Application of Didactic Strategies as Multisensory Teaching Tools in

Article pubs.acs.org/jchemeduc

Cite This: J. Chem. Educ. XXXX, XXX, XXX−XXX

Application of Didactic Strategies as Multisensory Teaching Tools in Organic Chemistry Practices for Students with Visual Disabilities Gabriela A. Fernań dez,*,† Romina A. Ocampo,† Andrea R. Costantino,† and Neś tor S. Dop‡ †

INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS)-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Argentina ‡ Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Av. Alem 1253, 8000 Bahía Blanca, Argentina

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S Supporting Information *

ABSTRACT: Visually impaired or blind students require adjustments to the traditional hands-on activities and methodological and didactic strategies employed by the teacher. These adaptations are based on multisensory teaching tools, which reinforce the learning of all students in general. This paper presents simple teaching resources that allow students with visual disabilities to solve problems of Organic Chemistry independently and on an equal footing with their nondisabled peers.

KEYWORDS: Organic Chemistry, Hands-On Learning/Manipulatives, Continuing Education, Stereochemistry, High School/Introductory Chemistry, Enantiomers

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There should be an “inclusive education” not because there are excluded students at school, but because people have different learning abilities, and educators must be prepared to face this diversity.5 Teachers should recognize that students with visual disabilities have different abilities, needs, and constraints, and that their competence, intelligence, motivation, and determination vary, similarly to the variations observed among nonimpaired students.6 Having blind or visually impaired students in the classroom leads to adjustments that do not affect prescriptive components, but only the activities, methodological or didactical strategies, and evaluation criteria. This is why these students attend the same lectures and courses as nonimpaired students; blindness or diminished sight does not entail an adaptation of the conceptual content; however, educational strategies adapted to these students can positively influence the activities to perform, without detrimental effects on the students with nonimpaired vision who study together with them. Because these adaptations are based on the implementation of multisensory teaching, the learning of all students will be also reinforced in general. “Minimizing the adaptation” is very important for students who are blind or visually impaired. Adaptation emphasizes the

INTRODUCTION

Chemistry is a discipline with an important visual component. In this context, the environment of a laboratory can be challenging for students with impaired sight or blindness, hampering their autonomy in the performance of their tasks.1 It is very important to identify three types of barriers to the success of the student: (i) pedagogical (lack of preparation of the instructors), (ii) accessibility (limited access to facilities and equipment), and (iii) acceptance (negative attitudes of educators who believe that students cannot succeed in Chemistry). The latter is the most significant barrier for pupils with disabilities who are studying degrees related to science and engineering.2 Organic Chemistry is one of the Chemistry specialties that most relies on visual considerations because it requires twoand three-dimensional representations of molecular structures. Students are evaluated by their ability to produce, interpret, and manipulate these structures.3 Traditional teaching still has a strong influence on higher education. Priority is usually given to the accumulation of conceptual contents, and students are expected to assimilate these previously organized conceptual structures in a passive, receptive manner. For many students with disabilities, entering a degree in science requires not only access to the classroom and the laboratory but also resources that will help mitigate the challenges posed by their respective disabilities.4 © XXXX American Chemical Society and Division of Chemical Education, Inc.

Received: October 5, 2018 Revised: February 12, 2019

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DOI: 10.1021/acs.jchemed.8b00816 J. Chem. Educ. XXXX, XXX, XXX−XXX

Journal of Chemical Education

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student’s disability. This emphasis creates a gap between the blind or visually impaired student and his peers, which may hinder the student’s social interactions.7

On the one hand, it is of utmost importance for the blind students to be part of working groups and participate actively, taking part in both the successes and the failures of the group in which they interact. Moreover, the student−instructor relationship is a key pillar in the university experience. For students with visual disabilities, this relationship is especially important: they should both discuss and critically comment how the course is progressing, how material is presented, and if the student is learning at the appropriate pace.16

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OBJECTIVES The overall objective of this work is to demonstrate how, from the inclusion of a blind student in Organic Chemistry, teaching resources can be developed in order for the student to be actively involved in educational activities with his classmates, contributing to his motivation and promoting the significance of the curricular contents. In particular, herein, we will explain in detail the modifications made to the format of Organic Chemistry tutorial handouts and the use of handmade models in order to facilitate the interpretation of the contents, using simple lowcost resources, providing tools that allow students with visual disabilities to solve the problems discussed in the tutorials, in the same independent way as his sighted classmates.

