Employing Contextual Examples and Graphing Activities to Enhance Students’ Understanding of the Relationship Between Differentiation and Integration in Calculus Kinley11,*,#, Wararat Wongkia22, Parames Laosinchai32,# 1 Master Program in Science and Technology Education. Institute for Innovative Learning, Mahidol University. Thailand 2 Institute for Innovative Learning, Mahidol University. Thailand *#kinleay@hotmail.com, #parames.lao@mahidol.ac.th Abstract Calculus is an important subject for science, engineering and other fields of studies but phenomenally it is abstract and difficult to learn. Introductory calculus courses were basically taught using traditional teaching methods focusing on algebraic computation. Students mostly focused on rote learning and the relationship between differentiation and integration was difficult to visualize. Due to the abstract nature of calculus, students found it difficult to understand the concepts and teachers rarely taught calculus using activities to help visualize the concepts. Therefore, contextual examples and graphing activities were developed based on the learning cycle approach and the lesson was taught for an hour in the classroom. This study investigates the effectiveness of the lesson in helping the students understand the relationship between differentiation and integration in Calculus and to measure the students’ attitude towards the learning unit. Fourteen undergraduate students from two colleges were selected for the study. A pre-test was conducted prior to the implementation of the learning unit and after the intervention of lesson, a post-test and an attitude test were conducted. The test scores showed that there was significance improvement in the post-test scores compared to the pretest scores. It was also found that the lesson was effective and enriching. Keywords: calculus, differentiation, integration, graphing activity Introduction A calculus course provides the basis for higher learning in several fields of studies, e.g. physics, chemistry, biology, engineering and business in order to understand deeply the concepts of rate of change of motion and its applications (1). However, a lot of students do not achieve basic understanding of calculus and find that calculus is abstract and difficult. Several studies revealed that students developed routine techniques and manipulative skills rather than understanding of the theoretical concepts and its applications (2, 3, 4, 5, 6, 7, 8). Orton (2) explained how students encountered the problems with reasoning behind integration especially when the connection was made with definite integrals. He also described the difficulty of understanding differentiation (3). Tall (9) also found that students formed a weak concept image of differentiation and integration when the teaching was focused on algebraic computation of symbols and notations. Teaching that emphasized procedural methods led students away from the conceptual understanding of differentiation and integration (10). Moreover, a vast number of calculus textbooks are available, seemingly covering every conceivable approach, but many problems remain and that make the understanding and teaching of calculus difficult (11). Textbooks used in higher secondary levels contain a lot of abstract symbols and notations which are more of a hindrance than a help to the learning. The symbols and notations are not explained in contextual applications (12). Therefore, students followed the procedures rather than trying to understand of the concepts and a wide range of problems in the textbooks were solved using memorized formulas and procedural steps. Several studies examined the learning of calculus and focused on students’ errors, misconceptions, inflexibility and inability to make the connections between what they learn and apply (2, 3, 9). The teaching methods need to be modified by focusing on activities based on context, so that the students can visualize and make connections between the contextual activities and the algebraic notations. Due to the applicability nature of differentiation and integration, the visualization of the phenomenon problem is a key concepts for learning and teaching process (13). Milovanovic et al. (14) suggested to the using multimedia to enhance the conceptual learning of calculus and to remove the difficulties encountered in learning calculus, because the visualization helped to better explain mathematical ideas, abstract terms, theorems, problems, etc. However, the relationship between differentiation and integration was not focused after the students were taught the differentiation and integration. The students recognized that “integration is the inverse process of differentiation” but they still encountered the difficulty in explaining how differentiation and integration related algebraically and graphically. This was because the teaching stressed the procedural steps to solve problems (15, 16, 17). Most students have learned calculus ‘how’ rather than ‘why’ due to extensive use of notations and symbols in teaching and learning of calculus. The real meanings of symbols and notations students learned in the classrooms are not interpreted explicitly in the context of real world situations and students have vague concepts