Article pubs.acs.org/jchemeduc
Using Audience Response Systems during Interactive Lectures To Promote Active Learning and Conceptual Understanding of Stoichiometry Sandra Cotes*,† and José Cotuᇠ†
Departamento de Química y Biología, Universidad del Norte, Barranquilla 080020, Colombia Grupo de Investigación Max Planck, Universidad del Atlántico, Barranquilla 080020, Colombia
‡
ABSTRACT: This article describes a method of instruction using an active learning strategy for teaching stoichiometry through a process of gradual knowledge building. Students identify their misconceptions and progress through a sequence of questions based on the same chemical equation. An infrared device and software registered as the TurningPoint Audience Response System, which can be integrated into Microsoft PowerPoint, is used to instantly retrieve students’ answers and provide them with appropriate feedback. The usefulness of breaking down topics in a consistent way and, in particular, emphasizing the subjective interpretation of connectivity and mass relationships in chemistry was evident. Most students felt that the use of the immediate response system combined with cooperative social interactions was positive and contributed to their understanding of the topic. KEYWORDS: First-Year Undergraduate/General, High School/Introductory Chemistry, Misconceptions/Discrepant Events, Stoichiometry, Collaborative/Cooperative Learning, Reactions
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INTRODUCTION The relationship between students’ skills in solving problems and their conceptual understanding is well documented, and it often appears that students are able to solve problems algorithmically but lack a qualitative understanding of the concepts involved in solving them.1 The number of students able to correctly answer conceptual questions is quite small compared to those who are able to correctly solve problems algorithmically. This trend has been observed throughout the world, and it is the focus of many studies on the chemistry teaching process.2 In this article, through the use of instant replay cards, students are prompted to discuss with their classmates a number of questions about a single chemical equation to improve their discussion abilities and conceptual understandings related to mass ratios and their importance in chemistry. A good qualitative understanding of the concepts in stoichiometry is essential for solving problems and understanding the ways in which it has developed chemistry as a science.3 Conventionally, laboratory practices have been used to illustrate these concepts,4 but their effectiveness has not been well established. On the other hand, stoichiometry has been cited as one of the most difficult subjects in introductory chemistry courses.5 Among the most common cited difficulties in stoichiometry is the interpretation of coefficients and subscripts to establish the concept of the limiting reagent. In particular, students do not realize that subscripts indicate the number of atoms within a © 2014 American Chemical Society and Division of Chemical Education, Inc.
molecule, while coefficients establish the number of chemical entities in a balanced equation.6 Commonly, students assume that substances react in equal molar numbers, molar ratios are confused with mass ratios, and molar mass is confused with the total mass in the problem.7 In this article, we describe a teaching method using an active strategy for learning through a gradual process of knowledge construction. Student understanding is compared before and after the students receive instruction using electronic systems for immediate response. Several studies have used electronic response systems for interactive classes,8−13 and one of the advantages of these systems is that students and instructors receive instant feedback. Currently, there are several commercially available electronic systems for providing such an immediate response. The development of new technologies in information and computing (NTIC) to provide wireless signals as well as software, storage capacity, and audio-visual systems allows improved access, transmission, and manipulation of information. The use of NTIC has increased in recent years as a means to facilitate meaningful learning processes for students; deliver the results of evaluations faster; generate different patterns of representation for social sciences, human sciences, natural sciences, and mathematics; and develop more dynamic classes to motivate students to become active participants in the classes taught in different grades of primary, secondary, and university Published: April 4, 2014 673
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interactive lecture was also of 120 min duration. Questions were formulated on the basis of the errors most commonly made by students reported on the literature.6 Mistakes made by students contain information, and recognizing pertinent information is the first step for students to consciously analyze their performance in a metacognitive analysis guided by the teacher. Using the instant replay cards, we subdivided problems into different parts for the purpose of preparing students to tackle the problem globally. In this teaching process, students answer questions in a multiple-choice test using an infrared device and software called the TurningPoint Audience Response System. First, the instructor explained the question and read the response options. Then, once the question was understood and the monitor revealed that 35% of students have answered, a timer was set giving the students 15 s to choose their final answer. Students were allowed to discuss and analyze the responses. The students’ responses appeared on a slide as the percentage of students who selected each choice. The instructor then analyzed the responses, explaining the conceptual error behind each incorrect choice. Then, the level of satisfaction with the applied methodology and the level of understanding of the material were evaluated in the final question.
