A Gamified Teaching Proposal Using an Escape Box to Explore Marine Plastic Pollution

Abstract

This work draws on the principles of Environmental Education as a framework for designing meaningful teaching interventions that foster a critical understanding of socio-environmental issues. The proposal focuses on the specific case of plastic pollution and its impact on marine ecosystems, adopting an integrative perspective that connects animal, environmental, and human health. To this end, the One Health approach is incorporated, highlighting the close interdependence between the health of ecosystems, animals, and people, which allows the issue to be analyzed from a systemic and global perspective. The intervention is grounded in the principles of Transformative Environmental Education—a pedagogical orientation that seeks to promote deep changes in how students understand their environment and engage with the challenges of today’s world. This approach encourages ethical reflection, critical thinking, and the ability to imagine sustainable futures, as well as the development of competencies for action and civic engagement. The teaching proposal takes the form of a learning experience designed and implemented in three 7th-grade classrooms (1º ESO) in Cádiz, Spain, through a mixed-methods approach with 79 students (12–13 years old), structured around an escape box activity. This is a variation of the escape room format in which students, working in teams, must open a series of boxes by solving a sequence of puzzles. In this case, the escape box is set in a marine context. Through a gamified narrative, students receive a suitcase containing objects, clues, and materials that require the application of scientific knowledge about ocean acidification, biodiversity loss, and types of plastics. Data were collected through field notes, student artifacts, and a final questionnaire. The proposal is designed to foster critical environmental literacy, a holistic vision of environmental challenges, and the capacity to propose collective solutions from a One Health perspective. The results revealed high levels of motivation, engagement with the storyline, and a solid understanding of the link between marine plastic pollution and its effects on animal and human health, aligned with the One Health perspective.

1. Introduction

Plastics represent one of the most pressing socio-environmental challenges of this century, largely due to the industry’s heavy dependence on fossil fuel consumption [1]. Marine plastic pollution can be understood within the framework of the planetary boundaries [2,3], which warn of critical thresholds being exceeded in processes such as climate change, biosphere integrity, and biogeochemical flows. This perspective allows us to frame the issue as part of a global, systemic environmental crisis.

According to Shen et al. [4], the plastic life cycle can emit up to two gigatons of CO₂ annually, with most of these emissions occurring during the primary production and manufacturing stages. Like climate change, plastic pollution has serious implications for ecosystem health, the economy, and humanity. Several studies have highlighted the connection between these two issues, further exacerbating the climate crisis [5]. These authors argue that extreme weather events and flooding can facilitate the spread of large quantities of plastic waste into the natural environment. A significant portion of this waste originates from land-based sources. Jambeck et al. [6] estimate that in 2010, 275 million metric tons (MT) of plastic waste were generated in 192 coastal countries, with between 4.8 and 12.7 million MT entering the ocean—figures that continue to rise. This has led to the increasing accumulation of plastics in marine environments, representing one of the greatest environmental challenges of our time, with severe consequences for marine biodiversity, human health, and planetary sustainability [7]. The emergence of large plastic gyres, such as the Great Pacific Garbage Patch, ocean acidification, and the loss of marine species, are visible manifestations of a global socio-environmental crisis that demands urgent and transformative educational responses.

In this context, Environmental Education (EE) must go beyond the transmission of content and instead foster critical, contextualized, and participatory action, promoting the development of citizens committed to environmental justice and sustainable development [8].

From this perspective, this study presents an educational intervention with students from 1º course of ESO (Obligatory Secondary Education) through the use of an emerging methodology: gamification, using the escape box or breakout box as an educational resource [9]. The teaching proposal is framed within the principles of Transformative Environmental Education (TEE), aiming to bring the issue of plastic waste closer to students, encourage active participation in seeking real-world solutions, and support the construction of environmentally engaged citizenship [8]. The One Health perspective is also incorporated, offering a holistic and interdependent approach to human, animal, and environmental health that moves beyond traditional biomedical views and points towards more sustainable and equitable health governance [10]. This vision is aligned with the Sustainable Development Goals (SDGs) set out in the 2030 Agenda [11]. Specifically, the intervention is framed within SDG 14 (Life Below Water) and the principles of ocean literacy, which recognize the interdependence between the ocean, climate, and human activity [12]. The use of an escape box enables the integration of scientific knowledge with the generation of positive emotions through cooperative work, enhancing students’ motivation—an effect supported by recent research on gamification in science education [13].

2. Objectives

Based on the above, the objectives of this work are:

• To design an educational proposal based on gamification and the use of an escape box as a teaching resource to promote TEE, contextualized within the issue of marine plastic pollution, aligned with the One Health [14] perspective and ocean literacy principles, and aimed at students in the 1º course of ESO.
• To analyze initial results from the implementation of the teaching sequence, as well as students’ evaluations regarding their learning, the activities carried out, and the puzzles that make up the escape box.

Following the stated objectives, the research questions were formulated:

• To what extent does the gamified teaching sequence promote student motivation and understanding of marine plastic pollution from a One Health perspective?
• What are students’ perceptions regarding the learning activities and the puzzles involved in the escape box?

In addition, the learning objectives of the sequence were aligned with specific competencies defined in the Spanish curriculum for 1º ESO: identifying the environmental, human, and animal impacts of plastic pollution, proposing collective actions to address marine pollution from a sustainability perspective and developing the ability to critically evaluate the consequences of individual actions on ecosystems.

3. Literature Review

3.1. Theoretical Design Principles: Transformative Environmental Education, One Health, and Ocean Literacy

Humanity is currently facing an unprecedented environmental crisis that threatens the stability of the natural systems that sustain life on Earth. This situation has been conceptualized through the framework of planetary boundaries, proposed by Rockström et al. [3] and later updated by Steffen et al. [4], which identifies nine fundamental biophysical processes whose balance is essential to maintaining safe operating conditions for humanity. These include climate change, biosphere integrity, biogeochemical cycles of nitrogen and phosphorus, ocean acidification, freshwater use, land-system change, atmospheric aerosol loading, chemical pollution, and stratospheric ozone depletion. At present, several of these boundaries have been significantly exceeded, particularly those related to climate change, biodiversity loss, and disruptions to the nitrogen and phosphorus cycles [15].

