The document provides instructions for 4 hands-on activities to teach students about carbon dioxide (CO2) by having them create models of the CO2 molecule, conduct experiments showing that CO2 is colorless, acidic, and acts as a fire extinguisher, and observe the phase changes of solid CO2 (dry ice) as it sublimates into a gas. The activities aim to increase students' interest in science, teach them about the properties of CO2, and concepts around reducing CO2 emissions to mitigate climate change.

1. Do I know you CO2?
Teacher´s manual for the development of
activities related to the project:
Promotion of scientific culture and innovation in
the population of the Merindad del Río Ubierna
Municipality in collaboration with CIUDEN
Fundación Ciudad de la Energía

2. Teacher´s notes:
Objectives:
The activities in this document have been designed to
awaken the interest of children in science, and more
specifically in CO2 and climate change.
Through these funny activities, students are
introduced to the properties of CO2, and to concepts
of reducing CO2 emissions to curb the greenhouse
effect through small changes in our daily lives.
Furthermore, students will learn how CO2 geological
storage works.
Materials:
The activities can be easily adapted by
teachers to suit groups of different ages.
The materials used should all be easy and
cheap to buy.
Each activity is scheduled to last for approx.
55 minutes, although this will vary
depending on the age and ability of the
students involved.
Classroom arrangement:
All the activities are based on the poster exposition called “Discover CO2 with us” developed by Ciuden´s “Ene” National Museum of Energy. It is
recommended that you decorate the classroom with the posters from the exposition and keep them visible during the development of the
activities. They will be a support for the teacher and will encourage the visual memory of the children.
For each experiment, it is recommended that the children wear a lab coat, which they can make themselves with a white plastic bag (see annex).
In some of the experiments, the teacher will be responsible for handling the materials which could be dangerous for the children (candles, dry
ice, etc). It will be the teacher´s responsibility to define which experiments are suitable for the age and experience of their students
There are warnings for the compulsory use of protective equipment such as eye goggles, gloves and tongs throughout the document.
Fundación Ciudad de la Energía

3. Activity 1
Discovering CO2
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4. Activity 1: Discovering CO2
Objective: Discovering the CO2 molecule and its activity in the planet
CO2 is an invisible gas. It is what we exhale, what plants use for breathing during the day, and the gas which is
present in Coca-Cola and other fizzy drinks.
CO2 gas is made up of one carbon atom and two oxygen atoms. Atoms are like really tiny balls - so tiny that they are
impossible to see using a microscope! But we will make a large model of a CO2 molecule using plastic balls and
toothpicks…
1.1: Model of a CO2 Molecule
3 plastic foam balls (2x 5cm & 1x6 cm),
toothpicks, paint, permanent marker
Development:
Paint two plastic foam balls (like ping pong balls) one colour and one slightly bigger ball
another colour. Only use a small amount of paint to make sure the ‘atoms’ dry quickly.
For painting, we can poke them with a toothpick and stick them in a lump of plasticine
to create a stand while they dry.
CO2 is made up of one carbon atom and two oxygen atoms.
Draw the letter ‘O’ on the small balls and the letter ‘C’ on the bigger ball. On the C ball
we can draw a smiley face on the back!
We will connect the balls with toothpicks leaving a centimeter or so of the toothpick
(or bond) in view, the two small balls should be on each side and the big one in the
middle. We can use a drop of glue if needed.
Now we have a CO2 molecule. If we hang all the molecules from the ceiling at different
heights using transparent thread, we can see how they move with the wind.
Fundación Ciudad de la Energía

5. Activity 1: Discovering CO2
Objective: Discovering the CO2 molecule and how it is created
Materials:
1.2: The
Cardboard with the letters “C” and “O” (“O” boards should
be half the size of the “C” boards), music player
Classroom arrangement:
In a large classroom or gym, draw a
chimney (or a chalk circle to
symbolise a chimney) in the corner.
CO2 Molecule Game
Explanation:
When fossil fuels are burnt in power stations,
carbon atoms are released from the chimney
and the oxygen atoms present in the air catch
carbon to form CO2.
Activity:
Explain to students that they are going to turn into atoms. Some will be carbon atoms and
others oxygen ones. Hand out the ‘C ‘and ‘O’ boards to the students making sure there is always
at least one extra atom - these participants will be eliminated from the game because they
won´t be able to form CO2 molecules.
In the beginning, “C” students will be placed in the chimney/stack and the “O” students will be
all around the classroom. When the music starts, all the “C” students will start running around
the room (being careful not to crash!)
The idea is for all the “C” atoms to be moving chaotically while the music is being played.
When the music stops, they shall form CO2 molecules by holding hands with the “O” atoms as in
the picture example above.
The children that aren´t able to form correct CO2 molecules will be out.
The game continues with further rounds, but at every round the students boards are changed to
make sure there is always one or two extra atoms who won´t be able to form CO2 molecules.
The game continues until only three children are left - they win the game.

