Climate change and the greenhouse effect
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: [email protected] [email protected] 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 Links to Australian curriculum 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 Links to Australian curriculum 42 Teacher notes 44 Student answers 46 Student activity 48 References 52 ------------------------------------------------------------------------------------------------------------Socioscientific issues and introducing argumentation 55 Links to Australian curriculum 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: What is the greenhouse effect? This activity provides information addressing the common alternative conceptions students hold about the greenhouse effect and climate change. Greenhouse gases and car travel 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. Links to Australian curriculum 12 Teacher notes 13 Student answers 16 Student information 17 What is the greenhouse effect? 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 Science Understanding 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 Use and Influence of 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 Science Understanding Earth and Space Sciences Explaining the causes and effects of the greenhouse effect Science as a Human Endeavour 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 Use and Influence of 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 WHAT IS THE GREENHOUSE EFFECT? 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 WHAT IS THE GREENHOUSE EFFECT? 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 WHAT IS THE GREENHOUSE EFFECT? 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 33C 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 4C 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 30C day the inside of a car can reach as much as 70C?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 35C 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 1.8C and 3.4C 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 0.78C12. This difference will keep increasing until a new thermal equilibrium is achieved. 3 REFERENCES REFERENCE LIST 1 Australian Curriculum, Assessment and Reporting Authority. Australian curriculum: Science, V6.0, 2014. [Online] Available from: http://www.australiancurriculum.edu.au/science/curriculum/f10?layout=1 [Accessed 28 May 2014]. 2 Georgia State University. Greenhouse effect, [no date]. Hyperphysics. [Online] Available from: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/grnhse.html [Accessed 10 March, 2014]. 3 D. Tompkins. (ed.). Exploring earth and environmental science, 2010. Western Australia: Science Teachers’ Association of Western Australia. 4 Woods Hole Research Center. The greenhouse effect, 2014. [Online] Available from: http://www.whrc.org/resources/primer_greenhouse.html [Accessed 10 March, 2014]. 5 Cool the World. The greenhouse effect: Why do increased greenhouse gas emissions cause climate change? [no date]. Available from: http://www.cooltheworld.com/greenhouse_effect.php [Accessed 10 March, 2014]. 6 V. Dawson, & K. Carson. Australian secondary school students' understanding of climate change. Teaching Science, 2013, 59 (3), 9-14. 7 P. Liljas. New greenhouse gas 7000 times more powerful than CO2, Dec 11, 2013. Time. [Online] Available from: http://science.time.com/2013/12/11/new-greenhouse-gas-7000-times-moreharmful-than-co2/ [Accessed 12 March, 2014]. 8 P. Adams. The great greenhouse plot, Feb 13, 2010. The Australian. [Online] Available from: http://www.theaustralian.com.au/opinion/columnists/the-great-greenhouse-plot/story-e6frg7fx1225828247089 [Accessed 12 March , 2014]. 9 World Meteorological Organisation. Frequently asked questions, [no date]. Commission for Climatology. [Online] Available from: http://www.wmo.int/pages/prog/wcp/ccl/faqs.html [Accessed 10 March, 2014]. 10 National Aeronautics and Space Administration. Effects of changing the carbon cycle, 2014. Earth Observatory. [Online] Available from: http://earthobservatory.nasa.gov/Features/CarbonCycle/page5.php [Accessed 10 March, 2014]. 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. Environmental Research Letters, 2013, 8 (2). 12 Intergovernmental Panel on Climate Change. Climate Change 2013: The Physical Science Basis, 2013. Cambridge, United Kingdom: Cambridge University Press. [Online] Available from: http://www.ipcc.ch/report/ar5/wg1/ [Accessed 10 March, 2014]. 13 National Aeronautics and Space Administration. Climate forcings and global warming, [no date]. Earth Observatory. [Online] Available from: http://earthobservatory.nasa.gov/Features/EnergyBalance/page7.php [Accessed 10 March, 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. Links to Australian curriculum 26 Teacher notes 27 Student answers 28 Completed travel log Student activity 30 31 Greenhouse gases and car travel 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 Science Understanding Earth and Space Sciences Science as a Human Endeavour 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 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 Use and Influence of Science 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 (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. 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. People can use scientific knowledge to evaluate whether they should accept claims, explanations or predictions (ACSHE194) Evaluating claims relating to environmental footprints The values and needs of contemporary society can influence the focus of scientific research (ACSHE230) Investigating technologies associated with the reduction of carbon pollution, such as carbon capture. Use and Influence of Science Science Inquiry Skills Communicating YEAR 8 Science Understanding YEAR 9 Use and Influence of Science YEAR 10 Use and Influence of Science 26 TEACHER NOTES GREENHOUSE GASES AND CAR TRAVEL 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 GREENHOUSE GASES AND CAR TRAVEL 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 GREENHOUSE GASES AND CAR TRAVEL 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). Calculating your CO2eq per year from travelling in cars 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 Calculating your CO2eq per year from travelling in cars 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. Table of kilometres travelled by car 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. 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 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 Australian Curriculum, Assessment and Reporting Authority. Australian curriculum: Science, V6.0, 2014. [Online] Available from: http://www.australiancurriculum.edu.au/science/curriculum/f10?layout=1 [Accessed 28 May 2014]. 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. Links to Australian curriculum 42 Teacher notes 44 Student answers 46 Student activity 48 References 52 Links to Australian curriculum1 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 Science Inquiry Skills Planning and Conducting Processing and Analysing Data and Information Evaluating YEAR 10 Science Understanding Earth and Space Sciences (ACSSU189) Science as a Human Endeavour 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 Science Inquiry Skills 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 25C 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 DEMONSTRATING THE GREENHOUSE EFFECT 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 DEMONSTRATING THE GREENHOUSE EFFECT 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 Australian Curriculum, Assessment and Reporting Authority. Australian curriculum: Science, V6.0, 2014. [Online] Available from: http://www.australiancurriculum.edu.au/science/curriculum/f10?layout=1 [Accessed 28 May 2014]. 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. Links to Australian curriculum 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 Links to Australian curriculum1 Content Strand Content Description Elaboration Year 7 Science as a Human Endeavour Use and Influence of Science 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 Questioning and Predicting Identify questions and problems that can be investigated scientifically and make predictions based on scientific knowledge (ACSIS124) 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 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 Science Inquiry Skills YEAR 8 Science as a Human Endeavour Use and Influence of Science 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 (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 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 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 Science Inquiry Skills YEAR 9 Science as a Human Endeavour Use and Influence of Science People can use scientific knowledge to evaluate whether they should accept claims, explanations or predictions (ACSHE160) 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 as a Human Endeavour Use and Influence of Science People can use scientific knowledge to evaluate whether they should accept claims, explanations or predictions (ACSHE194) 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 The values and needs of contemporary society can influence the focus of scientific research (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 2000C, 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 2000C. 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 What further information would help in making your decision? 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 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. What further information would help in making your decision? 2. What are the possible advantages of your decision? I don’t know 1 STUDENT ACTIVITY 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 REFERENCES REFERENCE LIST 1 Australian Curriculum, Assessment and Reporting Authority. Australian curriculum: Science, V6.0, 2014. [Online] Available from: http://www.australiancurriculum.edu.au/science/curriculum/f10?layout=1 [Accessed 28 May 2014]. 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
© Copyright 2024