Journal of Technology and Science Education

1. 1.The phenomenological dimension, which contains the definition of the phenomenological characteristics of the studied technological systems (TPP, HPS, WT, etc.). Within this dimension, school knowledge mainly involves the identification and description of the external features of EGS, either by using photos or visiting the real EGS. 

2. 2.The technological dimension, which distinguishes the different parts of the technological systems and also clarifies the structure and the operation of system components. The size of these systems and their complexity are their inherent characteristics. In order to highlight these characteristics, and to deal with the difficulties arising from the limitations of children’s thinking, three-dimensional EGS representational models need to be constructed. These representational models should be operational, in that students should be able to construct ideas not only to understand the structure of EGS, but their operation as well. 

3. 3.The scientific dimension, which describes, mainly in qualitative terms, the thermodynamic systems on which the storage, the transfer and the transformations of energy occur. Within this dimension, the aim of a teaching intervention could be students’ construction of the semi‑quantitative conceptual model of energy chains, as this model is an appropriate form for teaching energy at different educational levels. The conceptual model of the energy chains is (a) a valid epistemological transformation of scientific knowledge, since it is directly linked to the nature and the characteristics of the first and second laws of thermodynamics (Lemeignan & Weil-Barais, 1994; Domenech et al., 2007), (b) to a certain level, compatible with the linear causal reasoning (Tiberghien, 2004), activated by students from a very early age and (c) applied successfully in various teaching programs at various levels of education (Chen et al., 2014). 

4. 4.The environmental dimension which directly connects to the scientific dimension (Vince & Tiberghien, 2012; Besson & de Ambrosis, 2014; Johnson & Cincera, 2019) and, at the same time, describes the environmental impact of operating different natural and technological systems. Proposed school knowledge within this dimension includes: (i) knowledge concerning children’s familiarity with the environmental problems mentioned above which are mainly related to TPP operation, and (ii) knowledge highlighting the issue of sustainability of natural resources and related to the environmental impact of EGS, which operate with renewable energy. 

The “constructivist” framework of the science curriculum –which can co-exist alongside the “innovative” framework– is mainly characterized by the inherent integration of students’ mental representations during instruction (Fensham, Gunstone & White, 1994; Tiberghien, 1997; Leach & Scott, 2003). To begin with, research highlights that even very young students are capable of constructing systemic thinking skills (Jacobson & Wilensky, 2006), which are the kind of skills that align with the systemic nature of technological and scientific knowledge required for describing and explaining EGS (Frank, 2000). Additionally, it appears that the systemic thinking as cognitive ability can be cultivated through the systemic approach of complex technological systems (Ben-Svi Assaraf & Orion, 2010; Hmelo-Silver & Azevedo, 2006). In this context, the teaching suggestions of Van Huis and Van der Berg (1993) and Jewett (2008) are of particular interest, since they refer to the teaching of the energy concept in secondary school. In addition, relevant research indicates that if preschool and elementary school students activate linear causal reasoning, they can achieve the construction of a qualitative model for the description and the scientific explanation of simple and small-scale energy systems (e.g., “lighting a bulb with a battery”) (Koliopoulos, 2013). More specifically, there is evidence suggesting that students at all educational levels can describe many simple natural and/or simple technological systems either as a chain of objects in terms of their function (e.g. “the bulb lighting is due to the battery”), or as a chain of objects in terms of their distribution, such as a transfer of an action (e.g. “the battery is supplying energy to the lamp, and it lights up”) (Lemeignan & Weil-Barais, 1994; Tiberghien & Megalakaki, 1995; Delegkos & Koliopoulos, 2020). Such pre-energy mental representations are spontaneously activated, even before a teaching intervention, and can be used as pre-existing conceptions for the construction of school knowledge for the energy concept. Thus, we hypothesize that children aged 11 to 12 years-old can use the aforementioned school knowledge characteristics to describe and explain not only the operation of small technological systems used in school laboratories, but also the EGS or at least their respective representational models as well.

Introducing a series of proper, interrelated “problem-situations” can prompt students’ mental representations to emerge, so that they can subsequently be processed during instruction (Boilevin, 2005). The aim in engaging students through these activities is to gradually transition students’ mental representations toward more sophisticated representations that, in turn, more accurately reflect suggested school knowledge. More precisely, this series of interrelated problem-situations are designed through “hypotheses based on the elements of students’ prior knowledge, from which they can construct new knowledge, and not only on the prior knowledge which has to be modified” (Tiberghien, 1997: page 359). The key characteristic of the problem-situations included in this suggested teaching intervention is that they engage students in discussions about interactions between various dimensions of school knowledge. Establishing relationships between the world of objects and events (phenomenological dimension) and its various types of modelling (technological, scientific, environmental dimensions) seems to lead students toward building new knowledge through categorizations, causal explanations and other mental tools they employ (Tiberghien, Vince & Gaidioz, 2009; Ruthven, Laborde, Leach, & Tiberghien, 2009). In the case of this study, the problem-situations were designed with the assumption that 11-12 year old students, by using basic systemic thinking and activating their linear causal reasoning, are capable of constructing precursory, and mainly qualitative, explanatory models for the structure and operation of particular EGS, within every dimension of the required knowledge.