6. Activity 2
CO2 Experiments I
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7. Activity 2 Discovering CO2
Objective: Learning the properties of CO2
2.1: Fireman for a day I
Materials:
Bowl
Sodium bicarbonate
Vinegar
Candles
Lighter
Classroom arrangement:
Students are divided in to groups. A lab-coat should
be worn for this activity (see appendix 1). Each
group will have their own set of materials for the
experiment (except the lighter which will be kept by
the teacher).
WARNING:
Beware of fire! This experiment will need to be
adapted to a simple demonstration for younger
children.
Only a responsible adult should be allowed to
light candles and students must always be
monitored when working near lit candles.
Activity:
Put some bicarbonate in a bowl. Place some candles
on the bicarbonate and light the candles. Next pour
vinegar onto the bicarbonate, CO2 will be generated
that should extinguish the flames on the candles...
CO2 is a great fire extinguisher!
Scientific Explanation
Once you mix vinegar with bicarbonate, CO2 is
generated. CO2 displaces the oxygen. It is
impossible to have fire if there is no oxygen this is why the candle flame gets extinguished!

8. Activity 2 Discovering CO2
Objective: Learning the properties of CO2
2.1: Fireman for a day II
Classroom arrangement:
Students are divided in to groups. A lab-coat should
be worn for this activity (see appendix 1). Each
group will have their own set of materials for the
experiment.
Materials:
Tea bag
Sodium bicarbonate (bicarbonate soda)
Vinegar
Flask (a half-litre plastic bottle is ok too)
WARNING: This experiment can be messy!
Activity:
Pour a small amount of vinegar into a flask or a half
litre plastic bottle. Carefully open and fill the tea bag
with the bicarbonate soda, tying it tightly with the
thread of the teabag.
Add the teabag to the flask of vinegar - the
extinguisher will start bubbling and the CO2 will rise
out of the bottle like a real fire extinguisher. (To get
more bubbling add more vinegar). You have made
our own fire extinguisher!
Scientific Explanation
When you mix vinegar and bicarbonate, a chemical reaction takes
place and CO2 is generated, creating many bubbles. The CO2
displaces oxygen. It is impossible to have fire if there is no oxygen that is why CO2 is used to make real extinguishers.

9. Activity 2 Discovering CO2
Objective: Learning the properties of CO2
Classroom arrangement:
Students are divided in to groups. A lab-coat should
be worn for this activity (see appendix 1). Each
group will have their own set of materials for the
experiment (except the lighter which will be kept by
the teacher).
WARNING:
Beware of fire! This experiment will need to be
adapted to a simple demonstration for younger
children.
Only a responsible adult should be allowed to
light candles and students must always be
monitored when working with the lit candles.
Activity:
Half fill the flask or bottle with vinegar. Add a teaspoon
of bicarbonate and the mixture will start bubbling (but
less than with the previous experiment). Emphasise to
students that the CO2 is there, even though it is
invisible.
In order to prove it, they can hold the bottle close to a
lit candle. Hold the bottle/ flask close to the candle like
in the picture opposite – making sure that the liquid
remains in the bottle.
As the invisible CO2 moves little by little out of the
bottle. The candle will go out magically.
You have just made another home-made extinguisher!
Materials:
Candles
Sodium bicarbonate
Vinegar
Flask (a half-litre plastic bottle is ok too)
Scientific Explanation
When you mix vinegar and bicarbonate, a chemical reaction takes
place and CO2 is created. By holding the neck of the bottle next to
the candle, the CO2 present in the upper part of the mixture will fall
smoothly over the flame, putting out the candle.
CO2 is heavier than air, so it tends to fall.

