Download C1.7 - The John Warner School

Course
Subject
Topic
Pages
Science A
Chemistry
C1 7.1 Structure of the Earth
Pages 206-207
Learning objectives
Learning outcomes
Specification link-up
Kerboodle
Students should learn:
 the basic structure of the
Earth
 the relative size of each
layer of the Earth’s
structure
 where minerals and other
resources are found in the
Earth’s structure.
Most students should be able to:
 label the basic structure of the Earth
 describe the relative size of each layer of
the Earth’s structure
 state where minerals and other resources
are found in the Earth’s structure.
Some students should also be able to:
 describe how we discovered the Earth’s
structure.
The Earth consists of a core, mantle and
crust and is surrounded by the
atmosphere. [C1.7.1 a)]
Recognise that the Earth’s crust, the
atmosphere and the oceans are the only
source of minerals and other resources
that humans need. [C1.7]
Chapter map: Our
changing planet
Teacher notes: Our
changing planet
Support: Where does
it come from?
Lesson structure
Support, Extend and Practical notes
Starters
Citizenship – Write on the board: ‘How was the Earth made?’ Encourage the
students to list as many ideas as they can – scientific, religious and cultural.
Then hold a quick discussion about all of these ideas. Explain that scientists
have come up with a number of theories using the evidence they have observed
although no one can be absolutely certain if any of them are correct. (5 minutes)
Brainstorm – Ask the students to think about geography and rocks in science.
Ask them to complete a brainstorm about the structure of the Earth in the back of
their books. Support students by providing them with a framework for their
brainstorm. Extend students by asking them to consider the composition of the
atmosphere. Ask one student to be a scribe and write on the board. They could
pick students from the class to add ideas to the whole-class brainstorm.
(10 minutes)
Main
 It is important that the students recognise a diagram of the Earth and that
they can label its structure. Ask them to use secondary sources, e.g. the
internet (search for ‘Earth structure’ at www.bbc.co.uk) and the Student
Book, to make a poster about the Earth’s structure.
 To ensure that students include the relevant information, state that their
poster must include at least one diagram, one measurement and the key
terms ‘core’, ‘mantle’, ‘crust’ and ‘atmosphere’.
 For kinaesthetic and artistic students, a 3-D model of the Earth and its
structure could be made, although this may take a couple of lessons to be
completed fully.
 The students could use papier mâché to make the model of the Earth. Some
students may be allergic to wallpaper paste – cellulose paste can be
purchased that does not contain a fungicide. The shell should be cut in half
and then decorated to show the Earth and its layers. Small pieces of
coloured paper or card could be used to add information about the layers
and then stuck to the model. String or thread can then be attached, so the
model can be suspended, e.g. from the ceiling.
Plenaries
Label – Give the students a laminated diagram of the Earth’s structure. Supply a
paper towel and a washable pen. Ask the students to label as much as they can
remember on their diagram. Then show them a fully labelled image (which
should include a section of the Earth, depth, properties and materials) via a
projector or a photocopied sheet. Ask the students to count how many of their
labels were correct. (5 minutes)
Answers and questions – Give the students answers that are key to this topic.
They should put up their hand with a question that matches the answer. Some
answers could be ‘Earth’, ‘crust’, ‘mantle’, ‘core’, ‘iron’, ‘nickel’, ‘atmosphere’. You
could support students by asking them to work in small groups to come up with
questions. You could extend them by asking them to produce a ‘Foundation Tier’
and a ‘Higher Tier’ question, both of which should have the same answer.
Students should think about the choice of language in the questions. You may
wish to produce more expansive answers, which would allow students to write
questions that use a higher level of Bloom’s taxonomy, e.g. questions involving
evaluation or explanation. (10 minutes)
Support
You could support students by giving them a diagram of the
Earth’s structure and labels. They could then complete a cut and
stick to ensure that all the relevant information is correctly
positioned.
Extend
You could extend students by asking them to compare the
structure of the Earth with the structure of other planets in our
solar system. They could be encouraged to find out if other
planets also have layers and if their compositions are similar or
different.
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New AQA GCSE Science © Nelson Thornes Ltd 2011
1
Course
Subject
Topic
Pages
Science A
Chemistry
C1 7.2 The restless Earth
Pages 208-209
Learning objectives
Learning outcomes
Specification link-up
Students should learn:
 what tectonic plates are
 why tectonic plates move
 that earthquakes and
volcanic eruptions are
difficult to predict.
