Design and implementation of a STEAM Teaching/Learning sequence by Project-Based Learning for the training of future secondary school teachers

In high school teacher education, although work on didactic units for teaching the curriculum of science disciplines is common, they rarely include multidisciplinary STEAM viewpoint. For this article we are using the definition of STEAM that says it is a teaching method that integrates content, skills and beliefs from at least two disciplines that form the acronym and that focuses on real world contexts In this project, we show the design and implementation of a teaching/learning sequence (TLS) to show the STEAM methodology in High School with a project-based learning approach, with students of the Master’s Degree in Secondary Science Teacher Training. The TLS designed integrates content and skills from various STEAM disciplines, with physics and biology being the main ones and adding a Project-Based Learning (PrBL) teaching approach through the search for the best way to protect oneself from the sun. In this case, the Master’s degree students had two roles: on the one hand, they acted like secondary education students and, on the other hand, like future teachers. Thus, we evaluated the sequence in three different ways: content acquisition, scientific skills and attitudes towards STEAM education. The results indicated a positive impact in all the aspects analysed.


Introduction
The initial teacher training process for secondary school teachers in scientific-technical disciplines in Spain is usually a short period in which prospective teachers receive an enormous amount of information.In fact, this is a 9-month master's degree that combines training in general pedagogy with learning how to teach science.Due to this situation, trainee teachers ask to see examples that illustrate how the theory they have worked on can be brought into the classroom [1].
In this paper, we focus on the training of future teachers in the analysis and exemplification of Teaching/Learning Sequences (TLS) with a project-based learning (PrBL) approach in a STEAMcentered science curriculum.According to previous literature, trainee teachers find it difficult to implement STEAM projects in the classroom and, at the same time, have difficulties in correctly understanding the PrBL teaching approach.In contrast, when teachers experience and participate in STEAM projects with student-centered approaches, an increase in teachers' interest and motivation towards this approach has been observed [2].
In this paper, we show the design of a STEAM-centered TLS with a PrBL teaching approach and the subsequent implementation with students of Master's degree in secondary teacher training at the UPV/EHU (Basque Country, Spain).One of the objectives of this project is to analyze the effect of this teaching proposal on the conceptions of future teachers concerning the viability and effectiveness of this type of teaching.Therefore the research question of this study is: 1. What difficulties in understanding the contents and scientific procedures of the TLS do the future teachers have?2. What attitude towards the implementation of TLS and STEAM education do trainee teachers have towards their future teaching?We will first describe the theoretical framework of our STEAM proposal that defines the structure of the TLS and justify the project-based teaching approach we propose to develop the TLS.We will then explain the main structure of the sequence and describe the type of learners and assessment on which this study has been based.Finally, the results will be analyzed according to the two research questions proposed and the main conclusions will be described.

Theoretical framework
The idea of STEAM education started in the 90's and even today there is no consensus on its definition which has caused to become an ambiguous movement subject to personal interpretations [3,4].However, STEAM education movement has shifted as both its purpose and definition have changed over time [3].As Bybee (2013) explains, there is still no consensus on the definition and as a result it has often become an ambiguous movement subject to personal interpretations [4].
The definitions of the STEAM movement that appear in the literature have as a common feature the proposal to integrate STEAM disciplines, but depending on the authors, this integration is interpreted differently.STEAM acronym stands for Science, Technology, Engineering, Arts and humanities and Mathematics and the debate focuses on how they are integrated, which of them has the leading role and in which contexts is applied.Thus, the definition we align the most is the one that states STEAM education as the integration of two or more disciplines that form the acronym in a real-word context [5,6,7].In addition, it is also important to integrate not only content, but also scientific and technological skills and competences of various disciplines, and problem solving approaches can be suitable to achieve it [8].
Furthermore, using real world contexts with a problem/project based learning approach, students learn by engaging in problem discussion and using evidence based argumentation to reach conclusions.This way, students have to combine disciplines' concepts and procedures to make decisions [9].
In the design of the TLS presented in this article we have taken into account the aforementioned characteristics.Thus, the starting point is a project that explicitly includes, content from the disciplines of physics and biology in the science curriculum in higher education.Likewise, mathematics content such as proportionality is needed and the need to use scientific work skills and the ability to understand the content in different representation formats such as graphs and tables is also considered.
A project-based teaching/learning (PrBL) approach is proposed to articulate the above-mentioned contents and skills.Project/Problem-Based Learning approach involves moving beyond the traditional framework of each discipline and adopting a project-oriented curriculum structure to re-integrate and re-organize related STEM subject knowledge according to the chosen theme [10].It has six main steps (Figure 1): (1) first, you have to create a context related to the phenomena or model you want to analyze during the project.That context or issue should be interesting and familiar for the students, but it should not have a single and obvious solution.(2) After the presentation, students should be allowed to express their initial ideas and hypotheses about the project just presented by using graphs, drawings, and written argumentation... Thus, on this basis, the process of knowledge acquisition begins.(3) During the process, evidence has to be prioritized by planning, evaluating, or developing a design that can be closed, structured, guided, or open-ended.The decision depends on the experience and skills students have in PBL.(4) In order to bring realism to the project, it is advisable to analyze real or hypothetical data that allow the results to be represented, evaluated, and connected.(5) In this way, students can confirm or refute their initial ideas using the data analyzed and (6) solve the project according to their learning.Those conclusions have to be communicated while students become aware of what they have learned, how, and what application it had [10].These steps are not a rigid algorithm, but a working guide that may have variations depending on the type of students and the type of project.