Marine ecosystems—which cover more than 70% of the planet—are not exempt from this situation. Threatened by pollution, overfishing, ocean acidification, and global warming, these systems play a crucial role in climate regulation, food provision, and biodiversity conservation. In light of this scenario, urgent educational action is needed to promote a systemic understanding of these issues and to foster a transformation toward more sustainable societies.

TEE is grounded in a critical view of the world, promoting awareness that mobilizes students toward action [16]. It does not merely involve learning about the environment, but rather frames it as a field of social, economic, political, and cultural tensions. According to Milanés et al. [8], this perspective enables students to identify the structural causes of socio-environmental problems and actively participate in the construction of solutions. In this way, it becomes an educational tool for social change, contributing to the development of values such as environmental justice, intergenerational solidarity, and shared responsibility.

In the same vein, Escorcia and Orozco [17] propose a set of guiding principles for truly TEE. These include embracing the totality and complexity of environmental problems, interdisciplinarity, territorial contextualization, active and leading student participation, critical educational practices, the collective construction of knowledge, and an ethical and political dimension committed to social transformation. These principles position the learner as an agent of change and promote a critical and engaged ecological citizenship.

This approach aligns with the concept of One Health, which recognizes the interdependence between human, animal, and environmental health [11]. From this perspective, educating about issues that affect the marine environment—such as plastic pollution or ocean acidification—entails not only ecological concern but also a holistic understanding of planetary health and its implications for future generations. This approach is essential within the framework of Environmental Education, as it allows for an understanding of how disruptions to marine ecosystems, such as plastic pollution, can have direct consequences for human health. For example, the ingestion of microplastics by marine organisms can introduce contaminants into the food chain, affecting people who consume seafood [18].

Since 1950, global plastic production has increased exponentially, reaching 461 million tons in 2021 [19]. It is estimated that between 1950 and 2017, approximately 9.2 billion tons of plastic were produced, of which around 7 billion became waste, much of it poorly managed [20]. Each year, between 4.8 and 12.7 million tons of plastic end up in the oceans, severely impacting marine ecosystems [7]. The Great Pacific Garbage Patch—a massive accumulation of plastic waste—covers an estimated surface area of 1.6 million square kilometers, roughly three times the size of Spain [21].

Plastic pollution affects more than 1300 animal species, including seabirds, turtles, and marine mammals, which may ingest or become entangled in plastic debris [19]. Additionally, microplastics have been detected in European rivers such as the Ebro, in consumer products, and even in human tissues, raising concerns about their long-term health effects [22].

Ocean Literacy, defined as the understanding of the ocean’s influence on us and our influence on the ocean [23], provides a key pedagogical framework for addressing current challenges related to marine ecosystems, such as the issue of microplastics. The principles of Ocean Literacy have been reviewed by the National Oceanic and Atmospheric Administration (NOAA) [24] and have been applied in several countries to strengthen the connection between Ocean Literacy and school education [25]. Its seven fundamental principles provide a structure for an educational approach that links science, values, and civic action:

(1)

Earth has one big ocean with many features

(2)

The ocean and life in the ocean shape the features of Earth.

(3)

The ocean exerts a major influence on weather and climate.

(4)

The ocean makes Earth habitable.

(5)

The ocean supports a great diversity of life and ecosystems.

(6)

The ocean and humans are inextricably interconnected.

(7)

The ocean is largely unexplored.

These principles translate into educational competencies that promote systems thinking, informed decision-making, and active participation in the protection of the marine environment [12]. Fostering Ocean Literacy in the classroom not only means learning about the ocean but also cultivating a sense of belonging and responsibility toward global commons.

Finally, the Sustainable Development Goals (SDGs), proposed by the United Nations in 2015 as part of the 2030 Agenda for Sustainable Development, provide a global framework for addressing the major challenges of the 21st century. SDG 14, “Life Below Water,” calls for the conservation and sustainable use of oceans, seas, and marine resources. This goal emphasizes the importance of ocean ecosystems for climate regulation, biodiversity, and food security.

Three specific targets under SDG 14 are particularly relevant: Target 14.1 and Target 14.3, which refer to reducing marine pollution—especially from plastics and nutrients—and minimizing ocean acidification, mainly caused by increased carbon sequestration resulting from greenhouse gas emissions. Target 14.2 is directly related to restoring the health and productivity of the oceans [26].

In the field of education, Target 4.7 under SDG 4 proposes that by 2030, all learners should acquire the knowledge and skills needed to promote sustainable development. This includes, among other aspects, education for sustainability, respect for cultural diversity, the promotion of a culture of peace, and global citizenship [11].

Although this teaching proposal is designed in line with the Spanish national curriculum for 1º ESO, it is grounded in international frameworks that address global environmental challenges. These include the Sustainable Development Goals (SDGs), the One Health approach, and Ocean Literacy principles, all of which are universally applicable and transferable. However, the sequence was adapted to the local curricular context and to the specific socio-environmental realities of the province of Cádiz (Spain) a coastal region directly affected by marine pollution. This contextualization aims to foster meaningful learning by connecting global issues with students’ lived experiences [12].

3.2. Gamification as an Active Methodology and the Escape Box as a Teaching Resource

The use of gamification in science education has generated growing interest as an alternative and creative pedagogical approach to enhance student engagement and learning outcomes—particularly in understanding scientific knowledge, which is often highly abstract [27,28]. Gamification, understood as a learning strategy, involves the incorporation of game design elements into non-game contexts. It applies mechanics such as point systems, badges, leaderboards, and challenges aimed at encouraging specific behaviors and motivating learning [29].