schooling. The use of NTICs, such as an immediate response system, offers new opportunities for young people to learn how to share their experiences and attain meaningful learning in the process. For nearly three years at the University of Carolina, Irvine, Mizuko Ito and his group14 interviewed more than 800 young people and followed them for more than 5000 h to determine how NTIC media promote students’ autonomous learning, motivation, and networking. One conclusion of their study is that new media (NTICs) have altered the way young people socialize and learn and have increased the success of educators who use NTICs as a means and not as an end, so that students truly learn. Nowadays, to optimize the physical and human resources in a university context, it is necessary to teach to broader audiences. Therefore, different strategies are required to motivate students, make classes more dynamic, rapidly assess students’ performance, and ensure more significant teacher− student and student−student interactions. One useful strategy for this purpose followed in various schools and universities worldwide is the use of electronic response systems. These systems consist of software, an immediate response card, and a receiving antenna,8−13 and can be used to develop interactive lessons. Although a number of articles have reported the use of personal response systems, and numerous studies can be found about teaching stoichiometry,15−19 this article presents a method involving both subjects that provides information about the impact of cooperative social interactions on learning stoichiometry. The aim of this paper is to introduce a methodology that incorporates the use of interactive methods of teaching and learning in a basic general chemistry course to sort out preconceptions on the topic of stoichiometry and improve students’ interpretive skills. This work is not intended to compare these results with those of other methods of instruction but to highlight the importance of breaking down the subject into small consecutive blocks of knowledge in promoting a broader understanding and how social interactions can improve students’ motivation. Special emphasis was placed on the subjective interpretation of the connectivity and spatial relationships in chemistry, for which the use of models is still the best tool.
Implementing Clicker Questions
The theory of multiple intelligences developed by Howard Gardner in 1983 considers intelligence to be a set of skills that dominates human beings to some extent.20 Some people have strong auditory skills and learn easily from lectures, and others have verbal abilities and good memories and learn through the reading and writing process. Traditional systems of education can meet the requirements of people with the skills mentioned above, but there are other skills that facilitate learning, such as spatial visualization, logical thinking, interpersonal interaction, and self-reflexive capacity. Our questions were designed so as to involve these skills and thus provide a greater number of students the opportunity to learn under different circumstances and achieve the defined objectives. In addition to the questions being developed by taking into account conceptual errors found in the literature,6,7 and the idea of gradual learning from the simple to the more complex, the following criteria was considered: repetition to reinforce knowledge, exploration of a subject from different angles so that the questions achieve the widest possible coverage, reasoning through the sequential analysis of situations, and deduction of a conceptual expression of mass relationships in stoichiometry, to consolidate the acquired knowledge. The questions implemented with the audience response system (clicker questions) are as follows:
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IMPLEMENTING A LECTURE STRATEGY TO IMPROVE STUDENTS’ UNDERSTANDING OF STOICHIOMETRY The audience response system for teaching stoichiometry was implemented in an introductory chemistry course with 5 h per week of attendance that was part of the first-semester studies in a medicine program. The course consisted of 42 students: 27 women and 15 men. The students were mainly 17−18 years old. Prior to this experiment, students received instruction on stoichiometry in the form of 10 h of conventional lectures with a single instructor. Each class period was of 120 min duration. Then, the students took a conventional written problem-solving examination on the subject. All students were exposed to the same content and assessments, and the assessments were graded by the same instructor. In the final evaluation, 40% of grades for students on the written assessment were below 3.5, where the rating scale ranged from 1 for poor to 5 for excellent. After the written assessment, an interactive stoichiometry lecture was designed and taught by the same instructor. The
