**Approaches and Methods of Science Teaching and Sustainable Development**

Editors

**David Gonz´alez-G ´omez Jin Su Jeong**

MDPI • Basel • Beijing • Wuhan • Barcelona • Belgrade • Manchester • Tokyo • Cluj • Tianjin

*Editors* David Gonzalez-G ´ omez ´ University of Extremadura Spain

Jin Su Jeong University of Extremadura Spain

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This is a reprint of articles from the Topical Collection published online in the open access journal *Sustainability* (ISSN 2071-1050) (available at: https://www.mdpi.com/journal/sustainability/ special issues/sci teach edu sus).

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## **Contents**



## **About the Editors**

**David Gonz´alez-G ´omez** received his PhD in analytical chemistry at the University of Extremadura (2005) after different doctoral research stays at the National University of Rosario, Argentina, and at the University of Central Florida, the United States. After graduating, Dr. Gonzalez ´ obtained a two-year postdoctoral fellowship at the University of Washington, working with Professor Norman J. Dovichi in proteomic analysis. After returning to Spain, he has worked at the Technological Institute of Food and Agriculture (INTAEX) as the research group director. During this time, he also served as an associate professor at the University of Extremadura. Currently, he is a professor at the Department of Science and Mathematics Education at the University of Extremadura and the dean of the Teaching Training School of the University of Extremadura (Caceres). He is the author of more ´ than 100 international journal papers, has assisted in a great number of international conferences with peer-reviewed proceedings, and was the director of five doctoral theses. Dr. Gonzalez has been ´ involved in several national and European grants as well as collaborations with local industries. Due to his outstanding research, he had been awarded the Outstanding Thesis Award (2006) and Juan Jesus Morales Young Researcher Award (2011), both from the University of Extremadura (Spain).

**Jin Su Jeong** is currently an associate professor at the Department of Science and Mathematics Education, the Universidad de Extremadura (Spain), and was working with the Juan de la Cierva Program at the Universidad Politecnica de Madrid (Spain). He received his MS in architecture ´ from the Texas A&M University, College Station (United States); his first PhD with International Mention and Suma Cum Laude in Graphic Engineering, Geomatics, and Projects; and his second PhD with Suma Cum Laude and the Outstanding Thesis Award in Teaching Education from the Universidad de Extremadura and Universidad de Huelva (Spain), with a PhD course from the University of Washington, Seattle (United States). For his doctoral dissertation, he conducted different doctoral research stays and collaborations. He has published more than 250 papers in journals, books, and conference proceedings, including 55 papers in journals indexed in the Web of Science. He has participated as a keynote speaker, on scientific and organizing committees, and as the chairperson of several international conferences and associations and has served as a reviewer for more than 450 papers in a wide range of international journals. Additionally, he is serving as an editor (*Heliyon*—Education Section, *Frontiers in Psychology/Education*—Educational Psychology, and *Sustainability*—Sustainability Education and Approaches Section), invited editor for special volumes, and editorial board member for a couple of prestigious international journals.

### *Editorial* **Approaches and Methods of Science Teaching and Sustainable Development**

**David González-Gómez and Jin Su Jeong \***

Departamento de Didáctica de las Ciencias Experimentales y Matemáticas, Universidad de Extremadura, 10004 Cáceres, Spain; dggomez@unex.es

**\*** Correspondence: jin@unex.es

Unfortunately, science teaching at the university level has largely consisted of lectures in which the students' position is usually to gather information by listening and taking notes from the instructors [1–3]. However, in science, technology, engineering, and mathematics education (STEM) studies along with science education, new approaches and methods have established increasing devotion in recent years to stipulate appropriate preparations of students' abilities [4,5]. STEM education offers the integration of various scientific disciplines as a solid object, the teaching and learning of which are combined and organized so it can be utilized for problem-solving in daily circumstances [6]. Here, Wiswall et al. proposed that students participating in the courses and undertakings concentrated on STEM subjects attained better results in STEM topics than not participating students [7]. In these situations, to support the satisfaction, association, and motivation of students, various active methodologies could be integrated into the current classroom [8–10]. Despite the STEM methodology's implementation, which encourages students' scientific literacy, however, their disinterest was one of the main origins for negative scientific attitudes [11]. Additionally, an interdisciplinary method could be achieved through this active method in STEM courses. It considers the way to foster a realistic atmosphere with the better student experience as an objective [12,13]. Particularly, the decade of education for sustainability development (DESD) of the United Nations (UN) has designated the current situations of STEM education, which could stimulate the understanding of communal values and spread life-long preparation together with active instruction methods [14–17].

The educational sustainability development (ESD) has chased a life-long awareness and quality for individuals who are in varied educational sectors [1–3]. The DESD of the United Nations Educational, Scientific and Cultural Organization (UNESCO) and the UNESCO 2015–2030 Agenda incorporated the philosophies, objectives, beliefs, and exercises of sustainable education [16–18]. In the higher education context, it must be a part of a universal arrangement proposing sustainability education [19,20]. It can also shape its objective to individuals together with knowledge that will redirect the effects of their performance [19–22]. Specifically, it was elevated to a better comprehension of the notion of sustainability, was reoriented to the educational curricula, and was indicated toward the attainment of information, skills, value, and knowledge [23–25]. Here, sustainable education mentioned by Sterling [26] was conducting into transformative learning that was a modification of educational culture for the potential realization and economic, social, and ecological interdependency of people. Thus, in the same context of transformative learning, Mezirow [27] designated instructors the responsibility of helping students to accomplish more independent and reliable objectives. Finally, teaching resolutions in the context of an instructional culture are considered in approving teacher trainees along with communications, standards, abilities, and thinking methods, which could serve as transition delegates for sustainable development [28–30].

STEM education for sustainable development was associated with knowledge-acting and containing the values of sustainability education [31]. However, a distinct research area

**Citation:** González-Gómez, D.; Jeong, J.S. Approaches and Methods of Science Teaching and Sustainable Development. *Sustainability* **2022**, *14*, 1546. https://doi.org/10.3390/ su14031546

Received: 19 January 2022 Accepted: 23 January 2022 Published: 28 January 2022

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

could have its own dimensions, approaches and aptitudes, and scientific skills, which are not connected with its value [31–33]. Likewise, it was an emergent part within educational science, which had a robust connection to science education for sustainable development [34–36]. Equally, sustainability STEM in higher education was a beginning stage as ever, although they had performed different portions to transform societies/cultures by instructing key persons that were leaders, academics, and entrepreneurs [37]. Accordingly, it was essential to reflect on universities' characteristics that were altering at a comparatively slow pace [37,38]. In the aforementioned challenging situations, the life-long sustainability STEM education can generate a pedagogical probability for filling the niche of the current education system [1,39]. In higher education, the approaches and methods of science teaching for sustainable development are still in an early chapter, without a proper tool, while they could have some possibilities for teaching and learning. With higher confrontations and demands, this proposal can be connected with various active applications and research domains of STEM education in these circumstances [4,40].

With this Special Issue "Approaches and Methods of Science Teaching and Sustainable Development", we aimed to contribute a solid research corpus for concentrating the challenges required to deliver an adequate Science and Sustainable Development Education to different educational scholars. In many educational institutions, sustainability formed a part of their curricula. Efforts were stipulated for guaranteeing a correct implementation/development of sustainability topics looking for the sustainable development goals (SDGs) in the universities, as well as fresh viewpoints on ongoing challenges.

As a science teaching approach, in the first paper in this Special Issue, Lucian-Ionel Cioca and Raluca Andreea Nerisanu discussed a quasi-experimental and nonequivalent group design, for which the procedure involves the use of visual mnemonic devices. In the potential and boundaries of leading fields of creativity literature, there was always an area for the extension of methods, and novel conceptualizations were always involved. This paper, therefore, presents a concise organization of the methods utilized to improve originality and reflects whether visual mnemonic devices could grow creativity. In the teaching procedure, the devices were employed to relieve the memorizing process by making a graphic demonstration. The results indicated that the abstracting degree was amplified after exploiting visual mnemonic devices, together with fluency and other creativity extents. Accordingly, the paper presented that the creativity was also amplified based on a national percentile scheme once exploiting the visual mnemonics devices, thus representing an example for incorporating visual mnemonic devices amongst the methods to promote originality and creativity (Table A1 Contribution 1).