Given the positive results of implementing gamification in educational settings, there is an emerging interest among teachers in designing and applying so-called “serious games.” Among these, escape rooms and their variants—referred to here as escape boxes—stand out as tools for activating curricular knowledge [30]. In the literature, terms such as “escape room”, “breakout box”, and “escape box” are sometimes used interchangeably, but they refer to different formats. The “escape room” typically requires a dedicated space and immersive setup, while the “breakout box” or “escape box” involves unlocking a sequence of boxes through puzzles and can be implemented within a standard classroom. In this article, we use the term “escape box” as the primary format employed in our teaching proposal, considering it equivalent to the breakout box and distinct from the escape room. The goal is to foster active teaching, to be more engaging for students, and to be oriented toward collaborative and creative problem-solving [31]. According to Martín-Queralt and Batlle-Rodríguez [32], gamification aims to design interventions tailored to student groups with diverse interests, needs, and abilities. Sánchez [33] defines the educational escape room as a physical and mental game that transforms the classroom into an adventure setting, where students must collaboratively solve a narrative to escape within a limited time. To do so, students discover clues, solve puzzles, and overcome challenges to exit the room. Two key aspects are particularly important: teamwork is essential to solve the puzzles [34], and the challenges must be directly related to the curricular knowledge and competencies addressed in the classroom [35].

At the same time, digital adaptations exist that use applications like Genially, allowing students to solve puzzles and decipher codes online [36,37]. However, Carrión Candel and Mortimore [38] note some limitations in the use of escape rooms in educational contexts, mainly related to infrastructure requirements such as cameras, monitoring systems, and multiple physical spaces. As a viable alternative, escape boxes have been proposed. These focus on opening a series of locked boxes by solving puzzles, riddles, or challenges, rather than escaping a physical room [31]. Breakouts offer additional advantages. According to Martínez-Carmona et al. [39], the materials are easier to transport, can be used with multiple groups at the same time, adapt better to classroom spaces, and encourage collaborative rather than competitive designs.

Other proposals, such as the one by Yllana-Prieto et al. [13], combine both tools by designing a “BrEscapeRm” for teaching STEM content in initial teacher education. The integration of escape rooms into pedagogical strategies aligned with the STEM perspective is also evident in initiatives like the one developed by Soto Calderón et al. [40], which recreates the laboratory of scientist Marie Curie and immerses students in the scientific work environment. In other initiatives described by Ouariachi and Wim [41], students learn to use computational thinking language and design 3D-printed models, integrating science and technology.

Douglas and Brauer [42] highlight the high educational potential of gamification as a strategy to promote pro-environmental behavior. It has recently been used to address a wide range of socio-environmental issues such as reducing energy consumption, promoting sustainable mobility, improving air quality, managing waste efficiently, and conserving water resources. In a study with pre-service teachers, Carrión Candel and Mortimore [38] reported positive results when using an online breakout to teach theoretical content related to the SDGs and the 2030 Agenda. The study revealed a high level of acceptance of gamification as a strategy and the breakout as a teaching resource in higher education. Participants found the tool to be attractive, interesting, and useful for learning highly theoretical content.

Recent studies also emphasize the versatility of escape rooms in fostering critical thinking and collaborative learning in diverse educational settings. For example, Fagundo-Rivera et al. [43] highlight their value in higher education for promoting engagement and problem-solving among nursing students, while Sidekerskienė and Damaševičius [44] argue that digital escape rooms can serve as metaphors for removing barriers in STEM education by encouraging inclusive and out-of-the-box learning.

An exploratory study conducted by Ouariachi and Wim [41] analyzed two modalities of educational escape rooms used to address climate change: those designed by teachers and those created by students themselves. In both cases, the primary goal was to improve understanding of strategies to mitigate climate change at individual and collective levels, as well as its potential environmental consequences. However, the authors emphasize the need for further research to assess the effectiveness of escape rooms in generating transformative changes in students, especially given the complexity of the issue.

Meanwhile, Sajan and Sapkota [45] propose a gamified intervention based on a reward system inspired by the Pokémon game, which enables students to address biodiversity loss and the growing disconnection between youth and nature. Framed within a citizen science program, this initiative yielded positive results in supporting conservation efforts and promoting active participation in protecting local biodiversity.

Regarding the implementation of escape rooms and breakout boxes in educational contexts, Nicholson [34] describes different formats depending on their didactic purpose. These formats are distinguished by the relationship between the puzzles and their interconnection in solving the final challenge. One of the simplest formats is the “sequential” model, in which the challenges must be solved in a specific order, with the completion of one task being a prerequisite to access the next.

Martínez-Carmona et al. [39] propose a guide for the design and implementation of breakouts in science education, identifying the following key elements:

• Narrative: A narrative structure that contextualizes the experience and links the challenges and puzzles, promoting student immersion.
• Challenges adapted for educational use: Clear definition of the didactic goals, specific competencies, and core knowledge involved, allowing students to apply what they have learned in contextualized situations.
• Clues: Design of puzzles appropriate to students’ level of knowledge to maintain their engagement. Anticipation of potential difficulties and development of hints or aids to support problem-solving without revealing the answers.
• Cost and availability of materials: Prioritization of low-cost and easily accessible materials, encouraging reuse and the creation of a resource bank for use across different courses.
• Initial trial: Carrying out a pilot test of the design to ensure the proper functioning of the challenges and the suitability of the estimated duration.
• Post-activity reflection: After completing the breakout, it is essential to discuss the experience with the class group in order to connect the different puzzles (especially those that proved more difficult) and to make the learning outcomes explicit.

In this context, the use of escape rooms represents an innovative educational resource that makes it possible to operationalize the principles of Transformative Environmental Education. Its potential lies in fostering active participation, collaboration, the collective construction of knowledge, and the application of learning to real-world problems such as marine plastic pollution. When these challenges are contextualized in scenarios related to ocean health and its interactions with human health, an ideal space is created to work from the One Health perspective.

As noted by the Spanish Ministry of Education and Vocational Training [46], playful methodologies such as escape rooms “allow students to actively participate in the construction of their own learning process […] by facing challenges that require the application of knowledge to real situations” (p. 34). These experiences not only promote meaningful and motivating learning but also position students as agents of change in the face of complex socio-environmental challenges.