10. Activity 3
CO2 Experiments II
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11. Activity 3 CO2 Experiments II
Objective: Learning the properties of CO2 - CO2 is invisible and denser than air
3.1: Bubble Leak
Classroom arrangement:
Students are divided in to groups. A lab-coat should
be worn for this activity (see appendix 1). Each
group will have their own set of materials for the
experiment.
Materials:
Sodium bicarbonate
Vinegar
Soap-bubbles
5 litre water container with its upper part cut, in
order to have a transparent and broad container
Activity:
Pour vinegar up to 1cm height from the bottom in a
high, big and transparent container. Then, spread
bicarbonate all over the bottom of the container.
This reaction will generate CO2. It will start bubbling.
Once you try to make soap-bubbles in the container,
you´ll see that they don´t reach the bottom, CO2
pushes them up and towards the walls of the
container.
CO2 might be invisible, but it is there!
Scientific Explanation
The CO2 is filling the container little by little. When the soap-bubbles
fall over the CO2, CO2 displaces them sideways, so they don´t reach
to the bottom.

12. Activity 3 CO2 Experiments II
Objective: Learning the properties of CO2 - CO2 dissolves into water and is acidic
3.2: Magic CO2lours
Materials:
Lombardy cabbage
Flask or a half-litre water bottle
Mineral water
Sodium bicarbonate
Straw
Other acid and base (alkali)substances (eg. lemon, milk,
vinegar).
Preparation:
Boil some Lombardy (red) Cabbage leaves 10
minutes prior to the experiment. Drain the water
the cabbage was boiling in into a flask – it will
be a blue coloured liquid. The liquid (or solution)
is an excellent pH indicator. Leave the solution to
chill.
Activity:
Fill ¼ of the flask with mineral water and add a
couple of spoonfuls of the blue solution. If the water
is too dark, it must be diluted until it becomes
transparent and a violet colour.
The teacher should add a pinch of bicarbonate to the
water. It is important to add only a really small
amount or it will become difficult to see the effect.
Mix the solution until it turns greenish blue.
Put some straws in the container and 2-3 people
have to blow to make bubbles in the water. After
some minutes, the water will change back to a violet
colour again.
Scientific Explanation
The water from the Lombardy Cabbage is a pH indicator. When you
blow air through the straw, CO2 is introduced to the solution. The
CO2 is dissolved in water and makes it more acid, this is why the
water becomes blue. This is how we know CO2 is acidic.
Try the same experiment with other acid substances such as lemon juice or vinegar, which will turn the water different shades of
blue, and base (alkali) substances, such as milk or ammonia, which turn it green.

13. Activity 3 CO2 Experiments II
Objective: Learning the properties of CO2 - CO2 is a gas and it tends to expand!
3.3: The magic balloon
Materials:
Vinegar
Sodium bicarbonate
A flask or a half-litre water bottle
Balloons
A funnel.
Activity:
Fill the bottom of the flask/bottle with approx. 1cm
of vinegar. Blow up and then deflate the balloon to
soften it.
Pour a couple of spoonfuls of bicarbonate in the
balloon – use a funnel to make it easier. Fit the
balloon around the bottleneck and then let the
bicarbonate fall into the container.
You will see the balloon swelling as if by magic!
Classroom arrangement:
Students are divided in to groups. A lab-coat should be worn for this activity
(see appendix 1). Each group will have their own set of materials for the
experiment.
Scientific Explanation
When you mix vinegar and bicarbonate, a chemical reaction
takes place and CO2 is created. The CO2 is a gas and it will tend
to fill all the available space, so it will escape from the bottle
and fill the balloon.

14. Activity 4
CO2 Experiments III
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15. Activity 4 CO2 Experiments III
Objective: Learning the properties of CO2- CO2 changes from a solid state to a gas without being a liquid.
4.1: Mystic Mist
Materials:
Big bowl
3 litres of hot water (or enough to fill the bowl)
Dry-ice (pellets or small-cubes)
Thermal gloves
Plastic tongs.
Preparation:
Dry-ice is easy to buy on the internet. 5kgs is
enough for the development of this activity with
25 children.
Activity:
Pour 3 litres of hot water into a big bowl, and then add ¼ kg of small
bits of dry ice using thermal gloves and tongs.
The hotter the water, the more spectacular the effect, but be careful
or you will get burned!
The mist generated will spread all around the room. To create more
mist, add more dry ice.
Scientific Explanation
CO2 has a special skill – it can change from a solid (dry ice) to a gas
without becoming a liquid. This skill or ‘property’ is called
sublimation. When CO2sublimates a mystic mist is generated!
WARNING: Dry ice is CO2 in a solid
state and it is VERY cold -78ºC! So
cold that it can burn! You need
thermal gloves and tongs to handle it
and avoid direct contact with the
skin. Dry ice should only be handled
by responsible adults.