of algebraic notations in relation to geometric interpretations (18). Mundy and Graham (19) also reported that the discrepancy between the performances on the procedural items and conceptual ones was due to the separate understanding of geometrical and algebraic context in calculus. Therefore, teaching calculus using contextual examples and graphing activities and connecting activities to algebraic notations would help students in visualization and easily apply in the real world situations. This study focused on developing contextual examples and graphing activities based on the learning cycle approach help establish the relationship between differentiation and integration in calculus. The main objectivities of this study were to find out the effectiveness of the developed learning unit on the students’ understanding of the relationship between differentiation and integration in Calculus and to measure the students’ attitude towards the learning unit. This study aimed to address the following research questions; i). To what extent can the learning unit enhance the students’ understanding the relationship between differentiation and integration in Calculus? ii). What is the students’ attitude towards the learning unit? The Learning Cycle Approach The Learning cycle approach was seen as an effective hands-on, minds-on, inquirybased scientific pedagogy, especially for enhancing students’ understanding by the ways in which they learned the nature of the world (20). The learning cycle approach can result in greater achievement in learning, better retention of concepts, improved attitudes toward learning subjects, improved reasoning ability, and superior process skills (21, 22). Atkin and Karplus (23) believed that textbook teaching alone did not give students at any age the integration of conceptual understanding and process skills. Therefore, the guided-discovery system would make the complexity of concepts easier to learn by involving themselves in the activities (24). Later, Lawson (25) recognized that teachers can give students new knowledge but students must actively invent or generate the concepts. The learning cycle approach appears to be a potential means of promoting students’ understanding of difficult mathematical concepts besides difficult those scientific ones. Lawson and Abraham’s model of learning cycle consists of three distinct phrases of instruction. In Exploration Phase, students learn through their own actions and reactions with minimum guidance in activities designed to expose students to the concepts. The students are expected to raise questions they can’t answer with their present ideas or reasoning patterns. In Concept Introduction Phase, the concepts are introduced and explained with help from the teacher. The concepts are usually derived from the data or classroom discussions. In Concept Application Phase, the students explore the usefulness of the concepts they have learnt and then applied to new situations. Its range of applicability is extended to different contexts and situations related to the concepts. Methodology 1. Participants Single group pre-test post-test research design was used in this study. A pre-survey test for finding out the students’ basic knowledge in differentiation and integration in calculus was conducted on preparatory college students. Out of forty five of these students, eight students were selected after the pre-survey test. In addition seven voluntary first year undergraduate mathematics major students also participated. 2. Procedures A pre-test was conducted for 30 minutes prior to the intervention. The learning unit on the establishment of relationship between differentiation and integration in Calculus was taught for one hour. At the end of the instruction, a post-test and an attitude test were conducted. A same set of four open-ended questions was used for both the pre-test and the posttest. The first question examined whether students could relate the graph of an anti-derivative to that of its derivative as well as the units in those graphs in the straight-line motion context. The second question examined whether students could relate the graph of a derivative to that of its anti-derivative in the same context. The third and fourth questions examined the students’ conceptual understanding of integration and differentiation respectively. The attitude questionnaire consisted of thirteen Likert-type items and three open-ended questions. The purpose of the questionnaire was to find the students’ attitude towards the relationship between differentiation and integration and towards the learning unit. The Likert scale in the questionnaire included “1 = Strongly disagree”, “2 = Disagree”, “3 = Neutral”, “4 = Agree” and “5 = Strongly agree”. A paired sample t-test was used for data analysis to determine whether significant difference between the pre-test and post-test scores exists. The Cronbach’s Alpha reliability coefficient of the post-test was 0.58. The frequencies of the responses to each questionnaire item were separately tabulated and interpreted. The Cronbach’s Alpha reliability coefficient of the questionnaire was 0.79. 