Sent by: Mª Araceli Calvo Pascual
1. Introduction
If we go out into the street with a microphone and ask people if they believe that chemistry is present in the production of the energies that pollute the environment the most, surely the majority answer will be affirmative; If you are wondering if nuclear energy is included among them, surely the majority answer will also be yes.
What happens if you ask if chemistry is present in "clean energies", the ones that contribute the most to preserving the environment? The majority answer in this case would be negative.
Why these responses? Unfounded bad reputation? Scientific foundation? Vested interests? A consequence of society's lack of scientific culture?…
Information of this type is given in the media, without a correct scientific basis, so it is logical that people have this opinion, and therefore if secondary school students are asked these questions, they answer based on to the ideas they have heard, on television or their environment; Hence the importance of receiving correct information at school or institute so that from there they can forge their own personal opinion, but based on scientific foundations.
2. Classroom application
The objective of this work is to show a possible way to study with high school students, who have very basic knowledge about these topics (and those they have are quite distorted), the relationship of chemistry with the production of energy through a series of of activities, trying to clarify the errors that are spread the most in the media.
Stage: Compulsory Secondary Education
Subjects/courses: Natural Sciences. 2nd ESO; Physics and chemistry. 3º of ESO
Resources: ICT, scientific journals, scientific literature, blackboard.
It is interesting to apply most of the activities in 2nd ESO, the year in which the concept of chemical reaction is studied. However, it can be resumed in 3rd ESO since it is in this course where stoichiometric calculation is studied.
In several of the activities, extracts from popular science books are read, and magazines are provided; These are some examples, there are many others that can be cited in the classroom, which deal with this topic specifically or together with others. Students should be invited to see them in libraries, bookstores and other outlets, so that they themselves choose the ones that appeal to them the most, and they can enjoy not only reading, but reading science.
3. Developing
3.1. Clean energies, are they really?
What is meant by clean energy?
Faced with this question, the students answer that clean energy is the one that does not stain, the one that does not contaminate.
3.1.1. Natural gas, clean energy?
An interesting activity that can be done at this point is the following:
A few years ago, it was promoted that in the houses of neighbors in which there was butane gas it should be replaced by natural gas. The ad was “Natural Gas. Clean energy. Is it true or is it false advertising?
- Objective of the activity: encourage students to question and analyze advertising.
After listening to the opinions of the students, which are logically varied, they can be invited to consult the website of the Gas Natural company regarding natural gas, and the explanation they give in relation to environmental conservation.
From here, after a sharing, the teacher can remember, requesting the collaboration of the students, the classification of energy sources, distinguishing between renewable and non-renewable, naming among the non-renewable fossil fuels. It is helpful to make an outline on the board.
Fossil fuels: two words that can be used a lot from the point of view of teaching Chemistry applied to the subject of energy production.
Students can be asked the following questions:
- What does fuel mean?, and fossil?
- What are fossil fuels?
- Why have they been used traditionally as a form of energy production? What process is carried out?
Working on these questions allows us to see, among other key concepts: chemical reaction, distinguishing it from physical reaction, oxidation reaction, reduction, fuel and oxidizer, combustion, exothermic reaction vs. endothermic…
Then the following question can be asked so that the students look for the necessary information:
- What is the greenhouse effect? Is it an environmental problem? Why is it cited as a problem? What substances are responsible for it? How are they formed?
The answer remains pending as to whether considering natural gas as clean energy is correct or not. After dealing with the issue of the increase in the greenhouse effect and the products of combustion reactions, the students answer that it is not clean energy. So the ad is misleading?
At this time an eminently chemical activity can be done that allows answering the previous question, being another good opportunity for students to relate Chemistry to energy production.
The teacher can, after asking the students to cite the methane formula, indicate how butane is formulated, and explain which hydrocarbons are the major components of natural gas:
Write and adjust the equations that represent the complete combustion reactions of methane and butane, and justify which one contributes less to the increase in
greenhouse effect.
Goals:
- Identify and relate the formulation and chemical nomenclature, the adjustment and interpretation of chemical equations, the mole concept and stoichiometric calculations with energy sources. In 3rd year of ESO a quantitative study can be carried out.
- Reason the advantage of using one type of energy or another based on the carbon dioxide produced.
With this activity, the students see that it is true that natural gas is cleaner than butane, but the question that can be asked now is: is it necessary for combustion reactions to occur to obtain electricity?
They answer no, naming the rest of the energy sources that had been previously mentioned in class using a scheme, with which they conclude that natural gas is the cleanest energy compared to other fossil fuels, but that it also contributes to the increase in greenhouse effect.