The Teaching/Learning Sequence of a STEAM project: How to enjoy the sun in a healthy way?
We designed a sequence for High school students aged between 15 and 17 whose aim was to find the best way to sunbathe in a healthy way.But they had to apply it to the scenarios of different people who had different skin colors, who live in diverse places in Spain at different times of the year and who had a variety of habits.

Project planning
The students run a skin care consultancy company and have just received messages from 6 people asking for advice (Figure 2).Each of these people has different characteristics, such as skin colour, the place where they live, their skin care habits and the questions they ask.Forming groups of 3 people, the students have to answer their questions explaining and arguing the decision from a scientific perspective.
In order to answer correctly, students had to know what ultraviolet light is and why it is harmful, distinguishing between ionising and non-ionising radiation.They then had to analyse the impact of UV light on our skin and skin cells and, finally, they had to apply it to each specific case.This means that in order to help those people, students had to learn about physics and biology and then, they had to be Figure 1.Six steps for teaching by guided Project/Problem Based Learning approach able to apply to each specific scenario.However, although the main subjects were the ones just mentioned, there were also some contents about chemistry and mathematics during the sequence.
The last part of the Teaching/Learning sequence was focused on developing an experiment using UV beads that changed colour each time they absorbed UV light (Figure 3).These UV beads can be used to answer a wide variety of questions related to sun exposure, such as which sunscreen is best, are there better sunscreen brands, is it necessary to use sunscreen if it is cloudy, and so on.As a conclusion, students had the opportunity to design, try and interpret the results of their own experiments, always taking into account their initial problem.

The study: Materials and Methods
Even though the project was originally created for secondary education students, for this study we implemented it with teacher training master's degree students with the aim of showing them a STEAM project example and educating them on the analysis and understanding of this kind of sequence.Therefore the Master's degree students had two roles: on the one hand, they acted like secondary education students working on the sequence and, on the other hand, like future teachers analysing and understanding the objectives and teacher approaches of the TLS.After doing each activity as students, they received an explanation of concept, laws, models, scientific skills and the teaching strategy behind the exercise they had just performed.This gave them the opportunity to understand the design decisions we made.

Participants
In this study was carried out in the module of science education of the Secondary Teachers Training Master in the 2021/2022 study year.Thirty three teacher training master's degree students took part in the implementation phase, which took two and a half hours.All the students were from the science and mathematics module of the master's degree at the University of the Basque Country, which means that all the students came from scientific university degrees.In fact, most students were from biology-related study areas.This means that students' knowledge level about the topic was quite high.
Although the entire sequence was applied, in this study we have focused on the section dealing with biology-related content and the final experiment.So the activities related to the impact of ultraviolet radiation on the skin and the effect of skin colour on that were carried out.Also, in groups of three they designed and carried out experiments using the UV beads to answer different research questions.The materials provided in addition to the UV beads were sun creams (of different brands and SPF), water and string to put the beads in as well as the option to go outside.
To give a general idea of the type of experiments that can be carried out, the research questions were as follows: Do two creams of different brands with the same SPF protect the same?Do you need to apply cream on a cloudy day?Do creams work under water?Does a cream with SPF 50 block UV rays more than a cream with SPF 30?Can UV rays pass through window glass?
Based on these questions, students should develop the objective, materials, steps, hypotheses, results and conclusion.All this was guided by a table containing all the above mentioned sections in order to help the students in the task.