As an ESD in a problem-based university learnings, Alain Ulazia and Gabriel Ibarra-Berastegi indicated various goals for sustainability connected to not only clean energy and climate change but also in educational terms associated with co-operative learning, motivation, and reflective thinking in the new faculty of Engineering in Renewable Energies at the University of the Basque Country in Eibar. In this sense, the laboratory-windpump challenge situation was paradigmatic since it established effective problem-based learning for the students in the context of the activation of heuristic tools (analogies/diagrams); analytical discussions conjoining complicated thoughts about aerodynamics, mechanics, and hydraulics; and a suitable cluster atmosphere. Here, the conclusions of this paper were reinforced by qualitative and quantitative results inside of a theoretical background on the basis of the discovery logic and its related constructive-learning approach rather than on the justification logic within an aprioristic assumption that is well-known and given (Table A1 Contribution 2).

Thus, in the same context, Muhammad Waqar Ashraf and Faisal Alanezi reiterated that current university curricula utilization was to integrate sustainability components into engineering education. Here, the concepts of sustainability were presented into the courses designated by employing a micro-curriculum method. Higher education institutions (HEIs) are progressively hunting SDGs in engineering and technology education. The concepts correlated with production, operations, and consumption sustained to increase the significance for students in an engineering major. Therefore, it was required to advance an engineering education program together with the technical contents that also fostered a critical logic regarding the social and environmental fields. The existing sustainability education status in engineering programs suggested in Saudi universities was not very favorable. Furthermore, a standalone course was initiated. It could also be perceived that this attitude had been fruitful in incorporating sustainability into the engineering curriculum. Finally, it was indorsed that such an advance could be employed to grow sustainability consciousness in engineering education/programs (Table A1 Contribution 3).

In addition, in engineering education, Huang et al. offered and exemplified a designbased learning (DBL) method for nurturing individual competency for sustainability. Here, two studies were performed with engineering students in typical activities of educational areas. For the first study, it assisted students in performing a topic-specific design task for the practicum item of a sensor technology course, which paralleled the DBL performance approach and the conventional and passive learning method. For the second study, it directed students to improve innovative projects for contributing in the "Internet Plus" Innovation and Entrepreneurship Competition (IPIEC). The results illustrated that the DBL approach was worthwhile for teaching in sustainability competency in the context of teaching procedures and learning demand. In the DBL group, the students contributed more distinction in individual competencies such as system-thinking, multidisciplinary applications, and collaboration. Therefore, these discoveries proposed that applying the DBL approach to work sustainability competency into engineering education was advantageous for encouraging students' capabilities to deal with challenges concerning sustainability exercises (Table A1 Contribution 4).

In the STEM areas, it was necessary to progress a comprehensive education and to advance learning competences and student perceptions of these courses. Here, Matos-Núñez et al. examined the teaching efficiency in the view of a cognitive and emotional term of a STEM workshop versus an academic-expositional methodology in the primary science education classroom. With a quasi-experimental design, the research was conducted along with a control and experimental group and a pre- and two post-tests. According to the two teaching methodologies proposed, cognitive, emotional, attitudinal, and gender variables were assessed: the control group with expository academic methodology and the experimental group with active methodology on the basis of a practical STEM workshop development. The results disclosed that both methodologies proposed were correspondingly effectual in short-term education but statistically substantial differences were found in long-term education in favor of STEM workshops. Equally, the STEM workshops principally created positive emotions/attitudes for the students parallel to those the transmission/reception methodology generated in the control group (Table A1 Contribution 5).

In the SDGs' achievements, Gutiérrez-García et al. described the design, implementation, and assessment of the obtained didactic proposal knowledge for non-formal education that supported controlled education based on botanical content. Firstly, a workshop was held where young individuals contributed directly to emerging fieldwork with a real scientific procedure with the active methodologies' use based on experiences. Then, a student's group was selected for an interview to attain the overall concept of the learning gotten. Here, the students' motivation was somewhat positive, which allowed us to acquire voluntary contribution in the fieldwork and also offered the students as a participative attitude through the workshops' advance. Concerning the didactic application to its immediate setting, it was shown to upsurge interest in the students' own learning and value contexts. This educational experience's results had been highly positive such as the knowledge that was learnt, and the preservation of interest in the environment and the occupation of an investigator was encouraged (Table A1 Contribution 6).

In the cognitive and affective domain study in science education, Ortega-Torres et al. discussed various aspects. Firstly, the motivation and self-perception of Spanish secondary school students were presented by using approaches when acquiring science. Then, the nature of the association between learning strategies' motivation and observed usage was

examined. Finally, the effect of dissimilar motivational, cognitive, metacognitive, and management approaches on students' science attainment was assessed. Here, the relation between motivation and the usage of learning approaches was an emphasis of study to increase the learning of students. The obtained results from the Pearson's product–moment correlations, the variables, and stepwise regression examination were proposed. Firstly, motivation, cognitive and metacognitive, and resource management approaches had a substantial effect on the science achievement of students. Then, the motivation of students became an enabling feature for the knowledgeable exertion that was measured by the self-perceived usage of science learning approaches. Finally, motivational modules had a greater influence on students' science performance than cognitive and metacognitive approaches with self-efficacy variable as the strongest impact (Table A1 Contribution 7).

In addition, along with the Contribution 5, Nguyen et al. provided a review for pedagogical methods in STEM education, which could be positioned to educate the sustainability concepts. Generally, young persons are society's future for social alteration, and so it was essential to offer proper education that not only prepared them with skills and knowledge but also altered their behavior and attitudes towards ESD. In addition, it indicated how teachers of middle and high school education observed STEM education and how they pertained STEM disciplines integrated in planning projects to adopt development matters in Vietnam. Here, 77 teachers who thought of STEM projects throughout the country were examined. In addition, interviews were conducted with 635 teachers who contributed to the STEM agenda. Participating teachers appreciated STEM education and were willing to employ constructivist pedagogical approaches, which could help to resolve real-world glitches. It was expected that an incorporated STEM method could alter general education into an innovative/inclusive education for social equity and SD (Table A1 Contribution 8).

Through the context of Contribution 6, María-Pilar Molin-Torres and Raimundo Ortiz-Urbano assessed new teachers' training in terms of the particular skills desirable to progress active-learning methods associated with the teaching of heritage sustainability. Within the SD framework, the cultural heritage thought was interrelated with the heritage consciousness of a specific and spatial setting and to the maintenance of collective memory. The study, for this reason, took numerous scientific influences as the background for pondering ESD as a primary tool to recapture and preserve heritage assets both from an informative and an educational view. The results indicated that several opinions were associated with attaining and expediating the implementation of innovative methodologies because of an initial university training shortage. Therefore, this paper generally offered a chance for students to evaluate a sequence of prejudices concerning their working approaches and to overcome extreme theorization in their university educations (Table A1 Contribution 9).

To examine the game performance effects inside of an educational socio-constructivist viewpoint and a supportive learning model, Khalifa et al. firstly manifested a social tool for both teachers and students to gather and accomplish their thought procedures and then a tool to motivate contemplation and critical deliberation on implementation to produce transformation during game-action plans. In this study, with three tests, skill competence was measured. Here, the Loughborough Soccer Passing Test (LSPT), along with a shooting correctness examination, was performed as a 15 m ball dribbling assessment. With the Game Performance Assessment Instrument (GPAI), the performance of the game was evaluated, and the consequence variables measured encompassed decision making, skill execution, support, game performance, and game involvement. However, there were no such enhancements discovered in the dribbling and shooting tests, while both groups indicated noteworthy improvements in their short-passing capability. On the contrary, significant improvements were found only in the verbal interaction group formed in general game performance. Accordingly, verbal interaction might be an operational tool to improving tactical comprehension throughout cooperative learning (Table A1 Contribution 10).

In transdisciplinary ESD, Kubisch et al., looked first at transdisciplinary research and then discussed the potentials of translating this notion into a new education type, which could be called Transdisciplinary Education (TE). Ensuing the adoption of the

SDGs by the community of states, there had been augmented recognition of international education as being a key SD driver. The Science Education for Action and Engagement Towards Sustainability (SEAS) project proposed to target investigations into different corporations between schools and out-of-school institutes in European countries. By the comparation of the collaborative formats and delivering a notion and technique pool for instructors, SEAS aimed to facilitate the integration of TE in the future of formal schooling. This paper gave the insights into the Austrian research education teamwork k.i.d.Z.21. Representing k.i.d.Z.21 experiences and taking up transdisciplinary characteristics research, chances, and experiments of integrating TE in formal schooling were deliberated (Table A1 Contribution 11).