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METHODOLOGY This work was carried out in the Department of Chemistry at the Universidad Nacional del Sur (Bahiá Blanca, Buenos Aires, Argentina), in the context of the course on Fundamental Organic Chemistry, issued for the first year undergraduate Degree in Biological Sciences. The year group consisted of 80 students including one blind student. The students attended theoretical lessons with the teacher of the course and undertook practical activities. The latter, imparted by two teaching assistants and six auxiliary teachers, comprised two parts: problem solving tutorials and hands-on laboratory work (seven training sessions in total). The teaching staff was distributed as such: one auxiliary teacher supervising 10 students per laboratory bench, and an extra assistant was assigned to the group that included the vision-impaired student in order to facilitate the normal course of the practical class. The resources used to ease the understanding of the theoretical contents by blind students are detailed below.

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BACKGROUND To obtain an adequate interpretation of each of the concepts taught in Chemistry, it is necessary to work at a macroscopic (tangible and visible phenomenon), microscopic or submicroscopic (particles), and symbolic level (graphics, images, chemical symbols, equations, etc.). Many of the issues encountered while learning this science are related to difficulties in conceptual understanding, and this could be the result of a lack of discussion of all of the three abovementioned levels, as well as their inter-relations.8 Therefore, the experimental activities can help to connect these three categories.9,10 Observations and visual representations must be translated into a understandable and descriptive language for blind students, so that they can acquire concepts and demonstrate or discuss ideas in a satisfactory way.11 Because the teaching of Chemistry focuses on the representation and understanding of macroscopic and microscopic phenomena, adapted tutoring and hands-on activities combined with the use of technologies can be excellent tools during tutorials and experimental classes. Those would promote opportunities for questions, discussion, and for the students to propose hypotheses, which would help guiding the teaching−learning process. In particular, these resources give students with visual disabilities the opportunity to develop activities in a creative manner.10 Several authors have highlighted the importance of making scientific learning accessible to people with vision impairments, using different means including audio media, tactile, and written representations,11,12 as well as adaptations of the laboratory facilities.7,13 The concept of multisensory experimental approaches is crucial to allow students with visual disabilities to develop in a more independent, convenient, and efficient manner.14 Molecular model kits play an important role in the learning of Chemistry. Tactile models can be adapted easily for students with vision impairments through the modification of commercially available kits. Moreover, the changes made to these kits do not interfere with the learning of other students.13a The success in the use of commercially available products with models made with waxed yarn, as tactile learning aids in Organic Chemistry for students who have low vision, has been reported by Poon and co-workers.15

Exercise Guide Folder

A folder with separators was prepared. It allowed distinguishing easily the exercise guides associated with each of the theoretical contents, as well as the subjects of each partial examination (Figure 1). Separators had the chapter number

Figure 1. Exercise guide folder with separators.

marked in Roman numerals. The exercises were individually printed on tracing paper, increasing sizes 5-fold with respect to the handouts given to the other students, and the structures were carefully marked with a dotting tool, so that the blind student could recognize the relief of the molecules (Figure 2). This format was also used in partial and final oral examinations, evaluated by a teaching assistant under supervision of the professor or conversely. The other students were evaluated with the same test that took place on the same date and time but in another classroom within the University. The blind B



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Figure 2. Dotted structures for the exercises. Figure 4. Three-dimensional models of R and S enantiomers.

student oral answers were copied literally on the respective examination form for subsequent correction. In addition, the student was provided with the electronic versions of the guides and recommended bibliography that can be read using the free software NVDA (Non Visual Desktop Access). It serves as a support tool for people with partial or total visual impairment. In practice, the software reads aloud the text that appears on the screen of a computer.17 The following three models were used to explain stereoisomerism.

substituents. Furthermore, external balls could easily be differentiated from one another as they were covered with materials of different textures, for example, wool, rough paper, tin foil, and paperboard (in the figure, orange, red with white dots, silver, and light blue, respectively). In addition, the different ball sizes allowed establishing an order of priority for the substituents, based on the CIP (Cahn−Ingold−Prelog) rules, which was used to assign an absolute R or S configuration to the central carbon.

