Condensation and Precipitation of Water Vapor: The Emergence of a Precursor Model through the Engineering Design Process

Abstract

Early Childhood Science Education, within a wide range of research topics, studies mental representations of children aged 3–8 years about natural phenomena. Recently, there has been a strong scientific interest in the way children construct precursor mental models. The current study attempts to address children’s mental representations of clouds, as well as condensation and the precipitation of water vapour. To fulfill this goal, a qualitative study was implemented involving 19 preschool children. Specifically, the survey included pre-tests and post-tests for recording children’s mental representations, as well as a structured teaching process. The main activities of this teaching process followed the four stages of the Engineering Design Process and a STEAM approach, adapted both to children’s cognitive needs and the conditions of a real classroom. The results showed that most children of this age (mean age: 5.05 years) were able to approach the concepts of condensation and precipitation, as well as the process of cloud creation. It seems, therefore, that it is possible for young children’s initial mental representations to be transformed into representations compatible with school knowledge. Finally, the data and the results of the research lead to the conclusion that children of this age are capable of constructing a precursor model about clouds and the phenomena of condensation and precipitation.

1. Introduction

Early Childhood Science Education sets itself in a wide spectrum that encompasses distinct study fields such as Early Childhood Education, Educational Psychology, and Science Education. This new field, both from a theoretical and a research point of view, covers a number of issues that are related to the development of scientific educational environments and the training of teachers, as well as the learning and teaching of natural sciences to students aged 3–8 years old. Within this context, a distinct direction of research is the study of young children’s mental representations of scientific concepts and phenomena, the obstacles they create in the conceptualization of the scientific phenomena, and strategies to deal with these obstacles through developmentally appropriate activities [1,2,3].

Within a special perspective, modern research in this study area deals not only with the transformation and evolution of some mental representations but also with the formation of precursor models in children’s thinking. These are stable entities that have two main characteristics: (a) They interpose themselves, as dynamic forms of thinking, between naive mental representations and scientific knowledge taught in schools and (b) They hold specific characteristics of scientific models, such as the use of appropriate variables that allow satisfactory descriptions and the formulation of predictions for the evolution of physical phenomena [4].

During the last few decades, a new research field was shaped around STEM education that describes an interdisciplinary approach to Science, Technology, Engineering, and Mathematics [5]. Lately, Arts were added to the acronym, forming the term STEAM, to enhance creativity [6,7,8]. Regarding early childhood settings, STEAM could also be combined with non-STEAM areas such as Literature, History, and Storytelling. In addition, everyday life situations and problems can be used and solved through the Engineering Design Process, a four-stage problem-solving process that introduces and facilitates STEAM activities in Early Childhood Education [9].

In the current research, an attempt was made to study the possibility of constructing a precursor model for the condensation and precipitation of water vapor in the thinking of approximately 5-year-old children through the creation of an educational environment based on the Engineering Design Process.

2. Theoretical Background and Literature Review

2.1. Literature Review

Early Childhood Science Education covers a wide spectrum that extends from the study of children’s ideas about natural phenomena to the design and implementation of proper teaching interventions. It addresses a variety of natural science concepts and phenomena, such as mechanical phenomena [10,11,12], floating and sinking [13,14,15], thermal phenomena [16,17,18,19,20], light and shadows [21,22,23,24], and elementary astronomy [25,26,27]. A literature review that focused mainly on water state changes and the water cycle in nature revealed the positive experience that young children harbor regarding ice melting and water evaporation, as well as other related phenomena [28].

Students need to establish connections between scientific notions and their everyday life experiences and be able to utilize this new knowledge in problem-solving situations [29,30,31]. It seems that young children often face difficulties in learning and conceptualizing notions about water state changes. However, as research findings reveal, preschool students often have interesting experiences with thermal phenomena that enable them to approach scientific knowledge through appropriate teaching methods [1,2,3].

Although young children can understand phenomena such as boiling [32], most of them could face difficulties with other notions such as evaporation [33]. Tytler [34] studied the mental representations of young children, aged 6 to 7 years old, regarding evaporation and condensation, while Cruz-Guzman et al. [35] examined 2- to 4-year-old children’s mental representations about the change of matter in daily material.