The cognitive objectives of the particular teaching intervention built for this study were set up in such a way that prompted students to work through each of the four dimensions of knowledge construction for EGS. Thus, for the (a) phenomenological dimension, the objective was for students to recognize and name different types of EGS; for the (b) technological dimension, the objective was for students to be able to distinguish between the different parts of each EGS and describe the operation of each of these parts, for the (c) scientific dimension, the objective was for students to be able to describe the connection and interaction between particular key components of an EGS, using the semi-quantitative energy model of energy chains, and for the (d) environmental dimension, the objective was for students to be able to identify the environmental impact of operating an EGS. The conceptual content of the teaching intervention was structured into four thematic units: (A) What is an EGS? - The TPP, (B) Renewable energy sources, (C) Measurement of energy in EGS and (D) EGS and daily life. Each unit consists of 2 or 3 subunits, which each utilized a main problem-situation to introduce proposed school knowledge. The structure and content (11 subunits) of the teaching intervention appear in Table 1.

Figure 2. A 2-D representation of a TPP

Figure 3. A prototypical 3-D representation of a TPP

Figure 4. Schematic representation of the energy chain corresponding to the energy description of a TPP model

A typical example of a unit included in the teaching intervention is that of subunit 4, “How can we reduce or avoid air pollution generated by the TPP?”. Within this unit we attempted to activate three dimensions of required school knowledge (technological, scientific, and environmental), using the environmental issue of air pollution as a triggering event. More specifically, students discussed and identified the root of the problem (carbon dioxide emissions), while prompted to measure the carbon dioxide levels before, during, and after the operation of the TPP representational model (Figure 3), in three different positions: in close proximity to the TPP model, at a distance of one meter, and at a distance of five meters. Based on these measurements, they came to some initial conclusions and, afterward, studied the supplementary document labeled “Scientific reposting.” In the second activity, we posed the crucial question “How are pollutants created?” Consequently, students were expected to seek the answer in the system’s technological description, correlating pollutants to conventional fuel combustion. In the third activity, we attempted to focus the discussion on the kind of technological system that could replace the burner, or other components, in order to tackle this environmental issue. The fourth and fifth activities aimed for student discussion on the energy-related aspect of the pollution issue, in order to realize its quantitative nature and identify how it is connected to our energy needs. Therefore, our assumption was that each of these problem-situations would lead students toward the construction of the prerequisite multi-dimensional knowledge to sufficiently deal with these particular problems.

4. Methodological Framework

After their participation in our teaching intervention, were these students able to think through a multi‑dimensional framework to:

1. 1.Recognize and name different types of EGS (phenomenological dimension)? 

2. 2.Distinguish between the different parts used to construct each EGS and also describe the operation of these parts (technological dimension)? 

3. 3.Describe the connection and interaction between the components of each EGS using a qualitative/semi-quantitative energy model (scientific dimension)? 

4. 4.Identify the environmental impact of each EGS operation (environmental dimension)? 

The strategy of this research is pre-experimental (Cohen, Manion & Morrison, 2007), the essential feature of which is to intentionally control and manipulate any conditions that define the instances the researchers are interested in. Our work belongs to so-called feasibility (Astolfi, 1993) or developmental studies (Lijnse, 1995) which mainly focus on examining the potential for students’ cognitive progress within an in vitro, or research, environment, rather than their cognitive progress in real, or in vivo, teaching conditions.

The sample consisted of 21 students (13 girls and 8 boys) of a public primary school in a suburban district. All students were between 11 and 12 years old, which is typical for the last year of primary school. The teaching intervention was applied by one of the two researchers in order to minimize the “instructor” effect. All students were informed of the reason and the purpose of the research process in advance of the intervention.

5. Research Results

To analyze the data collected from the interviews, we used the following classification to code students’ answers: (a) sufficient answers were fully compatible with the suggested school knowledge content (b) intermediate answers were compatible with the suggested school knowledge content, but were incomplete in formulation or included elements beyond this content (c) insufficient answers were completely incompatible with the suggested school knowledge content, and (d) no answer was provided. The results presented here are derived from the quantitative results’ analysis (tables of absolute frequencies of the categories that have been formed from the students’ answers and justifications), as well as from the qualitative analysis (instances of justifications provided by the students).

