Exploring the Everyday Context of Chemical Elements: Discovering

Activity pubs.acs.org/jchemeduc

Exploring the Everyday Context of Chemical Elements: Discovering the Elements of Car Components Antonio Joaquín Franco-Mariscal* IES Juan Ramón Jiménez, Málaga 29006, Spain Universidad de Málaga, Málaga 29010, Spain

Downloaded by UNIV OF CAMBRIDGE on September 2, 2015 | http://pubs.acs.org Publication Date (Web): September 1, 2015 | doi: 10.1021/acs.jchemed.5b00164

S Supporting Information *

ABSTRACT: This paper presents a project about the chemical elements made by 15-year-old Spanish high school students of Chemistry. It focuses on contex-based teaching combined with the advantages of creating a large mural which subsequently is exposed in the school. The project consisted of researching the chemical elements in the different materials that make up a car, identifying the uses of some chemical elements in daily life, and remembering the names and symbols of the elements. Students’ response to the activity was evaluated through a survey in which progress can be seen in the pupils’ knowledge regarding the names, symbols, and uses of the chemical elements in daily life. An additional attitudes’ survey showed that students had enjoyed the project and the task had helped them understand how chemical elements are used to create materials. KEYWORDS: First-Year Undergraduate/General, High School/Introductory Chemistry, Physical Chemistry, Collaborative/Cooperative Learning, Humor/Puzzles/Games, Inquiry-Based/Discovery Learning, Applications of Chemistry, Student-Centered Learning, Periodicity/Periodic Table

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BACKGROUND Knowing the names and symbols of the chemical elements of the Periodic Table is considered an important skill at the beginning of the study of Chemistry in secondary education. However, students regard it as a boring and tedious memorizing task due to the high number of chemical elements that should be learned, the majority without a meaning for them. To overcome this obstacle, several strategies have been proposed by different authors to memorize the chemical elements. Among them, the use of games and other recreational resources such as puzzles or card games has consolidated them as successful tools in recent years.1−4 Another powerful strategy is context-based teaching and learning.5 Authors such as Gilbert,5 Aikenhead,6 or Wieringa et al.7 believe that context-based science education is a means to address the many challenges facing science education. However, contexts should be carefully selected.5 According to the Programme for International Student Assessment PISA,8 an important aspect of scientific literacy is engagement with science in a variety of situations, and the context is a specific setting within a situation. This paper provides the use of the strategy of a daily life context-based teaching and learning of the chemical elements. From our point of view, if we start from relevant situations for the students, we could help them interpret the natural world. Moreover, students will be motivated and their attitudes to chemistry could improve. The house,9 the class, or the car can be good daily life contexts to familiarize students with the Periodic Table because many of chemical elements can be found in these contexts. This article reports on an educational experience in a class of 15 year-old adolescents in which students research the chemical elements in the context of a car. This is a proper context for secondary pupils because there are over one billion cars in the © XXXX American Chemical Society and Division of Chemical Education, Inc.

world and presumably one in their family. Also, many students are interested in learning to drive, and they have probably helped their parents make repairs. The chosen context also aims to make students aware of the importance of environmental issues, since cars are an important source of air pollution. This context has already been used in Chemistry teaching, such as when Nash10 illustrated some principles of thermodinamic and electrochemistry from the working of the battery of a car and how it is affected by temperature, and when Knockemus11 illustrated principles of electrochemistry from the corrosion process of a car. Finally, several years ago, Britain’s Oxford Science Park decided to promote their facility by wrapping taxis and buses with the Periodic Table. The novel aspect provided in this paper is the combination of the context-based teaching with the use of murals. In this way, the use of murals and posters made by students as an active methodology for teaching Chemistry presents the following advantages:12 (1) Provides structure and facilitates the study of the topics allowing the ordering of ideas and reinforcing and consolidating knowledge. (2) Pupils interact and cooperate to learn working in small groups. (3) Responsibility, autonomy, and critical attitude of students are encouraged. (4) Pupils are the focus of the learning. (5) Key competences are developed. (6) The diversity of students is promoted. (7) A flexible, open, and dynamic spatiotemporal order can be used.