González-Peña et al. exposed learning outside the classroom (LOtC) activities that were part of pedagogical practices, which were presently applied in the students' skill development. The objective of this paper was to regulate faculty and undergraduate students' perceptions regarding industrial visits and to outline these activities' advantages and disadvantages. Here, to examine and compare participants' perceptions on industrial visits such as LOtC activities, descriptive statistics were employed. For constructing industrial visits, the results designated a positive perception, which produced more attention to the class material and assisted students in acquiring knowledge. Despite this examined positive perception, it was found out that lecturers were unlikely to establish industrial visits often because of the work necessary to design, perform, and appraise these activities. It is suggested that about 40% of the students might misplace the advantages of LOtC activities that could be proposed. Here, lecturers should be encouraged and reinforced by administrators to include industrial visits in their courses as a teaching approach to offer an advantageous practice to the students' majority registered in chemistry and sustainability undergraduate programs in the University (Table A1 Contributions 12 and 13).

With the gamification in STEM and sustainability, Yllana, Jeong, and González-Gómez specified that the usage of active and flipped methodologies has amplified in recent years. Escape Room games specially employed as educational tools have teaching–learning potential. Thus, they could be advantageous because of the improvement in students' motivation/emotions towards learning. While the cognitive factor and multidimensional fields were thoroughly associated, this was predominantly valuable in the STEM subjects. With science and sustainability matters, this paper offered an online-based Edu-Escape Room as an educative STEM course tool. It was investigated how this instrument predisposed the multidimensional domain such as attitudes, self-efficacy, and emotions of pre-service teachers (PSTs) with the intervention proposed. Based on attitude and self-efficacy analysis, it was perceived that most of the elements evaluated showed an upsurge in self-efficacy and more positive attitudes afterward toward the proposed intervention. Therefore, there were multiple advantages in the PSTs' multidimensional domain of devouring the proposed online-based Edu-Escape Room (Table A1 Contribution 14).

Along with the Contribution 11, Roberto Araya and Pedro Collanqui mentioned that education was critical for refining energy efficiency and diminishing CO2 concentration, but teamwork between countries is also critical. Accordingly, the research question of this study was whether synergistic cross-border science lessons with energy experimentations were practicable and could increase energy efficiency consciousness amongst middle-school students. An interactive cross-border session between Chilean and Peruvian eighth-grade classes was planned and confirmed. With the energy efficiency of APEC databases, this was the part of a STEM education project on Asian-Pacific Economic Cooperation (APEC). Here, we found high levels of student engagement. Students deliberated not only the energy cross-cutting characteristics but also its relationship to socioeconomic progress and CO2 emissions. The interactive cross-border science classes, in conclusion, were a possible educational alternative with probability as a scalable community policy plan for refining energy efficiency awareness amongst the population (Table A1 Contribution 15).

Finally, after COVID-19, the Special Issue was connected to the online and virtual learning. Abouhashem et al. proposed that unprecedented change in educational pedagogies because of the COVID-19 pandemic had appreciably disturbed to the students' learning procedure. During the closure of schools in the COVID-19 epidemic, this research explained the development of a STEM-based online course that could solve the limitations of virtual science classrooms, which could assure an active STEM instruction atmosphere. Here, as instructional tools, numerous resources based on digital learning were employed to attain the content objectives. Particularly, a methodology of feedback mechanisms was performed so as to increase online instructional distribution and the role of project learners as a student-oriented approach. Therefore, it could aid the qualitative assessment of course contents. In conclusion, the course assessment, student feedback, and SWOT analysis indicated the need to evaluate the efficiency of the course proposed (Table A1 Contribution 16).

With this Special Issue, we therefore published articles on innovative approaches and developments in education, which could encourage theoretical, methodological, and empirical research works on teaching and learning, competencies and assessment, policy, program development and implementation, instructor preparation, community- and project-based learning, institutional collaborations and partnerships, and other relevant subjects. Particularly, especial emphasis put on innovative teaching approaches and methodologies that had been proved to be relevant on the STEM education, not only considering the cognitive domain of the learning process but also the affective domain, such as flipped-classrooms, blended-learning, gamification, service-learning, etc.

**Author Contributions:** Conceptualization, D.G.-G. and J.S.J.; methodology, D.G.-G. and J.S.J.; software, D.G.-G. and J.S.J.; validation, D.G.-G. and J.S.J.; formal analysis, D.G.-G. and J.S.J.; investigation, D.G.-G. and J.S.J.; resources, D.G.-G. and J.S.J.; data curation, D.G.-G. and J.S.J.; writing—original draft preparation, D.G.-G. and J.S.J.; writing—review and editing, D.G.-G. and J.S.J.; visualization, D.G.-G. and J.S.J.; supervision, D.G.-G. and J.S.J.; project administration, D.G.-G. and J.S.J.; funding acquisition, D.G.-G. and J.S.J. All authors have read and agreed to the published version of the manuscript.

**Funding:** The authors gratefully acknowledge the Consejerería de Economía, Ciencia y Agenda Digital y Fondo Europeo de Desarrollo Regional (FEDER)—Project IB18004, which support this research possible.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **Appendix A**

**Table A1.** List of Contributions.



#### **Table A1.** *Cont*.

#### **References**


## *Article* **Enhancing Creativity: Using Visual Mnemonic Devices in the Teaching Process in Order to Develop Creativity in Students**

#### **Lucian-Ionel Cioca 1,2 and Raluca Andreea Neris, anu 3,\***


Received: 31 January 2020; Accepted: 3 March 2020; Published: 5 March 2020

**Abstract:** (1) Background: In the field of creativity studies there is always space for expansion and new conceptualizations of the methods involved. Therefore, we will present in this paper a brief arrangement of the methods used to enhance creativity and consider whether visual mnemonic devices can increase creativity. The devices are used in the teaching process in order to ease the remembering process by creating a visual representation. Visual mnemonic devices are techniques that increase creativity as part of their own performance. (2) Methods: We will use a quasi-experimental, nonequivalent group design, the procedure involving the use of visual mnemonic devices. (3) Results: The results show that the degree of abstracting increased after using visual mnemonic devices, along with fluency and other creativity dimensions. (4) Conclusions: The paper shows that the creativity increased, based on a national percentile system (along with standard creativity index), after using the visual mnemonics devices, thus demonstrating a case for integrating the visual mnemonic devices among methods to foster creativity.

**Keywords:** creativity development methods; visual mnemonic devices; creativity

#### **1. Introduction**

Creativity stands alone as the first flame of every accomplishment, by changing the usual mental pattern of information [1,2]. Without creativity, human development would not have been possible. Creativity is a competence that can be improved or affected in time by one's environment and activities practiced. If we seek to improve it, there are many techniques that can be used in different environments and by different types of users in order to enhance creativity. We argue that visual mnemonic devices should be included in that list of techniques.

The most suitable environment in which to use visual mnemonic devices is the school, at any level, including even homeschooling or e-schooling. As any of these environments are based on the educational process, we highlight the three approaches found in literature that aim to blend creativity into the educational process: teaching for the development of learner creativity, creative teaching (creative methods and techniques used in this process), and creative learning (creative learning methods and techniques) [3]. These three approaches to creativity at the educational level are defined by the convergence and subtle differentiation of the proposed objectives. In practice, it is also noted there can be resistance to creative adherence to education [4]. Perhaps one of the biggest problems when it comes to integrating principles of developing creativity at the educational level is the diversity and heterogeneity of the ideas and behaviors they generate [5,6].

#### *1.1. Creativity Developing Techniques*

Creativity was enhanced until now in some very different ways. We have tried to collect all the important creativity developing techniques and the conclusion is that the techniques usually focus on creating some internal motivations by activating divergent thinking. Although "Amabile (1983,1988,1996; Amabile & Hennessey, 1987) has found evidence that...extrinsic benefits can undermine intrinsic motivation" [7], creating some extrinsic motivation can be either too expensive or ineffective over a long period.

