Climate change and the greenhouse effect

Transcription

CLIMATE CHANGE &
THE GREENHOUSE
EFFECT
This development of these materials was supported under Australian Research Council's Discovery Projects
funding scheme (130103035).
© 2014 University of Western Australia ISBN 978-0-646-93241-5
Title: Climate change and the greenhouse effect
Authors: Vaille Dawson and Katherine Carson
This work is made available under the terms of the Creative Commons Attribution Non-Commercial NoDerivatives 3.0 license, creativecommons.org/licenses/by-nc-nd/3.0/.
If you wish to reproduce this work in whole or part other than for non-commercial purposes and without
changes please contact the authors.
Further information: vaille.dawson@uwa.edu.au
katherine.carson@uwa.edu.au
Faculty of Education, The University of Western Australia, 35 Stirling Highway, Crawley, 6009
Front cover image: NASA: Earth observatory. (n.d.). History of the blue marble.
http://earthobservatory.nasa.gov/Features/BlueMarble/BlueMarble_history.php
TABLE OF CONTENTS
TABLE OF CONTENTS
Introduction to climate change resources
5
Alternative conceptions
6
References
7
------------------------------------------------------------------------------------------------------------What is the greenhouse effect?
11
Links to Australian curriculum
12
Teacher notes
13
Student answers
16
Student activity
17
What is the greenhouse effect?
Electromagnetic radiation and the greenhouse effect
References
20
------------------------------------------------------------------------------------------------------------Greenhouse gases and car travel
25
26
Teacher notes
27
Student answers
28
Completed travel log
30
Student activity
31
Greenhouse gases and car travel
Travel log
Sample travel log
References
37
------------------------------------------------------------------------------------------------------------Demonstrating the greenhouse effect
41
42
Teacher notes
44
Student answers
46
Student activity
48
References
52
------------------------------------------------------------------------------------------------------------Socioscientific issues and introducing argumentation
55
56
Teacher notes
58
62
Student activity
Are ecobuses worth the cost?
Burning rubbish for electricity – waste to energy plants
Wind power
References
68
3
INTRODUCTION TO CLIMATE CHANGE RESOURCES
Climate change is a global concern, with the potential to affect every aspect of our daily lives. It is a
multidisciplinary, complex and controversial topic, however one with which students need to be familiar.
When students leave school science they require an understanding of both the natural and the enhanced
greenhouse effect and how this relates to climate change. This knowledge empowers them to make
decisions and alter behaviours to help mitigate the consequences of climate change, helping not only
themselves, but the global community.
These learning activities were developed to educate secondary school students about the greenhouse
effect and climate change and have been aimed at some of the most common alternative conceptions
students hold about these topics. The activities are as follows:
This activity provides information addressing the common alternative conceptions students hold about
the greenhouse effect and climate change.
This activity directly relates a student’s personal car travel with a carbon dioxide equivalent (CO2eq)
release of greenhouse gases, by using an online carbon calculator.
Demonstrating the greenhouse effect
This experiment demonstrates that an atmosphere high in carbon dioxide increases in temperature more
rapidly and remains at a higher temperature than an atmosphere low in carbon dioxide.
Socioscientific issues and argumentation
Socioscientific issues are topics with a scientific basis which are important to human society, such as
climate change. Teaching students the skills of argumentation allows them to formulate a well-developed
argument based on scientific fact when discussing these issues. Three scenarios have been included for
students to consider.
Useful resources
Science by Doing is a set of resources developed by the Australian Academy of Science. The Systems
on a Big Scale unit includes activities on the carbon cycle, climate change and biodiversity. These
resources are free to download.
http://www.sciencebydoing.edu.au/curriculum/teacher/download/yr10/systems/
The Science of Climate Change: Questions and Answers is a booklet developed by the Australian
Academy of Science to explain the greenhouse effect, climate change and the possible effects on
Australia now and in the future.
http://www.science.org.au/publications/science-climate-change-questions-and-answers
The Bureau of Meteorology has data from 1910 on atmospheric conditions such as temperature, rainfall
and sea temperature. Regions of Australia can be selected and compared and graphs show the annual
measurements over time.
http://www.bom.gov.au/climate/change/index.shtml#tabs=Tracker&tracker=timeseries
The Climate Council, headed by Tim Flannery provides independent and current climate change
information directly related to Australia. https://www.climatecouncil.org.au/
The CSIRO has developed the CSIRO Home Energy Saving Handbook, with tips on saving electricity
usage in and around the home. http://www.csiro.au/Organisation-Structure/Flagships/EnergyFlagship/The-CSIRO-Home-Energy-Saving-Handbook.aspx At this page there are some room by room
tips. http://www.csiro.au/Outcomes/Energy/Saving-energy-in-your-home.aspx
5
COMMON ALTERNATIVE CONCEPTIONS
In order to teach this topic effectively, it is necessary to be aware of some of the common alternative
conceptions held by students about both the greenhouse effect and climate change. Many of these have
been targeted in the Student Activities and are mentioned in the Teacher Notes, however here is a list of
the most common1.
Carbon dioxide is the only greenhouse gas. Mentioned almost daily in the media is the level of CO2 in
the atmosphere, or the repeal of the Australian carbon tax, or how to reduce your ‘carbon footprint’. It is
understandable that students believe this is the only greenhouse gas. Students need to understand that
CO2 is the primary greenhouse gas emitted through human activity, however there are other greenhouse
gases, some more ‘potent’ such as methane and others present in greater volumes, such as water
vapour.
Ozone layer is confused with the greenhouse effect.* This is one of several alternative conceptions
involving the ozone layer. Conflation between the two processes is common with students often aware of
greenhouse gases and their role in global warming, however believing this process occurs in the ozone
layer. Also some students include the ozone layer in the greenhouse effect process as they associate it
with ultraviolet rays.
Greenhouse gases destroy the ozone layer.* This is a common conflation where students believe
greenhouse gases weaken or destroy the ozone layer, causing a hole. The distinction needs to be made
between the processes of the ozone layer and its protection of the Earth from ultraviolet rays, as
opposed to the greenhouse effect which helps to warm the Earth.
Ultraviolet radiation is confused with infrared radiation.* Students confuse ultraviolet (UV) and
infrared (IR) radiation and which kind is involved in which area of the greenhouse effect.
Pollution causes the greenhouse effect. Students often hear that we are ‘polluting’ the atmosphere
with greenhouse gas emissions, thus students may believe pollution is a cause of the enhanced
greenhouse effect. Air pollution is when air contains any substance particulate or gaseous, in amounts
harmful to life. The most common air pollutants are: sulfur dioxide, carbon monoxide, nitrogen oxide,
volatile organic compounds, particulates and carbon dioxide2. Carbon dioxide differs from the other
pollutants as it does not cause any effects locally, however contributes to the enhanced greenhouse
effect.
Greenhouse gases are trapped by the atmosphere. Some students believe that the atmosphere or
greenhouse effect ‘traps’ greenhouse gases when in reality it is gravity that keeps the greenhouse gases
in our atmosphere. Another confusion here is that some students believe there is a distinct layer of
greenhouse gases in the atmosphere, when they are spread (although not evenly) throughout all the
layers of Earth’s atmosphere.
Climate and weather are confused. Students often are unaware of the difference. Weather is the daily
atmospheric conditions of Earth such as humidity, rainfall and temperature. Climate is these same
weather conditions measured over a long term, usually at least 30 years.
Greenhouse gases thicken the atmosphere. Many explanations of the greenhouse effect include the
term ‘a blanket of gases’. Some students then picture this layer thickening with greenhouse gases so
that heat literally cannot escape.
Greenhouse gases are harmful. This is students misunderstanding the difference between the natural
greenhouse effect and the enhanced greenhouse effect. Many students do not know that the
greenhouse effect is necessary for life on Earth and believe greenhouse gases to be harmful.
* The ozone layer has not been specifically addressed in this curriculum resource.
6
REFERENCES
REFERENCES
1
Carson, K., Dawson, V., & Rennie, L. High school students’ understandings of climate change.
Poster presented at the annual National Association for Research in Science Teaching 2014
conference, Pittsburgh, U.S.A., 31 March 2014.
2
Woodford, C. Air Pollution, 14 September, 2014. Explain that stuff. [Online] Available from:
http://www.explainthatstuff.com/air-pollution-introduction.html [Accessed 20 October 2014].
7
WHAT IS THE
GREENHOUSE EFFECT?
WHAT IS THE GREENHOUSE EFFECT?
This activity addresses some common alternative conceptions
students hold about the greenhouse effect and climate change.
12
Teacher notes
13
Student answers
16
Student information
17
Electromagnetic radiation and the greenhouse
effect
References
20
Links to Australian curriculum 1
Content Strand
Content Description
Elaboration
Science and technology contribute to finding
solutions to a range of contemporary issues;
these solutions may impact on other areas of
society and involve ethical considerations
(ACSHE120)
Considering how human activity in the community
can have positive and negative effects on the
sustainability of ecosystems
Energy appears in different forms including
movement (kinetic energy), heat and potential
energy, and causes change within systems
(ACSSU155)
Investigating different forms of energy in terms of
the effects they cause, such as gravitational
potential causing objects to fall and heat energy
transferred between materials that have a
different temperature
Identify questions and problems that can be
investigated scientifically and make predictions
based on scientific knowledge (ACSIS139)
Recognising that the solution of some questions
and problems requires consideration of social,
cultural, economic or moral aspects rather than or
as well as scientific investigation
Energy transfer through different mediums can be
explained using wave and particle models
(ACSSU182)
Discussing the wave and particle models and
how they are useful for understanding aspects of
phenomena
YEAR 7
Use and Influence of
Science
YEAR 8
Science Understanding
Physical Sciences
Science Inquiry
Questioning and
Predicting
YEAR 9
Physical Sciences
Investigating the transfer of heat in terms of
convection, conduction and radiation, and
identifying situations in which each occurs
Exploring the properties of waves, and situations
where energy is transferred in the form of waves,
such as sound and light
Science as a Human Endeavour
Science
The values and needs of contemporary society
can influence the focus of scientific research
(ACSHE228)
Considering how choices related to the use of
fuels are influenced by environmental
considerations
Global systems, including the carbon cycle, rely
on interactions involving the biosphere,
lithosphere, hydrosphere and atmosphere
(ACSSU189)
Investigating how human activity affects global
systems
YEAR 10
Earth and Space
Sciences
Explaining the causes and effects of the
greenhouse effect
Nature and Development
of Science
Scientific understanding, including models and
theories, are contestable and are refined over
time through a process of review by the scientific
community (ACSHE191)
Considering the role of science in identifying and
explaining the causes of climate change