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DOI: 10.1021/acs.jchemed.5b00164 J. Chem. Educ. XXXX, XXX, XXX−XXX

Journal of Chemical Education

Activity

Table 1. List of the Most Significant Chemical Elements and Their Uses in a Car Made by Students Part of the Car bodywork gasoline car battery motor pieces

lighting wheels paint


catalyst

combustion gases

airbags gases electrical system

electronic circuit

seats

Chemical Elements •Fe, C •Al •C, H •O •Pb, Sb •Fe, C •Mn, Cr, B •W •Xe, Kr, Ne, Ar •S, Te •Mg, Al •K, Cr •Sr, Cr •Fe, C •Pt, Rh, Pd •La, Ce •Mg, Al •C, O •N, O •S, O •C, H •He, Ar •N •Cu •Sn •Ba •Si, Ge •Ga, As •Ta •Ni, In, Sb •Mg

Chemical Compounds •Steel alloys •Aluminum alloys •Hydrocarbons CxHy − − •Steel boron alloys: -Majoritary elements -Minoritary elements − − − •Mg−Al alloy •K2Cr2O7 •SrCrO4 •Steel alloy − •Oxydes •Al2Mg2O15Si5 •CO and CO2 •NO, NO2 •SO2, SO3 •Hydrocarbons residues •Mixture of gases − − − − − •Gallium arsenide − − •Magnesium alloys

•Combustion •Electrodes •Structural components

•Filament of the bulb •Headlights, fog light, stop lamp and interior lamp, respectively •Vulcanization process of natural rubber for the tires •Rims •Components of paint •Structural component •A mix of precious metals is the catalyst itself •Ceramic support •Ceramic support •Gases eliminated by the catalyst

•Safety device •Wires •Weldings •Coating electrical conductors of the ignition system •Transistors •Transistors •Capacitors •Other electronic components •Cast magnesium seat frame

Guided instructions for students to follow have been included in Supporting Information.

(8) Different artistic techniques and materials allow developing creativity. (9) The exhibition of murals in class or in common areas (hallways, laboratories, etc.) creates an additional motivation and contributes to the learning, remembering, or consolidating of different scientific knowledge, in this case, the names and symbols of the chemical elements and their uses.

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Uses •Structural components

Research about the Materials Used in a Car

First, students searched on the Web individually in order to link a chemical element with a car part whose material was made of that element or one of their compounds. Brainstorming Session

Second, a brainstorming session was held to compare the research data obtained. Each student explained the information found on the Web. Then, more common or appropriate chemical elements for each part of the car were chosen by pupils. The most significant chemical elements and uses are given in Table 1. A more detailed information about each chemical element found in a material of the car is shown in Supporting Information.

PROJECT DESCRIPTION

The project was made with a sample of 27 ninth grade (15 year-old) students from an urban high school in the South of Spain. This project was developed in the Chemistry class in 2014. The educational goals for students were as follow: (1) to research and identify the chemical elements present in the materials of a car, and (2) to recognize and remember the names and chemical symbols of the elements. The project was developed in the following four steps:

Chemistry Topics Studied in Class

The research conducted was also used to study some chemistry topics related to some uses of the chemical elements in a car, such as metals and alloys, extraction and combustion of gasoline, redox processes occurring in the chassis and in the catalyst, and purpose of the materials used in lighting or wheels. Metals and Alloys. Seventy percent of the weight of a car is constituted of metals. This information can be used to study the properties of metals in general and for learning more about iron, the most abundant metal in a car, either alone or combined with other elements in steel. The teacher should insist on

(1) Research on the Web about the materials used in a car and the chemical elements involved. (2) A brainstorming session to compare results. (3) The study of some Chemistry topics related with many uses of the chemical elements in the car. (4) The construction of a large mural. B




Activity

Figure 1. Car mural made by students.

the importance of iron, both for industrial purposes and for its abundance on Earth. Students should search for information about the types of steel (Fe−C alloys, at least 1.7% C) and why certain elements are added to improve some of their physical, chemical, or mechanical properties. Some examples are the addition of zinc to protect the structure of the car from corrosion or the use of molybdenum to withstand high temperatures in some pieces of the motor. Along these lines, we can go in depth about aluminum alloys, also widely used in cars. Ultimately, pupils must conclude that steels and aluminum alloys are indispensable materials today as structural components, not only in cars but in ships and buildings too, mainly for their low price and excellent properties. Extraction and Combustion of Gasoline. The extraction of petroleum and the combustion reaction can be studied from car fuel, gasoline. Students should remember that gasoline is a mixture of hydrocarbons extracted from petroleum by fractional distillation, and search for information about other products of interest obtained in this process such as propane, butane, diesel, oil, tar, etc. The use of lead compounds to improve the characteristics of gasoline and their environmental consequences should be used as a topic of discussion in class. It should be mentioned to students that lead is also present in the battery, which will be used to analyze the advantages and disadvantages of using this type of battery or other alternative batteries. Furthermore, the combustion reaction of the gasoline with air in the motor was studied. Pupils should be able to write the corresponding chemical equation that takes place. This requires research on which gases are emitted by the exhaust of a car (carbon monoxide, carbon dioxide, nitrogen oxides, and sulfur