The creativity developing techniques and the creativity dimensions [5] could sometimes overlap, so the explicit sense can be found in one another. In this sense, it is necessary to specify that the techniques used to develop creativity could be identified with some ways of manifesting creativity, taking into consideration the large usage of the creativity itself. The dimensions of creativity could be identified with exactly those ways of manifesting creativity.

In [8], Smith evaluated 48 creativity techniques (such as morphological analysis, input–output, focused-object, transfer analysis, and bionics) used for idea generation, classified in 15 categories, represented by 48 devices. Three years before in their book [9], Smith, Ward, and Finke published a chapter about the potential of the creative techniques to succeed in problem solving. In his paper, Geschka proposed six techniques to be used for product design issues in organizations to enhance creativity: the morphological matrix, 6/3/5 method, brainwriting pool, card circulating technique, gallery method and collective notebook method [10].

The affective environment polarity also affects creativity, as Bledow [11] and Hirt [12] showed that a positive state affects cognitive flexibility and creativity by offering a feeling of freedom, eliminating constraints and enabling a complete and exploratory style of processing information. By searching the literature, we have found four techniques that are correlated to changes in the affective environment and can perform in the creative field: dark and dim illumination (improves unconscious creativity. It is also shown that an indirect light fosters creativity more than a direct one does [13]), empathy [12], the possibility of promotion [14] and, of course, positive feedback (the good feeling or the hedonistic philosophy enhances creativity by developing courage and self-confidence [12]).

According to Roozenburg and Eekeles (1995) and Schlicksupp (1989) [15], creativity techniques are structured into two types, namely the associative and provocative techniques. The principle of classification is based on the type of mental process applied to the preconceived elements; thus, associative techniques combine and bind together elements and provocative ones try to break and modify the given elements. In the literature of [10,16–27] and Osborn cited by [10,28], we have found 22 associative techniques from simple (association and consonance) to complex ones (The Masakazu Nakayam Method and the thinking hats) and 5 provocative ones (e.g., Extrapolation and Khatena Training Method).

In [29] there are 22 techniques, divided into two categories, based on analytical or intuitive thinking. In [30], Miller exposed 10 analytical (linear) techniques and 6 intuitive techniques. Analytical techniques imply the generation of a rational sequence regarding the elements involved, to gain a linear structure and to multiply the rational, linear sequences for a holistic viewpoint. Intuitive techniques are based on a single stimulus and generate a one-time response to that stimulus, usually used as a starting solution [15]. Searching the literature [10,31–37] we have found nine analytical techniques (including the morphological matrix, fragmentation, Ishikawa diagram, and Pareto diagrams) and six intuitive ones (e.g., imagery or expressive activities) [38–43].

In his paper, Tassoul [44] proposed five solution space categories for idea generator techniques. The associative, provocative, and intuitive techniques have the same structural pattern as described in [15,29,30]. In addition to those, Tassoul adds inventorizing and confrontative techniques to the categories mentioned. The inventory techniques are based on gaining all detail or information that surrounds an issue which will materialize into an inventory of ideas, details, or information [44,45]. The confrontative techniques try to break the boundaries of the common elements and offer unexpected solutions to widen the solution space and create new force-fit connections [44,45]. In the literature

of Torrance cited in [46], Crawford cited in [47], Osborn cited by [47], and Allen cited by [47] and [43,44,47–54], we found 4 confrontative techniques (e.g., starbursting and lateral thinking) and 11 inventorizing techniques (e.g., feature listing, checklists, and recursion trees).

#### *1.2. Visual Mnemonic Devices*

The word "mnemonic" refers to memory or in correlation to memory. Mnemonic devices are techniques that can be used to encode information for better memorization of the concepts given [55,56].

Mnemonic devices are categorized in different ways. We will focus on the *visual mental imagery* of mnemonic devices [55]. The visual imagery of mnemonic devices implies the imaginary elaboration of the aspects involved. "The imagery has to be of concrete objects or referents of the words, not of words themselves" [57]. The visual mental imagery mnemonic devices involve a mental representation "and the accompanying experience of sensory information without a direct external stimulus" [58]. The devices imply a verbal enumeration, classification, or definition of one concept (or more) and the imagery process of the component objects in their visual perception. "Visual imagery has many of the properties of a spatially parallel system" [57]. The imagery process is using the recall representations from other similar stimuli or a combination of them in order to re-experience the original representation. It is worth mentioning that the imagery is weaker than the original representation, acting as a weak perception [58].

Mnemonic devices were massively studied in the field of their purpose—better memorization of concepts. Visual mental imagery mnemonic devices were studied for the same purpose. Taking into consideration that the devices imply a process of imagery, meaning a group of some creativity fostering techniques (used unconsciously), we shall see that this method can itself foster creativity.

Visual imagery implies that the memorizing process has to be set upon some visual figures that are imagined and associated with the words given. It works especially when the words are concrete (they have a real representation), but it can be used even with abstract words (throw association technique) [59]. The mnemonics must be unusual, out of the ordinary, clear at first view, include at least two objects to have efficiency, and include motion, color, or exaggeration [60]. Lorayne and Lucas (1970) define four rules for an efficient visual mnemonics: substitution, exaggeration, out of proportion, and action [61].

Creating a visual mnemonic device by analogy means that one should imagine some analogical concept with the information that needs to be remembered. By the definition of the analogy, we search to create an abstract parallelism between two concepts from different areas and it can be used in visual mnemonics to find an easy to figuratively represent concept in a different area that is abstractly connected to the main concept, so the easier concept is easily remembered and it can be linked to the main one [48]. Talking about elaboration (Torrance cited in [46]), the process of adding details to information, we observe that it can be used in visual mnemonics [62] by adding details to the main information, more precisely a specific, very important detail, that can be easily remembered by its visual representation and will boost the process of remembering the main information by extrapolating the detail or linking it to the initial information. The combination technique refers to combining different attributes with an apparent unlinked object and may be used when there is a need to remember a list of information presented in various forms [50]. The details of the different concepts may be visually linked, so there is an easier way to remember the visually linked details and to extrapolate to the initial form. Feature listing can be used when there is a need to remember a very important concept that can have visual feature listing (Crawford, cited in [47]). The feature listing will be made visually, so it will be easier to remember and, after that, extrapolated to the initial information.

By the definition of the visual mnemonics [55,58,63] listed above, it is implied that visual mnemonics also take the use of imagery process (the literary process of transposing the information gained from stimulus into literary text), but without an external stimulus. This and the other definitions of the visual mnemonics (the device implies a verbal enumeration, classification or definition of one concept (or more) and the imagery process of the component objects in their visual perception [57]) imply that the process must rely on the use of analogy, elaboration, combination, or feature listing.

We specified that all the listed techniques can be used to augment creativity and the visual mnemonic devices use only extrapolation or the listed techniques to return to initial information.

#### **2. Materials and Methods**

#### *2.1. Overview*

Our goal was to verify if mnemonic devices could improve creativity. To achieve our purpose, we tested the subjects before and after the device was applied. We had two groups, a test group and a control group.

#### *2.2. Participants*

We targeted two groups, one called the experimental group, who used visual mnemonic devices and the control group, who were not briefed to use visual mnemonic devices. The sampling technique applied was convenience sampling, the groups being from two different classes.

The set was composed of 17 university undergraduates, age 23, and 20 high school undergraduates, adults only. The Torrance creativity tests in figural form were aggregated with the national percentile and score, using the highest age possible (16 years for Romanian score and percentile database).

All subjects gave their informed consent for inclusion before they participated in the study. The study was conducted in accordance with the Declaration of Helsinki and the protocol was approved by the Ethics Committee of LBUS-IRG-2019-05.

#### *2.3. Materials*

In order to compare the results of using visual imagery mnemonics on the creativity of the subjects, we chose creativity tests, one given before they used the mnemonic technique and one after. Regarding this aspect, the Torrance figural creativity tests were the most appropriate for observing the imagery mnemonic results, especially because of their figural form, enhanced with drawings and regular and irregular forms [29,53,54]. The reliability of the evaluation method used lies between 0.89 and 0.94, according to TTCT-Figural Manual of 1998 [64].