In their research, [36,37] revealed that young children were capable of constructing a precursor model that could support their scientific thinking regarding water state change phenomena. However, severe difficulties were recorded in the conceptualization of the condensation phenomenon. Bar’s [33] research showed that 5- to 7-year-old children hold the view that God is exclusively responsible for rain without mentioning any connection with clouds, while older 6- to 9-year-old children could justify the creation of clouds through the existence of steam. Ahi [38] stated that children were able to connect rain with clouds and tended to recognize both of them as important elements of the water cycle. However, he pointed out that children often encountered difficulties with notions such as evaporation and condensation. In Savva’s research [39], children also tensed to describe clouds as the source of the rain. Quite interestingly, as a literature review revealed, many 7- to 10-year-old children likened clouds to sponges with holes that let the rain fall [33,40].

Jelinek [41] used a narrative approach to examine to which extent children would be able to detect incorrect information regarding evaporation. Although only a few were able to detect errors in the story, half of the children connected cloud formation with evaporation. Malleus et al. [42] also investigated children’s ideas about clouds and rainfall. They stated that while young children mainly focused on the visible aspects of clouds (e.g., made of cotton), some of them were capable of giving synthetic responses that were close to scientific thinking, recognizing that clouds were made of water vapor. Savva [39] also examined the concept of rainfall with children and found that older children could associate clouds with rainfall.

Another item of research revealed that, despite the difficulties that children may have with complex entities such as clouds, they can often offer descriptions and recognize both the characteristics of clouds and their nature [43]. In conclusion, it seems that only those 4- to 7-year-old children who either completely or partially associate water vapor with clouds and rain can conceptualize rain and cloud formation phenomena as key components of the water cycle in nature [43,44,45].

Based on analysis of the relevant literature, as well as school-level science knowledge about the water cycle in nature, the key structural features of a precursor model for the water cycle in nature for children aged about 5 years are the following:

(a)

Firstly, the transition from the liquid to the water vapor state is solely limited to notable and well-observable ‘water reservoirs’ such as the sea or lakes and rivers. At the core of this choice lies the capability of utilizing the real-life experiences of young children, which can act as the starting point for teaching interventions.

(b)

As a transition process, the creation of water vapor in boiling states is primarily chosen, since the phenomenon is intense and allows the centralization of the children’s thinking. Although, in nature, the main process of water vapor production is evaporation without boiling, we chose boiling as it coexists with evaporation. In addition, part of the teaching process related to scratch applications on the sea, an issue which is based on the evaporation of water.

(c)

The transition of water vapor to the liquid state is attributed to condensation due to cooling by air.

(d)

The cycle of related phenomena is completed by precipitation and rain, which is attributed to the concentration of water droplets returning back to their original reservoirs on the Earth’s surface.

All these phenomena facilitate the gradual evolution of students’ thinking into higher-level models as (a) water reservoirs can incorporate the moisture of solid soil, (b) the transition from the liquid to gaseous state can be dominated by evaporation, (c) precipitation and rainfall are more complex mechanisms, and (d) the return of rain to Earth involves run-off, infiltration, and percolation.

2.2. Research Questions

In the current research, we dealt with the phenomenon of condensation and the precipitation of water vapor. In particular, our goal was to study the transition of water from the gaseous state to the liquid state, from the perspective of transforming children’s mental representations from pre- to post-test while establishing a precursor model in their minds. Key elements of such a model are, on the one hand, the recognition of the physical processes of condensation of water vapor in familiar phenomena and, on the other hand, the linking of condensation with precipitation so that the thermal character of this process is consistently recognized. In this context, three research questions were formulated to investigate the potential change in children’s reasoning between pre- and post-test.

The first research question examined children’s mental representations of cloud creation.

The second research question examined the way children approach the cycle of condensation and the precipitation of water vapor.

The third research question studied children’s mental representations of condensation of water vapor in everyday life situations.

3. Materials and Methods

3.1. Participants

The participants of this study consisted of 19 children (9 boys and 10 girls, mean age 5.05 years) who voluntarily participated in this research. They were chosen on a convenient basis as all of them attended a kindergarten class in a school in Piraeus, Greece. The research was conducted with the written consent of the children’s parents and the permission of the ethics committee of the Department of Educational Sciences and Early Childhood Education of the University of Patras. While no activities on ‘condensation of water vapor’ had been carried out within the classroom, all of the children were familiarized with the phenomenon of boiling and the vaporization of water.