In educational settings, gamification has demonstrated the capacity to foster learning by integrating emotional, cognitive, and social dimensions. The inclusion of playful elements, such as challenges, narrative structure, and hands-on materials, not only increases student motivation but also promotes cooperative work and deeper engagement with curricular content. According to Douglas and Brauer [42], gamification supports pro-environmental behavior through affective involvement, while Sánchez [33] and Martín-Queralt and Batlle-Rodríguez [32] emphasize the importance of teamwork and narrative immersion as key to learning. In the context of science education, these elements facilitate the integration of complex concepts, especially when students are actively involved in solving problems and connecting them with real-world issues, as occurs in the escape box format.

4. Methodology

This work adopts a methodological approach closely aligned with Design-Based Research (DBR), which seeks to understand how, when, and why educational innovations function in real-world settings [47]. Accordingly, the study focuses on the design and implementation of a Teaching and Learning Sequence (TLS). The TLS is structured around a constructivist-oriented learning cycle, inspired by the proposals of authors such as Sánchez Blanco and Valcárcel [48] and Sanmartí [49], which allows the TLS to be organized into several differentiated phases: (a) initiation and exploration of students’ ideas, (b) introduction of new knowledge and conceptual restructuring, and (c) application and review of knowledge. These phases align with approaches inspired by the pioneering work in science education by Driver and Oldham [50] on conceptual change. Similar learning cycles have been used in the design of teaching proposals to address issues such as ocean acidification [51].

4.1. Context and Participants

The TLS was implemented in the charter school “San Ignacio Salesianos” Secondary School in Cádiz (Spain) during the third trimester of the 2024/2025 academic year, as part of the Biology and Geology subject in the 7th-grade classroom (1º ESO). It was carried out by the researcher (first author of the article) in collaboration with the tutors and subject teachers. A total of 79 students participated—35 girls and 44 boys—aged between 12 and 13 years, from three class groups (A, B and C). The school is located in an urban area, on the edge of the historic city center and very close to the local beaches. Participants were selected through non-probability sampling, based on the authors’ accessibility to the school and the educational stage targeted by the designed teaching sequence.

4.2. Description of the TLS and Curricular Connection

In accordance with the learning cycle used as a didactic model, the TLS was structured into three sessions, each lasting 50 min.

Table 1. Teaching and Learning Sequence designed and implemented around marine pollution in three 1º ESO class groups.

Sesion	Didactical Intention	Activities	Specific Competencies and Core Knowledge	Grouping
1	Activate students’ prior knowledge about the topic of marine pollution. Introduce Ocean Literacy and the One Health perspective as reference frameworks for the sequence.	Act.1. Introduction to the topic: the oceans and the Ocean Literacy movement. SDG 14 and its targets as the framework for the sequence. Act.2. Exploration and explicit expression of prior knowledge about ocean plastic pollution through newspaper articles and an activity on types of waste that reach the sea and the time required for their decomposition. Act.3. Word network: What other (socio)environmental problems do you know that may affect the ocean besides massive plastic generation? Act.4. Introduction to the One Health perspective (three dimensions: environmental health, animal health, and human health) as an alternative for change.	Specific Competencies: SC1: Identify and describe elements of the physical environment. SC4: Analyze local environmental problems. SC3: Develop awareness of the impact of human activity. Core Knowledge: D.4: Water pollution: causes, consequences, and solutions. E.7: Factors affecting biodiversity. D.8: Responsible behavior regarding the use of water and air. B.1: Care for living beings and responsible consumption. C.4 (CCEC): Critical analysis of human actions on the environment.	WT/CG
2	Introduce new concepts and restructure prior ideas through an escape box centered on the narrative of a marine biologist specializing in sea turtles, who loses her work suitcase and asks the class for help to find one of the turtles she is studying.	Act.5. Escape box Initial puzzle to open the suitcase Types of plastics Plastic buoyancy Acidification of seawater Plastic sizes and presence in trophic levels Final puzzle	Specific Competencies: SC4: Identify human impacts on the environment. SC5: Participate in solving socio-environmental problems. Core Knowledge: E.6: Matter cycles and energy flow in ecosystems. E.8: Appreciation of biodiversity and the need for its conservation. C.2: Collective responsibility toward sustainability. C.5: Cooperative and solidarity-based participation.	WT
3	Apply new ideas, review the puzzles, and reconnect with the One Health perspective. Evaluate the activity sequence in terms of learning, motivational components, and introduce improvement proposals.	Act.6. Review activity (I): Relate each puzzle to one of the dimensions of the One Health perspective (environmental health, animal health, and human health). Act.7. Application activity: Card game to understand the consequences of our actions and raise awareness of environmental impact. Act.8. Review activity (II): Final questionnaire to evaluate the TLS.	Specific Competencies: SC3: Propose measures to improve the environment. SC5: Communicate in a reasoned and coherent manner. SC6: Adopt responsible and supportive attitudes. Core Knowledge: A.1: Inquiry strategies characteristic of scientific work. A.5: Recording and communication of results. D.4: Water pollution. C.3: Critical thinking and conflict resolution. C.6: Ethical commitment to the common good.	WT/CG/I

WT: Work Team; CG: Class Group; I: Individual.

presents each session along with the designed activities, didactic intentions in line with the teaching objectives specified above, student grouping, and their curricular alignment according to the national regulatory framework for the target educational stage [52].

In sessions 1 and 3, students from each class group were organized into six working teams (WTs) of four members each, and into four working teams of six to seven members, respectively. Throughout the TLS, moments for whole-class discussions were incorporated to promote the social construction of knowledge.

The TLS was implemented at the beginning of June, at which point the three class groups had already covered topics such as the hydrosphere, ocean currents, and pollution. Thus, the TLS was designed as an opportunity to integrate prior knowledge while also introducing students to new content that would be addressed in the following academic year, such as ocean acidification.

Session 1 consisted of initiation activities and the exploration of students’ prior ideas, as well as contextualization of the TLS. In this session, students were introduced to Ocean Literacy as a framework through its seven principles (Act.1). The Sustainable Development Goals (SDGs) were also presented, with special focus on SDG 14 (Life Below Water), particularly on Target 14.2.

Activity 2 aimed to identify and make explicit the students’ prior ideas about plastics and their understanding of plastics as a relevant socio-environmental issue. First, two newspaper articles related to the local context were presented to the class. Then, students participated in a dynamic activity to raise awareness about the diversity of waste types and the time it takes for them to decompose in the marine environment.