The visual mnemonic method [63] was used to heighten the following aspects:


The words that needed to be memorized were abstract in general, but also included some concrete words (labor, gothic, Victorian, art deco, art nouveau, shaker, eclectic, minimalist, neo-classic, shabby chic, Canada, South Korea, Russia, Spain, Australia, Mexico) [57,65,66], as Paivio's dual code theory assumed that concrete words "elicited more distinct imagery" than abstract words [59,67].

#### *2.4. Procedure*

For the experimental group, the form A was applied before using the visual mnemonic devices, and form B was applied after a visual mnemonic exercise. For the control group, the form A was applied before using a classical memorization process (they needed to memorize the same aspects but without further visual mnemonic device explanations), and form B was applied after.

All four exercises were accompanied by directions to develop the visual mnemonics and the usage of a paper was permitted, with the observation that the paper must only include drawings and must be turned to the other side when the evaluation form was addressed. The evaluation form was a form of evaluating the visual mnemonic method composed of a simple question regarding the memorized information. The directions that were given included the types of visual mnemonics that were possible for the specific case, including shapes, colors, means of hands and fingers, animals, letters, continents, body parts, etc.

The results were analyzed using the comparison of means, standard deviation, and relative standard deviation (as proposed in [68]) of the basic scores obtained, along with the variation of the composed creativity score from form A to form B and a statistical hypothesis test to validate the results. The significance level taken into consideration was the standard 0.05 and the hypothesis test chosen was the two-sample pooled test, mainly because the variances were not equal but under the significance level of failing the test [69].

#### **3. Results**

#### *3.1. General Results of the Influence of Visual Mnemonic Method over Creativity*

The results, represented in Figure 1, show a growth in the mean standard score, along with the standard creativity index and the percentile rank, from form A to form B. It is important to remember that form A was applied before the visual mnemonics exercises and form B was applied after. The absolute growth of the mean creativity index was nine points, meaning that the techniques that are implied in the usage of visual mnemonics are linked to creativity.

**Figure 1.** Representation of the mean of standardized creativity index for both groups in form A and B.

Creativity grew with a variance of 12% (see Table 1). Due to the use of the specific mnemonic device technique, creativity was raised 45% in the national percentile system. Next, we will analyze which were the main dimensions that contributed to this variance.

**Table 1.** Variation of the mean basic scores for each creativity dimension, from form A to form B, for test and control group.


Variation of the mean basic scores for each creativity dimension.

#### *3.2. The Five Dimensions of Creativity, before and after Visual Mnemonic Device*

The standard creativity score consists of five dimensions of creativity proposed by Torrance and their scores with the percentiles attributed to each one. In Figure 2, standard scores for creativity dimensions, we observe that fluency and the degree of abstracting had the most benefit of using visual mnemonics, but an up going rate exists for all of the five dimensions. Resistance to premature close-up remains on the same level of manifestation among respondents, presumably due to the lack of connectivity between the technique used in visual mnemonics and their power to create motivation, desire to create more, and maintain the active cognitive process. Table 1, variation of the mean basic scores for each creativity dimension, shows that originality stands with a positive variation of 5%, showing that the visual mnemonic devices did not have a big impact on originality, being a tool created for reproduction of the initial information, by creating a visual representation of a settled information. Elaboration grew 5%, from 94 to 98 points in the mean standard score and from 26 to 38 rank on the percentile system, exclusively because elaboration is already a technique that is part of the visual mnemonic device and could be used in the exercise proposed for the respondents. Fluency grew 9%, from 101 to 110 points in the mean standard score and from the 48 to 62 rank in the national percentile system. Fluency was enriched by the analogy and elaboration techniques that were used in the visual mnemonic devices. The two techniques also created new neurological connections between known concepts in order to find a suitable answer for the stimulus (that is the way fluency is measured). The degree of the abstracting of the title grew with the highest variance, 21%, from 67 to 87 rank in the national percentile system, likely since the abstracting of the initial information was the first phase of the visual mnemonic device and it was consciously and extensively used in the process, therefore creating an ease of usage when the form B of Torrance tests were applied.

**Figure 2.** Representation of mean standard scores for each creativity dimension.

The graph below shows the growth of the five dimensions, from form A to form B.

In the following table, we can observe the relative variation of each dimension along with the general results for both groups (mean standard score, bonus points, and standard creativity index among its national percentile rank).

#### *3.3. Overall Results*

There is an observable difference between the means of the variations of the two sets of creativity indexes, the experimental group means being 12.16% and the control group being 0.25%. The control group had only a tiny increase in creativity with a stability in time.

The null hypothesis was the zero effect that visual mnemonic devices would have on creativity. The null hypothesis was rejected, thus the t stat was 3.81 and the t critical two-tail was 2.0322.

The probability of observing a considerable difference in a null state, when visual mnemonic devices were not applied is 0.00055, placed under the significance level of alfa 0.05. The null value was rejected and there was evidence of difference between the variations of the scores obtained by the experimental group and control group.

#### **4. Discussion**

The results successfully validate the hypothesis involved in the study, arguing that visual mnemonic devices had a positive impact on creativity. To the best of our knowledge, there are no empirical studies to show the relationship between visual mnemonic devices and creativity in this direction (the impact of visual mnemonic over creative performance). In contrast, some studies debate the opposite relationship, the impact of creativity on visual mnemonic performance. In [70] and [59], the visual imagery and mnemonics depend on one's creativity, so a good creativity score could improve the performance on visual mnemonic devices.

Although in [71], one mnemonic device designed to help students when they get stuck during a creative process (SCAMPER) is mentioned. It is not a technique that boosts creativity by its mnemonic structure but is based on six different types of mental processes that could be applied to a piece of information to enhance creativity. The book does not mention visual mnemonic devices or other types of mnemonics as creativity techniques.

A review integrated visual mnemonics as a creativity technique based on its structural relation with imagery, and the "intimate" relationship between imagery and creativity. The visual mnemonic technique is presented as a creative method used to boost memory, which is based on imagery and aids to boost creativity through imagery [67]. Our study was focused on the five dimensions of creativity (fluency, originality, elaboration, degree of abstracting of titles and resistance to premature close-up), from which elaboration [67] and originality are the basic dimensions used in the imagery. By definition, the visual mnemonic technique is a device based on the visual imagery [55,57,58,63], imagery has a profound relationship with creativity, enforcing the connection between visual mnemonics and creative performance. Using a rational argument based on the fact that "Visual intelligence increases the effect of human intelligence, extends the creative spirit" (Dondis, cited in [72]), Eriksson states that using visual imagery in education is reasoned on the fact that visual thinking is an important part of the type of intelligence for generating creative ideas [72]. He argues for a holistic curriculum that includes creativity and he underlines visual intelligence as a factor to increase interactivity and diversification of the curriculum. To boost creativity, he proposes visual imagery as a within reach tool.

In [73], Brade stated that interactive mnemonic visualizations are suitable for managing creative works, involving highly complex data, without restricting creativity regarding a creative task. He specifies that the interactive mnemonic visualizations are to be structured as a map, containing connected information surrounding an issue, so the creativity being reinforced by flexibility and complexity of the data could be achieved by the proposed device. In [74], Brown proposed a visual mnemonic device (Loci's method) as a creative technique used to enhance memorization in the educational process. The technique's purpose is to enforce memorization, but Brown considered it a creativity technique due to its connection with imagery. The correlation between creativity and visualization underlines that "successful creating seems to depend on the degree to which mental images can be manipulated" [62]. The visualization process includes mental synthesis of sensory experiences, transformed into mental images. In the visual mnemonic devices, the visualization process is exactly the principle process used in order to gain the mnemonic needed [55,57,58,63], thus influencing immediate creativity, as shown in our study.

A study, presented during a conference focused on critical thinking, showed that visual imagery had positive implications in critical and creative thinking [75]. Similarly, Durio marks up the relationship between the two of them by the degree of imagery used in creative functioning [76]. Moreover, the first

study implied the relationship between visual mnemonic performance and critical thinking test scores and interpretation. The results show that visual mnemonic performance was directly proportionate to the critical and creative thinking and scores. Although, it was shown that the mnemonic device was not helpful with students having difficulties with visual imagery, the advantage of using imagery was maintaining a "relaxed receptiveness to the review of information" and a "lessening of anxiety in approaching the midterm as the information was 'owned' by the learner" [75].