3.2. The Research Process

The research design consisted of a pre-test, four (4) main stages that followed the Engineering Design Process (EDP) for Early Childhood Education [9], and a post-test (Figure 1). The main activities that followed the 4 stages of the EDP were: (1) Problem, (2) Inquiry, (3) Designing and Testing, and (4) Conclusions and Presentation. The pre-tests were conducted a week before the main activities while the post-tests were conducted a week after the completion of the main activities.

The entire research process was carried out by a researcher with extensive experience as an early childhood teacher.

3.2.1. The Pre-Test

The pre-test was conducted with semi-structured interviews, which were composed of 6 basic tasks by which children’s mental representations were recorded. The discussion with the children initiated with an introductory question asking them whether and where they had ever seen clouds. The fact that all children were able to talk about this experience led to the start of the interview. The key questions of every basic task of the interview were as follows. Research question 1: Task (1) What is a cloud? Task (2) How is it created? Research question 2: Task (3) Do you know what condensation is? Have you ever heard the word precipitation? Research question 3: Task (4) If there is a pot of boiling water in the kitchen, what would happen on the kitchen cabinets? What would happen on the kitchen windows? Task (5) What if cold air suddenly blows over the pot? Task (6) Have you ever seen a factory? Have you noticed the chimneys? What comes out of there?

The discussions with the children were recorded and analysis of the data was based on the corresponding transcripts.

3.2.2. The 4 Stages of Activities According to the Engineering Design Process (EDP)

The activities were implemented in real teaching conditions and were developed in 4 stages according to the EDP [9]. The EDP is a problem-solving process that follows specific steps and constraints in order to solve problems or create prototypes. The EDP was utilized in this paper in two ways. Firstly, to design the teaching intervention and secondly by children in order to solve the problem presented to them through its 4 specific steps. Through its four steps, the EDP offers the possibility to design individual activities or projects focused on solving a specific problem; with the appropriate visualization, children can be gradually introduced to its steps in order to follow a specific process to achieve their goal [9].

In the current study, the children were asked to identify the problem Paul faces in order to interpret and analyze the phenomena he observes. Thus, children first identified the elements of the story (Problem), then expressed their experiences and ideas about the elements they identified (Inquiry), designed ways in which they could make a cloud, and observed and participated in the implementation of the experiments (Designing and Testing). Finally, due to the nature of the topic, the children created a poster to ‘solve’ the problem that Paul faced within the original story. In particular, they attempted to interpret the phenomenon they investigated accurately and in a way that was compatible with school knowledge, as well as communicate it to others. Finally, they focused on how, when, and why the cloud forms, even in situations other than at the factory.

Particularly, in the first stage of the EDP (Problem), the researcher narrated a story about a child named Paul. The scenario of the story was as follows: ‘Paul lives in a town, near a factory, in which very large cauldrons of boiling water started to heat up. Suddenly, a white smoke, steam, began to rise from the tall and large chimneys. Large clouds began to form over the factory, which grew larger and larger’. Upon completion of the story, the children were asked to identify and define what these clouds were and how they were created. The choice of the analogy of factory chimneys was made in order to introduce the concept of steam to children through an analogy that is well-known in their everyday life experiences, as numerous factories exist in the area where these children are raised. In particular, during the implementation of the pre-tests, it appeared that some children had some experience with factories, even reporting on their own that ‘white clouds’ or steam and white smoke formed over the chimneys. In contrast, other children reported fire or grey smoke (when something burns) from factories or from ships in the harbor. Therefore, drawing on the distinction the children made on their own, the story of Paul, who introduces the concepts of a heat source, water, steam, and clouds, was created.

In the second stage of the EDP (Inquiry), the children were encouraged to express their ideas about the creation of clouds and the material they were made of. In addition, they were prompted to point out the role of the boiling water in the whole process, as well as to refer to everyday experiences related to the phenomenon of condensation (e.g., factories, ships, and cooking). Finally, they were encouraged to suggest possible ways of finding out what was really happening. Here, the researcher had the role of moderating the plenary discussion and recording their views on an interactive whiteboard.

In the third stage of the EDP (Designing and Testing), the children were initially asked to individually design and justify their responses regarding the possible ways of cloud creation. Subsequently, an interactive virtual simulation experiment was implemented on the classroom’s interactive whiteboard. This simulation experiment was designed in a Scratch programming environment by the research team and employed with the children (Figure 2).