Science
People can use scientific knowledge to evaluate
whether they should accept claims, explanations
or predictions (ACSHE194)
Considering the scientific knowledge used in
discussions relating to climate change
12
TEACHER NOTES
This learning activity has been created in two parts. WHAT IS THE GREENHOUSE EFFECT? has been
designed for use in Year 7-10, to introduce students to the basic science of the greenhouse effect, the
enhanced greenhouse effect and different aspects of climate change. The information addresses some
of the common alternative conceptions students hold about the greenhouse effect and climate change.
The science of the greenhouse effect is compared to a car with closed windows parked in the sun, which
is a situation Australian students should be familiar with. In this case the shortwave radiation (visible
light) enters the car through the transparent car window. The interior of the car absorbs some of this
energy and re-radiates it as longwave radiation (infrared) into the car’s atmosphere. The longer
wavelengths do not pass as easily through the car windows so are trapped inside the car. Also any
greenhouse gases inside the car such as carbon dioxide and water vapour will absorb the longwave
radiation2. These processes together cause the inside of the car to heat up. The lack of convection within
the car also contributes to the increase in temperature, however is not mentioned in this example.
The greenhouse effect works in a similar way, with the greenhouse gases working as the car windows
and land and water representing the car’s interior. About 30% of the incoming shortwave solar radiation
is reflected off clouds, ice, deserts and other bright surfaces back into space. The other 70% (visible light
and UV radiation) passes through the greenhouse gases to reach the water and land mass of Earth.
Here they are absorbed and slowly released back into the atmosphere as longwave radiation (infrared
radiation). The greenhouse gases absorb some of this energy and re-radiate it back in all directions,
some of which goes back towards Earth3. This results in a warming of Earth and its lower atmosphere.
Figure 1 shows the similarities between the heating of a car’s interior4 and the Earth’s atmosphere5 by
the greenhouse effect.
Figure 1: The heating of a car’s interior [4] is similar to the Earth’s greenhouse effect [5]
The enhanced greenhouse effect
The enhanced greenhouse effect describes the increase in
concentration of heat absorbing gases such as carbon
dioxide in the Earth’s atmosphere. Research shows many
students are unaware that the greenhouse effect is
necessary for life on Earth6. This is most likely due to their
failure to distinguish between the greenhouse effect and
the enhanced greenhouse effect. Media reports rarely
Figure 2: Media headlines [7, 8] often portray
the greenhouse effect in a negative manner.
13
TEACHER NOTES
distinguish between these processes and negative wording regarding the greenhouse effect (instead of
the enhanced greenhouse effect) and greenhouse gases, lead students to think that greenhouse gases
and the greenhouse effect are harmful.
When teaching this topic it is imperative to distinguish between
the greenhouse effect and the enhanced greenhouse effect.
Weather and climate
A common misunderstanding in students is the difference between weather and climate. Weather is the
daily, weekly and even annual atmospheric conditions of Earth (such as humidity, rainfall, maximum and
minimum temperatures, and wind). Climate is these weather conditions at a certain locality, statistically
averaged over a period of at least 30 years9.
Global warming and climate change
It is necessary for students to understand the difference between climate and weather, in order to have
an understanding of climate change. Most students are aware of global warming6 (the recent and
ongoing increase in the average global temperature over the past century9), which is ever-present in the
media forum. This continued increase in global temperature affects local weather patterns, which over
time affects the environment and the local flora and fauna. Global warming affects humanity as well, with
lack of water, food and habitation presenting an ever increasing concern.
Figure 3: These graphs from NASA [10] show the correlation between a rise
in carbon dioxide in the atmosphere and the rise in global temperature.
14
TEACHER NOTES
Questions from the student activity
Question 2 Explain why some people do not believe in the enhanced greenhouse effect
Students learn in their reading that scientists cannot prove that the enhanced greenhouse effect is
causing global warming, so some students may believe that human induced or anthropogenic climate
change is a political conspiracy and does not really exist. These opinions originate from the lack of ability
to prove the link – despite the overwhelming evidence. A paper published in 2013, analysed 944 peerreviewed papers on global warming and found that 97.1% of these papers agreed with anthropogenic or
human induced global warming. If you compare the number of scientists involved in these papers it
actually equates to 98.4% of scientists against 1.6% (those papers which did not agree with
anthropogenic global warming, usually have fewer scientists involved)11.
Question 4 Give a definition of climate change
Students need to define climate change, using the information presented and their own knowledge. The
IPCC defines climate change in their 2013 report:
‘Climate change refers to a change in the state of the climate that can be identified (e.g., by using
statistical tests) by changes in the mean and/or the variability of its properties, and that persists
for an extended period, typically decades or longer. Climate change may be due to natural
internal processes or external forcings such as modulations of the solar cycles, volcanic
eruptions and persistent anthropogenic changes in the composition of the atmosphere or in land
use.’ 12
FURTHER INFORMATION ON THE GREENHOUSE EFFECT is extra information developed for Year
10-12. Here the greenhouse effect is described in terms of electromagnetic (EM) radiation. Students
often confuse the types and lengths of radiation when describing the greenhouse effect. By introducing
the image and description of types of EM radiation, along with the diagram of the greenhouse effect
students should gain a better understanding.
The notion of thermal equilibrium may be familiar with students in upper school. This is the idea that
when an object with a higher temperature (such as a hot cup of coffee), comes into contact with an
object with a lower temperature (such as the air), there is a transfer of heat energy such that they both
approach the same temperature. This results in the cup of coffee eventually reaching room temperature
(the same temperature as the air). The same occurs with the complex heat exchange in the Earth’s
atmosphere. The Earth’s global temperature is determined by the difference between the incoming
energy from the sun and the outgoing energy. This is known as the Earth’s thermal equilibrium13. By
increasing the concentration of greenhouse gases in the atmosphere, there is less heat escaping into
space. This leads to an increase in the global temperature until a new equilibrium is achieved. Figure 4
from The Environmental Protection Agency in the USA [14] illustrates this process.
Figure 4: The increase in greenhouse
gases due to the enhanced greenhouse
effect disrupts the heat exchange of the
natural greenhouse effect. This results in
an increase in global temperature
(global warming) [14].
15
STUDENT ANSWERS
1.
Compare the heat exchange of a car’s interior with closed windows and the greenhouse effect.
Energy from the sun enters through the glass windows and is absorbed by the car’s interior (upholstery,
seats, dashboard). This is then re-radiated into the air inside the car, which heats up. The greenhouse
effect works in the same way, where energy from the sun enters through the greenhouse gases in the
atmosphere to be absorbed by land and water. This is then released back into the atmosphere where
some is absorbed by the greenhouse gases and re-emitted back into the atmosphere. This warms up
the Earth2.
For students who have read the FURTHER INFORMATION ON THE GREENHOUSE EFFECT
information sheet, the answer may contain more scientific content.
Some solar radiation (shortwave radiation) is reflected by the car’s exterior, however some enters
through the glass windows and is absorbed by the car’s interior (upholstery, seats, dashboard). This is
then re-radiated (as longwave radiation) into the air inside the car, which heats up the car’s interior. The
greenhouse effect works in the same way, where shortwave radiation enters through the greenhouse
gases in the atmosphere. Some is reflected off surfaces such as ice and clouds, however most (70%) is
absorbed by land and water. This is then re-emitted as longwave (infrared) radiation into the Earth’s air.
Greenhouse gases such as water vapour and carbon dioxide absorb some of this energy and then
reradiate it in all directions, including back to Earth3. This heats up Earth and its lower atmosphere.
2.
Explain why some people do not believe in the enhanced greenhouse effect.
Scientists cannot prove that the increase in carbon dioxide caused the increase in global temperature.
3.
What is the difference between weather and climate?
Weather is the atmospheric conditions over a short period of time, such as day to day. Climate describes
the atmospheric conditions averaged over a longer period, usually 30 years9.
4.
Give a definition of climate change.
Climate change is a change in atmospheric conditions such as rainfall, temperature and wind when
considered over a period of at least 30 years9. The change in weather conditions then leads to a change
in the local environment, including flora and fauna.
Figure 5: Climate change can
include a change in any of
these
measureable
atmospheric conditions [15]
16
STUDENT ACTIVITY
The greenhouse effect is a natural process which is necessary for survival of life on Earth. Without this
process, it is estimated that the Earth’s average temperature would be 33C lower than it is, making it
too cold for life to survive. To give you a comparison, the last Ice Age had average temperatures of only
4C lower than they are today3.
Figure 1: A car’s inside temperature
can become much hotter than the
outside temperature [17].
The greenhouse effect is named after a greenhouse, which is used
in some countries to help plants grow during cold weather, by
minimising heat loss. Imagine a car, sitting in the sun with all the
windows closed. We know not to leave animals or children inside a
car on a hot day, however did you know that on a 30C day the
inside of a car can reach as much as 70C?16 How does this
happen? Solar radiation enters the car mostly through the car
windows and this is absorbed by the interior of the car – the
dashboard, the seats, the carpet all absorb the heat energy. This is
then re-radiated into the air inside the car, effectively heating up the
car’s interior2.
On Earth, greenhouse gases are responsible for the greenhouse
effect. The four most common naturally occurring greenhouse gases
in the atmosphere are: water vapour (H2O), carbon dioxide (CO2),
methane (CH4) and nitrous oxide (N2O).The greenhouse effect
works in the same way as a hot car or a greenhouse. In this case,
the greenhouse gases act like the car windows, and the land and
water on Earth represent the car’s interior. When the solar radiation
passes through the natural greenhouse gases in the atmosphere,
30% is reflected back into space from ice, water, clouds and other
bright surfaces. The other 70% is absorbed by land and water,
which heats up. Some of this heat is slowly released back into the
atmosphere where some escapes into space and some is absorbed
by the greenhouse gases and re-emitted into the Earth’s
atmosphere. This warms the Earth and maintains a temperature
favourable to life.
Figure 2: The Earth’s natural greenhouse
effect [18]
The Enhanced Greenhouse Effect and Global Warming
The enhanced greenhouse effect describes the increase in concentration of heat absorbing gases such
as carbon dioxide (and other greenhouse gases) in the Earth’s atmosphere. Scientific data shows an
increase in carbon dioxide levels in the atmosphere in the last 150 years, mostly due to the burning of