oxides) and where they come from. They should consider questions such as if the gasoline has only octane. Redox Processes in the Chassis and in the Catalyst. Corrosion chemical reactions taking place in the chassis of the car and in the catalyst allow pupils to review redox processes. As a first task we could put forth to students is why we can see the paint raised as blisters in areas with small damages of the painting on some cars, with the idea of establishing the oxidation reaction of iron.11 Then, the teacher could ask about using metallic paints as a protective agent against corrosion. As second task we could pursue is the function of the catalyst in a car, i.e., the reduction of pollutants contained in the exhaust gases of a vehicle. Once the gases emitted by a car in a previous task have been studied, students should now research whether they are harmless to our health. Then, they should indicate which ones should be removed from the catalyst and which correspond to oxidation or reduction processes. Additionally, pupils should research the types of metals in these processes. Materials Used in Lighting. Different interesting aspects of the lighting system of a car can be why the presence of an inert gas around the tungsten filament is needed, how you can get a higher shine from the lighting source, or the advantages and disadvantages of using conventional lights compared to low consumption bulbs. Materials Used in Wheels. Some topics to study on the wheels are how the rubber can be harder in the vulcanization process with heat and sulfur, or how the use of some cobalt salts can achieve greater adhesion of the tire to the road. C




Activity

Figure 2. (a) Details of the motor; (b) details of the catalyst.

Construction of a Large Mural

Box 1. Survey To Assess the Students’ Knowledge of Chemical Elements

Students made the mural in Figure 1 in the last phase. The main aims of this mural were to show other students in the high school what they have learned, how Chemistry is present in daily life, and to facilitate learning the names and symbols of chemical elements for future pupils. To that objective, the mural was exhibited in the lab, a classroom which all students in the school use. Some details are shown in Figure 2.

1. What chemical elements do you know? Provide their names and chemical symbols. 2. Do you know any use of chemical elements? Cite the uses. 3. Do you think that the chemical elements are part of our everyday life?

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STUDENT RESPONSE AND ASESSMENT Students were encouraged to provide their opinions in a survey. This questionnaire consisted of three questions in open format (see Box 1) and was designed to assess the students’ knowledge of element names, symbols, and uses before and after making the activity.

Knowledge of Names and Symbols of Chemical Elements

Results of the first question are found in Figure 3, which shows the percentage of students who correctly quoted the name and the symbol of the chemical elements in the pre-test and post-test. D




Activity

Figure 3. Results of the first question about knowledge of chemical element names and symbols.

• “Chemical elements are used to create materials, without them we would not have all the things we use and need every day.” • “Without chemical elements, life would not exist as we know it.” • “I thought that some elements were used in life, but not as many as I have learnt in this project.” Additionally, a second survey with a numeric sliding scale was used to analyze student attitudes regarding the project. Students completed the survey of perceptions at the end of the unit. This survey consisted of four items (see Box 2) and was anonymous.

It is noticeable in Figure 3 that the frequency of the cited elements and the shape of the distribution are different before and after the project. Thus, almost 40% of students who completed the pre-test was unable to properly identify the name and symbol of any chemical element, while only 3.70% of pupils did not cite any element in the post-test. According to the shape, initially the distribution presents a decreasing exponential shape from 0 to 6 elements. However, the distribution is bell-shaped from 0 to 20 elements in the post-test. Before starting the project, students knew an average of 1.52 chemical elements, increasing to 6.11 elements after the task. This result suggests that this type of task may improve the knowledge of the chemical elements.

Box 2. Survey To Assess Student Attitudes

Knowledge of Uses of Chemical Elements

On a scale of 1−5, how strongly do you agree with these statements: 1. I enjoyed this project. 2. This project helped me understand how chemical elements are used to create materials. 3. I prefer to learn chemistry by carrying out these types of projects than use a traditional method. 4. I think Chemistry can be learned best when it has a connection with everyday life situations.