16. Activity 4 CO2 Experiments III
Objective: Learning the properties of CO2- CO2 changes from a solid state to a gas without being a liquid.
4.2: Huge Bubbles
Materials:
A big circular bowl
Warm water
Dry ice
A plastic cup
Dishwater detergent
Wide and flat string - 2 times the length of the bowl diameter.
Classroom Arrangement:
Students are divided in to groups. A lab-coat
should be worn for this activity (see appendix 1).
Children are allowed to try making bubbles, but
they should not handle the dry ice.
Scientific Explanation
CO2 has the property of changing from a solid to a
gas without being a liquid, that is to say, it
sublimates. During this process, it tends to fill all
the available space - swelling the soap bubble.
Activity:
Pour warm water into the bowl and some dry ice bits. The water will start bubbling and
generating a light mist.
Fill a plastic cup with ¼ detergent and ¼ with water and mix it together.
You are going to spread the mixture across the bowl. Immerse the string in the plastic
cup with the mixture. Hold the string tightly, and move it carefully from side to side over
the edge of the bowl, a bubble will be generated, covering the bowl. If you achieve that,
the bubble will grow due to the effect of the released CO2 once dry ice is sublimated.
Eventually it will explode creating a spectacular cascade!
WARNING: Dry ice is
CO2 in a solid state and
it is VERY cold -78ºC!
So cold that it can
burn! You need thermal
gloves and tongs to
handle it and avoid
direct contact with the
skin. Dry ice should
only be handled by
responsible adults.

17. Activity 4 CO2 Experiments III
Objective: Learning the properties of CO2- CO2 changes from a solid state to a gas without being a liquid.
4.3: Bubble cascade
Materials:
Half litre of water
Dry ice
Detergent
A high and narrow container (like a bottle of water with the
top cut off).
Preparation:
Dry-ice is easy to buy on the internet. 5kgs is
enough for the development of this activity with
25 children.
Scientific Explanation
CO2 can change from a solid to a gas without becoming a
liquid, that is to say, it sublimates. During this process, a
beautiful bubble cascade is easy to generate if you add
soapy water to the CO2!
Activity:
Fill the container with half a litre of water. Add three spoonfuls
of detergent. Then, pour some bits of dry ice and the bubbles will
appear and won´t stop growing! You have just created a CO2
bubble cascade!
WARNING: Dry ice is CO2 in a solid state and it is VERY
cold -78ºC! So cold that it can burn! You need thermal
gloves and tongs to handle it and avoid direct contact
with the skin. Dry ice should only be handled by
responsible adults.

18. Activity 5
The Greenhouse Effect
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19. Activity 5 The Greenhouse Effect
Objective: Learning about CO2’s role in the atmosphere as a Greenhouse Gas
Pre-activity Explanation:
With the help of a poster, it will be explained that the greenhouse effect is caused by a series of gases, like CO2, which are
present in the atmosphere. These gases allow the Sun’s heat energy to pass through to the Earth. The Sun’s rays are
reflected on the Earth’s surface and some of their heat energy bounces back to the atmosphere. There, the greenhouse
gases (like CO2) block part of the rays from escaping back into space – trapping some of the Sun’s heat energy on earth to
make the earth a comfortable temperature for life.
BUT… recent Human activities like burning coal, oil and gas for electricity, transport and fuel, deforestation, fires and sea
water contamination have all changed the natural CO2 cycle, so that much more CO2 than we need is going into our
atmosphere! This extra CO2 is trapping extra heat energy in our atmosphere and warming the planet too much. CO2 is
needed for life, but an excess of CO2 in the atmosphere can be very harmful.
5.1: The Greenhouse Effect Game - part I
Materials:
Giant poster with the word SUN
Giant poster with the word EARTH
Tape or something to mark the line
between the two sides
Face paints
Activity:
Each student is given a role:
5 of them will play the role of HEAT (paint a sun on their hands
or face).
10 of them will play the role of CO2 (paint a molecule on their
hands or faces).
The number of students playing the role of CO2 should always be
double the number playing the role of HEAT.
The HEAT students start the game on the side of the room with
the SUN poster - the sun produces heat, which arrives at the
earth’s surface. The HEAT children run from side to side showing
that solar heating goes from the sun to the Earth and that the
Earth reflects it sending it again to the space.
Preparation:
A poster with the word
‘SUN’ is placed on one
side of the classroom,
and a poster with the
word ‘EARTH’ is placed
on the opposite side.
A line is drawn down
the middle of the
room, dividing the two
halves.
Q: What would
happen if there
wasn´t any CO2 in the
atmosphere?
A: The Sun’s radiation
would escape and the
Earth would be really
cold, life would be
impossible!