Activity 3 was designed to explore other possible socio-environmental problems that students of this age might be familiar with and consider affecting the oceans. Each team received several colored post-it notes, and each student proposed a socio-environmental issue. Afterwards, the class shared their ideas and placed only the different ones on a large mural (Figure 1).

In Activity 4, the teacher (first author) introduced the One Health perspective, highlighting the interdependence between humans, animals, and their social and ecological environments [53]. Then, based on the problems identified by the students in the previous activity, the class grouped them into three main categories: those connected to animal health, environmental health, and human health, establishing links between them.

Session 2 includes activities aimed at introducing new knowledge and restructuring ideas through the escape box as the main resource (Activity 5). The objective is to introduce scientific concepts such as buoyancy, the increase or decrease in seawater pH [54], the presence of plastics of various sizes, and their bioaccumulation in the food web [55]. The escape box follows a linear design, with an ordered sequence of challenges, where the final puzzle must be solved in collaboration with another team [56].

To enhance immersion in the game, the session begins with an audio message from a fictional Colombian marine biologist, “Karla Georgina,” which helps to contextualize the narrative and give meaning to the final mission (https://goo.su/yNA7GU) (20 May 2025).

The storyline focuses on the search for a sea turtle (Anita) through the resolution of various puzzles, each related to a different dimension of the One Health perspective (

Table 2. Description of the puzzles designed for the escape box.

Puzzle and Connection to One Health	Description	Type of Lock and Code	Image
Opening the Suitcase	Identify types of invertebrates. Crustaceans: lobster and crab. Echinoderms: starfish and sea urchin. Mollusks: clam, mussel, and conch.	Entry Code: none Exit Code: three-digit numeric lock: 2-2-3.
Types of Plastics (Environmental Health)	Identify different types of plastics and symbols to classify them according to their ease or difficulty of recycling. The numbers are visible under ultraviolet light.	Entry Code: none. The clue is found in the marine biologist’s field notebook. Exit Code: four-digit numeric lock: 4-3-2-1
Plastic Buoyancy (Animal Health)	Understand the buoyancy of certain types of plastics in water.	Entry Code: 4-3-2-1 Exit Code: CPET. Four-letter lock, formed by the initial of the type of water plus the name of the type of plastic that sinks.
Ocean Water Acidification (Environmental Health)	Determine the pH of different solutions and interpret a table with values related to the acidification process in plastic patches.	Entry Code: CPET Exit Code: Opens a cryptex with the name of the plastic patch with the highest acidity: “INDICO”.
Plastic Sizes and Their Presence in Trophic Levels (Human Health)	Raise awareness of the presence of different sizes of plastics in the marine environment and their bioaccumulation across various trophic levels.	Entry Code: colored key Exit Code: four-digit numeric lock (3-4-3-4)
Final Puzzle	Find a microbit card containing information about the location of the sea turtle “Anita”.	Entry Code: 3-4-3-4

).

Each team begins with a suitcase locked with a three-digit combination padlock. Inside, there are additional boxes, an envelope, and a map with coordinates glued to the interior of the suitcase (Figure 2a). The map shows the various plastic patches or “islands” that the sea turtle will travel through. Students can learn about these areas through hidden messages—used as clues—found inside the different boxes.

The suitcase also contains additional objects to enhance immersion in the game, such as clothing and a passport belonging to the marine biologist who presents the story. One essential item for solving the second puzzle is the marine biologist’s field notebook (Figure 2b).

Session 3 allows students to apply ideas and review new learning. In Activity 6, each team receives a worksheet summarizing the escape box puzzles, with the aim of establishing connections between the puzzles and each dimension of the One Health perspective. Activity 7 is an application task that uses cards designed by the authors. On one side, the cards display information about everyday actions, while the other side shows the environmental impact generated by each action (Figure 3). The goal is to raise students’ awareness that every action we take has an environmental impact—and that one of the most sustainable actions is to reduce many of these behaviors.

In Activity 8, each student reflects on their learning, both cognitively and emotionally, as well as on the sequence itself, with the aim of evaluating the usefulness of the TLS. To do this, students are given a final questionnaire consisting of five questions: three closed-ended and two open-ended (Appendix A). A descriptive approach was used to analyze the Likert-type responses. Relative frequencies were calculated for each item. For the qualitative analysis, both researchers conducted a thorough reading of the responses. A thematic coding process was then carried out to identify emerging categories. Any discrepancies were resolved through consensus to ensure the reliability of the process. Finally, frequencies and percentages were calculated. Python 3.10, with the Scipy 1.8 and Numpy 1.26 libraries, was used for data processing.

Additional data collection instruments include written student work from Sessions 1 and 3, the field diary of the researcher who implemented the TLS, and observation notes recorded by the tutor of each class group. This information is considered highly valuable for assessing the quality of a teaching intervention [57].

5. Results and Discussion

In this initial analysis, data from the three class groups were examined collectively, as the SEA was implemented by the same instructor across all groups. This approach allowed for a unified interpretation of the results.

5.1. Analysis of the Outcomes from the Implementation of the SEA

In the first SEA session, time was devoted to exploring students’ prior conceptions about the importance of the oceans and plastic pollution. A high degree of concern and interest was observed among the students. Some expressed general apprehensions about the topic, with responses such as “it’s getting hotter every year”, and many perceived the overall situation of the planet as serious. Others linked the topic to phenomena observed in their daily lives, such as “there are more algae on the beach” or “I got stung by a jellyfish at the beach”, raising questions about the causes of these events. Most students reported being familiar with the SDGs, stating they appear in their textbooks, although they were less clear about the number of goals or their specific targets. This initial approach highlights the need for sustained pedagogical work to shift from a utilitarian to an ecocentric paradigm [58], which represents a key challenge for TEE.