fossil fuels for energy. Scientific data also shows that the last 30 years until 2012 were the warmest in
1,400 years12. Scientists have theorised that this increase in carbon dioxide has caused the increase in
global temperatures, but this cannot be scientifically proven. Because it cannot be proven, there are
many people who believe global warming is part of a natural cycle of the Earth and not caused by
humans.
Weather and Climate
The difference between weather and climate is a difference in time scale. Weather describes the
atmospheric conditions such as rainfall, temperature, humidity and wind over a relatively short period of
time. Climate is how the same atmospheric conditions behave over a longer period of time and can be
described as the weather of a certain locality averaged over a period which is usually 30 years. When we
talk about climate change, we are talking about the change in long-term averages of weather.
1
STUDENT ACTIVITY
Global Warming and Climate Change
The increase in average global temperatures over the past century is known as global warming. Global
warming then causes climate change, due to the consequences of the increased temperatures on the
local weather, which affects the environment and local flora and fauna. There are many consequences of
climate change and these vary according to the country and environment in which you live.
Scientists predict that in the south of Western Australia (which includes Perth) there will be a hotter drier
climate, with reduced rainfall leading to a reduction in water supply. The average number of days above
35C in Perth could increase from 28 per year, to 67 by 207019. These factors will lead
to an increased risk of bushfires as well as affect many species of native plants and
animals.
The Intergovernmental Panel on Climate Change (IPCC)
The leading international organisation scientifically investigating global warming and
climate change is known as the Intergovernmental Panel on Climate Change (IPCC).
The IPCC regularly produces reports based on their review of all published data
surrounding climate change. Each report involves gathering results from thousands of
scientists from all over the world and is reviewed by hundreds more. They predict that
at current rates of greenhouse gas emissions, the global temperature could increase
by between 1.8C and 3.4C by 210012.
1.
Figure 3: The IPCC
collects results from
thousands
of
scientists all over the
world.
Compare the heat exchange of a car’s interior with closed windows and the greenhouse effect.
__________________________________________________
__________________________________________________
_________________________________________________
2.
Explain why some people do not believe in the enhanced greenhouse effect.
__________________________________________________
__________________________________________________
_________________________________________________
3.
What is the difference between weather and climate?
__________________________________________________
__________________________________________________
_________________________________________________
4.
Give a definition of climate change.
__________________________________________________
__________________________________________________
_________________________________________________
2
STUDENT ACTIVITY
.ELECTROMAGNETIC
RADIATION AND THE GREENHOUSE EFFECT
The electromagnetic (EM) radiation spectrum is the range of radiation
which includes many types. On this scale, radiation with the shortest
wavelengths and most energy (i.e. gamma rays) is at the bottom and
radiation with the longest wavelengths and least energy (i.e. AM radio
rays) is at the top. This is shown in Figure 4.
Shortwave radiation (THE SUN)
Visible light and ultraviolet (UV) radiation (along with x-rays and gammarays) are commonly referred to as shortwave radiation. Shortwave
radiation contains more energy than longwave radiation. The Sun emits
energy mainly as visible light, with small amounts of UV and infrared (IR)
radiation. Because of this, solar radiation is usually considered shortwave
radiation.
Longwave radiation (THE EARTH)
21
Infrared (IR), microwave and radio radiation are commonly referred to as
longwave radiation. Longwave radiation contains less energy than
shortwave radiation. Almost all of the energy emitted from the Earth’s
surface is infrared radiation which we feel as heat. Because of this,
radiation from the Earth, is considered longwave radiation.
Now what has this got
Figure 4: The electromagnetic (EM)
to
do
with
the
spectrum [20]
greenhouse effect? Well
some people become
confused between the different types of radiation
involved in the greenhouse effect. Greenhouse gases
do not absorb shortwave radiation, so the Sun’s rays
(shortwave radiation) pass straight through the
greenhouse gases in the atmosphere to reach the
water and land mass on the Earth. Here they become
absorbed and slowly released back into the
atmosphere as infrared radiation or heat (longwave
radiation). The greenhouse gases absorb some of this
energy and re-radiate it in all directions including back
towards the Earth. As a result this warms the Earth and
its lower atmosphere.
Figure 5: This diagram of the greenhouse effect shows
shortwave solar radiation passing through the atmosphere.
Once this reaches Earth it is reflected or absorbed and reemitted as longwave (infrared) radiation [21].
Thermal equilibrium and the greenhouse effect
The global temperature is determined by the difference between incoming energy from the sun and
outgoing energy. This is known as the Earth’s thermal equilibrium. As the greenhouse gases increase in
concentration in the atmosphere and absorb more energy (the enhanced greenhouse effect), the amount
of outgoing energy decreases. This leads to a rise in the global temperature which is shown in global
average temperatures. The IPCC reports the increase between the average temperature of 1850-1900
and 2003-2012 is 0.78C12. This difference will keep increasing until a new thermal equilibrium is
achieved.
3
REFERENCES
REFERENCE LIST
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2
Georgia State University. Greenhouse effect, [no date]. Hyperphysics. [Online] Available from:
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3
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4
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5
Cool the World. The greenhouse effect: Why do increased greenhouse gas emissions cause
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[Accessed 10 March, 2014].
6
V. Dawson, & K. Carson. Australian secondary school students' understanding of
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7
P. Liljas. New greenhouse gas 7000 times more powerful than CO2, Dec 11, 2013. Time. [Online]
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8
P. Adams. The great greenhouse plot, Feb 13, 2010. The Australian. [Online] Available from:
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9
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10 March, 2014].
10 National Aeronautics and Space Administration. Effects of changing the carbon cycle, 2014.
Earth Observatory. [Online] Available from:
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11 J. Cook, D. Nuccitelli, S. Green, M. Richardson, B. Winkler, R. Painting, R. Way, P. Jacobs, & A.
Skuce. Quantifying the consensus on anthropogenic global warming in the scientific literature.
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13 National Aeronautics and Space Administration. Climate forcings and global warming, [no date].
Earth Observatory. [Online] Available from:
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2014].
14 United States Department of the Interior. What is climate change?, 2014. National Park Service.
[Online] Available from: http://www.nps.gov/goga/naturescience/climate-change-causes.htm
[Accessed 12 March, 2014].
15 R. Pielke. Sr. What does climate change mean? Does a lack of preciseness in its definition
discourage effective discussion of the risks of climate on key societal and environmental
20
REFERENCES
resources?, 2012. Climate science: Roger Pielke Sr. [Online] Available from:
http://pielkeclimatesci.wordpress.com/2012/01/19/what-does-climate-change-mean-does-a-lackof-preciseness-in-its-definition-discourage-effective-discussion-of-the-risks-from-climate-on-keysocietal-and-environmental-resources/ [Accessed 10 March, 2014].
16 Kidsafe Western Australia. Hot cars, 2008. Car safety. [Online] Available from:
http://www.kidsafewa.com.au/hotcars.html [Accessed 14 April, 2014].
17 J. Harrell. Dogs in hot cars: What to do if you see one, 2012. Petfinder. [Online] Available from:
https://www.petfinder.com/blog/2010/07/dogs_in_hot_cars_what_to_do/ [Accessed 14 April,
2014].
18 National Aeronautics and Space Administration. Life in a greenhouse? How ghastly, 2012.
Space Place. [Online] Available from: http://spaceplace.nasa.gov/greenhouse/en/ [Accessed
14 April, 2014].
19 Australian Government. Western Australia: Climate change impacts in WA, 2013. Department of
the Environment. [Online] Available from http://www.climatechange.gov.au/climatechange/climate-science/climate-change-impacts/western-australia [Accessed 14 April, 2014].
20 National Aeronautics and Space Administration. Electromagnetic Radiation, 2012. Goddard
Space Flight Centre. [Online] Available from:
http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html [Accessed 16 April, 2014].
21 North Carolina State University. Greenhouse effect, 2012. Climate education for K-12. [Online]
Available from: http://www.nc-climate.ncsu.edu/edu/k12/.greenhouseeffect [Accessed 21 October,
2014].
List of Figures
Teacher Notes
Figure 1
The heating of a car’s interior is similar to the Earth’s greenhouse effect
Figure 2
Media headlines often portray the greenhouse effect in a negative manner
Figure 3
These graphs from NASA show the correlation between a rise in carbon dioxide in the
atmosphere and the rise in global temperature
Figure 4
The increase in greenhouse gases due to the enhanced greenhouse effect disrupts the
heat exchange of the natural greenhouse effect
Figure 5
Climate change can include a change in any of these measureable atmospheric
conditions
Student Activity
Figure 1
A car’s inside temperature can become much hotter than the outside temperatur e
Figure 2
The Earth’s natural greenhouse effect
Figure 3
The IPCC collects results from thousands of scientists all over the world
Figure 4
The electromagnetic (EM) spectrum
Figure 5
This diagram of the greenhouse effect shows shortwave solar radiation passing through
the atmosphere
21
GREENHOUSE GASES
AND CAR TRAVEL
GREENHOUSE GASES AND CAR TRAVEL
This activity has been designed to directly relate a student’s personal car travel with a
carbon dioxide equivalent (CO2eq) release of greenhouse gases, by the use of an online
carbon calculator.
26
Teacher notes
27
Student answers
28
Completed travel log
Student activity
30
31
Travel log
Sample travel log
References
37
Links to Australian curriculum1
Content Strand
Content Description
Elaboration
Some of Earth’s resources are renewable, but
others are non-renewable (ACSSU116)
Comparing renewable and non-renewable energy
sources, including how they are used in a range
of situations
YEAR 7
Earth and Space
Sciences
(ACSHE120)
Considering how human activity in the community
can have positive and negative effects on the
sustainability of ecosystems
Communicate ideas, findings and solutions to
problems using scientific language and
representations using digital technologies as
appropriate (ACSIS133)
Using digital technologies to access information
and to communicate and collaborate with others
on and off site
Physical Sciences
Energy appears in different forms including
movement (kinetic energy), heat and potential
energy, and causes change within systems
(ACSSU155)
Recognising that kinetic energy is the energy
possessed by moving bodies
Recognising that potential energy is stored
energy, such as gravitational, chemical and
elastic energy
Recognising that heat energy is often produced
as a by-product of energy transfer, such as
brakes on a car and light globes
Science
(ACSHE135)
Investigating how energy efficiency can reduce
energy consumption
Investigating the development of vehicles over
time, including the application of science to
contemporary designs of solar-powered vehicles.
(ACSHE228)
Considering how choices related to the use of