20. Activity 5 The Greenhouse Effect
Objective: Learning about CO2’s role in the atmosphere as a Greenhouse Gas
5.2: The Greenhouse Effect Game – part II
Materials:
Giant poster with the word SUN
Giant poster with the word EARTH
Tape or something to mark the line between
the two sides
Face paints
Preparation:
A poster with the word ‘SUN’ is placed
on one side of the classroom, and a
poster with the word ‘EARTH’ is placed
on the opposite side.
A line is drawn down the middle of the
room, dividing the two halves.
Activity:
CO2 students will be placed in the centre of the room, with their
back towards the Sun poster.
The HEAT students will have to repeat their course from the Sun
to the Earth, but this time the CO2 students will try to catch the
HEAT students on their way back to the Sun - few of them will
be able to escape!
Q: What happens when
there is CO2 in the
atmosphere?
A: Part of the Sun’s heat
energy (radiation) is trapped
on Earth – without this there
would be nothing living on
Earth!

21. Activity 5 The Greenhouse Effect
Objective: Learning about CO2’s role in the atmosphere as a Greenhouse Gas
5.3: The Greenhouse Effect Game - part III
Materials:
Giant poster with the word SUN
Giant poster with the word EARTH
Tape or something to mark the line between
the two sides
Face paints
Preparation:
A poster with the word ‘SUN’ is placed
on one side of the classroom, and a
poster with the word ‘EARTH’ is placed
on the opposite side.
A line is drawn down the middle of the
room, dividing the two halves.
Activity:
To introduce the concept of global warming, all the CO2 students
are placed in the centre of the room. Then, they are asked what
would happen if there was more CO2 added to the Earth’s
atmosphere... Add more students to the CO2 group, leaving the
same number, or less, playing the role of HEAT.
The more CO2 there is, the more HEAT students are trapped –
this is how the ‘greenhouse effect’ creates global warming.
Q. What happens when there
is too much CO2 in the
atmosphere?
A. Heat can not escape back to
Space, it gets trapped by the
CO2, and the Earth’s
temperature slowly rises until it
gets too hot, making conditions
on Earth difficult to support life.

22. Activity 5 The Greenhouse Effect
Objective: Learning about CO2’s role in the atmosphere as a Greenhouse Gas
5.4: Reflections on the Greenhouse Effect
Materials:
Posters with basic information on the “consequences of the rise of CO2 concentration”, the “technology and economics of CO2” or the
“CO2 at home”
Activity:
In order to finish the activity on the greenhouse effect, we will explain the contents of the posters related to CO2 emissions. After that,
students can take their fact sheets home, including their drawing activities.
Discussion Questions:
What is happening in the planet?
What emits CO2?
Which things have CO2?
How can we save CO2 emissions at home?

23. Activity 6
The Greenhouse Effect II
Fundación Ciudad de la Energía

24. Activity 6 The Greenhouse Effect
Objective: Learning about CO2’s role in the atmosphere as a Greenhouse Gas
6.1: The greenhouse effect in a bottle
Materials:
2 thermometers
2 bottles of still mineral water
1 bottle of sparkling water
Reading lamp.
Classroom arrangement:
Students are divided in to groups. A lab-coat should
be worn for this activity (see appendix 1). Each
group will have their own set of materials for the
experiment.
Activity:
Take two bottles of water - one still and one sparkling water.
Both bottles should have the same amount of water.
Add a thermometer to each bottle and tap them until they
reach the same temperature. If there is any difference, then
record the starting temperature of each bottle.
Point the lamp towards the bottles – ideally you would use one
lamp for each bottle – but if only one lamp is available try to
make sure that both bottles are receiving equal amounts of
light.
After approximately 40 mins, you should see that the sparkling
water (which contains CO2) has increased its temperature.
Scientific Explanation
The CO2 in the sparkling water traps the heat
from the lamp, just as happens in the
atmosphere!