The present study confirmed the hypothesis considered; the visual mnemonic devices were able to boost creativity, as the results showed different means by the variations of the creativity tests before and after (12.16 for the experimental and 0.25 for the control group). Due to the profound connection to creativity and imagery [67], the visual mnemonic devices seemed to affect creative performance.

Limitations of the study involved the circumstance sampling technique and a relatively small sample (17, 20) for each group, due to limited resources. That interfered with the hypothesis testing but was validated due to a normal distribution and a small difference between variances [69]. The measurements of the level of imagery and internal visualization were not taken into consideration when observing the effect that visual mnemonic devices had on creativity, but were appreciated as average (due to direct observation and drawings of the internal visualization realized by participants through the experiment).

#### **5. Conclusions**

The creativity domain is always expanding, like creativity itself, from any point of view. The present study concluded that there were effects of the visual mnemonic devices on creative performance, thus supporting the initial hypothesis that visual mnemonic devices would be able to enhance creativity. Through the primary research that was performed, it was shown that creativity increased with 45% in a national percentile system (corresponding to 12% in standard creativity index) after using the visual mnemonic devices, supporting the case that the visual mnemonic devices should be considered a technique that fosters creativity. The present study extended the literature in the creativity field by adding a new creativity technique to the ones already established. A visual mnemonic device is a technique that can be used in any type of environment and circumstance, being also extremely suitable for educational purposes, promoting creativity in the curricula adaptations in practice. Future studies may focus on investigating visual mnemonic devices' effect on creativity on bigger samples of groups or choosing a different sampling technique. They may also focus on studying the influence of the other mnemonic devices on creativity or critical thinking.

**Author Contributions:** Conceptualization, R.A.N.; methodology, R.A.N.; formal analysis, R.A.N.; investigation, R.A.N.; resources, L.-I.C.; data curation, R.A.N.; writing—original draft preparation, R.A.N.; writing—review and editing, L.-I.C.; supervision, L.-I.C.; project administration, L.-I.C. funding acquisition, L.-I.C. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Lucian Blaga University of Sibiu & Hasso Plattner Foundation, grant number LBUS-IRG-2019-05".

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**


© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

## *Article* **Problem-Based Learning in University Studies on Renewable Energies: Case of a Laboratory Windpump**

#### **Alain Ulazia 1,\* and Gabriel Ibarra-Berastegi 2,3**


Received: 12 February 2020; Accepted: 20 March 2020; Published: 23 March 2020

**Abstract:** In the last eight years, the new faculty of Engineering in Renewable Energies at the University of the Basque Country in Eibar has developed several sustainability goals related to clean energy and climate change, but also in educative terms related to co-operative learning, motivation, and reflective thinking. The case of the laboratory-windpump challenge is paradigmatic in this sense, since it constitutes successful problem-based learning for the students in terms of the activation of heuristic tools (analogies or diagrams), critical discussions combining complex ideas about aerodynamics, mechanics and hydraulics, and a good group atmosphere. The conclusions of this work are supported by qualitative and quantitative results within a theoretical background based on the logic of discovery and its corresponding constructive-learning strategy, rather than on the logic of justification with given and well-known aprioristic assumptions.

**Keywords:** fluid mechanics; renewable energy; learn to learn; windpump; reflective thinking; higher education

#### **1. Introduction**

The pioneering faculty of Engineering in Renewable Energies in the University of Basque Country (Engineering School of Gipuzkoa at Eibar, [1]) is a challenging educational project that is tied in with the global sustainability agenda due to the importance of renewable energies in clean-energy production and in the fight against climate change [2].

The new grade started eight years ago with 70 students, and it has maintained these registration figures. After basic typical subjects in engineering, the students specialized in several renewable technologies in the third and fourth years. Our contribution, from the field of fluid mechanics, was related to wind energy (third course) and ocean energy (fourth course). The teachers obtained excellent results in the students' surveys in items related to motivation and reflective thinking [3]. According to the class observations of the teachers, the students carried out very active work on the basis of self-learning and co-operative problem solving, having a clear notion of the heuristic advantages of problem-based learning [4–7].

As the new grade was gradually implemented, apart from the technical aspects related to the subject contents, the methodological evolution of the educational features received special attention and was carefully monitored during these years. Along with our methodological developments in the area of fluid mechanics, we extensively shared our experience in papers and conferences [8–12].

The learning case presented here is part of the laboratory practices of the wind-energy subject in the third course, which comprises 25% of the class hours and of the final mark. The students learned basic notions of aerodynamic forces (lift and drag force) in the second course within the subject of fluid mechanics. During the program on wind energy, they learned, among other sections on resource assessment and mechanics, about the aerodynamics of wind turbines [13]:


The effective comparison between the more widely used horizontal-axis turbines vs vertical-axis turbines was illustrated in this practical learning activity. A small-scale windpump, constructed in the fluid-mechanics laboratory [14] using recycled elements, offered the possibility to design a complex group problem-solving activity contextualized in three fundamental sustainable goals:


A windpump is a system that uses wind energy to pump water. This type of windmill was used from ancient times to obtain clean water from underground or to drain water for agricultural or building purposes [16,17]. Nowadays, in many isolated regions of Africa or India, windpumping is, along with solar photovoltaic (PV) systems, the only option to obtain drinking water from wells [18–20].

The combination of aerodynamics, mechanics, and hydraulics converts the working principle of a windpump into a complex problem that can be categorized in different parts. Understanding its behavior and the computation of its working speed need the co-operation of various heuristic tools such as analogies and diagrams in a logic of discovery without clear and established assumptions, rather than in a logic of justification with given and well-known assumptions [4,21–23]. This logic of discovery creates a highly motivated problem-based learning environment that allows a constructivist pedagogical approach, as is shown in the results [24].

In this theoretical context, the University of the Basque Country has a general educative program called ERAGIN that develops co-operative and dynamic learning using active methodologies, such as problem- or project-based learning [25], in which some of the authors have developed a full program for the subject of fluid mechanics. The university also has another program related to sustainability called CAMPUS BIZIA LAB, derived from Erasmus Project's University Educators for Sustainable Development, in which university teachers collaborate to achieve sustainability goals [26]. The authors have been active in these programs. As part of the results, the students created a spin-off on the integration of wind energy in buildings [27].

The structure of the paper is as follows. First, the materials (windpump and wind tunnel) and methodology to solve the problem are shown. We then explain the theoretical background and learning strategy. Then, results are shown with the solution found by a student group, the marks in the student surveys about the activity, and the qualitative opinions and observations in class. Next, we discuss how to relate the learning strategies and the theoretical background with the didactic results. Finally, a short conclusion summarizes the main aspects, and some future improvements are suggested.

#### **2. Materials and Methodology**

#### *2.1. Background within Wind Energy Applications*

Although the leading wind turbines are three-bladed horizotal axis wind turbines (HAWT) based on the lift force and designed for the production of multi-megawatt power, vertical axis wind turbines (VAWT) based mainly on the drag force are very important for small wind energy production [28]. This kind of small turbines can be used for electricity production or storage in

isolated locations hybridising it with solar energy, and also for the integration of wind energy in buildings [13,27,29].

However, one of the advantages of drag-force based wind turbines is that its tip-speed ratio (the ratio between the tip speed of the blade and the wind speed) should be low and this turbine is therefore a 'slow machine'. The tip-speed ratio of a typical HAWT is around seven ('fast turbine'), and a drag-force HAWT's tip-speed ratio is bellow one [13]. Thus, being its rotation speed very low, the corresponding torque in the axis is high and is suitable to generate strong mechanical forces needed in applications such as water pumping.

#### *2.2. Laboratory Windpump*

In 2014, the layout of a small-scale laboratory windpump was designed and constructed in the context of a final-grade work by two students. Since then, around 350 students carried out the windpump problem-solving activity within the laboratory practices of the subject of wind energy taught in the Faculty of Engineering in Renewable Energies [1]. The main sections in the program of the subject of wind energy are resource assessment (which is taught using the R programming language [3]), wind-turbine aerodynamics and mechanics, and the design of wind farms. The windpump laboratory activity for the most part corresponds to aerodynamics, and it constitutes a great example to differentiate drag turbines and typical horizontal-axis lift turbines with three blades [13].