fuels are influenced by environmental
considerations.
Evaluating claims relating to environmental
footprints
(ACSHE230)
Investigating technologies associated with the
reduction of carbon pollution, such as carbon
capture.
Science
Science Inquiry Skills
Communicating
YEAR 8
YEAR 9
Science
YEAR 10
Science
26
TEACHER NOTES
The activity requires students to complete a travel log for 7 days of personal car travel. After
calculating the distance travelled they determine the amount of greenhouse gas emissions. An online
carbon calculator by Carbon Neutral2 at http://www.carbonneutral.com.au/carbon-calculator/vehiclesand-fuel-use.html determines their annual amount of greenhouse gas emissions in tCO2eq.
The activity can be adapted for students from Year 7-10. For Year 7/8, the students complete the
travel log, work out their CO2eq and answer the first five questions. The questions from page 3 have
been designed for Year 9/10. The activity will take between one and three lessons to complete. A
sample travel log has been included at the end of the student activity sheets, which can be used instead
of students completing their own log.
The production and transport of petrol, diesel and liquefied petroleum gas (LPG) creates greenhouse
gas emissions. However when used to fuel a car, these fossil fuels emit greenhouse gases from the
exhaust pipe, mostly in the form of carbon dioxide (CO2). For every litre of petrol used in a car, 2.3kg of
CO2 is released into the atmosphere. A litre of diesel releases 2.7kg of CO2 and a litre of LPG releases
1.6kg of CO23. Other greenhouse gases released from driving a car include methane (CH4) and
nitrous oxide (N2O) from the exhaust pipe and hydrofluorocarbons (HFCs) from leaking air
conditioners. The release of these gases is small compared to CO2 however these gases are more
potent in their global warming potential (see Table 1).
Switch the future campaign
Students may have seen the advertisements on television showing Sparky the chudditch running in his
hamster wheel to generate electricity5. At this link you can view the advertisement and then discuss how
using electricity releases greenhouse gases into the atmosphere
http://www.youtube.com/watch?v=J6LblvlOaPw6.
Carbon dioxide equivalent (CO2eq)
Carbon dioxide equivalent (CO2eq) is a unit which measures the global warming potential of different
greenhouse gases based on their heating potential and the length of time they persist in the atmosphere.
By using this measure, greenhouse gases are compared to carbon dioxide. The global warming potential
over 100 years of some common greenhouse gases are shown in Table 1. The tonne (t) is the most
common unit of mass used with CO2eq. A tonne (t) is equivalent to 1000 kg.
Table 1: The global warming potential over 100 years of some common greenhouse gases in carbon
dioxide equivalent (CO2eq) [7]
Greenhouse gas
Chemical
formula
Carbon dioxide
equivalent
(CO2eq)
Human sources of greenhouse gas
Carbon dioxide
CO2
1
Burning fossil fuels like coal, natural
gas and oil and deforestation (clearing
of trees)
Methane
CH4
25
Decomposition of landfill, farming of
livestock, production and use of fossil
fuels
Nitrous oxide
N2O
298
Agricultural practices including use
and manufacture of nitrogen fertilisers
Hydrofluorocarbons
Example:
HFC-134a
1,430
Air conditioning refrigerant
27
STUDENT ANSWERS
Calculating your CO2eq per year from travelling in cars
1.
What were your total kilometres travelled in the week? Use your table to add up your total.
155 km (This is the answer from the Sample Travel Log)
2.
What type of car were you in? (If you travelled in more than one type of car, only count the one you
used most often.)
This can be any car.
3.
You can now calculate your CO2eq in tonnes per year based on the kilometres you travelled. Go to
http://www.carbonneutral.com.au/carbon-calculator/vehicles-and-fuel-use.html 2
•
Click on the type of fuel your car uses. Most cars use petrol, however your car may use diesel or
LPG (gas).
Choose estimate by kilometres and put in your total from page 5.
Choose a frequency of every week.
The calculator will work out your estimated emissions in CO2eq in a year.
•
•
•
What are your calculated emissions in tCO2eq?
2.211 tCO2eq (Using the answer from the Sample Travel Log)
4.
Is there any journey during the week which you could have changed in some way to decrease your
CO2eq emissions?
•
•
•
•
•
5.
Walk or cycle to a close destination.
Use public transport.
Combine trips so that the car travels less.
Use closer destinations eg. shops that are closer to home.
Carpool so more people travel in the car to the same destination.
Are there other CO2eq emissions due to transport which could be considered in your yearly
emissions total?
Airplane travel. It is estimated that air travel produces as much carbon dioxide per passenger per
km as having one person in a small passenger car. Other greenhouse gases are produced as well
and the warming effect overall is 1.9 times that of carbon dioxide8. In fact a flight from Perth to
Sydney causes 1.35 tCO2eq to be released per person9.
Motorbike. When compared to a passenger car motorbikes emit, less CO2 however more of the
other more potent greenhouse gases, so overall are worse on emissions than a passenger car
carrying two people. This is due to their lack of restrictions on pollution control10.
Boat. Boats with an engine generally use either gas or diesel as fuel, so emit the same greenhouse
gases as driving a car.
Public transport. This is not included in a personal transport log because these buses, trams and
trains are travelling with or without passengers. Transperth estimates that its passengers save 232
tCO2eq per year by using public transport11.
28
STUDENT ANSWERS
Electric and hybrid cars
6.
How does driving a small car (eg. Volkswagen Golf) versus a large SUV (eg. Ford Territory) affect
the car’s fuel consumption? Why?
In general the lighter a car, then the less fuel it takes to drive it around. However some car’s engines
are more efficient on fuel consumption than others. Diesel cars use less fuel than a petrol car, but
hybrid cars (which combine features of an electric engine with a petrol engine) are the most efficient
on fuel.
7.
How is fuel consumption related to a car’s CO2eq emissions?
As fuel is being burnt in the car’s engine, greenhouse gases are being produced and emitted out of
the exhaust pipe. So the more fuel a car uses, the more greenhouse gas is being emitted.
Greenhouse gases are also produced in the manufacture and transport of fuel.
8.
What is a hybrid car? Why is it more eco-friendly than a petrol car?
A hybrid car combines features of an electric engine with a petrol engine. As the car drives, any
energy generated is collected and stored in a second battery. This allows the car to drive sometimes
on petrol and sometimes on electricity which means the car can drive further on one tank of petrol
and emit less greenhouse gases.
Rethinking your family’s CO2eq emissions due to car use
9.
Name five ways in which your family could reduce their CO2eq emissions due to transport.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
Drive a hybrid car
Drive a smaller car
Convert the car’s engine to use LPG
Car pool to take more passengers to school
Use more public transport
Walk or ride a bike to close destinations
Combine trips so the car does not travel as far
Maintain the car’s engine to ensure maximum efficiency
Keep the car’s tyres inflated sufficiently
Reduce the weight in the car. Take out anything that doesn’t need to be in the boot
Remove the roof rack when it is not in use
Avoid using the accelerator when not needed
Use cruise control when able
Spend as little time idling as possible
Use the air conditioner as little as possible
Students may come up with more answers than these.
29
STUDENT ANSWERS
COMPLETED TRAVEL LOG
Table of kilometres travelled by car
KMS ON THE DISTANCE
METER
DATE
WHERE FROM
WHERE TO
START
OF END
OF KMS
JOURNEY
JOURNEY
TRAVELLED
2 Sept
home
school
58,982
58,990
8
2 Sept
school
home
59,013
59,021
8
3 Sept
home
school
59,030
59,038
8
3 Sept
school
home
59,042
59,050
8
3 Sept
home
swimming lesson
59,050
59,054
4
3 Sept
swimming lesson
home via shops
59,054
59,060
6
4 Sept
home
school
59,060
59,068
8
4 Sept
school
home
59,091
59,099
8
5 Sept
home
school
59,106
59,114
8
5 Sept
school
piano lesson
59,132
59,142
10
5 Sept
piano lesson
home
59,148
59,155
7
6 Sept
home
school
59,155
59,163
8
6 Sept
school
home via shops
59,181
59,193
12
7 Sept
home
sport
59,199
59,210
11
7 Sept
sport
home
59,210
59,221
11
7 Sept
home
shops
59,221
59,225
4
7 Sept
shops
home
59,225
59,229
4
8 Sept
home
movies
59,237
59,248
11
8 Sept
movies
home
59,248
59,259
11
TOTAL KMS
TRAVELLED
155
30
Student name: ____________________________
STUDENT ACTIVITY
You have probably noticed all the reports about climate change in the media. It seems that local weather
including lower rainfall in winter and higher maximum temperatures in summer are being blamed on
climate change. Also we are seeing images of unusual weather events from all around the world (eg.
typhoons and floods) almost every week.
Many citizens, both young and old are concerned about how our climate will change in the future.
Politicians and the media are heavily involved in raising public awareness. For example, the Western
Australian Government along with the Future
Energy Alliance (made up of Western Australia’s
three electricity providers) introduced Sparky the
chudditch in a campaign to reduce our energy
usage5. You can see the full advertisement at
Figure 1: Sparky the chudditch is the mascot for the
http://www.youtube.com/watch?v=J6LblvlOaPw.
Switch the Future campaign. [5]
One important contribution towards climate change is carbon emissions from forms of transport. In 2010,
transport made up 15% of Australia’s carbon emissions. This means 83.2 million tonnes of carbon
dioxide equivalent (CO2eq) was emitted by road, rail, air and water transport vehicles. Passenger cars
were the largest source contributor of all vehicle types12.
What is carbon dioxide equivalent or CO2eq?
A tonne = 1000 kilograms
Each greenhouse gas has a different global warming potential due to:
i) The gases ability to absorb heat
ii) The concentration of that gas in the atmosphere
iii) The length of time that gas remains in the atmosphere before it is broken down by natural processes.
The global warming potential (GWP) of a greenhouse gas is a measure of the total heat energy that a
greenhouse gas absorbs over a particular period of time (usually 100 years). Scientists compare the
GWP of other greenhouse gases to carbon dioxide (CO2) which has a GWP of 1 and the unit of
measurement used is carbon dioxide equivalent (CO2eq) For example, methane (CH4) has a warming
effect 25 times greater than carbon dioxide (CO2) over a 100 year period. So methane is 25 CO2eq over
100 years7.
This unit is not often used in everyday language. As carbon dioxide (CO 2) is the easiest greenhouse gas
emission for individuals to reduce, people are often urged to reduce their carbon dioxide (CO2) emissions
or their ‘carbon footprint’. However there are other important greenhouse gases such as methane (CH4)
and nitrous oxide (N2O).
Your task is to make suggestions for how you can reduce your greenhouse gas emissions due to
transport by car. To be able to do this you need to first consider what your greenhouse gas emissions
due to personal transport are at the moment. For this task we will only consider your personal transport
by car (ie not using public transport).
Take the page titled TRAVEL LOG and carry it with you in
your car. Use the table to record any journeys you make in
the car in 7 days. For example, travelling to school.
Idea adapted from Science in Social Contexts. (2011). Science for life: Working with socio-scientific issues in school.
Retrieved from http://www.sisc.se/Materiel/Science%20for%20life.pdf
1
STUDENT ACTIVITY
Use your completed TRAVEL LOG to complete questions 1 – 5.
1.
What were your total kilometres travelled in the week? Use your table to add up your total.
______________________________________
2.
What type of car were you in? (If you travelled in more than one type of car, only count the one you
used most often.)
______________________________________________________
3.
You can now calculate your tCO2eq per year based on the kilometres you travelled. Go to
http://www.carbonneutral.com.au/carbon-calculator/vehicles-and-fuel-use.html