When exploring students’ perceptions of the oceans’ importance (Activity 2), their responses revealed a predominantly utilitarian perspective aligned with an anthropocentric worldview, rather than an ecocentric understanding of the environment [59]. This initial standpoint provides an opportunity to work toward constructing a non-anthropocentric paradigm in students, which is foundational for fostering a more sustainable and harmonious relationship between humans and nature [58]. From this perspective, Earth is assumed to have its own rights and is not merely viewed as a source of extractable resources for human benefit. Some student responses included comments such as “because it gives us food” or “because we go swimming at the beach”. This served as a relevant starting point to introduce the principles of ocean literacy, particularly the notion of the ocean’s intrinsic ecological value as an ecosystem.

Regarding plastic pollution, the news articles used during the session successfully connected the issue to students’ experiences. Many were particularly struck by the so-called “plastic islands.” This sparked questions about the origin of oceanic waste and broader issues, such as waste management alternatives, with student inquiries like: “Why don’t they bury the waste?” or “Why don’t they send it to space?” This discussion demonstrated a clear connection between the topic of waste and students’ interests.

The second part of Activity 2 elicited widespread surprise when students were asked to associate different types of waste with their respective decomposition times in marine environments. This activity proved effective in providing concrete information about the difficulty of recycling certain waste types. Recycling and changes in the energy model are usually the most common solutions proposed by students at this educational stage to address environmental problems such as climate change [60], often at the expense of other approaches like altering food systems. In general, secondary and high school students struggle to identify concrete actions to mitigate climate change [61]. These reflections were especially valuable for the researcher in preparation for Activity 7, which aimed to emphasize more environmentally sustainable practices such as waste reduction over reuse or recycling. Activity 2 also served to convey specific information about certain types of waste, such as the accumulation of cigarette butts on beaches or, as addressed in the escape box, the impact of plastic bags on the health of marine animals like turtles. At the end of the activity, students’ reflections included statements such as: “Waste takes longer to decompose than we thought” (S5, GCA) or “Plastic and other waste are more harmful than we imagined. We need to recycle and take care of our ecosystems by reducing plastic use” (S3, GCB).

Activity 4 was relevant for eliciting other socio-environmental problems identified by students, which they believed could affect the marine environment. Figure 4 illustrates the wide variety of issues proposed by the students. A total of 30.2% referred to marine pollution from ships, mainly due to oil or fuel spills. The second most cited issue was pollution from various types of waste (17.5%), likely influenced by prior classroom activities. Global warming was the third most frequently mentioned problem (14.3%), although students tended to refer more specifically to polar ice melt, which is a consequence rather than a direct environmental issue. These results show that students tend to identify visible and highly publicized impacts, such as oil spills, highlighting the need to address less apparent impacts as well, including microplastics and ocean biochemical changes.

After introducing the One Health perspective in Activity 5, students clearly began to connect the identified socio-environmental problems with the three key dimensions: human health, animal health, and environmental health. They reached the conclusion that we are all interconnected and that it is appropriate to speak of “one single health.”

During Session 2, the escape box activity was carried out following a similar procedure across the three class groups. Before the activity began, the class tutors organized the student teams, while the researcher prepared the suitcases in the classroom. This immediately generated great excitement among the students upon seeing the materials.

Subsequently, the researcher introduced a few guidelines regarding the proper use of the materials, encouraged students to carefully read the clues in order to access the boxes, and reminded them they could ask for help if they got stuck or did not understand a part of the activity. It was also emphasized that the escape box followed a linear format (Figure 5), meaning it was not possible to open all the boxes at once, but rather they had to be unlocked sequentially. The activity officially began with an audio recording from the marine biologist, setting the stage for immersion into the narrative of the game.

Excitement and motivation were clear both before and during the game; in some cases, the excitement levels among certain students (ET) became excessively high, prompting both the tutors and the researcher to intervene repeatedly to calm them down and remind them that it was not a competition. It was observed that some puzzles were more difficult than others, particularly the first lock that granted access to the suitcase. Some students took up to ten minutes to unlock it, as they were unable to identify marine invertebrates or failed to connect the suitcase illustrations with the lock mechanism; in such cases, they requested help. Additionally, it was noted that those students who took the time to read and follow the field journal were more successful in understanding the sequence of puzzles.

Other difficulties emerged, particularly in class group B, the last group to carry out the escape box activity, due to the deterioration of some materials, especially the trophic level puzzle. The items for this puzzle were stored in a paper envelope which, despite being sealed with a lock, could be opened without a key due to the fragility of the material. This issue should be addressed in future implementations, as students may misuse the materials even if clear rules are provided beforehand.

Another critical moment occurred during the final puzzle, which involved identifying the precise location of the turtle “Anita.” Students realized that they needed the help of another team, as the Micro:bit card consisted of two parts: the board and the battery. At this point, it was observed that some teams were eager to assist and speed up others so that the mission could be completed more quickly. This issue was addressed in the final discussion, as each team was free to use their own time and solve the puzzles independently.

One of the most significant limitations observed during the activity was the internal organization of the student teams. In some cases, students were not satisfied with the group members they had been assigned, which negatively impacted on their motivation and engagement in the game. This is a complex issue to address, particularly at this age, as tutors formed the groups based on their own pedagogical criteria. However, in this instance, the arrangement proved suboptimal, leading to disengagement among some students during the session. In fact, several students explicitly voiced their dissatisfaction after the activity.

On the other hand, several positive aspects were also observed. Many students expressed enjoyment while using micropipettes, opening water bottles to test plastic buoyancy, using magnifying glasses or ultraviolet pens, or witnessing the color change of liquids when testing acidity. Some students dressed up with the costumes provided in the suitcase, fully immersing themselves in the game. Items such as the cryptex, the variety of locks, and the puzzle boxes were particularly well received. Their expressions of amazement and satisfaction upon solving each puzzle highlight the potential of escape boxes to foster student engagement and interest, as supported by similar studies [12]. Beyond their playful nature, this enthusiasm represents a powerful gateway to scientific literacy, provided it is followed by reflective discussion that connects the experience with scientific knowledge.

Ultimately, all student teams were able to complete the game within an average of 40 min. The remaining class time was used to reflect on the activity, which was generally very well received by both students and tutors.