Its size and height are adequate to position it behind the wind tunnel of the laboratory in order to capture output wind flow (see Figure 1). Table 1 shows the main characteristics of the wind tunnel, its control panel, generator, and data-acquisition system in the School of Engineering of Gipuzkoa at Eibar (Laboratory of Fluid Mechanics [14]).

**Figure 1.** Windpump behind wind tunnel in fluid-mechanics laboratory at Engineering School of Gipuzkoa (Eibar).


**Table 1.** Wind-tunnel characteristics.

A vertical-axis drag turbine with eight arms and corresponding double semicylindrical profiles (PVC pipes cut in half) were connected with a dual-gear system recycled from a bicycle. A crankshaft turns the motion of the second gear to the linear motion of a hydraulic piston that pumps the water.

Figure 2 shows the entire system with the value of its main radius *R*, the drag profile, and the piston connected to the crankshaft. Table 2 presents the list of the most relevant parts, parameters, and their dimensions and aerodynamic values.

**Figure 2.** (**a**) Entire windpump view; (**b**) frontal view of drag profile; (**c**) hydraulic piston connected to the gear by a crankshaft.


**Table 2.** System parts, parameters, and their dimensions and aerodynamic values.

The following video shows all the moving parts of the working windpump while the wind tunnel is generating air flow in the exit and the hydraulic piston is pumping water from the ground to a tank at 2 m height: https://www.youtube.com/watch?v=cVXv\_ga18Eg.

#### *2.3. Motivational Problem-Solving Activity*

A constructivist approach of a problem-solving challenge was proposed to the students in groups of three randomly selected persons. The groups were expected to build a step-by-step solution in a co-operative way. This challenge had a clearly positive influence in their motivation and attitude, and fostered co-operation between members [31]. Every year, more than 20 groups of the Faculty of Engineering in Renewable Energies participate in the challenge. For a given wind speed, pumping height, and pumping water volume, they have to guess the pumping time of the windpump in the public experiment carried out during the last week of the course.

These are the statements of the proposed problem and the first delivery work before the computation of the final experiment's pumping time:

	- (a) Construct and give the equation of the absorbed wind power by the turbine.
	- (b) Construct and give, taking into account the rotation speed of the turbine, the equation of the hydraulic power that generates the piston considering flow rate and pumping height.
	- (c) In the ideal case, these two powers (wind and hydraulic power) are equal, but according to our previous experiments, the energy that goes from the wind to the pump is reduced by 70%. Assuming *U* = 10 m/s and *h* = 2 m, generate a graphical solution in R using the turbine rotation speed as a free variable.

In this way, a maieutic method is used by the question and answers to elicit facts from the students supporting a teaching environment with strong critical thinking [32]. Verbal interaction with the teacher is minimal. In this way, ideas are assumed to be untainted from the lack of feedback from the teacher, but students do have internet access and access to classical handbooks, manuals, and lecture notes, with an important theoretical background on fluid mechanics and wind-turbine aerodynamics.

#### *2.4. Paradigmatic Solution*

The previous questions show a constructive path to solve the general problem that is based on a final motivational didactic group challenge. The solution is therefore deterministic and can be summarized as follows.

The eight arms of the drag turbine show positive (drag coefficient *CD*1) and negative drag (drag coefficient *CD*2) in the rotation of the turbine (see the final table of the abbreviations). The values of both drag coefficients could be obtained in the students' fluid-mechanics-data handbooks [33].

Given that there was one arm absorbing wind flux *U* of the tunnel, and eight arms showing the reverse drag, total drag force is [13,34]

$$F\_D = \frac{1}{2}\rho A \left[ \mathbb{C}\_{D1} \mathbb{U}\_{rel}^2 - 8 \mathbb{C}\_{D2} (w\_1 R)^2 \right] \tag{1}$$

where *Urel*, relative wind speed given by the difference between *U* and lineal motion of the arm *w*1*R*: *Urel* = *U* − *w*1*R*; *ρ*, air density in the laboratory; *A*, frontal area of the aerodynamic surface; *R*, radius of the arms of the turbine; and *w*1, angular velocity of drag turbine. Air density can be considered standard for first computation (*ρ*<sup>0</sup> = 1.225 kg m−3), but the students had to consider laboratory temperature (*T*) and pressure (*p*) in the moment of the experiment to obtain the real air density for *M* = 28.9 (air molecular mass) and *Rg* = 8314 J/kmolK (ideal gas constant):

$$
\rho = \frac{pM}{R\_{\%}T} \tag{2}
$$

In fact, this is an important aspect because air-density fluctuations due to temperature can produce strong changes of up to 20% in aerodynamic wind forces [35–38].

Thus, the generated power by the wind-turbine axis is torque (*FDR*) times *w*1. This power *Pe* is reduced by the total efficiency of the windpump (*η*) to yield the final hydraulic power obtained in the piston pumping (*Ph*):

$$
\eta P\_\varepsilon = \eta F\_D R w\_1 = P\_h \tag{3}
$$

In the same way, the expression of *Ph* is obtained as a function of the piston characteristics (diameter *D*, stroke *L*, oscillation frequency *w*2), and pumping height *h*. Thus, hydraulic power considering piston water flow *Q* is [19]

$$P\_{\rm h} = \rho\_{\rm w} \text{g} \,\text{Q} \,\text{h} = \rho\_{\rm w} \text{g} \frac{w\_2}{2\pi} \frac{\pi}{4} \,\text{D}^2 \,\text{L} \,\text{h} \tag{4}$$

The key factor that relates *Pe* with *Ph* is transmission relation *N* of the gears ( students had to count the number of teeth in both gears), which established proportionality relationship between angular velocities *N* = *<sup>w</sup>*<sup>1</sup> *w*2 .

This constructive procedure of the problem-solving activity implies only one unknown parameter (*w*2) in Equation (3), which could be solved graphically or numerically. Obviously, the final objective of the collaborative challenge, that is, pumping time *Pt* of a volume of water *V*, is given by piston oscillation frequency *w*<sup>2</sup> that establishes the value of water flow *Q*:

$$P\_t = \frac{V}{\mathcal{Q}} = \frac{V}{\frac{W\_2}{2\pi}\frac{\pi}{4}D^2L} \tag{5}$$

In this way, the apparently simple and specific question on pumping time involves a complex theoretical and technical solution process that could involve highly motivated initial brainstorming. Results in Section 3 confirmed this didactic hypothesis, and it is very important for activating the teaching strategy (see Figure 3).

#### *2.5. Theoretical Background*

This initial astonishment produced by the pumping-time question is considered by many philosophers as the origin of the logic of discovery in the framework of abduction, overcoming the axiomatic thinking of deduction and the probabilistic perspectives of induction [23,39,40]. This work based on the windpump challenge is therefore in the context of abductive thinking, as is discussed in Section 4, via the co-operation between heuristic tools. Abduction overcomes the typical discovery/justification dichotomy established by Popper [21,41], combining cycles of generation and evaluation in the creative process [4].

From a pedagogical perspective, constructivism and meaningful learning taken from Piaget or Vygotsky [24] is also present in the design of this learning strategy based on problem solving. Thus, the students are the protagonists since they participate in the construction of the solution from a heuristic and attitudinal perspective.

#### *2.6. Execution Phases of Windpump-Problem-Based Learning Strategy*

In the previous sections, we generally described the execution phases. Figure 3 shows the workflow diagram of the execution phases for the windpump problem's learning strategy, which are well-known within strategies to promote competencies in sustainability [42].


**Figure 3.** Phases of teaching and learning strategies of windpump problem-solving challenge.

The first phase of problem definition and planning is characterized by a questionnaire of previous ideas about drag machines, generation of new analogies based on well-known drag turbines, and group debate and brainstorming to present different proposals. This allows for reflective thinking and criticism, and the systematization and categorization of the general problem in different parts mainly related to mechanical parts involved in aerodynamic forces and hydraulic pumping.

In the second phase of monitoring and execution, students search for information about drag coefficients, hydraulic and aerodynamic torque and power, and other relevant data, and contrast the best relational ideas in the group discussions. In this way, they prepare the final report (see Section 3.1).

Finally, in the third phase of assessment, the final experiment to measure the pumping time produces heteroevaluation within the group challenge about the feelings and motivation of the group, the self-learning process, and the specific contents of the technical construction of the solution (see Section 3.2).