Click on the type of fuel your car uses. Most cars use petrol, however your car may use diesel or
LPG (gas).
Choose estimate by kilometres and put in your total from question 1.
Choose a frequency of every week.
The calculator will work out your estimated emissions in tCO2eq in a year.



What are your calculated emissions in tCO2eq?
______________________________________
4.
Is there any journey during the week which you could have changed in some way to decrease your
CO2eq emissions?
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
5.
Are there other CO2eq emissions due to transport which could be considered in your yearly
emissions total?
______________________________________________________
______________________________________________________
______________________________________________________
______________________________________________________
2
STUDENT ACTIVITY
FURTHER RESEARCH
Use the Internet to research the following questions. Some websites have been provided which may be
useful in your research.
Fuel consumption and CO2eq emissions
Factors which affect fuel consumption according to the RAC13.
http://www.racq.com.au/cars-and-driving/cars/owning-and-maintaining-a-car/facts-about-fuels/fueleconomy
Article by The Sydney Morning Herald about factors to consider when choosing a car. Includes
discussion on car sizes and different types of fuel14.
http://www.smh.com.au/money/investing/think-before-you-fuel-around-20110611-1fxw3.html
6.
How does driving a small car (eg. Volkswagen Golf) versus a large SUV (eg. Ford Territory) affect
the car’s fuel consumption? Why?
__________________________________________________
__________________________________________________
__________________________________________________
__________________________________________________
7.
How is fuel consumption related to a car’s CO2eq emissions?
__________________________________________________
__________________________________________________
__________________________________________________
__________________________________________________
Electric and hybrid cars
An electric car is powered by an electric motor
which gets its power from rechargeable batteries
instead of a petrol engine. An electric car cannot
travel for a long distance (with a range of usually
about 100km) which makes it suitable for city
driving only. However, the cost of recharging the
batteries is considerably less per km when
compared to a petrol engine. For example the fully
electric Nissan Leaf costs about $2 per 100km in
electricity, compared to a Mazda 3 which would
cost $12 in petrol to drive 100km15. The advantage
to the environment is that there are no emissions
from the tailpipe of an electric car, however the
greenhouse gas emissions from the electricity used to
recharge the batteries need to be considered. Currently
there are very few electric cars on the Australian market
and they are very expensive to buy.
Figure 2: A hybrid car has a petrol engine but stores
energy in a second battery as you drive. [16]
3
STUDENT ACTIVITY
Several manufacturers produce an electric hybrid car which has a petrol engine but collects and stores
energy as you drive and places it in a second battery (see Figure 2). You may remember that energy is
never lost – it just changes from one form into another. So in a petrol car for example, when you brake
the brake pads convert movement energy (kinetic) into heat energy through friction. An electric hybrid
car uses an electric generator to slow the car down, which converts the movement energy into electricity.
Modifications like this improve the car’s fuel consumption so you can drive further on one tank of petrol17.
8.
What is a hybrid car? Why is it more eco-friendly than a petrol car?
________________________________________________________
________________________________________________________
________________________________________________________
________________________________________________________
Rethinking your family’s CO2eq emissions due to car use
Now you have some more knowledge on what affects the greenhouse gas emissions
from your car, consider the following questions on how to reduce your family’s transport
related CO2eq emissions.
9.
1.
2.
3.
4.
5.
Name five ways in which your family could reduce their CO2eq emissions due to transport.
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
4
Student name: ____________________________
STUDENT ACTIVITY
TRAVEL LOG
During the week, please complete the following table. Make a note of
only the trips in which you are in the car. This includes trips to school, the
shops, sport, after school activities and any other trips you make.
KMS ON THE DISTANCE
METER
DATE
WHERE FROM
WHERE TO
START
OF END
OF KMS
JOURNEY
JOURNEY
TRAVELLED
TOTAL KMS
TRAVELLED
5
Student name: ____________________________
STUDENT ACTIVITY
SAMPLE TRAVEL LOG
During the week, please complete the following table. Make a note of
only the trips in which you are in the car. This includes trips to school,
the shops, sport, after school activities and any other trips you make.
KMS ON THE DISTANCE
METER
DATE
WHERE FROM
WHERE TO
START
OF END
OF KMS
JOURNEY
JOURNEY
TRAVELLED
2 Sept
home
school
58,982
58,990
2 Sept
school
home
59,013
59,021
3 Sept
home
school
59,030
59,038
3 Sept
school
home
59,042
59,050
3 Sept
home
swimming lesson
59,050
59,054
3 Sept
swimming lesson
home via shops
59,054
59,060
4 Sept
home
school
59,060
59,068
4 Sept
school
home
59,091
59,099
5 Sept
home
school
59,106
59,114
5 Sept
school
piano lesson
59,132
59,142
5 Sept
piano lesson
home
59,148
59,155
6 Sept
home
school
59,155
59,163
6 Sept
school
home via shops
59,181
59,193
7 Sept
home
sport
59,199
59,210
7 Sept
sport
home
59,210
59,221
7 Sept
home
shops
59,221
59,225
7 Sept
shops
home
59,225
59,229
8 Sept
home
movies
59,237
59,248
8 Sept
movies
home
59,248
59,259
TOTAL KMS
TRAVELLED
5
REFERENCES
REFERENCE LIST
1
2
Carbon Neutral. Carbon calculator, 2011. Vehicle and Fuel Use. [Online] Available from:
http://www.carbonneutral.com.au/carbon-calculator/vehicles-and-fuel-use.html [Accessed 9
September, 2012].
3
Australian Broadcasting Corporation. Cars, 2007. Carbon Cops. [Online] Available from:
http://www.abc.net.au/tv/carboncops/factsheets/cc_cars.pdf [Accessed 9 September, 2012].
4
United States, Environmental Protection Agency. Reducing greenhouse gas emissions. Report
EPA-420-F-11-041, 2011. Office of Transportation and Air Quality. [Online] Available from:
http://www.epa.gov/otaq/climate/documents/420f14040.pdf [Accessed 9 September, 2012].
5
Synergy. About Sparky, 2012. Switch the Future. [Online] Available from
http://www.switchthefuture.com.au/About/About-Sparky/ [Accessed 9 September, 2012].
6
YouTube Australia. Switch the Future Advert on WA TV, 2011. Sustainable Energy Now.
[Online]. Available from http://www.youtube.com/watch?v=J6LblvlOaPw [Accessed 9 September,
2012].
7
Manitoba Eco Network. CO2 equivalents, 2014. Climate Change Connection [Online] Available
from: http://climatechangeconnection.org/emissions/co2-equivalents/ [Accessed 21 October,
2014].
8
Manitoba Eco Network. Air travel, 2014. Climate Change Connection. [Online] Available from:
http://climatechangeconnection.org/solutions/transportation/air-travel/ [Accessed 21 October,
2014].
9
Carbon Neutral. Air travel carbon calculator, 2011. [Online] Available from:
http://www.carbonneutral.com.au/carbon-calculator/air-travel.html [Accessed 9 September,
2012].
10 A. M. Vasic, & M. Weilenmann. Comparison of real-world emissions from two-wheelers and
passenger cars. Environmental; Science and Technology, 2006, 40 (1), 149-15.
11 The Government of Western Australia. The Environment, [no date]. Public Transport Authority.
[Online] Available from:
http://www.pta.wa.gov.au/OurSystem/TheEnvironment/tabid/67/Default.aspx [Accessed 9
September, 2012].
12 Carbon Neutral. Australia’s greenhouse gas emissions, 2011. [Online] Available from:
http://www.carbonneutral.com.au/climate-change/australian-emissions.html [Accessed 9
September, 2012].
13 RACQ. Fuel Economy, [no date]. [Online] Available from: http://www.racq.com.au/cars-anddriving/cars/owning-and-maintaining-a-car/facts-about-fuels/fuel-economy [Accessed 21 October,
2014].
14 Sydney Morning Herald. Think before you fuel around, June 11, 2011. [Online] Available from:
http://www.smh.com.au/money/investing/think-before-you-fuel-around-20110611-1fxw3.html
[Accessed 9 September, 2012].
37
REFERENCES
15 Origin Energy. Electric cars, 2013. Energy Explorer. [Online] Available from:
http://www.originenergy.com.au/electriccars [Accessed 9 September, 2012].
16 Donate Car US. How hybrid cars work, 2014. [Online] Available from:
http://donatecarus.com/how-hybrid-cars-work/ [Accessed 21 October, 2014].
17 United States Department of Energy. How hybrids work, 2013. www.Fueleconomy.gov. [Online]
Available from: http://www.fueleconomy.gov/feg/hybridtech.shtml [Accessed 9 September, 2012].
List of Tables
Teacher Notes
Table 1
The global warming potential over 100 years of some common greenhouse gases in
carbon dioxide equivalent (CO2eq)
List of Figures
Student Activity
Figure 1
Sparky the chudditch is the mascot for the Switch the Future campaign
Figure 2
A hybrid car has a petrol engine but stores energy in a second battery as you drive
38
DEMONSTRATING THE
GREENHOUSE EFFECT
DEMONSTRATING THE GREENHOUSE
EFFECT
This experiment demonstrates that an atmosphere high in carbon
dioxide increases in temperature more rapidly and remains at a higher
temperature than an atmosphere low in carbon dioxide.
42
Teacher notes
44
Student answers
46
Student activity
48
References
52
Content Strand
Content Description
Elaboration
Plan, select and use appropriate investigation
methods, including field work and laboratory
experimentation, to collect reliable data; assess
risk and address ethical issues associated with
these methods (ACSIS165)
Explaining the choice of variables to be controlled,
changed and measured in an investigation
Considering how investigation methods and
equipment may influence the reliablity of collected
data
Select and use appropriate equipment,
including digital technologies, to systematically
and accurately collect and record data
(ACSIS166)
Using probes and data loggers to record
information
Applying specific skills for the use of scientific
instruments
Analyse patterns and trends in data, including
describing relationships between variables and
identifying inconsistencies (ACSIS169)
Designing and constructing appropriate graphs to
represent data and analysing graphs for trends and
patterns
Use knowledge of scientific concepts to draw
conclusions that are consistent with evidence
(ACSIS170)
Comparing conclusions with earlier predictions and
reviewing scientific understanding where
appropriate
Suggesting more than one possible explanation of
the data presented
Evaluate conclusions, including identifying
sources of uncertainty and possible alternative
explanations, and describe specific ways to
improve the quality of the data (ACSIS171)
Identifying gaps or weaknesses in conclusions
(their own or those of others)
Identifying alternative explanations that are also
consistent with the evidence
Global systems, including the carbon cycle,
rely on interactions involving the biosphere,
lithosphere, hydrosphere and atmosphere
Explaining the causes and effects of the
greenhouse effect
YEAR 9
Planning and Conducting
Processing and
Analysing Data and
Information
Evaluating
YEAR 10
Earth and Space
Sciences
(ACSSU189)
Nature and Development
of Science
Scientific understanding, including models and
theories, are contestable and are refined over
time through a process of review by the
scientific community (ACSHE191)
Considering the role of science in identifying and
explaining the causes of climate change
Plan, select and use appropriate investigation
methods, including field work and laboratory
experimentation, to collect reliable data; assess
risk and address ethical issues associated with
these methods (ACSIS199)
Deciding how much data are needed to produce
reliable measurements
Considering possible confounding variables or
effects and ensuring these are controlled
Select and use appropriate equipment,
including digital technologies, to systematically
and accurately collect and record data
(ACSIS200)
Selecting and using probes and data loggers to
record information
Applying specific skills for the use of scientific
instruments
Identifying where human error can influence the
reliability of data
Analyse patterns and trends in data, including
describing relationships between variables and
identifying inconsistencies (ACSIS203)
Using spreadsheets to present data in tables and
graphical forms and to carry out mathematical
analyses on data
Planning and Conducting
Processing and
Analysing Data and
Information
42
Describing sample properties (such as mean,
median, range, large gaps visible on a graph) to
predict characteristics of the larger population
Acknowledging uncertainties and the effects of
outliers exploring relationships between variables
using spreadsheets, databases, tables, charts,
graphs and statistics
Evaluating
Evaluate conclusions, including identifying
sources of uncertainty and possible alternative
explanations, and describe specific ways to
improve the quality of the data (ACSIS205)
Evaluating the strength of a conclusion that can be
inferred from a particular data set
Distinguishing between random and systematic
errors and how these can affect investigation
results
43
TEACHER NOTES
DEMONSTRATING THE GREENHOUSE EFFECT
This experiment demonstrates that an atmosphere high in carbon dioxide increases in temperature more
rapidly and remains at a higher temperature than an atmosphere low in carbon dioxide. The experiment
works well with Year 9-12 students in groups of 4, however can also be done as a demonstration with
groups of students being called every five minutes to read the temperature of the bottles and write the
results on the board.
The demonstration of the greenhouse effect is achieved by using two 2 litre plastic bottles and two cans
of Coca Cola©. For Bottle 1, the Coca Cola© is agitated in a beaker before being poured into the bottle.
This releases the carbon dioxide into the air, meaning that when the liquid is poured into the bottle, the
atmosphere will have much less carbon dioxide than Bottle 2. In Bottle 2 the Coca Cola© is poured into
the bottle using a funnel and then agitated by shaking the bottle for approximately 2 minutes. This
releases the carbon dioxide into the air inside the bottle, creating an atmosphere high in carbon dioxide.
A thermometer is placed inside each bottle and students then place the two bottles outside in the
sunshine. Students will take measurements of the temperature in each bottle every minute for 20
minutes.
Equipment
Cola brands - Two cans of cola are required and even though different brands can be used,
Coca Cola© brand has been shown to work best. All of the equipment including the cans of
cola need to be at room temperature. If the cola liquid has been in the fridge, less carbon
dioxide will be released and the temperatures inside the bottles will take longer to heat up.
Thermometer - A stopper which tightly fits the top of the bottle and can hold a thermometer inside the
bottle should be used. If this is not available, then use plasticine or playdough to hold the thermometer in
place and to form an airtight seal. A digital thermometer or probe gives the most accurate results. An
alcohol thermometer can also be used, however will give less precise results.
Weather
This experiment works best on a warm and sunny day. If the temperature is below 25C and/or is
cloudy, then the experiment can also be performed using a heat lamp. It is imperative that both bottles
receive the same amount of heat. Even placing one bottle in the shadow of the other bottle can affect
the results.
Method
 Because both bottles appear the same, they need to be clearly labelled as Bottle 1 and Bottle 2.
 Students need to agitate the Coca Cola© for Bottle 1 vigorously for two minutes. If this is not done
effectively then both atmospheres will be high in carbon dioxide.
 Ensure the stoppers used are airtight, otherwise as the gases heat up they will escape out the top of
the bottles.
 The temperature reading is affected (raised) if the bulb or sensor is touching the sides of the plastic
bottle.
 Both thermometers need to be at the same level in each bottle for a fair comparison.
What to expect
Within the first five minutes Bottle 2 (with a higher carbon dioxide content) should rise to a higher
temperature than Bottle 1. It should remain at a higher temperature for the duration of the experiment. As
the example of typical results take from Keating (2007) demonstrates, the stable temperature is reached
at about 15 minutes.
Adapted from Keating, C.F. (2007). A simple experiment to demonstrate the effects of
greenhouse gases. The Physics Teacher. 45, 376-378.
44
TEACHER NOTES
Figure 6: Example of results on a sunny day,
using a digital thermometer [2]
Explanation of the results
Bottle 1 represents an atmosphere with a lower concentration of carbon dioxide and is made up mostly
of oxygen (O2) and nitrous oxide (N2O). The agitation of the Coca Cola© in the beaker outside the bottle,
releases the carbon dioxide into the air. Some carbon dioxide will remain in the cola liquid and still be
present in the air inside the bottle, however there will be considerably less than in Bottle 2. Bottle 1 is
used for comparison.
Bottle 2 represents the Earth’s atmosphere with a higher concentration of carbon dioxide. The agitation
of the Coca Cola© inside the bottle releases carbon dioxide into the air inside the bottle which is sealed
inside by the lid. Due to the higher amount of carbon dioxide, this atmosphere retains more heat than
Bottle 2, allowing it to heat up faster and stay at a warmer temperature than Bottle 1. Bottle 2
demonstrates the greenhouse effect on Earth.
45
STUDENT ANSWERS
Question 1.
Before you begin, write a short description or draw a diagram of how you think
the greenhouse effect works.
Light from the sun passes through the atmosphere and warms the surface of the Earth. This heat is
released back into the air and greenhouse gases in the atmosphere such as carbon dioxide, methane
and water absorb this heat. This keeps the planet warmer than it would be and allows life to exist.
Question 2.
What does shaking the Coca-Cola® do? Think about why the liquid becomes fizzy.
Shaking the Coca Cola® releases the carbon dioxide from the liquid into the air inside the bottle.
Question 3.
What is the difference between Bottle 1 and Bottle 2? Think about the different gases
(representing the atmosphere) in the bottles.
Bottle 1 had the Coca Cola® released into the air outside, so the air inside the bottle is similar to the air
outside. This atmosphere will be mostly oxygen and nitrous oxide. Bottle 2 has had the Coca Cola®
released into the air inside the bottle creating an atmosphere high in carbon dioxide.
Question 4.
Describe three patterns that your graph shows.
1. The temperature of Bottle 2 increased faster than Bottle 1.
2. The temperature of Bottle 2 reached a higher temperature than Bottle 1.
3. The temperature of Bottle 2 remained at a higher temperature than Bottle 1 once the temperatures
were stable.
Question 5. Can you think of any possible sources of error in this experiment?