Regarding the development of Session 3, Activity 6 served to link each puzzle to one of the dimensions of the One Health perspective. Figure 6 shows the initial responses provided by the 17 students. In general, students successfully connected each puzzle with at least one of the One Health dimensions. However, they tended to associate each puzzle with one specific type of health more than with others. For example, 88.2% linked Puzzle B with animal health, likely due to information provided by the teacher and discussions held in prior activities (Session 1), which emphasized the danger of certain types of waste that may be mistaken for food by marine animals—such as plastic bags being confused with jellyfish by sea turtles.

Puzzles A and C were most often associated with environmental health (70.6% in both cases). Puzzle D was linked to both animal and human health, likely because students repeatedly referred to the idea that fish ingest microplastics, which then enter the human food chain. This concept appeared to be readily understood by students; however, there was evidence that the concept of bioaccumulation was not fully grasped, likely due to its abstract nature. Further instructional efforts will be necessary in later courses to address this concept in depth, possibly through the use of visual aids or other concept exploration strategies [62]. In this regard, various studies have reported positive learning outcomes when teaching bioaccumulation through games to students aged 13 to 15. Along with biomagnification, these concepts tend to pose significant learning challenges [63]. According to these authors, understanding these processes is essential to comprehending the environmental impact of human activities.

Activity 7 proved useful for revisiting the information shared during the collective discussion in Activity 3 (types of waste and their decomposition times in the marine environment), since many waste products are composed of multiple materials, for example, milk cartons, which significantly hinders their recycling. This activity captured students’ attention, as many of them reported not being aware of the environmental impact of common everyday actions described in the cards, such as “playing video games,” “shopping on Amazon,” or “using TikTok and other social media platforms.”

On the other hand, the activity also prompted reflection on possible alternatives for action. Some students began to express a sense of frustration or helplessness with remarks such as “everything I do pollutes” or “what can we do? is there nothing we can do?” These reactions may be interpreted as early signs of eco-anxiety, which highlights the need to promote feasible sustainable practices grounded in students’ immediate surroundings [64].

Therefore, it was important to facilitate a discussion around actionable solutions. The “3Rs” were addressed, reduce, reuse, and recycle, since most students were already familiar with them. However, previously observed conceptual tendencies re-emerged, with students typically prioritizing recycling as the main strategy. As such, it is essential to encourage students to reflect on the importance of more impactful measures such as reducing consumption and critically examining the dominant consumption model, in favor of more conscious behavior focused on real needs.

5.2. Students’ Evaluation of the SEA

The final questionnaire (Activity 8) provided valuable information regarding three key aspects: perceived learning, evaluation of each activity, and assessment of the puzzles (Appendix A). With respect to perceived learning, the results indicate that students felt they had acquired relevant knowledge as a result of the SEA implementation (Figure 7).

The most highly rated statements were, “I understand how plastics reach the ocean and affect animals”, which received a high percentage of responses in the “Quite a lot” and “Very much” categories, 21.8% and 35.9%, respectively, and “I know that the health of the ocean is connected to our own”, which received 19.5% and 32.8% in the same categories. These results suggest that students developed a strong understanding of the connection between marine pollution and the One Health perspective as a result of the SEA.

In contrast, the statement “I understand that plastics reaching the ocean can break down into particles so small that they can accumulate at various levels of the marine food chain” received slightly lower ratings, with more responses falling into intermediate categories. This may indicate that this concept is more abstract and complex, requiring instructional designs that specifically address such learning difficulties [62]. This finding aligns with students’ responses in Activity 7, which also highlighted the need for a higher level of abstraction—suggesting that this topic may be more appropriate for treatment in later school years.

Regarding the evaluation of the activities, the results indicate that they were generally well received by the students. In particular, Activity 2, “Viewing images and news about ocean pollution” and “Estimating how long different types of waste take to decompose in the environment”, stood out, with 65.4% and 64.1% of students, respectively, selecting the “I liked it” option, and very few negative responses.

Activity 3, “Word network”, while still positively evaluated, showed a more balanced distribution of responses, with a higher proportion of “So-so” ratings (29.6%) compared to the other activities. This suggests that, although interesting, it may not have been as appealing from a visual or playful standpoint.

Lastly, Activity 7, “Card game about the impact of our daily actions”, received the highest average rating (73.1%), reflecting a strong positive preference among the students.

Finally, regarding the evaluation of the six puzzles used in the gamified SEA, students were asked to assess each one in terms of fun, difficulty, and originality. Overall, all puzzles were considered more fun than boring, with a clear tendency toward “Medium” and “High” ratings on the fun scale (Figure 8). This suggests that the storyline and challenge format were effective in maintaining student engagement—an impression confirmed by classroom observations from both the researcher and the class tutors. This balance between difficulty and enjoyment supports Duggins’ claim that moderately challenging tasks stimulate collaboration without undermining motivation [30].

In terms of difficulty, the results were balanced: some puzzles were perceived as accessible, while others presented a greater challenge. This variety can be seen as a positive feature, as it encourages group work and collaborative problem-solving. The originality dimension stood out in particular. Most puzzles were considered highly original, reinforcing the idea that the proposed dynamics were both novel and engaging for the students.

The puzzle evaluations were further complemented by students’ answers to Question 4 of the questionnaire, which was open-ended. Their responses were grouped into four categories. In this question, students were asked what they would improve about the activities. A total of 46.2% of the responses indicated that they would not change anything, with comments such as: “It was really good, and I also learned a lot—so I wouldn’t improve anything” (S34) or “I wouldn’t change a thing, I’d leave it as it is because it’s really fun” (S4).

About 24.4% of the responses suggested improving the materials, clues, or the storyline: “I would improve the escape room by adding more clues” (S28) or “Check the condition of the materials” (S1), which echoes issues identified after the activity was completed. Another aspect mentioned in 12.8% of the responses related to improving teamwork and group organization. For instance, some students said: “Let students choose their own teams” (S39) or “Allow us to choose the classmates we want to work with” (S12), which aligns with previous observations and post-activity feedback. For some students, group composition was a decisive factor in their ability to fully engage with the escape box experience.

Lastly, 16.7% of students referred to the duration of the activity and the strategy used, with comments such as: “It should last longer and be done in other classes too” (S23), reflecting the overall enjoyment and satisfaction expressed by the students regarding the SEA.