1. Choose the most suitable representation for methane, CH4.
2. Choose the most suitable representation for 2O2. 674
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11. Choose the correct answer: a. Equal reagent masses react completely. b. Reagents react in molar ratios. c. Equal numbers of moles of reagents react completely. 12. After using the TurningPoint Audience Response System jointly with the applied question methodology, you: a. Have understood the significance of the mass relationship in a chemical equation. b. Still experience difficulties in understanding. c. Do not find the system necessary, because the initial approach of solving problems was enough. The sequence of selected questions follows this reasoning: stoichiometry is the study of the mass relationship using a chemical equation that represents the reactions with a symbolic language conveying the chemical formulas and ratios. It is necessary for students to understand this notation to assimilate stoichiometry correctly. Therefore, the questions are structured from simple to more complex, and a chemical equation with a simple mass relationship is chosen. The combustion of methane, which has a 1:2 mass relationship, was selected for quick analysis by the students. To facilitate the correct interpretation of the chemical formulas, we used graphics to show the composition of the reagents. Graphical analysis can be a better approach to understanding the chemical structure represented by a chemical formula. The numerical ratio of atoms is explored through the response options that present different interpretations of the molecule and the connectivity of atoms. To reinforce the concept of chemical compositions, a second question about molecular oxygen composition is reviewed and coefficient interpretation is introduced. Once the chemical notation and molecular coefficients can be interpreted correctly and sufficient time is given to the students to discuss this concept with their partners, the next step is to examine a complete equation with the same chemical entities previously analyzed and in the same molar quantities used so far. Graphics are used again in Question 3 to illustrate the stoichiometric and nonstoichiometric ratios for this reaction. Subsequent analysis of all the response options along with classmates and the lecturer allows the students to review the error implicit in each wrong answer and gradually reach an overall understanding of the topic. At this point, the concept of the molar mass for oxygen was introduced in order to analyze stoichiometric ratios when the mass is expressed in units of grams. Then, in Question 5 the students realized that the reactions are expressed neither in equimolar ratios nor in grams, and in Question 6 the students realized that the limiting reagent can only be determined by analyzing the mass ratios from the balanced equation, not on the basis of the relative amounts of reagents. It is important to spend some time discussing Questions 5 and 6, as this is the core of stoichiometry. Questions 7 and 8 reinforced the concept of the limiting reagent by expressing the masses in moles and grams; Question 9 asked students to calculate the amount of remaining reagent. At this point, students should be able to determine the amount of product that was obtained. By way of conclusion, in Question 11 students were asked to establish the principles of stoichiometry in a sentence. In particular, they must explain that substances react in quantities according to the molar ratio established in the balanced
Given the equation above, answer the following questions: 3. The following reaction boxes are representations illustrating three different conditions for the reaction above. Choose the correct set of conditions corresponding to these reaction boxes in the order they appear.