The Coca Cola® was not shaken or stirred enough to release the carbon dioxide.
The bottles did not receive the same amount of sunlight/heat.
The bottles were placed on different surfaces.
The lids were not completely airtight.
The thermometers were read incorrectly (if using alcohol thermometers).
Either of the thermometers were touching the side of the bottle.
The thermometers may have been at different levels in the bottles.
Question 6.
How do these bottles represent the Earth’s atmosphere and the greenhouse effect? Draw
a diagram to help with your explanation.
Atmosphere low in CO2
but high in O2 and NO2
Atmosphere high in
CO2
This is for comparison
This represents the
enhanced greenhouse
effect
Bottle 1
Adapted from Keating, C.F. (2007). A simple experiment to demonstrate the effects of
greenhouse gases. The Physics Teacher. 45, 376-378.
Bottle 2
46
STUDENT ANSWERS
Question 7.
Look at your previous explanation of the greenhouse effect. Did you learn anything new or
different about the greenhouse effect from doing this experiment? Please explain.
Solar radiation passes through the atmosphere and warms the surface of the Earth. This heat is released
back into the air and greenhouse gases in the atmosphere such as carbon dioxide, methane and water
absorb this heat. This keeps the planet warmer than it would be and allows life to exist. Increasing levels of
greenhouse gases, cause more heat to be absorbed, which raises the temperature of the Earth’s surface.
This is called global warming.
47
Student name: ____________________________
STUDENT ACTIVITY
Today you will be doing an experiment showing how the greenhouse effect works.
Question 1
Before you begin, write a short description or draw a diagram of how you think the
greenhouse effect works.
Aim: To demonstrate how greenhouse gases contribute to warming the Earth.
Materials:
2 clear 2 litre plastic bottles (empty)
2 cans of Coca-Cola® at room temperature
2 thermometers
2 rubber stoppers or plasticine to seal the bottle top
500ml beaker
stirring rod
funnel
timer
Method:
Read through the method very carefully before beginning your experiment and answer
Questions 2 and 3.
1. Label each bottle 1 and 2.
2. Bottle 1