6. Final Conclusions and Improvement Proposals

The results obtained allow us to conclude that the SEA designed and implemented has been effective in promoting, among 1º ESO students, a deeper and more critical understanding of marine plastic pollution from a systemic perspective aligned with the principles of TEE, Ocean Literacy, and the One Health approach. The gamified proposal, based on the use of an escape box, generated high levels of emotional and cognitive engagement, fostering a meaningful, immersive, and collaborative learning experience. Student feedback, both in terms of knowledge acquisition and motivation and enjoyment, confirms the educational potential of this type of resource for addressing complex socio-environmental issues. Although this study focused on analyzing students’ perceptions through self-reported data, it is acknowledged that this approach may be influenced by social desirability bias. However, additional sources of data, such as the researcher’s field diary and the class tutors’ observation notes, were also collected and are expected to be analyzed in greater depth in future studies. Due to space constraints, these materials were not included in the present article, but they will contribute to a broader triangulation of findings regarding the educational impact of the SEA.

Among the most consolidated learning outcomes were students’ understanding of the connection between the health of marine ecosystems and human health, and the identification of the impact of plastic pollution on marine biodiversity. Furthermore, the activities allowed for the explicit expression of students’ prior conceptions, often anthropocentric in nature, which in turn created valuable opportunities to progress toward a more ecocentric worldview, as suggested by Simón Medina [58]. Integrating the escape box into a SEA structured around a specific science education learning cycle proved essential to ensuring conceptual progression, emotional engagement, and collective reflection, all of which are key elements in educational proposals with a transformative orientation.

However, both the qualitative and quantitative analyses of the data collected also revealed areas for improvement that can help optimize future implementations. First, it is recommended to review the quality and durability of the materials used, particularly those subject to intensive handling, such as envelopes, locks, or game cards. Regarding potential improvement proposals to address the durability of the materials, it is important to note that one of the main challenges in this study was, without a doubt, the large number of teams and students per class group, as well as the fact that the sessions were conducted in quick succession. Consequently, there was not enough time to replace all the materials. While in certain specific cases—such as the cryptex and bottles with different solutions for determining pH—these were prepared in advance and could be replaced, other resources, such as paper envelopes or certain types of locks, experienced greater wear.

It is recommended to use homemade, low-cost, and easily accessible materials that can be readily replaced and found at home or in educational centers [65]. Another alternative is to opt for a virtual escape box design by digitizing the clues. This virtual format also allows teachers to better adapt to a student profile that is more accustomed to new technologies and audiovisual formats, thereby increasing interactivity [66]. This involves the use of tablets and applications such as Genial.ly, Escapp, or BreakEdu. Moreover, Ref. [67] highlights the educational potential of virtual escape boxes, which could be combined with a physical format to create hybrid gamified learning environments. Such combinations could serve as an alternative to minimize the cost, wear, and environmental impact of the materials used.

Additionally, group organization was found to significantly influence student motivation and participation. Therefore, it would be advisable to consider more participatory strategies for forming groups or to implement rotation mechanisms. The hybrid format appears to be a good alternative for alternating between individual and collaborative learning as students face different types of puzzles. Veldkamp et al. [68] propose the design of a hexagonal-shaped box, with each student positioned in front of one of its sides to solve the final puzzle. This design would ensure the participation of every student within their team. It is considered an interesting alternative that could address some of the improvement suggestions raised by students in this study, particularly those referring to certain classmates taking a more prominent (and sometimes excessive) role during the game.

Another aspect to take into account is the timing of implementation. As the SEA was carried out at the beginning of June, negative effects were observed due to high classroom temperatures and accumulated fatigue at the end of the school year. Consequently, a concrete improvement proposal is to schedule the intervention a few weeks earlier, preferably in mid-third term, when weather and school conditions are more favorable for active and collaborative learning.

In relation to scientific content, some difficulties were noted in understanding more abstract concepts such as bioaccumulation or the chemical effects of ocean acidification. To support these learning processes, it is recommended to introduce complementary visual resources such as diagrams, simulations, or graphic representations, and to reinforce these concepts in later school years. In this regard, a good example is the proposal by Fauville et al. [69], which involves the use of several interactive and visual resources. On the one hand, a virtual laboratory allows secondary school students to experiment and test the impact of ocean acidification on sea urchin larval development. On the other hand, an open-access animation includes an interactive model that enables students to manipulate variables involved in this process across different scenarios. Both appear to be valuable resources with a significant impact on learning such an abstract concept. Another interesting proposal is the introduction of immersive Virtual Reality as an educational tool. In their study, Markowitz et al. [70] confirmed its effectiveness in teaching the consequences of climate change, particularly ocean acidification, and in fostering greater knowledge and positive attitudes toward the environment.

The absence of a pretest is acknowledged as a limitation in the methodological design of this study. While the results of the final questionnaire indicate a positive student response and perceived learning gains, the lack of baseline data limits the ability to establish a clear causal relationship. It is therefore recommended that future implementations of the teaching sequence include a pretest to enable a more robust assessment of conceptual change.

The richness of the data collected opens up new possibilities for conducting a fine-grained analysis [71] within a Design-Based Research (DBR) framework. Such an analysis would not only validate the design principles underlying the current proposal but also allow for the formulation of new principles (conceived as “modest theories” [72]) in real educational contexts. In this case, they would guide the development of didactic sequences focused on transformative environmental action from a critical, interdisciplinary, and context-sensitive perspective. The aim is to continue along this line, drawing on information gathered from other instruments used (e.g., the researcher’s field diary and the tutors’ observations), which allowed for data triangulation and a deeper exploration of the impact of the designed SEA in view of a second implementation.

Finally, the educational potential of this proposal extends beyond the specific context in which it was implemented. The use of interdisciplinary frameworks such as Ocean Literacy and One Health, as well as the gamified methodology, make this sequence transferable to other national and international educational settings facing similar challenges in environmental education. By adapting the activities to local realities, this approach may contribute to fostering environmental awareness and transformative action in diverse coastal and inland regions worldwide.