3.1.2. Nuclear power, clean energy?
It is interesting to start this section by reading two fragments from Uncle Tugsteno (Sacks, 2007) to the students:
I loved chemistry in part because it was a science of transformations, of innumerable compounds from half a dozen elements, all of them fixed, unchanging, and eternal. […] But now the radioactivity brought some of the most incredible transformations. What chemist would have thought that uranium, a hard metal similar to tungsten, could produce an alkaline earth metal such as radium, an inert gas such as radon, an element similar to tellurium such as polonium, radioactive forms of bismuth and thallium, and finally, lead: examples from almost every group on the periodic table?
I had strangely mixed feelings about the atomic bomb […] Like many, I was elated at the scientific achievement of splitting the atom […] Until then, chemistry and physics had been a source of pure enjoyment and wonder, and perhaps he was not sufficiently aware of his negative powers. The atomic bombs affected me deeply, just like everyone else. One had the impression that atomic or nuclear physics could never recover the innocence and insouciance it had been in the days of Rutherford and the Curies.
After reading the text, without making any comments, you can ask yourself: What other sources of energy are polluting?
The majority response, as already mentioned in the introduction to the subject, is nuclear energy.
At this point it is essential that students look for information regarding this type of energy, because it is a clear example of how they can obtain totally different data depending on the source they consult.
The activity could be the following:
- How is electricity obtained from nuclear energy?
- What is the difference between nuclear fission and nuclear fusion?
- Nuclear energy pollutes?
- Why can it be considered a controversial energy?
Answer these questions based on the conclusions you reach after a rigorous search for information.
Goals:
- Remember concepts related to the atom: atomic number, mass number, isotope, associating them with radioactivity.
- Identify the concept of nuclear reaction, differentiating it from physical and chemical reaction.
- Analyze the data provided in relation to the sources of information consulted.
- Differentiate information that has a scientific foundation from opinions based on other types of foundations.
With this activity, a debate can be held in which students give arguments for or against nuclear energy based on objective and reliable data.
When students cite bibliographic sources, if they have not been named, it is important that the teacher refer to the page of the Spanish Nuclear Industry Forum (www.foronuclear.org), and that they see the documents section in which there are videos , and the Energy 2009 publication that can be downloaded and, in turn, the teacher can work in class, as a place where there is updated data, with tables and graphs, on nuclear energy and other energies.
In relation to the aspect of considering it clean or not, it is interesting to read a phrase from the popularizer James Lovelock quoted in an interview by Punset (2007): Nuclear energy is good: it is the only energy source that does not harm the atmosphere. Does not cause damage. It only poses a threat to people, but not to the Earth.
The analysis of this sentence, controversial without a doubt, can be very useful in the development of the debate, a reason to explain the necessary protection measures and the no less controversial issue of radioactive waste.
In addition, since it is certain that data from Hiroshima or Chernobyl appears among the information found, the two fragments of Uncle Tugsteno can be read again to comment that it seems that many media want to continue seeing only the negative powers of chemistry and physics. This allows students to reflect on how a scientific fact can be applied for very different purposes, but that we cannot limit ourselves to seeing the negative side that has existed in the past, the destructive use in the case of Hiroshima, or the consequences of not have the necessary security measures in the case of Chernobyl, but also see the current applications and security measures.
On the other hand, reading excerpts from books and commenting on them in class is an opportunity to encourage the reading of popular science books, which contribute to enriching scientific culture and motivation for science.
3.2. Renewable energies, chemistry free?
So far, one of the problems of the use of fossil fuels has been studied from a chemical point of view, and the real advantages and disadvantages of the use of nuclear energy, distinguishing fission from nuclear fusion as a bet, the latter, Of future.
Students must know what energy planning currently exists, what it consists of and why the energy mix is necessary.
It would therefore remain to speak of the renewable energies currently used, the investment that is being made in them, and that despite the fact that, like everything else, they have drawbacks (there being quite a difference between them in this aspect), they are well regarded by society.
They have already verified in the development of the subject and carrying out the indicated activities, that Chemistry is present in non-renewable energies, but:
Is Chemistry present in renewable energies?
If this question is asked, the majority answer is no, since, as has already been commented, biased information leads to Chemistry being frowned upon.
From a pedagogical point of view, it is considered important, once again, not to limit ourselves to a methodology based exclusively on the explanation by the teacher.
teacher, but rather that it comes after a search for information by the students, an analysis and sharing.