As soon as a child placed a pot of water in the kitchen, the water would start to boil, and steam and small droplets would rise upwards. Then, the kitchen window would suddenly open, and a cold wind would blow. As a result, a cloud was created in the room. Subsequently, cloud creation was transferred to the context of the sea, where the sun would heat its surface and droplets would rise up to the sky. These droplets met cold air masses which led to the creation of clouds. At this phase, the teacher introduced the terms ‘condensation’ and ‘precipitation’.

At the end of this activity, two experiments were carried out in the physical space of the classroom: (a) boiling water in a pot next to a side window and (b) boiling water in a pot covered with a transparent lid. The children were asked to carefully observe and predict what would happen in each experiment.

Finally, the children divided into groups had the opportunity to play the music-motor game ‘steam–cloud’. According to the game, the children were able to move freely in the classroom as steam, while they had to approach each other and move in a cloud-group as soon as the ‘cold wind’ started blowing.

In the final stage of the EDP (‘Conclusions and Presentation’), children were invited to present their findings and conclusions to another class of the school as well as their parents. The teacher provided children with a number of different materials (cardboard, brushes, and paints) and, as a group, the teacher along with the children decided how to carry out their presentation. Here, the children were asked to emphasize how they rediscovered what clouds are made of, when and why this happens, and in what other situation something similar can happen other than at the factory.

The whole process was videotaped while non-verbal observation protocols were also followed.

3.2.3. The Post-Test

Having completed the four stages of activities, a post-test was carried out. Here, the children participated in a test similar to the pre-test interview, in order for the researcher to explore the possible effects of the above-mentioned activities on their way of reasoning.

3.3. Data Analysis

3.3.1. The Pre- and Post-Test

Children’s responses to the pre- and post-test were classified into two categories:

(a)

Sufficient responses were those that were consistent with the school-level knowledge of water vapor condensation and precipitation in the various phenomena. These were answers in which the variations associated with condensation were described with the appropriate variables and were predicted satisfactorily.

(b)

Insufficient responses were those that were incompatible with the school-level knowledge of water vapor condensation and precipitation in the various phenomena. These were answers in which the variations associated with condensation were not described with the appropriate variables and did not adequately predict the changes associated with condensation.

3.3.2. The EDP Analysis

Qualitative data were collected through (a) recordings of both the researcher’s narration and children’s dialogues during the four stages of activities (duration: 1 h and 30 min), (b) children’s drawings after each stage of activities (95 drawings in total), (c) children’s non-verbal behavior protocols, and (d) analysis of the video footage. Analysis of the narrative and dialogue was based on the transcripts, with simultaneous documentation of the video footage, drawings, and protocols. The texts were divided into episodes based on themes related to condensation and precipitation [46,47,48]. The analysis of the episodes was aimed at identifying the critical points at which the formation in children’s thinking of mental representations compatible with knowledge learned at school takes place. These critical points were actually the key elements of the precursor model. From this qualitative analysis, the creation of clouds and the processes of evaporation, condensation, and precipitation, as well as precipitation in everyday conditions, emerged as central themes, whose main dimensions will be presented in the following section.

4. Results

4.1. The Pre- and Post-Test

In the following paragraphs, the findings of the pre- and post-test, which qualitatively share the same characteristics, are presented. This data are displayed in a frequency table, while for each response category, characteristic descriptions made by the children are given (

Table 1. Frequencies of children’s responses to pre- and post-test questions.

	Pre-Test				Post-Test
	Sufficient		Insufficient		Sufficient		Insufficient
	Students	f	Students	f	Students	f	Students	f
Task 1	2,4,5,7,8,13,14,15	8	1,3,6,9,10,11, 12,16,17,18,19	11	1,4,5,7,8,9,10, 11,13,14,15,16, 17,18,19	15	2,3,6,12	4
Task 2	9,14,15	3	1,2,3,4,5,6,7,8, 10,11,12,13,16,17,18,19	16	1,3,4,5,7,8,10, 11,14,16,17,18,19	13	2,6,9,12,13,15	6
Task 3		0	1,2,3,4,5,6,7,8,9, 10,11,12,13,14, 15,16,17,18,19	19	1,3,4,5,7,8,10, 11,14,16,17,18,19	13	2,6,9,12,13,15	6
Task 4	3,6,8,14,17,18	6	1,2,4,5,7,9,10,11, 12,13,15,16,19	13	1,3,4,5,6,7,8,9, 10,11,13,14,15, 17,18,19	16	2,12,16	3
Task 5		0	1,2,3,4,5,6,7,8,9, 10,11,12,13,14, 15,16,17,18,19	19	1,3,4,5,6,7,8,9, 10,11,13,14,15, 17,18,19	16	2,12,16	3
Task 6	3,4,8,11,15,16,18	7	1,2,5,6,7,9,10, 12,13,14,17,19	12	3,4,5,6,7,8,9, 10,11,12,13,14, 15,16,17,18,19	17	1,2	2

).