Newman Projection Models

Wire Models with One and Two Stereogenic Carbons for Three-Dimensional Structures and Fischer Projections

Models of Newman representations were custom-made to explain the different conformers that are generated by the rotation of a C(sp3)−C(sp3) bond. They were made by cutting two X-ray film papers in a regular “Y” shape (10 cm length × 1 cm width for each branch at a 120° angle) that were placed on top of each other and linked in the center by a brass fastener, allowing one “Y” shape to rotate with respect to the other to generate the different conformations. As an example, Newman conformations for 2,3-butanediol are represented in Figure 3. At the same time, each and every edge of the “Y” was differentiated by dots that were marked with a hot pin (a single dot, two horizontal dots, and two vertical dots, respectively, as can be seen in Figure 3). Those were punched on the front as well as the back “Y” for an easy tactile identification.

With respect to the 109° angles, three-dimensional models with flexible copper wires representing structures with one and two asymmetric carbons were designed (Figure 5). The four bonds were differentiated with linear termination (without additional feature), ending in a circle, with a small ball at the edge and with triple strands of wire.

Models To Assign Absolute Configuration Using Different Textures

Models representing two enantiomers of a simple molecule were built with Styrofoam balls of different sizes. Those were connected to a central ball by 10 cm long wires (Figure 4). The wires were separated from each other by an angle of approximately 109° to represent schematically an sp3hybridized quaternary carbon atom with four different

Figure 5. Three-dimensional wire models for one and two asymmetric carbons.

Figure 3. Eclipsed (left) and staggered (right) Newman conformations and a draft made to differentiate the extremes of the “Y” shape. C



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generated when an electron-donating substituent delocalizes its free electron pair into the aromatic ring. As an example, resonance structures for aniline are illustrated in Figure 8. It is clear that the above-mentioned model can be adapted to other electron-donating groups as well as electron-withdrawing substituents in EAS reactions.

It should be noted that these models are very versatile because it is easy to incorporate substituents or to make structures with longer carbon chains. These models being flexible, wires could be accommodated in order to switch between three-dimensional structures and Fischer projections (Figure 6).

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RESULTS The use of models allowed the blind student to interpret exercises and to subsequently solve them. These were used not only for the tutorial exercises but also in a formal examination. The folder with separators allowed a comfortable distribution and quick location of content. The exercise handouts printed on tracing paper enabled the students to identify the structures thanks to the relief printing (dotted lines). Likewise, using these tools, the vision-impaired student was able to conveniently and successfully sit examinations and gave positive feedback, which validates this didactic approach. The Newman projection model was an easy-to-use tool that allowed converting a 2D drawn representation into a tangible 2D object and quickly obtaining and determining different molecular conformations. Three-dimensional models with Styrofoam balls with different textures and wires allowed a correct assignment of absolute configurations for stereogenic carbon-containing structures. In addition, it was possible to convert rapidly and simply three-dimensional structures to 2D Fischer projections. The wire model used to represent the aromatic ring resonance was very useful to introduce the concept of electronic delocalization in conjugated systems and for the study of EAS reactions in substituted benzenes, with an electron-donating group as an example. It should be noted that the whole group of students was very enthusiastic about the use of the proposed models; many students even made their own ones. This approach helped to complement the explanations given by the teaching staff, facilitating the comprehension and resolution of exercises.

Figure 6. Conversion of a three-dimensional structure to a Fischer projection with a wire model.

Wire Models To Explain Resonance in Aromatic Hydrocarbons

This model was used to explain electrophilic aromatic substitutions (EAS). Rigid iron wire was used to form a hexagonal structure (10 cm each side) with a substituent that has a free pair of electrons (the central atom of the substituent is represented by a plastic ball (Figure 7, left). A double strand