3. Contextual examples and graphing activities learning unit The Lawson-Abraham model of learning cycle was used to frame the development of a learning unit on the relationship between differentiation and integration in calculus, which employed contextual examples and graphing activities. The students were divided into groups of 3–4 students. All the instructions for the group activities were provided on the worksheet given to the students. The details of the activity in each phase of the learning cycle are described below: i) Exploration phase In this phase, the context was a car moving for five hours at a constant speed. The students were asked to sketch the graph of the constant speed and to divide the area under the line into five equal parts (see figure 1(a)). They were then asked to find the unit and the meaning of those areas, which should help them realize the graphical relationship between speed and distance. The students then plotted the distances on another graph paper (figure 1(b)) and compared the two graphs, which were actually the graphs of a derivative and its anti-derivative. They were further asked to find the equations of the two graphs. Being more familiar with algebraic notation, the equations should help them in confirming the relationship of the two graphs. To help them see that the graphical relationship worked for non-integers as well, they were asked to find the areas and the distances after 0.5, 1.5, 2.5, 3.5 and 4.5 hours. Finally, they were asked to directly calculate the area under the line in figure 5(a) from t = 0 to t = 0.5 by integration and to confirm that the result agreed with the area and the distance in the two graphs. They were also asked to find the slope of the line in figure 2(b) at t = 0.5 hours. Figure 1(a). Area under the line for t =1, 2, 3, 4, and 5 hour. Figure 2(a). Speed-time graph Figure 1(b). Distance at t =1, 2, 3, 4, and 5 hours Figure 2(b). Distance-time graph ii) Concept introduction phase From the exploration phase, students should begin to have an idea about the relationship between differentiation and integration. The concept introduction phase should help them formulate the idea more completely. To that end, the students were asked the following questions. What do you get if you find the area under the graph in figure 2(a) by integrating the equation of the line from t = 0 to t = 5 algebraically? What is the unit of the area? And what does the unit of the area tell you? The students should be able to see that finding the area under the line and integrating the line of the equation would give 100 km, which would indicate the distance travelled by the car in 5 hours as shown in figure 2(b). Then, the students were also asked the following questions. What do you get if you find the slope of the line graphically and differentiate the equation of the line algebraically of the graph in figure 2(b)? What is the unit of the slope? The students should be able to see that the finding the slope of the line graphically and differentiating the equation of line algebraically would give 20 km/hr which would indicate the speed of the car on the graph as shown in figure 2(a). Then, the students were asked; do you see any relationship between the graphs in figures 2(a) and 2(b) in terms of differentiation and integration in calculus? Explain? Now, the students should be able to see the relationship between differentiation and integration graphically, algebraically and contextually from the activity and to conceptually understand that integration is the inverse process of differentiation. iii) Concept application phase In this phase, the context was still a moving car but accelerating at 2 m/s2 for 10 seconds instead of travelling at a constant speed. The students were asked to sketch its graph, to find the area under the line as shown in figure 3(a) and to plot the area, which was in fact the speed, on another graph paper as shown in figure 3(b). Then, finding the area under the line in figure 3(c) would give the distance, whose graph is shown in figure 3(c). Finding the derivatives at instances of time on the distance-time graph in figure 3(c) would give back the speed-time graph in figure 3(b) and finding the derivative of the speed-time graph would give the acceleration-time graph as shown in figure 3(a). The students could use both algebraic and graphical methods of integration to find the speed and distance from the given acceleration and the same was true for the reverse process of differentiation. It should be noted that the nonlinearity of the distance-time graph could also be used to emphasize the instantaneous nature of a derivative, both graphically and algebraically. Figure 3(a). Acceleration-time graph Figure 3(b). Speed-time graph Figure 3(c). Distance-time graph Results 1. Students’ performance A paired sample t-test showed that the average post-test score was significantly greater than the average pre-test score (see table 1). After the intervention, there was significant improvement in students’ performance. The mean score in the pre-test was extremely low as many students found the questions difficult which indicated that students had no conceptual understanding in regard to differentiation and integration in general and to the relationship between differentiation and integration in particular. Some of the students scored much higher in