5.1. Phenomenological Dimension of Knowledge

Based on the responses before the teaching intervention in the pre-test interviews, it can be concluded that most students could not effectively recognize and name either a real TPP or 3D model of a TPP. After the teaching intervention, however, we noticed students’ transition towards efficient answers, as expected (Table 3). Changes in the opposite direction, that is, toward less efficient answers, were not observed. This finding is statistically significant (Test Wilcoxon, question 1: Z = -3.542, p < 0.001, question 2: Z = -3.035, p < 0.01).

Table 3. The sufficiency of mental representations in responses to questions 1 & 2

Questions 3 and 4 investigated students’ mental representations about the technological dimension of knowledge. Students’ responses before the teaching intervention in the pre-test interviews indicated that they were not only unaware of the parts that construct the TPP, but also unaware of their operation (Table 4). Specifically, during the pre-test, students provided exclusively insufficient answers or didn’t answer these questions. The common characteristics between these answers were that students (a) were unaware of the components of the TPP representational model, (b) did not perceive the representational model of TPP as a whole system, and (c) as a consequence of (b), could not identify functionality of these components.

Table 4. The sufficiency of mental representations in responses to questions 3 & 4

However, after the teaching intervention, the majority of students provided either sufficient (9/21) or intermediate (11/21) answers to question 3 in the post-test interviews. Changes toward the opposite direction, that is, toward less efficient answers, were not observed. This finding is statistically significant (test Wilcoxon Z = -3.017, p < 0.01). From these answers, it appears that students either learned all, or most, of the parts of the representational model of TPP. Additionally, the majority of students provided either sufficient (14/21) or intermediate (2/21) answers to question 4 (16/21 in total) in the post-test interviews. This finding is also statistically significant (test Wilcoxon Z = -3.557, p < 0.001). After the teaching intervention, we also noticed that students were able to distinguish between the representational model parts of the TPP, while also describing their functions. Further, students were able to describe the operation of the parts of the representational model of TPP, even if, in some cases they didn’t remember their respective names.

“Number one is the burner and there is fire inside the burner…; the heat is transferred to number two, and therefore the water evaporates due to the warmth; number two is the boiler and thus the steam is transferred through the pipe and goes to number three…; number three is the turbine and, due to the steam, the turbine begins to turn while the movement goes to number four, which is the boiler… hm… no, that’s wrong, it is the generator…; the generator converts the motion to electricity, and electricity, through the wires, is transferred to the lamp and the lamp turns on.”

This student gave the same answer to question 4 in the post-test interview: “The same applies here as in question 3.” From this,, we can claim that the scientific dimension of knowledge (school knowledge for energy) did not work completely autonomously, but rather also attributed meaning to the technological dimension of knowledge (recognition of technological components that belong to a technological system).

5.3. Scientific Dimension of Knowledge

Questions 5 and 6 investigated students’ mental representations about the scientific dimension of knowledge.

Table 5. The sufficiency of mental representations in responses to questions 5 & 6

A typical example of an insufficient response within category (i) was student M17’s answers. Responding to question 5 in the pre-test interview, this student said: “I see how you have connected the machines with some wires. The wires produce current, which moves from the vehicles to the wires, and the wires transfer it to the lamps.” Moreover, in question 6 in the pre-test interview, the same student insufficiently justified the way they ordered the cards to represent the TPP (surroundings, arrow, burner, generator, arrow, turbine, arrow, boiler, arrow, lamp):

“I started with the surroundings because the current is produced by the surroundings, then I moved on to the coal… I saw the order you had placed them and then I added the surroundings at the beginning, and I placed the lamp because the current goes to the lamp.”

As for an insufficient response within category (ii), a typical example is that of student M3’s answer. Responding to question 5, this student said: “When it moves and produces energy, the machines connect, and the energy reaches the wires. The wires at some point connect on the maquette, and the energy goes to the lamp and turns it on.” Additionally, in question 6 the same student insufficiently justified way they ordered the cards to represent the TPP (generator, arrow, turbine, arrow, boiler, arrow, burner, lamp, arrow, surroundings):

“I believe that the generator is machine 1; then the energy goes to the turbine which is machine 2; then the energy leaves toward machine 3 that is the boiler; the boiler sends the energy to the burner; then, the energy goes to the lamp and goes to the surrounding.”

The examples above show that students, in both categories, did use elements of systemic thinking, as well as linear causal reasoning. However, these responses were classified as insufficient because they (a) used imprecise or incorrect conceptions of the components included in the technological system and/or (b) expressed pre-energy conceptions that mainly reflected only a vague nature of the intermediate action that connects the source to the receiver.