Question 2.
Pour a full can of Coca-Cola® into the 500ml beaker.
Stir vigorously with a stirring rod for 2 minutes to make the liquid fizzy.
Pour into bottle 1 using the funnel.
Place the bung in the neck of the bottle and adjust the thermometer so the
bulb is in the atmosphere of the bottle and you can read the temperature. Make sure the
thermometer is not touching the side of the bottle.
Ensure the stopper is airtight.
What does shaking the Coca-Cola® do? Think about why the liquid becomes fizzy.
__________________________________________________
__________________________________________________
__________________________________________________
1
STUDENT ACTIVITY
3. Bottle 2




Question 3.
Pour a full can of Coca-Cola ® into the bottle using the funnel.
Now shake the bottle for 2 minutes to make the liquid fizzy.
Place the stopper in the neck of the bottle and adjust the thermometer so the
bulb is in the atmosphere of the bottle and you can read the temperature. Make
sure the thermometer is not touching the side of the bottle.
Ensure the stopper is airtight.
What is the difference between Bottle 1 and Bottle 2? Think about the different
gases (representing the atmosphere) in the bottles.
__________________________________________________
__________________________________________________
4. Place both bottles outside in the sun so they receive the same amount of sunlight.
(If the day is not warm or sunny enough, your teacher may give you a heating lamp to warm the
bottles. In this case place the bottles in front of the lamp so they receive the same amount of heat).
5. Record the temperature from both bottles using Table 1. Repeat this every minute for 20 minutes.
Results:
Table 1: Table of time and temperature
Time (mins)
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Bottle 1 temperature (C)
Bottle 2 temperature (C)
2
STUDENT ACTIVITY
Draw a graph of your results. Remember to: 1) include a title for your graph, and 2) a legend showing the
different results for Bottle 1 and Bottle 2.
Temperature
(C)
Time
(minutes)
Question 4.
1.
2.
3.
Describe three patterns that your graph shows.
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
_______________________________________________
Question 5.
Can you think of any possible sources of error in this experiment?
__________________________________________________
__________________________________________________
__________________________________________________
3
STUDENT ACTIVITY
Question 6.
How do these bottles represent the Earth’s atmosphere and the greenhouse effect? Draw
a diagram to help with your explanation.
Question 7.
Look at your previous explanation of the greenhouse effect. Did you learn anything new or
different about the greenhouse effect from doing this experiment? Please explain.
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
4
REFERENCES
REFERENCE LIST
1
2
C. F. Keating. A simple experiment to demonstrate the effects of greenhouse gases. The Physics
Teacher, 2007, 45, 376-378.
List of Figures
Teacher Notes
Figure 1
Example of results on a sunny day, using a digital thermometer
52
SOCIOSCIENTIFIC ISSUES
AND INTRODUCING
ARGUMENTATION
SOCIOSCIENTIFIC ISSUES AND
INTRODUCING ARGUMENTATION
Socioscientific issues are topics with a scientific basis which are
important to human society, such as climate change. Teaching students
the skills of argumentation allows them to formulate a well-developed
argument when discussing these issues.
56
Teacher notes
58
Student activity
62
Are eco-buses worth the cost?
Burning rubbish for electricity – waste to energy
plants
Wind power
References
68
Content Strand
Content Description
Elaboration
Year 7
Science
solutions to a range of contemporary issues; these
solutions may impact on other areas of society
and involve ethical considerations (ACSHE120)
Considering how human activity in the
community can have positive and negative
effects on the sustainability of ecosystems
Questioning and
Predicting
cultural, economic or moral aspects rather than
or as well as scientific investigation using
information and knowledge from
Evaluating
Use scientific knowledge and findings from
investigations to evaluate claims (ACSIS132)
Using the evidence provided by scientific
investigations to evaluate the claims or
conclusions of their peers
YEAR 8
Science
solutions to a range of contemporary issues; these
solutions may impact on other areas of society
and involve ethical considerations (ACSHE135)
Investigating requirements and the design of
systems for collecting and recycling household
waste
Investigating how energy efficiency can reduce
energy consumption
Questioning and
Predicting
cultural, economic or moral aspects rather than
or as well as scientific investigation
Evaluating
Use scientific knowledge and findings from
investigations to evaluate claims (ACSIS234)
Identifying the scientific evidence available to
evaluate claims
Deciding whether or not to accept claims based
on scientific evidence
Identifying where science has been used to
make claims relating to products and practices
YEAR 9
Science
Using knowledge of science to test claims made
in advertising or expressed in the media
Describing how science is used in the media to
explain a natural event or justify actions
Evaluating claims relating to products such as
electrical devices, fuels, indigestion tablets
Considering the impacts of human activity on an
ecosystem from a range of different perspectives
Critically analyse the validity of information in
secondary sources and evaluate the approaches
used to solve problems (ACSIS172)
Describing how scientific arguments are used to
make decisions regarding personal and
community issues
Science Inquiry
Evaluating
56
YEAR 10
Science
Describing how science is used in the media to
explain a natural event or justify people’s actions
Considering the scientific knowledge used in
discussions relating to climate change
Evaluating claims relating to environmental
footprints
(ACSHE230)
Considering innovative energy transfer devices,
including those used in transport and
communication
Processing and
Analysing Data and
Information
Use knowledge of scientific concepts to draw
conclusions that are consistent with evidence
(ACSIS204)
Using primary or secondary scientific evidence
to support or refute a conclusion
Constructing a scientific argument showing how
their evidence supports their claim
Evaluating
Critically analyse the validity of information in
secondary sources and evaluate the approaches
used to solve problems (ACSIS206)
Researching the methods used by scientists in
studies reported in the media Judging the
validity of science-related media reports and
how these reports might be interpreted by the
public
Describing how scientific arguments, as well as
ethical, economic and social arguments, are
used to make decisions regarding personal and
community issues
Communicating
Communicate scientific ideas and information for a
particular purpose, including constructing
evidence-based arguments and using appropriate
scientific language, conventions and
representations (ACSIS208)
Constructing evidence based arguments and
engaging in debate about scientific ideas
Science Inquiry
57
TEACHER NOTES
SOCIOSCIENTIFIC ISSUES
What are socioscientific issues?
Socioscientific issues are topics with a scientific basis which are important to human society. They are
often controversial, with a range of views in society as they often involve ethical, social, economic and
political considerations. The science underpinning these issues is usually multidisciplinary, involving
more than one area of science and the science itself may be contested. These issues are very often
debated in popular media.
Examples include: climate change, genetically modified food, population growth, and surrogacy.
Why are they important to teach?
Including socioscientific issues in the classroom increases the relevance of science to students’
everyday lives and can improve students’ attitudes to science. There can also be an improvement in
students’ scientific literacy and their understanding of a science topic.
How can I include socioscientific issues in my classroom?
Because socioscientific issues are controversial, students may hold strong and firm opinions about an
issue. Teaching strategies thus aim to provide accurate and up-to-date science content and give
students the information which will enable them to make and justify their decisions about an issue. It is
also an opportunity to raise students’ awareness of an issue which may impact their lives in some way.
Teaching strategies used to teach socioscientific issues include:

Co-operative group work. This involves students working together as a team. Benefits of this
include development of social skills such as leadership and communication, as well as more
effective learning as students listen to and learn from each other.

Role plays. This is where students act out different parts of people who may be affected by an
issue. This allows students to consider different point of views of an issue.

Debate. Students form teams representing two sides of an issue: for and against. Students can
be randomly placed on a team or choose which side they would like to represent. They then
argue in front of members of the class, who judge the value of their arguments.

Independent research. This can be in the form of a simple worksheet or an assignment.

Consensus meetings. Meetings are performed in small groups where students discuss and
negotiate an issue until they all come to an agreement.