Evaluation
We evaluated the sequence in three ways: content, skills and attitudes.To answer the first research question, we applied the biological part so students were asked to evaluate if four biology sentences were true or false and to explain why.The aim of this evaluation was to know whether or not they had achieved the minimum biology knowledge needed to develop the project.The sentences were as follows: 1.The type of ultraviolet radiation that causes cancer is UVA.
2. The purpose of tanning is to increase the uptake of sunlight.
3. Melanin is placed around skin cells to protect DNA. 4. Burns occur when excessive damage occurs.To identify students' problems in the application of the scientific skills we used the UV beads experiment.In this part students were given a table to fill in with the following sections: Research question, objective, materials, steps, hypothesis, results and conclusion.Then we analysed their answers and classify them in three different levels: blank spaces were given none points, superficial answers one and precise ones two points.Superficial answers are separated from the precise ones due to the lack of details on the item.Thus, if the item lacks information to properly understand the experiment is determined as superficial.On the contrary, it is a precise answer if there are enough details to comprehend the idea.
Finally, in order to answer the second research question we also analysed the attitudes of the students toward the sequence and the STEAM education approach using 1-4 Likert scale and open questions (Table 1).Students answered this after the sequence.

What difficulties in understanding the contents and scientific procedures of the TLS do the future teachers have?
In the content section we obtained overall a high percentage of correct answers in the true/false questions, which means that that practically all students understand that the purpose of skin darkening is not to increase the amount of sunlight absorbed and that they are able to locate the function of melanin.A lower but still very good percentage is able to identify the type of ultraviolet radiation that causes cancer and finally, three quarters of the students understand the cause of sunburn.Therefore, we could say that they have achieved the minimum knowledge necessary to develop the project.Similarly, the arguments given for each answer are very specific and use language that matches the material worked on during the session.
However, the hit rate for the item related to sunburn is much lower than the rest.After analyzing the arguments received, we saw that most of the students who had marked the statement as false argued their answer correctly.Therefore, although the percentage of correct answers was lower we could see that the vast majority of students understood the cause of sunburn.
Turning to the procedural section, we recorded a generally good performance on almost all items in the experimental part (Figure 4).However, the students did not express in detail the objective, the hypothesis, and the conclusion.Although they explained the main point, there was not enough detail to fully understand the experiment.As described previously, we classified the answers into two levels (superficial and precise), and in those three items, more groups did not give enough details.In table 2 we present some examples that illustrate the difference between the superficial and precise answers.
By analyzing that, we think that this methodology of giving students the sections to fill in when developing the experimental part has been useful to help them describing their idea.Even so, it may have been too much of a guide for students with such a high level of knowledge.

Superficial answer
Precise answer

Objective
To know how to protect correctly from the sun radiation To study if 50 SPF sunscreen protects better from the UV radiation of the sun than clothes or staying in the shade does.

Hypothesis
Only the beads with no cream change the color.
The UVB beads without sunscreen are going to become red because they don´t have any kind of protection.The ones with sunscreen, are going to stay the same during the time stipulated by the sunscreen used.This time will be longer on a cloudy day because the amount of solar radiation is lower.

Conclusion
Sun cream is effective and the hypothesis is correct.
The efficiency of the sunscreen is good as it resists to water.Also, we concluded that the UV light is able to go through water so it's also important to use sun cream even in the water.