After the teaching intervention, however, several of the students’ responses made the transition toward intermediate and sufficient explanations. In responses to question 5, the majority of students continued to provide insufficient answers, while some did provide intermediate responses (7/21). Nevertheless, this finding is also statistically significant (test Wilcoxon Z = -2.226, p <0.05). Student M6 provided a typical example of an intermediate response to this question:

“Because at the turbine there is kinetic energy, and because this kinetic energy is transferred to the generator, and from that point, it converts to electric current. That electric current is transferred through the wires, and this is how the lamps turn on.”

These results would have been discouraging without the more efficient responses to question 6 which sketched a considerably different picture. As shown in Table 5, the majority of students properly constructed the graphic representation of the energy chain, giving a sufficient (10/21) or an intermediate response (7/21), for a total of (17/21) efficient responses. This finding is statistically significant (test Wilcoxon Z = -2.226, p <0.05). According to the following example, the same student (M6) made a transition toward a sufficient response. They now correctly justified the correct order in which they have placed their cards of technological components and arrows/forms of transferred energy (burner, heat, boiler, movement, turbine, movement, generator, electricity, lamp, light/heat, surroundings):

“First I put the burner, which is an energy storage. All chains start with an energy storage. Afterward, when the combustive material burns, the heat is transferred: it goes to the boiler, the boiler converts the heat into movement; afterward it goes to the turbine and it produces more movement; afterward, the movement is driven toward the generator, which converts the movement into electricity; the electricity goes to the lamp and converts it into light/heat that goes to the surroundings.”

Based on the examples mentioned above, we assumed that the majority of students gained the capability to construct a qualitative chain energy model to explain the function of the TPP representational model. Students’ poor verbal and/or written ability to express their mental representations, which can be expected at this age, could explain the considerable difference in student performance between their answers to questions 5 and 6. On the contrary, the use of a “language” based on energy representations, such as the energy chains, probably offered a more semiotically stable context, within which students could express their newly constructed knowledge.

5.4. Environmental Dimension of Knowledge

Questions 7 and 8 investigated students’ mental representations within the environmental dimension of knowledge.

As shown in Table 6, before their participation in the teaching intervention, most students provided mainly insufficient answers to both questions 7 and 8, as they failed to connect the environmental problem and its solution(s) to the TPP’s structure and operation. Typical examples of insufficient answers to question 7 in the pre-test interviews included the following: “I would suggest installing a filter in the plant, so they wouldn’t pollute the environment that much,” from student M6; and “The small tube that emits smoke to the environment should not exist,” from student M14. Meanwhile, respective examples for answers to question 8 in the pre-test interviews included: “To save money… we won’t give the electric company that much money,” from student M1; and “We obviously do not need it since we are in a different place,” from student M8.

Table 6. The sufficiency of mental representations in responses to questions 7 & 8

Two typical sufficient answers to the post-interview questions included the following. To question 7, student M8 replied:

“We would use the hydroelectric power station [more] because it uses a renewable material that can be used many times, and it does not produce as many pollutants as the thermoelectric. But we can also use the wind farms, the wind turbines that produce energy from the air”

while to question 8, student M1 replied:

“When the lamps are turned on, they spend some Watts that we pay for. We pay the energy we use, therefore, we turn them off so we do not waste the energy when we do not need them…; also, not to pollute the environment, not to burden the environment, because for the plants to produce energy they pollute the environment with the fumes that come out, if it is produced by a thermoelectric plant.”

6. Discussion and Conclusions

In this research, we attempted to illustrate that designing a teaching intervention for 11 and 12-year-old students aiming for their understanding of complex technological systems, such as the EGS is, in fact, an attainable goal. More specifically, we focused on presenting how our proposed teaching intervention (a) is based on an epistemologically valid didactic transposition of the required knowledge and (b) leads participating students toward a respective cognitive progress in reference to this knowledge.

Concerning the didactic transposition of the reference knowledge, we suggest that the required knowledge for the description and explanation of the various EGSs operation is multidimensional, since it consists of at least four dimensions (phenomenological, technological, scientific, environmental). The basic elements of our approach are the following:

In any case, the epistemological content of the school knowledge mentioned above must be compatible with students’ explanatory schemes, which are developed when students confront natural or technological systems. Therefore, regarding the sampled students’ cognitive progress, based on the analysis of the results collected from the pre- and post-tests, we can claim that our empirical research illustrated the following:

Therefore, a complementary direction in which to take the current research would be its extension to a broader base of actual classes from various socio-economic backgrounds. At the same time, pertinent research could explore the potential to penetrate students’ thinking patterns during the teaching intervention, asking questions like: “How do students think while these activities take place?” and “Which teacher-students and/or student-student interactions formulate students’ thinking?” Such research questions can be addressed merely by qualitative methodological approaches, like class observation, and could greatly contribute to a more profound interpretation of the results presented in this research.

Declaration of Conflicting Interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

References