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a. Stoichiometric, excess oxygen, excess methane b. Stoichiometric, methane limiting reagent, excess oxygen c. Excess methane, stoichiometric, excess oxygen How many grams correspond to one mole of oxygen? a. 32 g b. 64 g For the given reaction: a. When 2 mol of CH4 react with 2 mol of oxygen, there is no starting material remaining. b. When 10 g of methane react with 10 g of oxygen, there is no starting material remaining. c. None of the above. Given the equation for the combustion of methane, if 15 mol of methane was allowed to react with 10 mol of oxygen, the limiting reagent would be: a. Methane b. Oxygen c. Water d. Carbon dioxide If 15 mol of methane was allowed to react with 10 mol of oxygen, the limiting reagent would be oxygen because a. There are more moles of methane than moles of oxygen. b. 10 mol of oxygen requires 5 mol of methane. If 32 g of oxygen was allowed to react with 16 g of methane, the limiting reagent would be a. Oxygen b. Methane If 15 mol of methane was allowed to react with 10 mol of oxygen, the remaining number of moles of excess reagent would be a. 15 mol of methane − 10 mol of oxygen = 5 mol b. 20 mol of methane − 15 mol of methane = 5 mol c. 15 mol of methane − 5 mol of methane = 10 mol If 15 mol of methane was allowed to react with 10 mol of oxygen, the amount of water produced in moles would be a. 30 mol b. 10 mol c. 20 mol d. 5 mol 675
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Question 5: When expressing the mass ratios in terms of moles and in terms of grams, 6% of students continued to believe that the reactions are given in 1:1 mass and mole ratios. Question 6: When the limiting reagent concept was presented in molar terms, 8% of students failed to determine the limiting reagent. Question 7: All students understood the limiting reagent when moles were used as the unit of mass. Question 8: 72% of students did understand the limiting reagent when units of grams were used. Question 9: In addition, 81% of students successfully chose the correct answer, although 19% of students were not able to calculate the number of moles of excess reagents. Question 10: An impressive 92% of students obtained the correct answer, indicating that students realize the importance of the limiting reagent in determining the amount of product. Question 11: When the mass ratios were expressed in words, 92% of students responded correctly. Question 12: The short survey about the usefulness of the methodology for facilitating the understanding of the subject established that students (81%) did obtain a better understanding of the issue. However, 2% of students found it unnecessary, and 17% of the students stated that they still experience difficulties. Students also showed a higher level of engagement in learning chemistry expressed by the exciting classroom ambience and the enthusiasm of students for taking the test. The lecturers believe the students’ attitudes were improved because their confidence was built by discovering their own mistakes after each question and because they had the opportunity to correct their misconceptions before the following question was asked. In addition, discussions among the students allowed them to externalize their doubts and try to sort out their questions, which helped them actively improve their communication skills in science with someone of their own age. There was also some positive competition because of the control students acquired over their own learning process, which let them raise their self-confidence.
equation. In this way students are exposed to the topic from different angles, and ordered questions that are strategically aimed while taking advantage of the motivation and engagement that the audience response system produces in students.
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RESULTS
Student Responses
Table 1 reports the students’ responses. Analysis of student responses took into account the most commonly reported Table 1. Distribution of Student Answers to the Test Using the Audience Response System Student Responses by Choice, % (N = 42) Question 1 2 3 4 5 6 7 8 9 10 11 12
1 a
100 8 17 89a 0 8 0 72a 8 0 6 81a
2
3
4
0 3 33 11 6 92a 100a 28 11 92a 92a 17
0 89a 50a NAb 94a 0 NAb NAb 81a 0 2 2
0 NAb NAb NAb NAb 0 NAb NAb NAb 8 NAb NA
a Indicates the correct response. bThis response was not available for selection.
misconceptions in the literature and the general sense of the mistakes perceived in the discussions that followed the questions. Because of time limitations, students were not interviewed to explore their individual misconceptions. The following remarks describe the results of student responses to the clicker questions mentioned before. Question 1: All 42 students correctly interpreted the molecular connectivity representations. Therefore, we assume that the students could correctly interpret molecular structures. Question 2: When they encountered molecular coefficients, 8% of students assumed the coefficients to represent numerical relationships between elements in a molecule; that is, they assumed that there are four oxygen atoms in the molecule. Another 3% of students believed the coefficients to represent independent atomic units lacking bonds, that is, 4 free oxygen atoms. Question 3: Half of the students interpreted the molar mass relationships in chemical equations adequately. The remaining 50% assumed that the reactions always occur in equal molar ratios. Because the percentage of wrong answers was high, long discussions of answers to Questions 3 and 5−8 were allowed, focusing on making the ratios expressed in terms of moles and grams clear for the students. The special emphasis in these questions was originally planned, because this is what stoichiometry is about. No further steps were taken until the students were completely satisfied by the explanations and guidance provided by their partners or lecturer. Question 4: When evaluating the molar mass, 11% of students incorrectly took into account the coefficients in the reaction and obtained the wrong result.