What attitude towards the implementation of TLS and STEAM education do trainee teachers have towards their future teaching?
Finally, we also received good feedback from the master's degree students in the attitudes section.In the results we can highlight that the mean of the answers is in all cases between "agree" and "completely agree", which means that most of them liked the design of the TLS, thought that it was suitable for using with students, had learned a new teaching strategy and also had a greater interest in STEAM education (Figure 5).The results of the figure 5 were also reinforced by their answers to the open questions.Here there are some responses that encapsulate the main ideas received in the open questions:  In the Master's course we have received information about STEAM education, but not activities that apply it.That is why I found it very interesting to see how it is done and its practicality. I think that projects like this must be very nice and suitable for students to learn better, but depending on the school, due to organisational and willingness issues, I think there may be difficulties in carrying them out. I found it useful for training, especially for students to develop a scientific methodology and to think about the practical design of experiments.
It was also interesting to see that students loved the experimental part where they had the opportunity to develop all the experiment.According to their responses, they liked how easy the material was to use and the number of options it offered both students and teachers to apply scientific practices.Apart from that, they also mentioned their concerns about the applicability of such projects, as in many cases they require the coordination of different subjects.This made it possible to talk about the importance of project innovation and the motivation of the teaching staff to do so.

Discussion
In the research presented here, we analysed the impact of a STEAM project for high school on teacher training master's degree students.It consisted of two and a half hours in which 33 students from natural sciences and mathematics played the role of both secondary school students and trainee teachers.That allowed them to experience the dynamics proposed while analyse the educational intention behind them.
According to the results obtained for the first research question in which we analysed the content acquisition and science-procedures, we could say that, on the one hand, the activities proposed have been useful for the students' knowledge acquisition and on the other hand, that the guided version of developing the experiment helped them to perform well in almost all the sections.However, two of the main limitations of the study should be mentioned here since they are related to those results.The participants of the study were all from science studies, most of them from biology-related degrees, which means that some of the students already knew a lot about the content of the exercises performed in class.
That prior knowledge of the students could affect the interpretation of the content evaluation results, but taking into account the average results of students, we could conclude that most of the students selected the correct answers and among them were also non-biology-related ones.Knowing that, we believe the exercises proposed helped all students learn what was needed to move the project forward.
The second main limitation of the study related to the students' characteristics was their level of experience in science procedures.All the students had finished their science studies so their expertise in developing experiments should be much higher than the expected from high education students.This may be one of the main reasons why we have achieved such good results in all sections of the experimental development.As explained in the results section, the methodology proposed for this process was very guided and this, together with their knowledge in the area, may have positively affected their performance.
We could also see that even after completing scientific studies, students still have difficulties in writing hypotheses, objectives and detailed conclusions.This gives us an idea of the high level of difficulty of such a task and the emphasis that should be placed on it with younger students.
For future research, we believe it would be interesting to see the whole experiment's process without providing participants with a guidance table with the sections to be considered.In this way, it would be possible to analyse which items are more common to explain in an experimental report, which ones would be missing and how they would develop the process.Those results could also give us interesting information about students' difficulties in this task.
Turning to the second research question related to the students' attitude towards the project and STEAM education, the response received was more than positive.Their previous training in this subject was minimal and many students appreciated the opportunity to see it in practice.Moreover, even though it was a short session of two and a half hours, the results indicate that the students had time to understand the perspective that was presented and to get some ideas to put into practice.
It seems that students have become interested in STEAM education and STEAM projects thanks to this workshop and if this has been achieved with only two and a half hours of sessions, it would be interesting to analyze the impact that longer training sessions would have on trainee teachers.

Conclusion
The most noteworthy conclusion of all this research is the usefulness of interventions of this type in the training of future teachers, as it allows them to see how innovative proposals work while they learn their theoretical basis, thus providing a bridge between theory and practice.
Furthermore, given the importance that STEAM education is gaining nowadays, it is essential that teachers are trained in it before they are faced with the need to create a project themselves.Therefore, increasing their knowledge, interest and motivation towards this educational perspective is a very positive factor.
So, summarizing the main conclusions, we can say that the proposed sequence has helped to increase knowledge on the subject, has made it easier for students to develop the experimental approach correctly and has increased their knowledge, interest and motivation around STEAM teaching and the usefulness of their projects.

Figure 2 .
Figure 2. Client messages received in the counselling company to which the learner has to reply.

Figure 3 .
Figure 3. UV beads used in the experiment

Figure 4 .
Figure 4. Average score for the performance of each experiment part explanation.There were three categories: no answer (0 points), superficial or no detailed (1 point) and precise explanation (2 points).

Figure 5 . 4 I
Figure 5. Mean score for the level of agreement with four statements about the TLS and STEAM education.(1) Completely disagree, (2) disagree, (3) agree, (4) completely agree

Table 1 .
Questions used for the evaluation of students' attitudes