4.1.1. What Is a Cloud? What Is a Cloud?

In this question, two categories of responses appeared:

(a)

Sufficient responses where children seemed to acknowledge that clouds are created by water. For example, S14, post-test: ‘very small droplets that stick’.

(b)

Insufficient responses where children described clouds as entities that are artificially created, without making any association with water. For example, S10, post-test: ‘white… like cotton’.

4.1.2. How Is It Created?

In this question, two categories of responses also appeared:

(a)

Sufficient responses where children seemed to recognize that clouds are created by water droplets. For example, S14, post-test: ’very small raindrops, the first cloud becomes rain and falls, and then other clouds join… and multiply’.

(b)

Insufficient responses where children tended to attribute the creation of clouds to the wind, cotton, ice, snow, or even God.

4.1.3. Do You Know What Condensation Is? Have You Ever Heard the Word Precipitation?

In these questions, two categories of responses also appeared:

(a)

Sufficient responses in which children seemed to identify the two physical processes of condensation and precipitation regardless of whether they used these two terms. However, it should be noted that sufficient responses were exclusively recorded during the post-test, and only four children used both terms. For example, S16, post-test: ‘the sun warms the sea and steam comes out, cold air blows and the cloud is made’ and S3, post-test: ‘steam goes over the pot and droplets are made and air is blown…’

(b)

Insufficient responses where the two physical processes were not recognized at all by children. For example, S17, pre-test: ‘when water runs’, S3, pre-test: ‘something that gets hot’, and S12, pre-test: ‘that means it’s smoke and means we shouldn’t follow it somewhere’.

4.1.4. If There Is a Pot of Boiling Water in the Kitchen, What Would Happen on the Kitchen Cabinets? What Would Happen on the Kitchen Windows?

In these questions, two categories of responses also appeared:

(a)

Sufficient responses where children were able to detect water vapor or haze on the glass or kitchen cabinets when a quantity of water boils in a pot. For example, S8, pre-test: ‘water goes out with the evaporation and gets on the windows’.

(b)

Insufficient responses where children did not anticipate evaporation and precipitation on room surfaces. For example, S6, pre-test: ‘the water will melt’ and S12, pre-test: ‘some bubbles are bubbling’.

4.1.5. What If Cold Air Suddenly Blows over the Pot?

In this question, two categories of responses also appeared:

(a)

Sufficient responses where children described the creation of a ‘cloud’ when a pot of water boils in the kitchen and suddenly a mass of cold air is blown out. Quite interestingly, sufficient responses were only recorded in the post-test. For example, S4, post-test: ‘it will become steam, it will become droplets, it will become a cloud and go into the sea’.

(b)

Insufficient responses where children did not recognize the interaction of hot water vapor with cold air. For example, S9, post-test: ‘…it will cotton remain…’

4.1.6. Have You Ever Seen a Factory? Have You Noticed the Chimneys? What Comes Out of There?

In these questions, two categories of responses also appeared. It should be noted here that in the analysis of the results, a distinction was made between ‘grey smoke’ and vapor, and clouds and ‘white smoke’.

(a)

Sufficient responses where children recognized the production of smoke and its relationship to the creation of ‘clouds’. For example, S6, post-test: ‘steam… from water, boil water and steam come out… it will become a cloud (if cold air blows)’.

(b)

Insufficient responses where children did not recognize the relationship between smoke and clouds. For example, S9, pre-test, ‘fire... smoke, it (the chimney) takes all the air out and smoke comes in’ and S14, pre-test, ‘usually smoke comes out when it is very cold… smoke comes out of the fire, and they melt things to melt other things’.

4.2. The Four Stages of Activities

The data presented here were derived from the four main stages that followed the Engineering Design Process. The flow and content of the activities are presented with a focus on the critical moments and processes with regard to the transformation of children’s mental representations and the construction of the precursor model.