Most students should be able to:
 state that the outer layer (crust and the
upper part of the mantle) of the Earth
is made up of tectonic plates
 state why the tectonic plates move
 list what happens at plate boundaries
 explain why Wegener’s ideas on
continental drift were not generally
accepted in his time
 explain why earthquakes and volcanic
activity are difficult to predict.
Some students should also be
able to:
 explain in detail how convection currents
cause tectonic plates to move.
The Earth’s crust and the upper part of the mantle
are cracked into a number of large pieces (tectonic
plates). [C1.7.1 b)]
Convection currents within the Earth’s mantle
driven by heat released by natural radioactive
processes cause the plates to move at relative
speeds of a few centimetres per year. [C1.7.1 c)]
The movements can be sudden and disastrous.
Earthquakes and/or volcanic eruptions occur at the
boundaries between tectonic plates. [C1.7.1 d)]
Explain why Wegener’s theory of crustal
movement (continental drift) was not generally
accepted for many years. [C1.7]
Explain why scientists cannot accurately predict
when earthquakes and volcanic eruptions will
occur. [C1.7]
Kerboodle
Lesson structure
Support, Extend and Practical
notes
Starters
Pictionary – Ask for five volunteers. They are each given a key word (crust, atmosphere, mantle,
core, Earth). They should draw a picture: no noise, symbols, numbers or text are allowed; the image
should explain their key word to the class. The first student in the remainder of the class to guess the
word could win a prize. (5 minutes)
Card sort – Give the students cards with different theories about how the features on the Earth’s
surface were created. Start with religious viewpoints, e.g. Creationism, James Dwight Dana (The
Contracting Earth), Clarence Dutton (Isostacy), Geological Society of America (Mighty Creeping
Movements), Alfred Wegner (plate tectonics/continental drift) and finish with Alexander du Toit
(supporter of Wegner). Ask the students to sort them into date order, and guess the dates. You could
support students by giving them the century or decade the idea was published. You could extend
students by asking them to think about whether scientists definitely now know how features have
been created. (10 minutes)
Main
 The tectonic plates move on convection currents. Convection currents should have been studied
in KS3. However, students may benefit from seeing the convection current demonstration.
 This can be completed as a demonstration or a class practical. Pieces from a polystyrene tile can
be floated in larger beakers to model the tectonic plate movement. Discuss the limitations of this
model.
 Students could be encouraged to draw a diagram of the experiment and label it (e.g. beaker,
potassium manganate(vii), convection current, Bunsen burner) in blue. Then ask students to
relate this to the Earth, and label these in red (e.g. mantle, magma, heat spot, tectonic plates).
 Students need to know what happens at plate boundaries and the effects of natural disasters.
Show some images of plate boundaries and the destruction caused. Split the class into three
groups: one group researches volcanoes, another earthquakes and the third looks at prediction
and prevention of damage/loss of life.
 Each group should be supplied with video footage of natural disasters caused by earthquakes
and volcanoes. For example http://video.nationalgeographic.com. Search under ‘Natural
Disasters’. Students then use this information, coupled with textbooks, to write a revision page
for an imaginary textbook. The pages could be collected and selected ones photocopied and
given to each student to add to their notes.
 Students should appreciate how theories were developed and others disproved. Ask students to
imagine that they are Wegener and that they are going to attend an international conference for
scientists. They are to have a ‘slot’ to explain his new theory and explain why previous theories
were incorrect. Students should prepare a presentation that is about 3 minutes long.
Plenary
Lava lamps – Set up a lava lamp (this needs to be done at least 30 minutes before the end of the
lesson). Ask the students to look at the lava lamp and relate it to the lesson. You should extend
students by encouraging them to link the movement in the lava lamp with that which occurs in the
mantle of the Earth. You could support students by explaining the link to plate tectonics using
separate sentences and asking them to put them in order, working in pairs. (5 minutes)
Support
To support students you may wish to provide
a writing frame and a few websites for
students to use for their research into plate
boundaries.
Extend
To support students you may wish to provide
a writing frame and a few websites for
students to use for their research into plate
boundaries
Practical support
Convection currents
Equipment and materials required
Potassium manganate(vii) crystals (oxidising
agent and harmful), tweezers, large glass
beaker, cold water, Bunsen burner and safety
equipment, tripod and gauze, eye protection.