25. Activity 6 The Greenhouse Effect
Objective: Learning about CO2’s role in the atmosphere as a Greenhouse Gas
6.2: The greenhouse effect in a glass
Materials:
2 thermometers
2 transparent drinking glasses
Mineral water
Reading lamp
Big transparent bowl.
Activity:
Half fill two glasses with water and expose them to the sun
(close to a window or outdoors - if it is cloudy you will need a
reading lamp).
Add a thermometer to each glass for some time, then record
the temperature of the water.
Next, cover one of the glasses with a transparent bowl. Wait
about 40 minutes.
The water of the covered glass will be warmer than the other.
Classroom arrangement:
Students are divided in to groups. A lab-coat should
be worn for this activity (see appendix 1). Each
group will have their own set of materials for the
experiment.
Scientific Explanation
The transparent bowl simulates the greenhouse
effect caused by CO2 and other greenhouse gases
in the atmosphere – they act like a greenhouse
retaining the heat from the sun.
.
You can start to prepare the next activity while you are waiting for the water to increase in temperature...

26. Activity 6 The Greenhouse Effect
Objective: Learning about CO2’s role in the atmosphere as a Greenhouse Gas
6.3: Puzzle
Materials:
Backing foam or card
Scissors
Glue
Glue spreader
Colour pencils
Printed puzzle in A-3 format
Activity:
Colour in the printed puzzle then paste it to the backing foam or card
using glue. A very thin layer of glue should be carefully spread all over
the back of the poster. Once it is dry, cut out the puzzle pieces, being
sure to stick to the dotted lines! You can keep the jigsaw pieces in a zip
bag once they are cut out to make sure you don´t lose them.

27. Activity 7
Rocks are CO2 Reservoirs I
Fundación Ciudad de la Energía

28. Activity 7 Rocks are CO2 Reservoirs
Objective: Learning about the CO2 Storage Process
7.1: Geological Storage mock-up
Materials:
Different coloured plasticine
Transparent tupperware container
White sand
Newspaper
Straws
Plastic syringe that fits in the straw
Coloured oil and water.
Classroom arrangement:
In order to explain how geological storage works put posters of
storage images where you can see different layers of rock
underground up in the classroom.
Divide students into groups. A lab-coat should be worn for this
activity (see appendix 1). Each group will have their own set of
materials for the experiment.
Activity:
CO2 is created when fossil fuels (coal/oil/gas) are burned.
Scientists have found ways to capture and remove the CO2 from
the smoke produced when fossil fuels are burned in power
stations or in other large industrial sites. This CO2 can be
transported (usually by pipeline) to a geological store deep
underground.
Geological storage describes storing CO2 in a natural rock
formation more than 1000 metres below ground.
In order to securely store CO2, these rock formations (or
reservoirs) have to be made up of a reservoir rock, which is
porous and will often contain very salty water (brine) or
sometimes oil or gas, and a seal or cap rock, which is
impermeable and above the porous rock – acting like a seal.
When CO2 is injected into a well, more than 1000 metres deep
into the ground, the porous rock absorbs it like a sponge and the
seal rock, which is impermeable, keeps the CO2 stored there,
preventing it from coming back to the atmosphere and harming
the environment.
Over a long time, some of the CO2 will turn into a carbonate rock
like the White Cliffs of Dover.

29. Activity 7 Rocks are CO2 Reservoirs
Objective: Learning about the CO2 Storage Process
Activity:
Pour white sand into the transparent container until it is
approximately one third full of its height. Drop in some water
and mix until the texture is similar to beach sand. Shape the
sand into a small mountain the centre, so the profile view is like
a wave.
Cut a bit of the newspaper of a size slightly bigger than the
section of the container and put it over the sand.
Mould the plasticine and stretch it until you have a piece similar
in size of the sand section and place it over the paper.
You have to make sure that it is attached to the walls of the
container by pushing it up with the fingers.
You can add more plasticine layers of different colours over it,
until the container. Is full. These coloured layers to represent the
different layers of rock. If you make the top layer green to
represent the surface of the Earth - perhaps you can add small
trees to it? You should make sure that all these layers are also
pushed up tight against the container walls.

