to
the length of the cable rather than the distance from the cable.
E15.
(a) Two thirds of the students failed to score any marks on this question. Many students
failed to gain marks due to the idea that this was the first day of generating electricity and
nuclear needed a long start-up time so gas would be used until nuclear was ready. This
misconception gave students little chance to gain any credit. Those who did score credit
usually recognised the idea that gas could be turned on quickly and / or could be used to
supply at peak demands. Many students thought that the gas power station provided gas
to the home.
(b)
E16.
Nearly all students attempted this question and most got some credit, usually for
comparing the costs of the two methods. Many students gave vague statements where
the science was weak and incomplete. Some of these students were the more able who
wrote eloquently but failed to gain credit because of phrases such as “eco-friendly”,
“environmentally friendly” or made statements which did not go far enough such as “cause
pollution”, “harmful”. Many students wrote about visual pollution, noise, harming birds,
smells on the farm, etc. In the future, they need to elaborate ideas, giving more exact
details. Most students made a choice and gave sensible reasons for that choice. The
more able students were able to compare the advantages and disadvantages of both
systems, and provide an overall conclusion at the end. Many students simply listed
advantages and disadvantages of the two methods and did not attempt to fully answer the
question by making a clear conclusion – as the question asked. Some students thought
that the animal waste was dead animals or animals that need to be killed as the energy
source. Other misconceptions included methane being non-renewable, the production of
carbon dioxide being an advantage (helping the farmer's plants grow better) and that the
major disadvantage of biogas was the smell. It was pleasing to see that more students
were planning their answer before starting it.
(a) The question was poorly answered. The main mark gained was for the fact that the
fractions or hydrocarbons have different boiling points. The explanation of the separating
into fractions was often confused and many responses lacked the detail to gain any
marks. The omission of any reference to vapours was common. Some students confused
processes and had a catalyst splitting up crude oil; slag falling to the bottom of the tower
and even filtering made an appearance.
(b)
The question was poorly answered. Knowledge that alkanes are hydrocarbons was the
most common mark, although a very small number of students included saturated for the
second marking point. Many students did not gain the mark because of contradictions
such as saturated compounds have carbon-carbon double bonds. The inclusion of the
general formula for alkanes was rare.
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(c)
Students have become more familiar with these longer QWC questions and most
students scored marks. Disadvantages were well described, possibly as they fitted in with
learning about finite resources and types of pollution. Advantages were harder to define as
it required using a combination of information from the graph, information in the text and
their own analytical powers. Despite this some good answers were seen. However, there
were several students who just simply copied out the question word for word without telling
us what was an advantage or a disadvantage.
Of the science points, the most common advantage was that this represented a large oil
reserve. However no credit was given for figures taken directly from the text without
explanation. Increased employment was another advantage,which better students related
to the economy of the area and Canada and sometimes to improved facilities and
infrastructure for local people.
For disadvantages, many students were able to list two or three forms of pollution with the
best descriptions linking deforestation to a reduction in biodiversity as well as contributing
to global warming by removal of photosynthesising trees. There was great concern for the
trees; usually because this would result in a lack of oxygen in the atmosphere. Only the
better students mentioned that crude oil is non-renewable or the large amounts of energy,
with resulting pollution, are needed to extract and processthe oil. There were some
common misconceptions, such as natural gas being carbon neutral because it was
‘natural’.
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