Details
Fill the beaker about 75 per cent with cold
water and put onto a tripod. With a set of
tweezers, add one potassium manganate(VII)
crystal to the bottom of the beaker. Put the
Bunsen burner under the beaker at the point
where the crystal is and heat on the blue
flame. The convection current should become
visible.
Safety: CLEAPSS Hazcard 81 Potassium
manganate(vii) – oxidising and harmful.
Handle carefully, as crystals will stain hands
and clothing.
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New AQA GCSE Science © Nelson Thornes Ltd 2011
2
Course
Subject
Topic
Pages
Science A
Chemistry
C1 7.3 The Earth’s
atmosphere in the past
Pages 210-211
Learning objectives
Learning outcomes
Specification link-up
Kerboodle
Students should learn:
 what the Earth’s
atmosphere was like in
the past
 how the mixture of gases
in the Earth’s atmosphere
was produced
 how oxygen was released
into the Earth’s
atmosphere.
Most students should be able
to:
 name the gases that probably
made up the Earth’s early
atmosphere
 list the major events that
formed today’s atmosphere
 state how oxygen entered the
Earth’s atmosphere.
Some students should also be
able to:
 explain a theory how the Earth
and its atmosphere were
formed.
During the first billion years of the Earth’s existence, there was
intense volcanic activity. This activity released the gases that
formed the early atmosphere and water vapour that
condensed to form the oceans. [C1.7.2 b)]
There are several theories about how the atmosphere was
formed. One theory suggests that during this period the Earth’s
atmosphere was mainly carbon dioxide and there would have
been little or no oxygen gas (like the atmospheres of Mars and
Venus today). There may also have been water vapour and
small proportions of methane and ammonia. [C1.7.2 c)]
Plants and algae produced the oxygen that is now in the
atmosphere. [C1.7.2 f)]
Explain and evaluate theories of the changes that have
occurred and are occurring in the Earth’s atmosphere. [C1.7]
Bump up your
grade: How did
the
atmosphere
get to be like
this?
Practical: How
did plants alter
the Earth’s
atmosphere?
Lesson structure
Support, Extend and Practical
notes
Starters
Chemical equations – Ask students to copy out the word equation for photosynthesis. Then set
them the task of completing the symbol equation. Ask students to explain why this equation is so
important. [This chemical reaction is believed to be responsible for putting oxygen into the Earth’s
atmosphere.] (5 minutes)
Grouping gases – Ask students to list as many gases as they can think of. Then put three titles on
the board: ‘element’, ‘compound’ and ‘mixture’. Encourage each student to go to the board and add
a gas from their list under the correct column heading. Look at the board and, if there are any
incorrect answers, tell the class how many mistakes there are. Then ask the students to see if they
can pick out the errors. You could support students by giving them cards with the name of a gas
and a simple particle model of the gas, rather then generating their own list. You could extend
them by asking them to write the chemical formula of each gas rather than its name. (10 minutes)
Main
 Give students a cartoon strip with five frames, with space to draw a picture and write notes.
Encourage students to use a textbook to detail five stages in the development of the
atmosphere. They should draw an image and write text to explain the atmosphere’s
composition and how it compares to other planets in our solar system.
 Separate the class into groups. Ask the groups to imagine that they are astronauts who have
landed on Earth in the different stages of atmospheric development. Ask them to design a
sketch or role-play to describe the surroundings. The activity could include a predictive stage in
which students consider the atmosphere in 500 years’ time.
 Not all students need be involved in the acting side but all students should collect research
about the development. This activity could encourage students to manage their own time and
group dynamics.
 Alternatively, you could give each student a role, e.g. chair person or resource manager, and
encourage the students to stick to their roles, allowing them to experience a different role in a
group compared to their preferred choice.
 Groups of students could act out their sketch. The rest of the class comments on
misconceptions in the sketch and then votes on the best. A prize could be awarded.