30. Activity 7 Rocks are CO2 Reservoirs
Objective: Learning about the CO2 Storage Process
Activity:
Make a hole with a straw, crossing all the layers until reaching
the sand. The hole should be made ion one side of the sand
mountain close to the wall of the container so you can see the
results.
Discard this straw as it will be full of plasticine. Take another
straw and place it in the same hole. Insert straw bendy end first,
a few centimetres down.
Put some plasticine around the straw entrance to seal the area
between them.
Fill the syringe with coloured water and inject it several times
through the straw until the sand is saturated with water. Then,
fill the syringe with oil, preferably coloured, and inject it; we will
need to inject for several times to see the effect.
After a time, we will see the oil bubbles located in the upper
part of the sand with the plasticine keeping them trapped
there..
Scientific Explanation
Oil, like CO2, is lighter than water. The reservoir
rock (sand) is saturated in water, so the oil will
tend to rise above it. The seal or cap rock
(plasticine) prevents the CO2 (oil) to move
upwards.

31. Activity 7 Rocks are CO2 Reservoirs
Objective: Learning about the CO2 Storage Process
7.1: Geological Storage Mock-up
The oil in this experiment represents CO2, the plasticine is the seal or cap rock, and the sand the reservoir rock. What has
happened? Why did the oil migrate upwards to the area below the plasticine? Why does it not escape?

32. Activity 8
Rocks are CO2 Reservoirs II
Fundación Ciudad de la Energía

33. Activity 8 Rocks are CO2 Reservoirs
Objective: Learning about the geotrapping mechanisms of CO2 in the reservoir
rock
8.1: Geological Storage mock-up II
Materials:
Small bottle of water
Foam balls
Water
Oil
Colouring.
Pre-activity Explanation:
When CO2 is injected into a reservoir rock, it has two
immediate ways of getting trapped:
The seal or cap rock creates a physical barrier
preventing CO2 from migrating upwards.
Capillary forces mean the CO2 molecules get trapped in
the tiny rock pores.
We will imagine that the foam balls are mineral grains
of a rock.
Oil will act as CO2 and water will simulate the brine
filling the pores of the rock in a saline aquifer.
Classroom arrangement:
In order to explain how geological
storage works put posters of storage
images where you can see different
layers of rock underground up in the
classroom.
Divide students into groups. A lab-coat
should be worn for this activity (see
appendix 1). Each group will have their
own set of materials for the experiment.

34. Activity 8 Rocks are CO2 Reservoirs
Objective: Learning about the geotrapping mechanisms of CO2 in the reservoir
rock
8.1: Geological Storage mock-up II
Activity:
Fill the bottle to the top with foam balls.
Fill ¾ of the bottle with coloured water, using food colouring.
Fill the remaining space with oil, until the bottle is full.
Tightly close the bottle and wash it with soap.
Observe what happens.
Oil will simulate the behaviour of CO2 in the rock, the foam balls are the rock grains. Once the bottle is turned you
will see the oil bubbles accumulate in the upper part of the bottle, but the bottle cap acts like the seal rock,
preventing it from leaking out. There are other oil drops that remain between the balls; they are being trapped by
capillary forces just like the CO2 in the reservoir rock.
TIP: If you use coloured oil the effect will be more obvious.
What happens to the
CO2 (oil) once it is
injected in the
reservoir rock?
What will migrate
upwards and end up
in the upper part of
the rock given that it
is lighter than water?
Will it leak?
NO, because the seal
rock (bottle and
bottle cap) prevents
it from escaping.
How is CO2 trapped?
1. The seal or cap
rock prevents it from
escaping.
2. CO2 bubbles
remain trapped in
the rock pores by
capillary forces (they
get stuck).