Hypotheticals. Here students are given a hypothetical situation and need to analyse the situation,
perhaps making decisions based on the information they have been given.
EVIDENCE-BASED DECISION MAKING
In order for students to become scientifically literate and to make decisions as citizens which affect
themselves, their family and/or their community, they require the skills to balance the consequences of
their decision. Evidence-based decision making is a process of weighing up the risks and benefits of a
decision and considering the consequences, both long and short term of different courses of action.
In order to weigh up various options, a risk–benefit analysis can be used, or the consideration of equity,
where benefits are maximised and harm is minimised. Because of the difficulty in making a decision
when considering the environment, a formal guideline for policy-makers has been developed called the
precautionary principle2. This guideline has four components: 1) taking preventative action when there is
58
TEACHER NOTES
uncertainty; 2) shifting the responsibility of proof to the advocates of an activity; 3) exploring all of the
alternatives to a possibly harmful action; and 4) increasing public contribution to decision-making.
The process of decision making often involves looking at an issue from the perspectives of different
stakeholders. For example: At the beginning of 2014, Mundella, one of Western Australia’s largest
dairies was sold to a Chinese company. This followed several purchases of large amounts of agricultural
land by other Chinese companies, sparking fears of future food security in Western Australia3. If students
were to consider the question, Should the WA government limit the amount of land able to be purchased
by overseas companies? they would need to consider the issue from several stakeholders’ views: a WA
farmer, the WA government, a WA citizen, a Chinese company, the Chinese government. They would
also need to consider their duties and responsibilities as a citizen of the WA community as they make
their decision.
Evidence-based decision making is included in the rationale for the Australian Curriculum for Science,
stating “The curriculum supports students to develop the scientific knowledge, understandings and skills
to make informed decisions about local, national and global issues” (1, p.4). Students at any age can be
taught and encouraged to support their arguments with data. It is as they mature that this data becomes
more complex. Evidence-based decision making is specifically mentioned in Year 10 under Science
Inquiry Skills (see Links to Australian curriculum on page 56).
ARGUMENTATION
For students to present and defend their decisions in a logical manner they require skills in
argumentation, which is a standard process for developing and evaluating decision making. The
inclusion of argumentation in the classroom has been shown to increase students’ understanding of
science, as they use their knowledge in authentic situations.
An argument has been defined by Stephen Toulmin (4) to consist of the following features: claim, data,
qualifier and backing.
CLAIM - These are assertions about what exists or values that people hold. This is the main point or
controlling idea of the argument.
What is the author trying to prove? = CLAIM
DATA - These are statements or reasons that are used as evidence to support the claim. The data can
be in the form of facts, expert opinions, examples, explanations or logical reasoning.
What does the author say to persuade you of his/her claim? = DATA
QUALIFIERS - Because argumentation is about probability and not certainty, the argument needs to be
qualified (softened) with expressions like many times, possibly, could, few and sometimes.
How certain is the author of his/her claim? = QUALIFIER
BACKING – These are underlying assumptions that support and back up the data. They are used to
make the data more believable.
What extra information supports the data? = BACKING
For example:
I believe the Western Australian government should charge people more for their electricity so that
people are more considerate about how much energy they use (CLAIM) At the moment (QUALIFIER),
people are charged the same price per kilowatt hour (KWH) no matter how much energy they use
(DATA). This seems unfair when I make efforts to limit my energy usage by closing up the house during
the day and opening it at night, and my neighbours run their air conditioner 24 hours a day (DATA). They
59
TEACHER NOTES
may have more money than me to pay their electricity bill, however we all share the same world
(BACKING).
ARGUMENTATION SCENARIOS
Three real-life scenarios are presented in this booklet, based on climate change. Questions have been
used to scaffold students’ thinking to form the features of a strong argument. Some teachers may wish to
have the students’ research the topics further or present the students with more information before
students complete the scenario questions. If students simply use the information given in the scenario,
question one asks them to consider further information they would like to help make their decision. This
encourages students to evaluate and question what data is present and what may be missing.
Students should read the information before answering the question asked of them about the scenario.
This is their claim. Encourage the students to make a decision and answer yes, no or I don’t know, so
they can back up their claim with data and consider the advantages and disadvantages of their decision.
At this stage it is useful to draw a table on the board showing the numbers of students supporting each
claim. It is recommended that students answer questions one to four by themselves, before group
discussions or a class discussion of each question. Students can then answer question five and the
numbers of students supporting each claim can be tabulated again. Students who changed their mind
can share with the class why they did so. This is usually because they did not have enough information
at the time or properly understand the situation when they initially made their decision.
Are Eco-buses worth the cost?
Figure 7: Where the fuel cell and hydrogen tanks
are situated in an Eco-bus [5].
Transperth was part of a study in nine cities around the
world to investigate the use of alternative-fuelled public
buses. Perth was the only city in the Southern hemisphere
to participate. Other cities to take part included Barcelona,
Beijing, London and Reykjavik. After three years the entire
trial was deemed a success, however the Perth
government decided the cost of this technology for just
three buses was too high. The trial found that the running
costs were decreased if hydrogen was produced by
renewable energy rather than from crude oil, and that
adaptations to the bus design such as regenerative braking
would also improve efficiency. The buses were slightly
wider than normal (at 2.55m instead of a usual maximum of
2.45m) making them difficult to drive in suburban streets
and could carry fewer passengers (59 instead of 82) due to
the extra weight of the fuel cells on the bus’s roof5.
Burning rubbish for electricity: Waste to Energy plants
Forty countries worldwide have embraced burning rubbish
to produce energy as well as reduce landfill. Some
countries such as Norway and Sweden burn more rubbish
than they produce so import it from neighbouring
countries. In fact Sweden imports 800,000 tons of rubbish
to turn into energy every year6. Australia currently has no
Waste-to-Energy plants, however plans are in progress to
have the first plants built in Western Australia7.
Figure 8: Perth waste may be used as a nonrenewable energy source [7].
60
TEACHER NOTES
The Waste-to-Energy plants work by burning non-recyclable rubbish at around 2000C, turning water
into steam which runs turbines that produce electricity. The gas produced is passed through filters to
remove all toxic chemicals such as metals and acids, until only carbon dioxide and water vapour are left.
The ash which is still toxic is usually turned into bricks and disposed of in landfill6. Critics of this process
highlight that the process still produces carbon dioxide and toxic ash which becomes landfill, so how is
this better than burying the rubbish? When rubbish is buried it produces methane as it decomposes
which can also be captured and burned to generate electricity. The Environmental Protection Agency in
the USA completed a scientific study in 2013 comparing these two methods of energy production. They
found that burning rubbish produced about ten times more electricity from the same amount of waste.
The study also found that per unit of electricity generated, the greenhouse gas emissions from burying
rubbish are two to six times higher than when rubbish is burnt8.
Wind power
In 2013, a local Western Australian co-operative called Moonies Hill Energy, was given permission to
begin construction of a wind farm on land in Kojonup in the Great Southern area of Western Australia.
The planned wind farm is predicted to generate local employment during both the construction and
maintenance phases and will produce enough energy to supply the needs of over 90,000 homes. More
importantly by using renewable energy, it will reduce the greenhouse gas emissions by over 450,000
tCO2eq per year. This is equivalent to taking 100,000 cars off the road9.
At the time there was opposition from local landowners and farmers, due to concern about possible
health effects10. Anecdotally, ‘wind turbine syndrome’ is believed to cause health issues such as nausea,
dizziness, tinnitus and sleeping problems due to the low level frequency of sound11. There is however no
peer reviewed studies available to support this theory. Other problems associated with wind turbines,
include a possible decrease in the value of neighbouring properties and noise. Reports show that at
300m from a wind turbine has a sound pressure level of 43 decibels. This is less than an average
refrigerator which runs at about 40 decibels12. Figure 9 shows the comparison between wind turbines
and other common household items. The issue of difficulty in aerially spraying crops or firefighting was
also raised, as was the possible threat to local birdlife and livestock. Research from the United States
shows that there is negligible bird deaths from wind turbines13 and there are no reports of a decrease in
agricultural production from having wind turbines on farming land9.
Figure 9: The noise of wind
turbines compared to common
household appliances [9].
61
STUDENT ACTIVITY
ARE ECOBUSES WORTH THE COST?
Between 2004 and 2007, Transperth trialled three EcoBuses in
Perth which ran on hydrogen fuel cells as their fuel source. The
benefit of using a hydrogen fuel cell is that the only waste
emissions produced are water and heat. At the conclusion of
the trial, the three buses had travelled 258,000 kms and carried
over 320,000 passengers. 300 tCO2eq were saved by not using
regular diesel buses. Although the trial was deemed a success
by Transperth, the WA government has decided not to proceed
any further with the EcoBuses, claiming the cost to maintain
each bus was too high a price to pay compared to a regular bus.
Figure 1: Transperth trialled three buses which
used hydrogen as their fuel source [14]
Do you think the WA government made the right decision?
Yes
1.
No
I don’t know
What further information would help in making your decision?
Glossary
t = This unit stands for a tonne and measures mass. It is equivalent to 1000 kilograms.
CO2eq = The global warming potential (GWP) of a greenhouse gas is a measure of the total heat energy that a
greenhouse gas absorbs over a particular period of time (usually 100 years). Scientists compare the GWP of
other greenhouse gases to carbon dioxide (CO2) which has a GWP of 1 and the unit of measurement used is
carbon dioxide equivalent (CO2eq or CO2e) For example methane (CH4) has a warming effect 25 times greater
than carbon dioxide (CO2) over a 100 year period. So methane is 25 CO2eq over 100 years.
1
STUDENT ACTIVITY
2.
What are the possible advantages of your decision?
3.
What are the possible disadvantages of your decision?
4.
If someone disagrees with you, how would you convince them that your answer is the best?
5.
Has your original decision changed? In what way?
2
STUDENT ACTIVITY
BURNING RUBBISH FOR ELECTRICITY – WASTE TO ENERGY PLANTS
When considering household waste (rubbish) local governments
promote the 4Rs – Reduce, Reuse, Recycle and Recovery. The
fourth R, Recovery, means converting what is non-recyclable into
resources (eg. electricity, heat, compost and fuel). A common
global process is to burn rubbish to make electricity and this
occurs in over 40 countries worldwide. Norway burns so much
rubbish to make electricity and heat for homes that they have to
import rubbish from neighbouring countries. But is this an
environmentally sound process?
Industrial plants which carry out this process are called ‘Waste-toEnergy’ plants and they burn the rubbish at approximately
2000C.
This is as hot as the lava from a volcano! At this
Figure 1: Processes to consider when
temperature the water turns into steam which runs turbines to
dealing with waste include Recovery
produce electricity. Gases and ashes are also produced in the
(recovering energy from waste) [15].
process. The gases are run through a series of filters to remove
toxic metals and acids, leaving only carbon dioxide (CO2) and water vapour. The ash left over, is turned
into bricks, which are used as landfill (buried underground).
Opponents of Waste-to-Energy plants criticise possible toxic emissions from burning the rubbish leading
to both public health and environmental concerns. Also they believe this process does nothing to reduce
the amount of waste produced by the population and discourages people from recycling.
The first Waste-to-Energy plant to be built in Australia is being planned for Port Hedland, with another
one planned for Kwinana. The plant in Kwinana expects to produce enough electricity to provide power
to between 55,000 - 127,000 homes, as well as disposing of 300,000 tonnes of rubbish.
If you were the mayor, would you allow a Waste-to-Energy plant to be built
in your Council area?
Yes
1.
No
I don’t know
1
STUDENT ACTIVITY
2.
3.
4.
5.
2
STUDENT ACTIVITY
WIND POWER
A WA company called Moonies Hill Energy has proposed to build WA’s largest
wind farm of 74 wind turbines near the town of Kojonup. This wind farm can
produce enough electricity to power over 90,000 homes. It will avoid up to
450,000 tonnes of carbon dioxide equivalent (CO2eq) each year. The wind
turbines will only be built on land where farmers agree to their construction. When
built the turbines will occupy less than 1% of productive farmland.
In July, 2013 the government gave the wind farm the go ahead, which means they are allowed to
begin building the wind farm. Local farmers are angry with this decision. They say the 146m wind
turbines will prevent them from aerially spraying their crops with either fertiliser or pesticide. They also
believe it will decrease the value of their property.
If you were a wheat and sheep farmer in Kojonup, and were approached by
Moonies Hill Energy to have two wind turbines built on your property would
you agree?
Yes
No
1.
2.
I don’t know
1
STUDENT ACTIVITY
3.
4.
5.
2
REFERENCES
REFERENCE LIST
1
2
D. Kriebel, J. Tickner, P. Epstein, J. Lemons, R. Levins, E. Loechler, M. Quinn, R. Rudel, T.
Schettler, & M. Stoto. The precautionary principle in environmental science. Environmental
Health Perspectives, 2001, 109 (9), 871-876.
3
B. Speedy. Bright Food swallows WA cheese and yoghurt producer Mundella, Jan 15, 2013. The
Australian. [Online]. Available from http://www.theaustralian.com.au/business/companies/brightfood-swallows-wa-cheese-and-yoghurt-producer-mundella/story-fn91v9q3-1226801838025#
[Accessed 4 September 2013].
4
S. Toulmin. The uses of argument, 1958. Cambridge: Cambridge University Press.
5
Bus Preservation Society of Western Australia. Hydrogen fuel cell buses, 2010. [Online] Available
from http://bpswa.org/index.php/from-the-rattler/historical/108-hydrogen-fuel-cell-buses-rattler4312010 [Accessed 18 September 2013].
6
J. Dorrier. Oslo burns so much trash for energy they’re importing rubbish, 2013. Singularit Hub.
[Online]. Available from http://singularityhub.com/2013/06/10/oslo-burns-so-much-trash-forenergy-theyre-importing-rubbish/ [Accessed 4 July 2013].
7
P. Edmand. Your garbage could be powering your home, March 7, 2012. Perth Now. [Online]
Available from http://www.perthnow.com.au/your-garbage-could-be-powering-your-home/storyfn6mhct1-1226292581174 [Accessed 4 July 2013].
8
United States Environmental Protection Agency. (2013). Energy from waste: Burn or bury.
Science Matters newsletter. [Online] Available from
http://www.epa.gov/sciencematters/april2010/scinews_energy-from-waste.htm [Accessed 4 July
2013].
9
Moonies Hill Energy. Flat Rock Wind Farm Faq, [no date]. [Online] Available from:
http://www.mhenergy.com.au/images/docs/MHE_FRWF_faq.pdf [Accessed 20 October 2014].
10 R. King. Kojonup gets wind farm despite bluster, 6 December, 2011. Farm Weekly. [Online]
Available from: http://www.farmweekly.com.au/news/agriculture/agribusiness/generalnews/kojonup-gets-wind-farm-despite-bluster/2377024.aspx [Accessed 20 October 2014].
11 J. Layton. Do wind turbines cause health problems?, 2012. How stuff works. [Online] Available
from http://science.howstuffworks.com/environmental/green-science/wind-turbines-health1.htm
[Accessed 20 October 2014].
12 General Electric. How loud is a wind turbine?, August 2, 2014. General Electric Reports. [Online]
Available from http://www.gereports.com/post/92442325225/how-loud-is-a-wind-turbine
[Accessed 20 October 2014].
13 National Wind Coordinating Committee. Avian collision with wind turbines: A summary of existing
studies and comparisons to other sources of avian collision mortaility in the Unites States, August
2001. [Online] Available from: http://www.west-inc.com/reports/avian_collisions.pdf [Accessed 20
October 2014].
69
REFERENCES
14 M. Bennett. (2007). Why Perth’s Eco-buses have been consigned to the scrapheap, October 19,
2007. Stateline. [Online] Available from:
http://www.abc.net.au/stateline/wa/content/2006/s2068142.htm [Accessed 18 September 2013].
15 Barkingside 21. The big recycling myth, 2010. [Online] Available from:
http://barkingside21.blogspot.com.au/2010/12/big-recycling-myth.html [Accessed 4 July 2013].
List of Figures
Teacher Notes
Figure 7
Where the fuel cell and hydrogen tanks are situated in an Eco-bus.
Figure 8
Perth waste may be used as a non-renewable energy source.
Figure 9
The noise of wind turbines compared to common household appliances.
Student Activities
Figure 1
Transperth trialled three buses which used hydrogen as their fuel source
Figure 1
Processes to consider when dealing with waste include Recovery (recovering energy from
waste)
70

Climate change and the greenhouse effect

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