Plenaries
Ordering – Ask the students, in small groups, to arrange a series of key events in the creation of
the atmosphere in chronological order. Support them by allowing them access to the Student Book
to revise for one minute before they start the task. Extend students by asking them to try to
remember the formula of the gases in the atmosphere during the key events. (5 minutes)
Pass it on – Give each group of three students a piece of paper with the same question printed
on: ‘Where does oxygen come from?’ On the piece of paper, the first student starts the answer and
is timed for 30 seconds. Then ask the students to pass the paper to their left (even if they are midsentence) and give the next student one minute, then pass the paper again and give the final
student one-and-a-half minutes. Each student should read the answer so far, change anything that
they feel is incorrect and add further information they think they can. Then pick a few groups to
read their papers. (10 minutes)
Support
You could support students by supplying them with
images and text to explain the five stages of
development of the Earth’s atmosphere. They
could then cut and stick them into the appropriate
cartoon strip boxes.
Extend
You could extend students by asking them to
discover some examples of other theories and
ideas used to explain how the atmosphere
developed. For example, some scientists disagree
about the composition of the gases in the early
atmosphere, thinking that there was a greater mix
than in the currently scientifically accepted theory.
Encourage students to consider what evidence
has been collected to support the current main
scientifically-accepted theory. Students could think
about how this theory could still be refined or what
evidence would need to be collected for the theory
to be disproved.
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New AQA GCSE Science © Nelson Thornes Ltd 2011
3
Course
Subject
Topic
Pages
Science A
Chemistry
C1 7.4 Life on Earth
Pages 212-213
Learning objectives
Learning outcomes
Specification link-up
Students should learn:
 the reasons why there are
many theories for how life
began on Earth
 how ammonia,
hydrocarbons and
lightening could have been
the source of life on Earth.
[HT only]
Most students should be able to:
 explain why there are so many theories to how
life started on Earth
Some students should also be able to:
 explain how ammonia, hydrocarbons and lightening
could have started life on Earth. [HT only]
 evaluate the theories about how life started on
Earth. [HT only]
There are many theories as to how life was
formed billions of years ago. [C1.7.2 d)]
One theory as to how life was formed
involves the interaction between
hydrocarbons, ammonia and lightning.
[C1.7.2 e)] [HT only]
Describe why we do not know how life
was first formed. [C1.7] [HT only]
Kerboodle
Lesson structure
Support, Extend and Practical notes
Starters
Life in the universe – Ask the students to decide if they think that there is life
elsewhere in the Universe. Ask them to give and justify a rating out of 100, where 100
is definitely life elsewhere and 0 that there is only life on Earth. (5 minutes)
Have a think! – Ask students to consider how they think life could have started on
Earth. Ask for volunteers to share their thoughts. Manage the class discussion. You
could support students by providing them with some cards showing some
theories/religious ideas. They can choose which they think is most likely. You can
extend students by asking them to group the suggestions as ideas [e.g. religious
views, which are not backed up by scientific evidence] and theories [ideas backed up
by scientific evidence]. (10 minutes)
Main
 Students often have their own thoughts about how life started on Earth. However,
they have rarely considered that ideas for how life has started have changed over
time. Discuss with students why ideas change in science. This may be due to
technological developments, research being completed and information being
circulated.
 The Miller–Urey experiment was a radical experiment and its results have been
reanalysed many years later. Encourage students to work in small groups to write
a 2-minute radio news report to explain the importance of the experiment. You may
wish to record the report using a suitable piece of computer software. The best
recording could be used as a podcast on the school’s virtual learning platform as a
revision tool. [HT only]
 Ask students to make a timeline, showing some of the different theories and ideas
about how life started on the Earth. Their timelines should briefly outline the theory
and they should bullet point any evidence used to support it or persuade people to
accept it. They could also list any reasons/evidence that could be used to argue
that the theory or idea is not correct. Encourage students to include the Miller–Urey
experiment and the Murchison meteorite.
 You could encourage students to write an advert to try to persuade people that the
generally accepted theory for how life started on Earth is correct. Students could
work in their preferred learning styles and could make a billboard poster, if they are
visual learners, a radio advert if they are auditory learners and they could be filmed
doing a TV advert if they are kinaesthetic learners. Ask students to share their
adverts with the class. They could assess each other’s work. [HT only]
Plenaries
Life in the universe part two – Ask the students to reconsider and decide if they think
that there is life elsewhere in the Universe after studying this lesson. Again ask
students to give a rating and reflect on their new score and original score. If it has
changed, why? (5 minutes)
Summarise Miller–Urey – Ask the students to imagine that they are trying to advertise
the Miller–Urey theory for how life began on Earth. They should try and construct an
advertising strap line. Students could be supported by the whole class working
together to generate the strap line. Students could be extended by being told key
words that they must include. The best strap line could be given a prize. (10 minutes)
[HT only]
Support
 You could support students by giving them short
bulleted printouts of the main points about the different
theories about how life on Earth began. They could
then order them and stick them onto their time line.