35. Activity 9
Rocks are CO2 Reservoirs III
Fundación Ciudad de la Energía

36. Activity 9 Rocks are CO2 Reservoirs
Objective: learning about differences between rocks
9.1: Carbonate and siliciclastic rocks
Materials:
Different rocks like marble, granite, sandstone, shale (you
could try and collect these during a nature walk?)
Lemon juice
Vinegar
Juice squeezer
Dropper
Glasses
A glass fragment.
Classroom arrangement:
Encourage students to go for a walk and
pick up rocks with different colours and
textures. You should be prepared with
some rock samples in case you can’t
find good ones while out in the field.
Once back in the classroom, split into
groups and provide materials for each
group.
Activity:
Pick some rock samples during the walk. Make sure students are
choosing different ones, it doesn´t matter if they are small in
size.
Once in the classroom, wash and dry the rocks.
Prepare an acid solution by squeezing lemons and adding
vinegar. 3 parts of lemon juice per one of vinegar.
With a dropper, pour the mixed solution on to the rocks.
Carbonate rocks will cause the solution to start bubbling.
Rocks mainly composed of quartz (siliciclastic rocks), will scratch
the glass.
Which group has more siliciclastic rocks? And carbonates? Which ones have
more carbonates (the ones that produce more bubbles)?
Scientific Explanation
The carbonate rocks are rocks which are created
from CO2. When you drop an acid on them you
will see how it dissolves and starts bubbling.
Which of your rocks are carbonates?

37. Activity 9 Rocks are CO2 Reservoirs
Objective: learning about the differences between rocks
9.2: Porous and nonporous rocks
Materials:
Rock cores
Precision scales
Chronometer
Water
Newspaper
Trays
Cleaning cloths.
Classroom arrangement:
Place the precision scales on the table,
level and zero them. Share the material
among the groups, each group should
have one porous and one nonporous
rock.
Pre-experiment Explanation:
Some rocks are very porous – they have many empty
spaces between the grains that form the rock.
Other rocks are impermeable - they have very few
pores or spaces between grains making it a perfect seal.
Nature uses the porous rocks for storing water, oil or
gas. Humans have then extracted these resources by
drilling into these rocks. We can also use these rocks for
storing CO2. We are going to see which ones are suitable
to become a reservoir and are not.

38. Activity 9 Rocks are CO2 Reservoirs
Objective: learning about the differences between rocks
9.2: Porous and nonporous rocks
Activity:
• Weigh each rock and write the exact weight of each one.
• Place two sheets of newspaper in a tray. Add some water until the paper sheets are soaked.
• Put the rocks over the paper and start the chronometer for 3 minutes.
• In the meantime, take a cleaning cloth, soak it in water and wring out slightly. After three minutes, dry the side of the cylinder that is
immersed, putting it on the cleaning cloth for a second and then weigh it. Write the weight. Repeat the procedure with both rocks.
• Remember to set the precision scale to zero before weighing each sample.
Write the results of all groups on a blackboard. The difference between the weight of a dry sample and the wet one will be the amount of
absorbed water. If we compare the weights 2 and 10 minutes after, we can conclude which one has been faster at absorbing water. We can
leave the rocks immersed for one hour and weigh them again. The most porous one will be the ones that absorb the most liquid..

39. Activity 9 Rocks are CO2 Reservoirs
Objective: learning the differences between rocks
9.2: Porous and nonporous rocks
Which rocks have
absorbed more
water? Why?
The most porous
ones absorb more
water, because
they have more
connected, empty
spaces (pores).
Which rock is the
best for CO2
Storage?
The one that has
absorbed the
most liquid.
Which rock is the
worst for CO2
Storage?
The one that has
absorbed the least
liquid - the most
impermeable one.
This one would make
the best seal!
In which rock did
the water reach
highest? In which
one did water
raise fastest?
The one that has
highest capillarity
The water level in rock A is higher
than in rock B. Rock A has more
capillarity (traps more in its pores)

40. Annex II
Making Your Own Lab-coat
Fold
You can make your own scientists lab-coat with just a big and white plastic bag,
scissors and a permanent marker.
-Draw lines as indicated on the image to the left.
Belt
-Cut the bag following the lines. Warning! Only cut the front side of the bag.
-If you cut the whole bottom part of the bag it can be used as a belt.
-Fold the lapels below the neck.
-Draw some pockets, buttons, a pin or whatever you want to make it more realistic.

41. Thanks for your attention
Daniel Fernandez-Poulussen
Business Development Unit
CO2 Geological Storage Programme
Tel.+34 987 456 323
Mobile +34-689 586 637
d.fernandez@ciuden.es
Technological Development Plant for CO2 Storage
www.ciuden.es
Special thanks to: Andrea Pérez, Marta Ferrero, Beatriz Taladrid, Roberto Cuadrado, Montse, Veronica and all the
colleagues who have kindly collaborated in the project.