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CONCLUSIONS The students’ skills were increased, as evidenced in responses 3 and then 11 and 12. Initially, 60% of students understood the mass ratios in a chemical equation from conventional noninteractive stoichiometry classes. Approximately 81% of participating students showed improved knowledge at the end of the clicker questions’ exercise, indicating an increased understanding of the mass ratios defined in a chemical equation. In general, students experience more difficulties understanding mass relationships in terms of grams. With regard to misconceptions, no important differences from those frequently cited in the literature were found.21 We are unable to speculate on the effects of the age, sex, and prior training on the preconceptions of these students. Most students agree that the use of immediate response systems along with the applied question methodology was positive and contributed to their understanding of the topic. Students also found that using an immediate response system facilitated communication and dialogue in a motivating environment because of the expectation generated with each question. The interactive lecture introduced in this article, along with research published by other authors, has demonstrated that cooperative learning produces student results superior to those obtained using conventional lecture-only methods.22−24 Con676
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(5) Huddle, P. A.; Pillay, E. A. An In-Depth Study of Misconceptions in Stoichiometry and Chemical Equilibrium at a South African University. J. Res. Sci. Teach. 1996, 33 (1), 65−77. (6) Sokoloff, D. R.; Thornton, R. K. Using Interactive Lecture Demonstrations To Create an Active Learning Environment. Phys. Teach. 1997, 35, 340−348. (7) Haidar, A. Prospective Chemistry Teachers’ Conceptions of the Conservation of Matter and Related Concepts. J. Res. Sci. Teach. 1997, 34 (2), 181−197. (8) Milner-Bolotin, M. Increasing Interactivity and Authenticity of Chemistry Instruction through Data Acquisition Systems and Other Technologies. J. Chem. Educ. 2012, 89 (4), 477−481. (9) Murphy, K. Using a Personal Response System To Map Cognitive Efficiency. J. Chem. Educ. 2012, 89 (10), 1229−1235. (10) Bunce, D. M.; Flens, E. A.; Neiles, K. Y. How Long Can Students Pay Attention in Class? A Study of Student Attention Decline Using Clickers. J. Chem. Educ. 2010, 87 (12), 1438−1443. (11) Vital, F. Creating a Positive Learning Environment with the Use of Clickers in a High School Chemistry Classroom. J. Chem. Educ. 2012, 89 (4), 470−473. (12) King, D. B. Using Clickers To Identify the Muddiest Points in Large Chemistry Classes. J. Chem. Educ. 2011, 88 (11), 1485−1488. (13) Woelk, K. Optimizing the Use of Personal Response Devices (Clickers) in Large-Enrollment Introductory Courses. J. Chem. Educ. 2008, 85 (10), 1400. (14) Ito, M.; Horst, H.; Bittanti, M.; Boyd, D.; Herr-Stephenson, B.; Lange, P. G.; Pascoe, C. J.; Robinson L.; Baumer, S.; Cody, R.; Mahendran, D.; Martínez, K.; Perkel, D.; Sims, C.; Tripp, L. Living and Learning with New Media: Summary of Findings from the Digital Youth Project. http://digitalyouth.ischool.berkeley.edu/report (accessed Mar 2014). (15) Baranski, A. The Atomic Mass Unit, the Avogadro Constant, and the Mole: A Way to Understanding. J. Chem. Educ. 2012, 89 (1), 97−102. (16) Sostarecz, M. C.; Sostarecz, A. G. A Conceptual Approach to Limiting-Reagent Problems. J. Chem. Educ. 2012, 89 (9), 1148−1151. (17) Radhakrishnamurty, P. Stoichiometry and Chemical Reactions. J. Chem. Educ. 1995, 72 (7), 668. (18) Kauffman, G. B. A Schematic Summary of General Chemistry Stoichiometry. J. Chem. Educ. 1976, 53 (8), 509. (19) Weerasooriya, R. Chemical Equations, Moles, and Stoichiometry. J. Chem. Educ. 1981, 58 (10), 792. (20) Gardner, H. Frames of Mind: The Theory of Multiple Intelligences; Basic Books: New York, 1983. (21) Wood, C.; Breyfogle, B. Interactive Demonstrations for Mole Ratios and Limiting Reagents. J. Chem. Educ. 2006, 83 (5), 