the post-test despite the fact that the intervention lasted for only one hour. Table 1. Paired sample t-test of pre-test and post-test result Test Mean Standard deviation t Pre-test 1.75 0.83 5.46 Post-test 4.54 1.89 Number of students = 14 and total score of the test = 17 Sig. (2-tailed) 0.00 2. Students’ attitude towards the learning unit Nine students indicated that they had learnt differentiation and integration in an introductory calculus course before but five students were not sure about it. Thirteen students found that the activities were interesting and enriching and helped them understand the relationship between differentiation and integration better. The majority of the students found that the lesson was well organized and the instructor encouraged the students in the learning process. Table 2: Students’ attitude questionnaire responses Items I have learnt about differentiation and integration in calculus before My Mathematics teacher never taught me the relationship between differentiation and integration in calculus I understood the relationship between differentiation and integration in calculus from the activities in the lesson I found difficult to see the relationship from area under line in integration to slope of line in differentiation I found difficult to see the relationship using mathematical notation used in differentiation and integration in calculus Did the lesson improve your understanding of the topic? The lesson was well organized in a way that helps me understand the relationship between differentiation and integration in calculus The lesson was useful to understand the differentiation and integration better The instructor has been well-prepared for the class The instructor has encouraged the students to participate actively in class The instructor has made an effort to enhance learning The instructor has been open to students’ opinion I found the class very interesting and enriching 0 0 5 8 1 Average Response 3.71 3 3 7 1 0 2.43 0 0 6 8 0 3.57 0 8 2 4 0 3.14 0 7 2 5 0 3.21 0 1 4 6 3 3.79 0 1 4 6 3 3.64 0 0 0 0 0 0 3.79 4.29 3.93 4.07 4.07 4.29 1 2 3 4 5 2 0 0 0 0 0 4 1 4 2 2 1 3 8 7 9 9 8 5 5 3 3 3 5 Discussion and Conclusion The pre-test result showed that the students often lacked certain conceptual understanding in differentiation and integration from traditional mathematics teaching. The students learnt calculus without actually understanding differentiation and integration as well as their relationship. The concepts of differentiation and integration were traditionally taught by focusing only on algebraic methods in an introductory calculus course at the higher secondary level. The students saw calculus as a series of process associated with algorithms and could not apply the concepts in the contextual situations. This agrees with Tall’s (26) findings that students instead of having conceptual view of the symbols and notations in differentiation and integration, they focus only on a process-oriented view. The students encountered difficulty in relating the functional notations of differentiation and integration to the context of motion. The average score of the post-test was significantly higher than that of the pre-test, indicating that the developed learning unit could enhance the learning achievement of the students. The hands-on graphing activities helped the students think logically, develop their own reasoning skills, and ultimately invent their own concepts of the relationship between differentiation and integration. Sokolowski et al. (17) and Orhun (18) also employed graphing activities in contextual settings to enhance students’ understanding of calculus. The reliability of the posttest was rather low due to the difficulty in learning calculus and to the openendedness of the questions. The students found the activities interesting and enriching probably because they took active roles in the lesson and felt motivated to learn calculus, hence leading to better performance. To really understand the relationship between differentiation and integration, students obviously need to understand both differentiation and integration which are themselves based on more fundamental concepts like limit and continuity and discontinuity of a function. To understand these concepts, the lessons must focus on context-based activities rather than on algebraic methods (26). Students usually learn and retain better when they are actively involved in the lessons and the concepts can be visualized. The coverage of the fundamentals of calculus is a must before the learning of the relationship between differentiation and integration can take place. Such a coverage will require a much longer intervention duration. It is hoped that a coherent lesson on calculus based on contextual activities will be developed. Acknowledgement The first author would like to thank Thailand International Development Cooperation Agency (TICA) for providing scholarship to pursue Master Program in Science and Technology Education in Mahidol University. References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. Mokhtar MZ, Tarmizi MAA, Tarmizi RA, Ayub AFM. Problem-based learning in calculus course: perception, engagement and performance. 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