4.2.1. First Stage: Problem

Given the difficulties detected in the pre-test, the learning object emerged in the narration about the story of a child named Paul and the factory. This story was designed to link the water vapor coming out of the boiler with the formation of a kind of cloud. Within this connection, it appeared that the children could easily identify the specific features of the phenomenon, such as the water, the fire in the boilers, the steam, and the formation of the cloud, which was the main object of the activity. Therefore, it seemed that the role of this narration was important as it allowed the necessary connections to be made between the different snapshots, which is a kind of reasoning that refers to a precursor model. The following dialogue, which took place after the narration, clearly shows these connections.

Researcher. How was the cloud created?

S16. From the steam coming out of the chimneys.

S1: From the smoke.

S14: The water became steam and the cloud.

Researcher. So how were they made?

S7: From drops.

During the discussion, some children used their bodies to represent the process and expressed views such as ‘in the beginning it was water, then it became steam and finally it went up into the sky and became a cloud’ (S14) or that ‘it (the cloud) became steam’ (S15). At the same time, the researcher moderated this classroom play by re-describing the key elements of the narration and by using formulations to describe the process in which reference was made to the concept of the condensation of water vapor.

4.2.2. Second Stage: Inquiry

In this stage, children were asked to express their thoughts on the following topics: (a) how are clouds created, (b) how they could build a factory that produces steam, (c) how they could try to create their own cloud in class, (d) whether water has to be heated or boiled in order to create a cloud, and (e) what happens in the context of the sea. For this reason, children’s initial answers were recorded on the interactive whiteboard in the form of a concept map related to the creation of clouds (Figure 3).

For these recordings, the children freely expressed their ideas in open discussions without the researcher reacting to what was being said. Thus, the children exchanged views on the materials related to the cloud. During these discussions various entities emerged such as drops, steam, water, cotton, ice, snow, stars, glass, rainbows, stones, etc.

The researcher then asked the children to identify the materials used in the story so that it would be possible to build a similar factory. Trying to respond to this suggestion led many children to select the necessary materials. For example, some children pointed out that the cloud is made ‘from very small droplets’ (S14) and easily identified the basic materials such as water, fire, and a cauldron. The following dialogue is a typical example of the direction of these discussions with the children. A feature of this dialogue is the actual group discussion as the children follow the thoughts of others and fill in the actual missing elements to complete the description of the necessary experimental set-up.

Researcher. What do we need to build an identical factory?

S3. Gaz…

Researcher: What else?

S3. Water…

S15. …within a pot

S6. Fire…

S8. Chimney…

Researcher. And what would happen then?

S16. It comes out of the chimney and the air blows and becomes a cloud

Subsequently, the way the children approached the need to ‘heat’ water was explored, along with whether or not water needs to be boiled in order to create a cloud. In the wider circle of discussion, all of the children seemed to recognize that a pot of water with no heat source would not lead to the creation of a cloud. A typical dialogue is presented as follows:

Researcher. What does it take to create the cloud?

S18. Water and fire

Researcher: And what would happen?

S13. It will boil

S5. It will become steam

Researcher. What if the water didn’t boil? Would the factory be able to create clouds?

S15. No

Researcher: Why?

S18. Because it wouldn’t boil.

S14. Because there would be no smoke… they would not be stunned (drops) to make smoke and create (the cloud).

Finally, the children were asked to discuss what they needed in order to create their own cloud in the classroom. Moreover, they were asked to ask themselves what happens in the context of the sea. The dialogue below shows a typical example of the direction of these exchanges with the children.

Researcher. What could we bring in the classroom in order to create our own cloud?

S3. Pot

S1. Water

S6. Fire

Researcher. I wonder what happens in the sea if it gets hot?

S18. They are leaving (the drops)…

4.2.3. Third Stage: Designing and Testing

In the third stage, children were asked to individually design how they could make their own clouds and to think about the processes that take place in nature for the creation of clouds. Thus, the children designed their own ideas, although they had the opportunity to discuss them in small groups (Figure 4(4.1,4.4)). Most of the children chose to create their own factory, influenced by the story presented to them, by designing a heat source (‘φωτιά’) (fire or gas stove), a water (‘νερό’) container (steamer or cauldron), steam (‘ατμός’), and clouds ‘(σύννεφα’) (Figure 4(4.3)).