In this case, the activity is approached as group work, in which each group chooses a type of energy and must make a presentation.
It is recommended that they consult several sources, but specifically the pages of the Center for Energy, Environmental and Technological Research (www.ciemat.es) as a representative body and of the Institute for Energy Diversification and Saving (www.idae. es), consulting the section on renewable energies in both.
They are also given two scientific journals: Química e Industria and Anales de Química, in which two articles by Bayo and Varona (2008) and Mestres (2008), respectively, appear, which study the role of chemistry in sustainability, treating the greatest part of energy sources.
When providing them with these magazines it is important, if it has not been done at another time during the course, to stop to name the most important ones, which organizations publish them, who writes the articles and what process is carried out, where they can be found and under what name if they are translations, and the difference between serious scientific journals and other publications, better known to them, that although they serve to have a greater motivation towards science, they may have articles that do not show contrasting and rigorous scientific information.
Explain by groups, the following sources of energy: solar, biomass, hydraulic, wind, geothermal and sea. Justify advantages and disadvantages of each one, investigations that are being carried out to improve them and if Chemistry is present in them. Provide qualitative and quantitative data
Goals:
Encourage group work among students, demonstrating its advantages if all members do it seriously (the number of students in each group is distributed based on the complexity and extent of each energy source).
Work on the techniques of selecting relevant information from different sources, analysis of tables and graphs, preparation of a general synthesis (development of written expression, use of Word and PowerPoint) and communication of said information in public (development of oral expression). .
When making the presentations, it must be taken into account that the students correctly explain the relationship between Chemistry and renewable energies, and in case of not
Indicate it, you have to ask questions that guide them to conclude said relationship. This forces them, within their level, to understand the chemical concepts involved (photovoltaic cell, fuel cell, electrolysis, catalyst, fermentation, hydrolysis, pyrolysis, gasification, transesterification,…) for which it is essential that the teacher guide the work and explain what you consider appropriate or propose new sources of information for students to consult.
It is important to see that although there are forms of energy production that are directly based on physical principles, Chemistry is also present since the original raw materials are chemical substances.
4. Conclusion
Chemistry and clean energy, a compatible relationship?
In the development of the subject, the students have been able to see that Chemistry is present in everything, the good and the bad, what destroys the environment the most and what protects it the most, in the most traditional technology and in the most innovative methods.
One last activity, as a conclusion, could be the following:
Think about the meaning of these two quotes, relating them to Chemistry and energy production.
We stop fearing what we have learned to understand (M. Curie)
Dare to think for yourself (Kant)
It is good that the teacher puts the two quotes on the blackboard, and in the case of the second one, he can read it from the introduction of a popular science book: Life, nature and science (Ganten, Deichmann and Spahl, 2008), inviting his reading. After leaving a few minutes for the students to think about it and write their conclusions, a discussion is done.
Goals
- Promote the analysis and synthesis of scientific topics studied from different perspectives.
- Develop the oral and written expression of students.
- Encourage the reading of popular science books.
- Promote the need for a scientific culture that allows students to have information from various sources so that they can be critical, form their own opinions and act accordingly, but based on correct scientific knowledge..
In this final pooling it should be clear that:
Misinformation regarding Chemistry and the possible complexity of understanding some ways of producing energy, can lead to being able to consider them something negative, and therefore, what a priori seems simpler to be seen better.
Chemistry and energy production are totally linked; It is not only a totally compatible relationship, it is a necessary relationship for the production of energy, any form of energy production, to exist, because without chemistry, without chemical substances, without chemical reactions, that energy could not be produced, and without research of new materials with new properties, new methods with alternative chemical reactions, the drawbacks of each of the forms of energy production could not be reduced to respect the environment as much as possible. Sustainable Chemistry represents the future in energy production.
5. References
BAYO, I.F. y VARONA, D. (2008). La energía de la química. Química e Industria nº 575, 14-28.
GANTEN, D.; DEICHMANN, T. Y SPAHL, T. (2008). Vida, naturaleza y ciencia. Madrid: Taurus. Santillana Ediciones Generales.
MESTRES, R. (2008). La química en la mitigación del cambio climático. Reducción de la generación de dióxido de carbono. Anales de Química, 104 (2), 126-133.
PUNSET, E. (2007). Cara a cara con la vida, la mente y el universo. Conversaciones con los grandes científicos de nuestro tiempo. Barcelona: Ediciones Destino.
SACKS, O. (2007). El tío Tunsgsteno. Recuerdos de un químico precoz. Barcelona: Anagrama. Compactos.