741−748. (22) Blackburn, E. V.; Browne, L. M. Teaching Introductory Organic Chemistry: A Problem-Solving and Collaborative-Learning Approach. J. Chem. Educ. 1999, 76 (8), 1104−1107. (23) Felder, R. M. Active-Inductive-Cooperative Learning: An Instructional Model for Chemistry? J. Chem. Educ. 1996, 73 (9), 832−836. (24) Francisco, J. S.; Nicoll, G.; Trautman, M. Integrating Multiple Teaching Methods into a General Chemistry Classroom. J. Chem. Educ. 1998, 75 (2), 210−213. (25) Hake, R. R. Interactive-Engagement vs. Traditional Methods: A Six-Thousand-Student Survey of Mechanics Test Data for Introductory Physics Courses. Am. J. Phys. 1998, 66, 64−74. (26) Barr, R. B.; Tagg, J. From Teaching to LearningA New Paradigm for Undergraduate Education. Change 1995, 27 (6), 12−25. (27) Knight, J.; Wood, W. B. Teaching More by Lecturing Less. Cell. Biol. Educ. 2005, Winter, 4 (4), 298−310. (28) Driver, R.; Scanlon, E. Conceptual Change in Science: A Research Program. J. Comput. Assisted Learn. 1989, 5, 25−36.
ventional lectures are not efficient, because students require more active, motivating environments that allow them to actively take part in the learning process. Social interactions, challenging situations, and gradual rewarding of students for their achievements are successful strategies for motivating students to engage in learning, not only in chemistry but also in other subjects.25 The lecturer’s former role as a knowledge source is no longer valid nowadays; instead, lecturers should encourage students to discover and appropriate knowledge.26 Interactive lectures such as the model described in this article not only engage the students in becoming proficient at the topics but also teach students how to learn and develop thinking skills.27 Knowledge is built as an outcome of a personal experience and learning is a multidimensional process that includes not only the topics but also the intrinsic features of students’ dispositions to the subject, students’ characters, and emotional aspects related to their individuality that come out only under social interactions.28 The evident advantages of social interactions suggest that further development of educational strategies is required now that technology and social networking play large roles in the day-to-day lives of young people.
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FUTURE WORK It would be advisable for future works to track remaining misconceptions, relate the final scores to remaining misconceptions, and identify students still experiencing difficulties. Interviews with those students would enable lecturers to get feedback about what is not working properly for these students. Additionally, the number of interactive lectures for knowledge consolidation is another important topic to consider ahead. The test questions might need to be reconsidered to include more gradually complex questions and the sample size of students is also an important aspect to consider if statistical significance is pursued.
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AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS We give our thanks to the Universidad del Norte’s library for the administration of the immediate instant replay cards and the Division of Ciencias Básicas for support and funding.
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REFERENCES
(1) Nurrenbern, S. C.; Pickering, M. Concept Learning versus Problem Solving: Is There a Difference? J. Chem. Educ. 1987, 64 (6), 508−510. (2) Rojas de Astudillo, L.; Niaz, M. Reasoning Strategies Used by Students To Solve Stoichiometry Problems and Its Relationship to Alternative Conceptions, Prior Knowledge, and Cognitive Variables. J. Sci. Educ. Technol. 1996, 5 (2), 131−140. (3) BouJaoude, S.; Barakat, H. Secondary School Students’ Difficulties in Stoichiometry. Sch. Sci. Rev. 2000, 81 (296), 91−98. (4) Meyer, L. S.; Schmidt, S.; Nozawa, F.; Panee, D. Using Demonstrations To Promote Student Comprehension in Chemistry. J. Chem. Educ. 2003, 80 (4), 431−435. 677
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