Download P7 Ideas in Context “Climate `fix` could deplete ozone”

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Questions produced by Oxfordshire Science Service
Suggested answers to these questions produced by Miss Whitehouse.
Selected questions copied from previous Twenty First Century Science
Exams that relate to the physics likely to be tested in this summer’s P7
and Ideas paper.
Suggested useful links for preparation
Further ideas for questions and preparation.
I hope you find this useful.
Prepare carefully and you will do well.
P7 Ideas in Context “Climate ‘fix’ could deplete ozone”
Taken from Module P2: Radiation and life
1. Which of the following gases are found in the Earth’s atmosphere: nitrogen, methane,
oxygen, carbon dioxide, water vapour, argon?
2. Which of the gases listed above are not greenhouse gases?
3. Explain what is meant by the greenhouse effect, using the terms correlation and cause
appropriately?
4. Explain why a correlation between a factor and an outcome does not necessarily mean that
one causes the other, and illustrate with an example.
5. Explain why a single study on climate change cannot produce convincing evidence for or
against a correlation.
6. Why is the ozone layer important to life on Earth?
7. Explain the chemical reactions involved in the ozone layer absorbing ultraviolet radiation.
8. What are the advantages and disadvantages of using a computer model to predict climate
change?
9. Describe three consequences of climate change and their effect on the environment.
10. What would be the positive impact on the environment if sulfate particles are used to cool
the planet?
11. What are the arguments against using sulfate particles to reduce the temperature of the
planet?
12. What evidence does the article use to support the idea that sulfate particles might help to
cool the planet?
13. Some people think that ‘ozone depletion’ is a naturally occurring phenomena and is part of
the life cycle of our planet. Do you agree? Give reasons for your answer.
14. Discuss next steps in developing the use of sulfate to cool the planet using the terms
‘technical feasibility’ and ‘values’.
Questions produced by Oxfordshire Science Centre.
Suggested answers on next page…
P7 Ideas in Context “Climate ‘fix’ could deplete ozone”
Taken from Module P2: Radiation and life
1. Which of the following gases are found in the Earth’s atmosphere: nitrogen, methane, oxygen,
carbon dioxide, water vapour, argon?
Nitrogen, oxygen, water vapour, carbon dioxide, methane
2. Which of the gases listed above are not greenhouse gases?
Nitrogen and oxygen
3. Explain what is meant by the greenhouse effect, using the terms correlation and cause
appropriately?
The greenhouse effect is the method by which the Earth is kept warmed. The cause of the
greenhouse effect is that the Earth’s atmosphere prevents some of the radiation from escaping back
out into space. There is a correlation between the amount of gases in the atmosphere and the
temperature on the Earth, the thicker the atmosphere the more radiation is prevented from leaving
the atmosphere.
4. Explain why a correlation between a factor and an outcome does not necessarily mean that one
causes the other, and illustrate with an example.
A correlation does not necessarily mean that the factor causes the outcome as it could be that the
two are linked not to each other but to something else. For example the sales of ice cream and the
amount of hay fever show a strong correlation, but it does not mean that ice cream CAUSES hay
fever.
5. Explain why a single study on climate change cannot produce convincing evidence for or against a
correlation.
One single study on climate change cannot produce enough evidence as it could be that the single
study is misleading, whereas looking at a whole range of studies would give a broader view on
climate change. Climate change cannot be indicated by one method alone.
6. Why is the ozone layer important to life on Earth?
The ozone layer is important to life on Earth as it is good at absoring a large proportion of the UV
radiation emitted by the Sun. This means that the UV radiation does not penetrate through the
atmosphere and as a result means the amount of cancer (caused by the UV radiation) is reduced.
7. Explain the chemical reactions involved in the ozone layer absorbing ultraviolet radiation.
When UV radiation is absorbed by the ozone layer it causes the ozone molecules to break down and
form both molecules of oxygen as well as free atoms of oxygen. It could also cause the oxygen
molecules to be broken down to form free oxygen atoms.
8. What are the advantages and disadvantages of using a computer model to predict climate
change?
Advantages:
Can look at how different scenarios will lead to differing outcomes and also how a small change
in one factor can affect the overall picture.
Allows governments to plan ahead for potential problems that they may face over a long period
of time.
Disadvantages:
Does not give detailed descriptions of how climate change will affect each individual area – it
can only give a broad overview.
The results are very much subject to the initial conditions which are prescribed by the
programmers.
There are aspects of the climate which scientists do not understand and hence cannot be
accounted for.