Other information, such as diagrams, could be
supplied, which students could also transpose onto
their work.
 Students often struggle to understand how a primordial
soup became a life form. Scientists are also trying to
find out how this occurred and they are trying to start
life from a mixture of chemicals. Theories range from
lightening striking the primordial soup to dormant life
forms from a meteorite starting life when they hit the
surface of the early Earth. It is worth stressing to
students that no one currently knows the answer. The
idea of a missing part of the theory can be
demonstrated by mixing a ground up vitamin tablet with
protein powder and water. This has all of the chemicals
needed for life but the mixture does not come into life.
Extend
Students could be extended by being asked to suggest how
scientists could try to find out if life existed elsewhere in the
universe (SETI, study of meteorite, space probes).
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New AQA GCSE Science © Nelson Thornes Ltd 2011
4
Course
Subject
Topic
Pages
Science A
Chemistry
C1 7.5 Gases in the
atmosphere
Pages 214-215
Learning objectives
Learning outcomes
Specification link-up
Students should learn:
 the sinks for the majority
of the carbon dioxide from
the early atmosphere
 the main gases in the
current atmosphere the
percentage composition of
the current atmosphere
 how the gases in the air
can be separated. [HT
only]
Most students should be able to:
 list the main gases in the
atmosphere and the
approximate proportions of
gases in the atmosphere
 explain how carbon dioxide was
removed from the Earth’s
atmosphere.
Some students should also be
able to:
 explain how air can be
separated by fractional
distillation [HT only]
 state some uses of the products
of the fractional distillation of air.
[HT only]
For 200 million years, the proportions of different gases
in the atmosphere have been much the same as they
are today: about four-fifths (80%) nitrogen, about onefifth 20% oxygen, small proportions of various other
gases, including carbon dioxide, water vapour and noble
gases. [C1.7.2 a)]
Most of the carbon from the carbon dioxide in the air
gradually became locked up in sedimentary rocks as
carbonates and fossil fuels. [C1.7.2 g)]
Air is a mixture of gases with different boiling points and
can be fractionally distilled to provide a source of raw
materials used in a variety of industrial process. [C1.7.2 j)
[HT only]
Explain and evaluate theories of the changes that have
occurred and are occurring in the Earth’s atmosphere.
[C1.7]
Controlled Assessment: SA4.2 Assess and manage
risks when carrying out practical work. [SA4.2.1 a) b)]
Kerboodle
Lesson structure
Support, Extend and Practical
notes
Starters
Reflection – Give the students an A4 sheet of paper and ask them to make three columns. The first
should be headed with ‘what I already know’, then ‘what I want to know’ and finally ‘what I know
now’. Ask the students to consider the title of the double-page spread and complete the first two
columns with bullet points of information. (5 minutes)
Pie chart – Ask the students to estimate the percentage of each gas in the current atmosphere. This
should bring out any misconceptions that oxygen is the predominant gas in the atmosphere. Then
give the actual percentages so they can see how close they were. Encourage students to consider
the way this data could be displayed scientifically (table, bar chart or pie chart). Support students by
only asking them to complete a table of gas percentages, then represent this data in a bar chart.
Extend students by asking them to present the data using a pie chart. (10 minutes)
Main
 After a brief explanation about the movement of carbon dioxide from the early atmosphere into
rocks, students could test seashells to show that they contain carbonates. See ‘Practical support’
for more detail. Encourage students to reflect on the work completed in C1.2 and to use this
information to help them suggest a method. You could extend students’ understanding of
Controlled assessment by asking them to write a full risk assessment for their chosen method.
 The percentage composition of gases in the Earth’s atmosphere has changed over time but has
remained relatively constant in the last 200 million years. Ask students to imagine that they are
Earth and to write a creative story about how its ‘clothes’ (its atmosphere) has changed and why.