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DISCUSSION Practical experience is essential for experimental sciences such as Chemistry. A student with a disability may feel restricted, to greater or lesser extent, in terms of the activities she or he can perform. This often affects the degree of participation of the student. Continuous dialogue (prior, during, and after the period of study) is fundamental to discern the needs of each particular situation. Unquestionably, the students whose efforts in practical work are strongly restricted by a disability are not necessarily excluded from careers that involve experimental work. This is where the didactic resources employed by the teachers play an essential role. For blind students who study Chemistry, practical training is not only educational but also desirable: for them, the hands-on experience is vital.18 For this reason, these three-dimensional, easy-to-assemble, and inexpensive models will be of great help in understanding and solving the exercises of Organic Chemistry problems. The strategies developed and detailed herein allowed us to make a correct analogy to the theoretical contents and proved to be valuable teaching resources to explain stereochemistry and resonance in aromatic systems, two fundamental concepts in Organic Chemistry. The use of the models engaged students in general, and it also aroused their curiosity in using them to solve the exercises. It was possible to create an atmosphere of

Figure 7. Wire model for aniline (left). C−H and N−H bonds are represented with a double strand of intertwined wire; a singlestranded wire was used to represent the movement of electrons (right).

of flexible wire (5 cm length) was used to represent bonds with hydrogen atoms on five vertices (carbon atom) of the aromatic ring and the two X−H bonds in the substituent; an amino group was used as an example in this case (X = N, Figure 7). Six single strands of flexible wire (5 cm length) were added at each vertex of the ring, which could be moved to both sides, indicating electronic delocalization due to the resonance of the π-system. It should be noted that a pair of electrons or a net negative charge in a given atom might be represented by the folded wire, as shown in Figure 7. The vertex with the ball allows representing the additional resonance structure D



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Figure 8. Wire model used to represent the resonance in an aromatic ring.

Although this assimilation is effected through their own cognitive strategies, it will most likely persist over time and the student will be able to recover and transfer it in future situations. The challenge is to design strategies and propose activities that encourage reflection, questioning, and analysis to enable these processes and capabilities at the same time. In this way, contribution is enriching for the whole group of students. According to the blind student’s opinion, the highlights of this work are detailed below:

cooperative work among all the students as well as to get a better interpretation of the exercises to validate their usefulness. This was reflected in the percentage of approval of the subject, in comparison with previous years where these models were not used (Chart 1). Even more, the attendance to the practical classes was increased, which indicates a greater motivation of the students. Chart 1. Graph Showing the Percentages of Approved, Disapproved, and Attendance to Problem Solving Tutorials (*Year When the Models Were Implemented)

• The applied methodologies allow all students to access and assimilate the contents. • Performing practical activities in a group or individually lets the blind student explore his skills and abilities. • Developing multisensory strategies is essential to address the different aspects involved in higher education. • A constant assessment of the group is very important to identify the needs and potential of each student, in order to execute relevant methodologies. The overall experience has been extremely enriching. Its best learning is that students with visual disabilities can study and learn both social and experimental sciences, such as Chemistry, without major inconveniences, they simply need to be given the opportunity to do so,6 with the support of adequate tools that bridge the gap between the theoretical contents and their practical applications. It is very important to implement teaching strategies in the classes for the entire course, without the need to be a resource to satisfy the needs of a student in particular. Given that the use of teaching materials generated positive changes in the predisposition of the students to attend classes and they improved their performance, the next challenge is to be able to sustain the implemented changes over time and even design new practical tools for other contents of Organic Chemistry.

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CONCLUSIONS It should be remembered that observation is a fundamental aspect for any topic in experimental sciences, as it is the first step of the Galileo scientific method, “Every scientist or scientist trainee, must observe before formulating a hypothesis”. Generally, when the term “observe” is used, it is associated with the action of seeing or looking, that is, essentially a visual observation; however, it does not necessarily have to be so. From the perspective of the teaching we intended to apply in this work, observation can occur using other senses such as touch. This proposal affects the attitude and motivation of the students. When they use representations or tangible threedimensional models, they can interpret the spatial arrangement of atoms in a molecule more easily. If the students can comprehend a methodological approach or a concept, without learning by heart, they will be able to give meaning to what has been learned and therefore to better assimilate that knowledge.

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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.8b00816. Detailed description of the preparation of the models (PDF, DOCX) E



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AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. ORCID

Gabriela A. Fernández: 0000-0003-3605-4986 Andrea R. Costantino: 0000-0001-8878-8717 Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS The authors acknowledge the participation and contributions of students and, especially, the Centro de Rehabilitación y Biblioteca Popular “Luis Braille” and the Chemistry Department of Universidad Nacional del Sur. The authors also thank Dr. M. Muratore for his comments.

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REFERENCES

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