9. Describe three consequences of climate change and their effect on the environment.
1. Sea level rises – this will lead to people being displaced as well as farmland being lost.
2. Warmer temperatures – this will lead to some currently tropical diseases being spread further
around the world.
3. Food and water resources – water and food may become more of a premium, due to current
crops not being able to cope with the change to the climate.
10. What would be the positive impact on the environment if sulfate particles are used to cool the
planet?
The positive impact on the environment if sulfate particles were used to cool the planet is that some
of the solar radiation would not reach Earth in the first place, meaning that less radiation overall
would be trapped by the atmosphere – leading to less global warming.
11. What are the arguments against using sulfate particles to reduce the temperature of the planet?
The sulfate particles will provide a surface on which thee chlorine gases in polar clouds can become
activated this will result in causing chemical reactions that lead to the destruction of ozone molecules.
This could lead to as much as ¾ of the ozone layer above the Arctic being destroyed. In the Antarctic
it could delay the recovery of the ozone layer between by between 30-70 years.
12. What evidence does the article use to support the idea that sulfate particles might help to cool the
planet?
The evidence given that sulfate particles might help to cool the planet was that when the volcano at
Mount Pinatubo erupted in 1991 it emitted vast amounts of sulfur containing compounds which then
seemed to cool the planet significantly.
13. Some people think that ‘ozone depletion’ is a naturally occurring phenomena and is part of the life
cycle of our planet. Do you agree? Give reasons for your answer.
The evidence that volcanoes emit the sulfur-containing compound, which seem to lead to both
cooling the planet as well as ozone depleting suggests that it is a natural phenomena. However
increasing the amount of man-made sulfate particles in the atmosphere may change the balance that
nature currently has, as this is likely to cause other effects as well.
14. Discuss next steps in developing the use of sulfate to cool the planet using the terms ‘technical
feasibility’ and ‘values’.
The loss to the atmosphere due to emitting the sulfate particles, in particular the ozone layer, may
cause a large amount of damage as it may well cause the rates of skin cancer to increase, due to an
increase in the amount of UV radiation at the surface. There may also be more microwave radiation
on the surface. The increase in UV radiation on the surface may also result in crop failure, as UV
radiation could also damage plants and crops.
Technical feasibility of sulfate injection seems to be relatively easy to carry out, mostly involving
dropping or spraying particles into the atmosphere from height, however as it has not been attempted
then the amount and distribution of the sulfate particles would need to be investigated.
Many thanks to Miss Whitehouse for preparing these suggested answers.
Jan 07 Qu8
Jan 07 Qu10
Jan 08 Qu3
Jan 08 Qu4
Jan 09 Qu4
Jun 07 Qu4
Ideas in Context Preparation May 2010 Physics GCSE
Useful links
http://pubs.usgs.gov/pinatubo/self/index.html
background pinatubo - http://en.wikipedia.org/wiki/Mount_Pinatubo
the ozone layer and ozone hole - http://ateam.lbl.gov/coolsense/references/ozone.html
The ozone hole (animation of the development of the ozone hole) - http://www.theozonehole.com/
Oxfordshire Science Centre – guidance for teachers (some of these questions come from this source)
http://portal.oxfordshire.gov.uk/content/publicnet/other_sites/science/resources/Secondary/KS4Interventionreso
urces/Triple_ideas_in_context_2010.pdf
Comments from the Examiners’ Report
(Read it all at http://www.ocr.org.uk/download/rep_09/ocr_35359_rep_09_l_gcse_jun.pdf)
The questions on the pre-release material were not done well; many candidates did not seem well prepared
for this section.
Comments on Individual Questions
1 This question was based on the pre-release article. Part (a) and (b) were common with the foundation paper.
A surprising number of candidates were not well prepared to answer questions on the physics referred
to in the pre-release material.
AGD’s ideas
1. Revise the photon model of radiation – emission (from source), transmission (though e.g. the
atmosphere) and reflection / absorption (by e.g. sulphate particles or leaves).
2.
3.
4.
5.
6.
What is the composition of dry air?
Which other gas (present in very variable proportions) is present in the atmosphere?
Which of these gases are greenhouse gases?
Which are pollutants released as a result of human activity?
How is the ozone hole linked to the the greenhouse effect? Describe any correlation or causal link.
7. Where is the ozone layer?
8. What part of the em spectrum is absorbed by the ozone layer?
9. Draw a molecule of ozone?
10. What damages the ozone layer?
11. During which months is the antarctic ozone hole at its largest?
12. What effects does the ozone hole have on (a) climate, (b) wildlife, (c) people?