 The class could be split into three groups. Students in the first write the beginning of the story,
another group writes the middle and the final group writes the end. In order to complete this last
suggestion, a link sentence from each section needs to be provided to the groups so they know
where/how to start and/or finish their part of the story.
 Ask students taking the Higher Tier paper to make a flow chart to explain how air can be
separated. On their flow chart they should include details of the uses for each of the gases. The
RSC Industrial Chemistry series has a short video of this process, which you could play to the
students before they complete this task. You should link the fractional distillation of air to the
process used to separate crude oil (C1 4.2). [HT only]
Plenaries
Guess what – Ask the students to break off into pairs. Give each pair a pack of cards with separate
key words per card, e.g. oxygen, nitrogen, air, gas, carbon dioxide, photosynthesis, argon, fractional
distillation. The students should take it in turns to pick a card and look at the key term. They should
explain it to their partner without using the key word and the other student should guess the word.
You could support students by giving them the explanation to read out and then work together to
match it up to the key word. You could extend them by asking them to mime the key word rather than
describe it. (5 minutes)
Reflection part two – Ask the students to return to their A4 table. Ask them to add information to the
last column, ‘what I now know’, that isn’t included in the middle column. They should also correct any
misconceptions from the middle column and ask for help if they have not found out some information
that they wanted. (10 minutes)
Support
You could support students by providing
them with discrete sentences, which they
could use to generate the story about the
changing Earth’s atmosphere. Flow chart
boxes could be provided and information
given for students to cut and stick directly
onto the diagram.
Extend
You could extend students by asking them to
find out what scientists predict will happen to
the composition of the Earth’s atmosphere. It
is important that the students list their
sources. In the next lesson the information
can be compared and students can consider
whether bias has crept into the evidence
gathered.
Practical support
Investigating sea shells
Equipment and materials required
Sea shells (e.g. cockle, oyster), pestle and
mortar, spatula, hydrochloric acid (2 mol/dm3)
– irritant, 2 × dropping pipettes, boiling tube,
bung with a hole in the centre fitted with a
delivery tube, test tube, test tube rack,
limewater – irritant, eye protection
Details
Students can plot their own investigation to
see which type of shell contains the highest
percentage of carbonate mineral. The same
mass of crushed shell could be added to
excess dilute hydrochloric acid. Any
remaining sediment can be filtered off,
washed and left to dry, then re-weighed. You
can show that the gas liberated is carbon
dioxide using limewater. Check the students’
plans, including risk assessment, before
allowing any practical work to commence.
Safety: CLEAPSS Hazcard 47A Hydrochloric
acid – corrosive. CLEAPSS Hazcard 18
Limewater – irritant.
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New AQA GCSE Science © Nelson Thornes Ltd 2011
5
Course
Subject
Topic
Pages
Science A
Chemistry
C1 7.6 Carbon dioxide in the
atmosphere
Pages 216-217
Learning
objectives
Learning outcomes
Specification link-up
Kerboodle
Students should
learn:
 that carbon
dioxide moves in
and out of the
atmosphere
 that the amount
of carbon
dioxide is
increasing in the
atmosphere.
Most students should be able to:
 describe how carbon dioxide moves
into and out of the atmosphere
 state that burning fossil fuels has
increased the amount of carbon dioxide
in the atmosphere and describe why
this could cause problems.
Some students should also be able to:
 explain why there is a general trend
that the amount of carbon dioxide in
the air is increasing and evaluate the
possible consequences.
The oceans also act as a reservoir
for carbon dioxide but increased
amounts of carbon dioxide absorbed
by the oceans has an impact on the
marine environment. [C1.7.2 h)]
Nowadays the release of carbon
dioxide by burning fossil fuels
increases the level of carbon dioxide
in the atmosphere. [C1.7.2 i)]
Explain and evaluate the effects of
human activities on the atmosphere.
[C1.7]
WebQuest: Capturing carbon
Extension: What’s the link?
Interactive activity: Our changing planet
Revision podcast: The development of
the Earth’s atmosphere
Test yourself: Our changing planet
On your marks: The early atmosphere
Examination-style questions: Our
changing planet
Answers to examination-style
questions: Our changing planet
Lesson structure
Support, Extend and Practical notes
Starters
Demonstration – If solid carbon dioxide can be obtained, e.g. from a spare black carbon
dioxide fire extinguisher, put it into water and dry ice will be created. Be careful not to handle
the solid for too long or burns will be caused. Tweezers should be used to manipulate it.