#### **3. Results**

#### *3.1. Student Solutions*

All the calculations of the students were carried out in the framework of the R programming language. R is an open-source language and environment for statistical computing that is widely used in the scientific community [43–45]. Using such a programming language represents an additional motivational element to the problem-solving challenge, since the broad online community involved in the construction and design of new tools and packages offers free information and help within a powerful motivational context of 'learn to learn'. The authors showed these didactic advantages of R in their previous publications about the teaching wind and ocean energy [3,12].

Figure 4 shows the code in R generated by a group of students and the graphical solution of oscillation frequency *w*<sup>2</sup> for a given pumping water volume *V*, wind speed *U*, and pumping height *h* (see Equation (3)): *ηPe*(*w*2) = *Ph*(*w*2).

The teachers had to develop various trial-and-error experiments with several aerodynamic configurations to optimize the windpump before it was used in the classroom. In these preliminary experiments, they computed the transmission efficiency of the aerodynamic power on the basis of drag forces into hydraulic power. These previous experiments showed that efficiency *η* of the windpump system was around 30% (loss of 70%, as mentioned in Section 2.2), and this is available information to students for the initial proposed problem to guess pumping time.

**Figure 4.** (**a**) R script of a group of students; (**b**) graphical solution presented by that group.

#### *3.2. Student Evaluation*

#### 3.2.1. Quantitative Evaluation: Enquiries

Table 3 shows the averages of the students' evaluation scores in the last five courses (2014–2019) for different didactic items involved in the practical activities in the laboratory, in which windpump activity plays an important role (30% of laboratory hours). Only relevant didactic items are shown, and a comparative result is shown for the subject of wind energy (SS5) and for the general engineering high-school center's score (CS5), both with a score of 5.

**Table 3.** Students' evaluation scores of practical laboratory activities for different didactic items.


The items related to motivation, participation, co-operative work, and practical resources are very good compared to the general averages of the engineering school, and use of reflective thinking is also higher than the average creating a better group work atmosphere. These items justify the final exceptional mark obtained in the overall evaluation of the subject of Wind Energy in its laboratory practices.

#### 3.2.2. Qualitative Evaluation: Student and Teacher Opinions

After interviews with the student groups and observations during the resolution process of the windpump challenge, these qualitative facts were collected:

	- **–** They drew many diagrams and sketches to be able to think about the problem and to categorize its parts (see Figure 5).
	- **–** They tried to remember analogous problems related to different parts of the construction of the solution. For instance, they initially used the example in the section about drag machines in the referential book of Manwell et al. [13] (see Figure 6), in which a vertical-axis drag machine with plane blades, protected by a semicylinder, was analyzed.
	- **–** The combination of ideas via abstraction was first expressed algebraically and then computationally via the R language (see Figure 4).

**Figure 5.** Sketch by a group of students using diagrammatic thinking to solve the problem.

**Figure 6.** Scheme of drag machine with plane blades protected by semicylinder, used as an analogical source [13].


These qualitative facts were coherent with the quantitative results obtained for the items in the enquiries (see Table 3) and the learning strategies described in the Figure 3. The first item of the table is about the development of competencies, and its very good results showed that this kind of complex group problem-solving challenge develops, in the students' opinion, real competencies needed in future work life and transformative social action towards sustainability [46].

#### **4. Discussion**

Co-operation between heuristic tools, within the 'art of solving problems', is a well-known mental activity in modern studies on scientific creativity [4,40,47–50]. This modern approach criticises the classical Kuhnian view of the construction of new concepts based on cognitive persistence of paradigms, paradigm shifts triggered by anomalies, and the role of thought experiments in disconfirming theories [51]. Lakatos [52] was one of the first authors that criticized the strong and sudden changes in Kuhnian paradigms, and introduced a view based on step-by-step proofs, refutations, concept sketching, counterexamples, and informal moves for the gradual construction of a solution to a problem. Polya and others also defended and demonstrated this gradual view in different problem-solving examples in mathematics versus paradigmatic disruptions in classical theory [22,53].

Recent common criticisms of the classical theory of conceptual change say that it is incomplete because it does not consider the motivation, social learning ('learn to learn' co-operatively), or other metacognitive aspects that are present in these combinations of heuristic tools with analogies or diagrammatic thinking. Clement [4] (p. 107) underlined this anomaly and the search for a proper analogy as a source of motivation to solve a given problem because the associated tension with the dissatisfaction with their understanding apparently drives students to keep re-attacking the problem until they make a breakthrough.

In our case, the main anomaly was the counterdrag in the reverse side of the eight moving blades that was dominated not by relative velocity, but by absolute lineal velocity. The abstraction process to insert this important element into the final equation and the R code generated a deep discussion in the groups. In fact, abstraction is one of the key concepts of object-oriented programming languages such as R, which handles complexity by hiding unnecessary details. It allows to implement more complex logic on the basis of the abstraction process and the consequent development of computational thinking [54].

In the context of abstraction, anomalies, and the search for adequate analogical sources, we also observed that understanding dissatisfaction is increased if there are other students in the group that think that they understand the problem or part of it, and that it opens a rich group discussion towards understanding. This establishes successful group-learning self-evaluation for all, and continuously reflective thinking generating and evaluating ideas. Therefore, this co-operation accounted for the good group atmosphere that could be described as a 'learn to learn' environment with rich heteroevaluation proposed in the third phase of the learning strategies, shown in Figure 3.

Furthermore, Sustainable Development Goals (SDG, [55]) were present in this work [15]. Apart from advances in educational practices and their quality, mentioned before (SDG 4), the windpump activity iswasclearly contextualized in the fight against climate change (SDG 13), the development of clean-energy sources (SDG 7), and the access to clean water in developing countries (SDG 6).

Several studies in Africa and India showed the importance of the windpumps to obtain clean water from wells, and their positive effects on a community's health [19,20,56]. In the present case, the use of statistical wind distribution in a given location based on reanalysis or mesoscale models (extensively used by the authors [3,10,35,38]) could relate each wind-speed occurrence with corresponding water flow (Equation (4)); this method enabled more projects for our students to estimate the daily amount of pumped water. This daily water storage for different months or seasons is a key issue for sustainable development in developing countries, but not only there. There are regions like the Canary Islands (Spain) in which wind-powered hydrostorage systems contribute to increase the share of renewable energies with real achievements in the island of El Hierro [57–59].

In the students' opinion, this kind of complex challenge helps develop their competencies for future work life. This was to be expected, since the challenge was integrated in social and sustainable goals, and enabled reflective and creative thinking, and hard group work. Furthermore, this was not a guided problem-solving activity with a previously established axiom. On the contrary, students had to solve the problem from scratch, find relevant information, properly classify it, and generate new heuristic perspectives.

#### **5. Conclusions**

The windpump group challenge activated reflective thinking via co-operation between different heuristic tools (analogical reasoning, diagrammatic thinking, and abstraction) in a highly motivated class atmosphere. Windpumping is also a renewable source of energy, so this educational challenge was fully integrated in the objectives of sustainable development within the Faculty of Engineering in Renewable Energies [1].

In the future, new versions of the windpump will be designed and fabricated to extend the complexity and the degree of freedom of the problem-solving activity. The form of the blades in the reverse side could be changed to adapt the counterdrag force. The number of blades and arms could also be changed, or the pumping height could be higher—lengthening the tube to the upper floor. Other kinds of drag machines could also be fabricated on the basis of simple working principles like the one in the Savonious turbine [20], since it was also developed in this laboratory for the integration of wind turbines in buildings [27].

**Author Contributions:** Conceptualization, methodology, software, investigation, writing—review and editing, supervision, project administration, and funding acquisition, A.U. and G.I.-B. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was funded by the Spanish Government's MINECO project CGL2016-76561-R (AEI/FEDER EU) and the University of the Basque Country (UPV/EHU funded project GIU17/02). It also had assistance from the ERAGIN educative program and the CAMPUS BIZIA LAB sustainability program of UPV/EHU. All calculations were carried out in the framework of R Core Team (2018) [43]. The authors would also like to thank former students Christian Arriola and Lukas Tapia for their invaluable help at manufacturing the windpump with brilliant laboratory technician Gorka Quintana.

**Conflicts of Interest:** The authors declare no conflict of interest

#### **Abbreviations**

The following abbreviations are used in this manuscript:


#### **References**


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