Pupils’ response was largely positive. The majority of them commented in the post-test that “the project has helped to connect the chemical elements with their uses in daily life”. In addition, we observe an important change in the students’ ideas about the applications of the chemical elements in daily life. Therefore, before performing the activity, students believed that the chemical elements had few uses in the daily life, as shown in these comments of some pupils: • “I think only some chemical elements are present in daily life, like the air we breathe or the water we drink.” • “Milk contains calcium or iron is present in magnets.” • “Carbon is in lead and aluminum is in windows frames.” Other students thought that chemical elements were linked exclusively to science or chemicals: “I think that chemical elements are only found in the things of Chemistry”. We can observe how their opinions were different after accomplishing the activity indicating that the chemical elements are used thoroughly in our lives. Some comments from students reinforcing this idea were as follows: • “Researching the materials in a car I realized the great utility of chemical elements in all things in life.” • “Chemical elements are everywhere, because everything around us is made of these elements.”

The results of the survey (Figure 4) showed that the project had a positive impact on the students’ attitudes obtaining all the items a score higher than 4 on a 1−5 scale. In the opinion of pupils, the project is a useful tool for understanding how chemical elements are used to create materials (4.07 points) and matching the chemical elements with their uses in everyday life can help them gain a better understanding of chemistry (4.29 points). Finally, students also prefer this method to a traditional one (4.18 points).

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CONCLUSION One way to learn Chemistry is to contextualize its learning in daily life. This article has attempted to show how starting from a car as context of daily life, we can help and motivate students E



Activity


Figure 4. Mean scores on a 1−5 scale for each item. (7) Wieringa, N.; Janssen, F.; Van Driel, J. Biology teachers designing context-based lessons for practisethe importance of rules-of-thumb. Int. J. Sci. Educ. 2011, 33 (17), 2437−2462. (8) OECD. Assessing Scientific, Reading and Mathematical Literacy. A Framework for PISA 2006; OECD: Paris, 2006. (9) Franco-Mariscal, A. J. La búsqueda de los elementos en secundaria. [The Search for Chemical Elements at Secondary School]. Alamb. Didác. Cienc. Exp. 2007, 51, 98−105. (10) Nash, L. K.; Plumb, R. C. Car won’t start? J. Chem. Educ. 1970, 47 (5), 382. (11) Knockemus, W. When your car rusts out. J. Chem. Educ. 1972, 49 (1), 29. (12) Díaz, M. R.; Muñoz, A. Los murales y carteles como recurso didáctico para enseñar ciencias en Educación Primaria [Murals and posters as a didactic resource for teaching sciences in elementary education]. Rev. Eureka Ens. Div. Cienc. 2013, 10 (3), 468−479.

to interpret reality and facilitate understanding and functionality of the contents, in this case, the study of chemical elements and the appreciation of their applications in daily life. Furthermore, the translation of the results in a large mural has enabled the cooperation among students and their exposure in the high school opens the possibility that other students interested in Chemistry and can learn about the work done by their classmates.

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ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available on the ACS Publications website at DOI: 10.1021/acs.jchemed.5b00164.

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Guided instructions for students to follow (PDF, DOC)

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS This work is part of the “I+D Excelencia” project “Development and evaluation of scientif ic competences through context-based and modelling teaching approaches” case studies (EDU2013-41952-P), funded by the Spanish Ministry of Economy and Finance through its 2013 research call.

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REFERENCES

(1) Franco-Mariscal, A. J.; Oliva-Martínez, J. M.; Bernal-Márquez, S. An Educational Card Game for Learning Families of Chemical Elements. J. Chem. Educ. 2012, 89, 1044−1046. (2) Bayir, E. Developing and Playing Chemistry Games to Learn about Elements, Compounds, and the Periodic Table: Elemental Periodica, Compoundica, and Groupica. J. Chem. Educ. 2014, 91 (4), 531−535. (3) Franco-Mariscal, A. J.; Oliva-Martínez, J. M.; Almoraima Gil, M. L. Students’ Perceptions about the Use of Educational Games as a Tool for Teaching the Periodic Table of Elements at the High School Level. J. Chem. Educ. 2015, 92 (2), 278−285. (4) Daubenfeld, T.; Zenker, D. A. Game-Based Approach to an Entire Physical Chemistry Course. J. Chem. Educ. 2015, 92 (2), 269− 277. (5) Gilbert, J. K. On the nature of ‘context’ in chemical education. Int. J. Sci. Educ. 2006, 28 (9), 957−976. (6) Aikenhead, G. Humanistic perspectives in the science curriculum. In Handbook of Research on Science Education; Abell, S. K., Lederman, N. G., Eds.; Lawrence Erlbaum: Mahwah, NJ, 2007; pp 881−910. F


Exploring the Everyday Context of Chemical Elements: Discovering

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