Only one child drew a pot of water, the sea, and the sun as a heat source in order to show the formation of a cloud over the sea and over a pot of water (in the upper and right part of Figure 4(4.2)). Quite interestingly, most children verbally mentioned air in the description of their drawing but did not capture it in their picture, while no child mentioned water vapor or droplets. Finally, under the guidance of the researcher, the children presented their designs to the class.

Then, the experiments were carried out. The virtual experiment (Figure 2) was implemented by the children who already had a good familiarity with the Scratch 3.0 software. The two experiments of boiling water with gas and a pot were carried out by the researcher in front of the children (Figure 5). In both virtual and real experiments, children were asked to make predictions and confirm or modify them based on the final results of the experiments. First, they tried to predict what would happen in the virtual experiment, in the case of boiling water in the kitchen and then in the case of the sea. Most of the children could not express previous experiences from their daily lives but were able to predict that steam would come out from a pot full of boiling water placed on a stove.

In addition, some children correctly predicted that a kind of cloud will be formed as soon as cold air blows over a pot with boiling water or the sea. The same happened in the case of the sea. These data highlighted considerations that fit into a precursor model for condensation.

Researcher: We put a pot of water in the stove… and…

S16: It’s boiling.

Researcher: And what does it come out?

S11: Bubbles.

S18. Steam…

Researcher: Suddenly Paul noticed something in the cupboards of the kitchen and on the glass.

S18: Droplets!!!!!

Researcher: From where?

S16. From the water

Researcher: Suddenly Paul opens the window. What could happen?

S16: The wind is blowing.

S14. Cloud

Researcher: What about the sea?

S16: Steam is coming out.

Researcher: How did drops came out from the sea?

S14: With the sun

Researcher: And then?

S16: It became a cloud

Researcher: How?

S18: The wind blew… cold wind…

Finally, all children were able to analyze the virtual experiment and describe it in detail, even with reference to drops and water vapor, after the first implementation of the experiment.

In the case of the experiments with water boiling in a small pot next to the classroom window or under a transparent bowl (Figure 4(4.3)), few children were able to predict what would happen to the glass while none of them were able to predict what would happen to the transparent bowl. After the experiment was implemented, each child was able to describe the experiment while the majority of them identified the droplets and water vapor that came from the steam. In addition, some children managed to connect the two experiments as ‘the glass becomes blurred like the bowl’ (S13).

Researcher: How about we boil some water?

S14: We’ll make a cloud.

S3: And we will open the window…

During the experiment with the bowl and the pot, initially, the water was made to boil in order to create steam.

Researcher: Can you see the steam?

S8: Yes

S3. Because it is white

Researcher: Can you see the droplets?

S18. No

Researcher: What do you see?

S18. Steam

Later, the bowl was placed in the steam path so that the steam becomes liquid and drops appear on the surface of the bowl.

What happened?

S11: Blurred, as our breath is like air

S18. Small droplets

S14: Sir, shall we all blow it together? (to make a cloud)

Quite interestingly, some children wanted to ’touch’ the steam and noticed that as soon as they placed their palms in the steam before it reached the bowl, their hands became wet. At this point, the researcher introduced the terminology ‘condensation’ and ‘precipitation’ to describe the experiments. However, none of the children chose to use these terms.

In addition, at this stage, the connection between the gaseous form of water as steam and its liquid form of water vapor within a cloud was made through a music-motor game (Figure 6). In this game, the children took the form of steam with their bodies in the beginning, before later taking on the form of a cloud. The children were able to move freely in the classroom as steam/gas, and had to approach each other and move as a cloud/group as soon as ‘cold air’ was blowing.

4.2.4. Fourth Stage: Conclusion and Presentation

In the fourth and final stage, the children were asked to present their findings and conclusions to another class of the school as well as their parents. After a plenary discussion, they chose to make a group poster since they had more experience with this approach. The children freely created their poster and chose to represent the clouds that are created over a factory due to the steam and cold air blowing, as well as the clouds that are created over a lake or the sea. In the posters, important details were emphasized, showing the water vapor, the clouds, and the air. Furthermore, having created the poster, the children divided themselves into the roles of presenter and cameraman in order to film their presentations (Figure 7).