Students can then put their hands briefly into the water (as long as they do not touch the
solid) and it will feel really cold. Ask the students to suggest what is happening. [The solid
carbon dioxide is boiling in the water.] (5 minutes)
Describe – Supply carbon dioxide gas in a gas jar to each table. Ask the students to
describe its physical appearance [colourless, transparent gas]. You could support students
by giving them a list of words on the board [colourless, coloured, transparent, opaque, gas,
liquid, solid] and they would have to choose from the list. You could extend students by
asking them to explain the laboratory test for carbon dioxide (links to C1 2.2). Ask students to
discuss their ideas in small groups and then manage whole-class feedback. (10 minutes)
Main
 The carbon cycle is a network of different reactions, which remove carbon from, or add it
into, the atmosphere. However, in C1 students are only required to understand that
carbon dioxide sinks include the oceans and sedimentary rocks and fossil fuels.
Students need to know that burning fossil fuels releases carbon dioxide and that heating
the oceans reduces the amount of carbon dioxide that they can absorb. They should also
be aware that when carbon dioxide is absorbed, the pH of the oceans is reduced.
 Carbon dioxide is produced as a product of respiration. You may wish to measure the
amount of carbon dioxide in air and contrast this to exhaled air. See ‘Practical support’
for more detail.
 To demonstrate the effect on the pH of water when carbon dioxide is dissolved, blow
carbon dioxide through a mixture of water and universal indicator. See ‘Practical support’
for more detail. Ask students to suggest what affect this may have on ecosystems [it
changes the species that can live in an area].
 Give students a graph that shows the percentage of carbon dioxide in the atmosphere
over the last 300 years. Ask students to state the trend [carbon dioxide levels were
stable until about 1850, then the levels increased, and the rate of increase is
accelerating]. Students should then be encouraged to explain the trend, thinking about
the use of fossil fuels.
Plenaries
Agree? – Ask for a volunteer to stand in the centre of the classroom. The volunteer should
make a statement about the content of the lesson (it could be correct or deliberately
incorrect), e.g. ‘carbon can be found in rocks’. The rest of the class decides how much they
agree with this statement. The more they agree, the closer they should stand to the person
who spoke. Then ask a few students why they are positioned as they are and feedback
whether the statement is correct. Ask all the students to sit down and for another volunteer to
repeat the idea. (5 minutes)
Key reminders – Ask students to copy out the key points onto a flash card. On the other
side, draw an image that will help them remember/represent the key point. Students could be
supported by being supplied with the diagrams, which they should match to the key point.
Students can be extended by representing the first key point with balanced symbol equations
showing the hydrolysis of carbon dioxide and photosynthesis. (10 minutes)
Support
 You could support students by supplying key
words on the board to help them follow what
happens to carbon dioxide in the natural course
of events. Alternatively, the exercise could be
turned into a ‘cut-and-stick’ activity.
 Show students some posters from environmental
charities such as Greenpeace and the WWF. Ask
students to design a similar poster to explain how
burning fossil fuels could affect marine
environments.
Extend
You could extend students by asking them to suggest
or research some ways in which the amount of
carbon dioxide in the atmosphere could be reduced
(e.g. carbon capture schemes).
Practical support
Measuring carbon dioxide
Equipment and materials required
Carbon dioxide probe, data logger, lung volume bags.
Details
Use the carbon dioxide probe attached to a data
logger to record the concentration of carbon dioxide
in the air. Exhale into a lung volume bag and then put
the probe into the bag and measure the
concentration of carbon dioxide in exhaled air.
Acidification of water
Equipment and materials required
Carbon dioxide cylinder with regulator, rubber tube,
250 cm3 beaker, universal indicator solution, distilled
water.
Details
Half-fill the beaker with distilled water. Put a few
drops of universal indictor into the water. Connect the
rubber tube to the carbon dioxide cylinder and put the
open end into the water. Turn the gas on, so that the
flow rate is about one bubble per second. Observe
the colour change of the universal indicator as the
water becomes acidified.
Safety: CLEAPSS Hazcard 32 Universal indicator –
highly flammable and harmful.
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New AQA GCSE Science © Nelson Thornes Ltd 2011
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