In this stage, children were capable of justifying how and when clouds are formed and giving a reasonable explanation of why this happens. The analysis of the recordings showed that the children described and presented the poster in a way that was obviously influenced by their experiences from the previous activities, mentioning detailed information. In particular, children identified that initially ‘the sun warms the sea’ (S2) and the fire heats the water in the pot, then ‘steam comes out with droplets’ (S7), and finally, ‘the wind blows and clouds are made… since the droplets all gather together’ (S18). Quite interestingly, one toddler was able to fully describe the process by using the phrase ‘steam comes out of the chimney and condenses’ (S14) with the sudden cold air.

5. Discussion and Conclusions

In the research presented here, the possibility of transforming mental representations and constructing a precursor model in the thinking of children aged about 5 years for the condensation and precipitation of water vapor was studied. The design of this qualitative research included a pre- and post-test for the recording of mental representations, as well as a structured teaching process consisting of four stages of activities during which multiple forms of pedagogical action were used, completely adapted to the cognitive needs of the children and the organization of the school class.

The first research question was addressed through tasks 1 and 2 in the pre- and post-test. In particular, in the first task, where children were asked to identify the clouds, almost 4/10 of them responded in a correct manner in the pre-test. This percentage was doubled during the post-test. In task 2, where children were asked to describe the conditions for cloud creation, only 3/19 of them gave responses compatible with school knowledge in the pre-test. On the contrary, after the teaching process, 13/19 children were able to satisfactorily describe the creation of clouds in terms of the condensation of water vapor, while frequent references were made to the precipitation of clouds in the form of rain. An important qualitative element of children’s thinking here is their constant reference to ‘drops’, which seems to play a key role in their mental thinking. Indeed, the concept of drops acts as the connecting element of the repeatable continuous cycle of water–clouds–rain, since all these three entities in children’s thinking are made up of water drops. This finding is a strong element of a precursor model as drops are an element of children’s thinking that allows descriptions while being compatible with school knowledge. These findings are in line with those of other relevant studies [33,36,37].

The second research question was addressed through task 3, where an attempt was made for open discussions about condensation and precipitation. Quite interestingly, in the pre-test, there were no children who were able to propose schemes for describing the phenomena in a way that was compatible with school knowledge. On the contrary, a significant change was recorded in the post-test, as approximately 7/10 children gave answers in which they satisfactorily described the two physical processes and, in some cases, were able to name these processes with terms used in school knowledge. This change is remarkable, not only because it shows that the overall teaching process was well-adapted to the cognitive needs of children, but also because it emerged that the children showed a readiness to reorganize their experiences. These data clearly reinforce the establishment of a precursor model.

The third research question was addressed through tasks 4, 5, and 6, where children’s mental representations of condensation in everyday phenomena were explored. In all three tasks, the discussions with children led to the condensation or precipitation of water vapor. In the fourth and sixth tasks, while 3/10 and 4/10 children, respectively, gave responses compatible with school knowledge in the pre-test, this percentage was increased to 8/10 and 9/10 children, respectively, in the post-test. In the fifth task, children were asked what would happen if cold air met water vapor. Here, while no children gave a scientifically accepted response in the pre-test, almost 84% in the post-test were able to describe the precipitation of water vapor in a systematic way.

From the overall research data, it seems that it is possible to some extent to transform young children’s initial mental representations into representations compatible with school knowledge. Indeed, it appears that a teaching intervention based on the four levels of the Engineering Design Process, which combines a narrative with the simultaneous performance of critical design experiments, creates a favorable teaching environment for achieving cognitive transformations in young children’s thinking. The successful combination of a storytelling approach with the simultaneous organization of simple experiments has been shown to create an effective learning and teaching perspective in thermal phenomena [49,50]. Perhaps, in the context of the Engineering Design Process, it acquires new dynamics which, however, should be substantiated with empirical data for other concepts and phenomena.

The data retrieved from the post-test of the current study highlight that children’s mental representations are consistent with school knowledge across all tasks. Indeed, more than half of the children (10/19) gave satisfactory predictions and descriptions in all tasks. The stability of these findings gives a strong indication that children are able to conceptualize entities in their minds that have the characteristics of a precursor model at this age.

However, the study is characterized by specific limitations such as a limited number of participants and an exclusively qualitative nature. Further efforts along the same direction with a larger number of participants and quantitative analyses could shed light on other aspects of the research question. It would also be interesting to address children’s mental representations of clouds, condensation, and precipitation of water vapor with participants from different cultural backgrounds to highlight possible differences in the perception of these phenomena.