Validity of Teaching Modules with Problem-Based Learning (PBL) Model Assisted by E-Book to Improve Problem-Solving Skills on Renewable Energy Material and Implementation of Independent Learning Curriculum

Problem-solving skills are an important basic competency in 21st-century learning through the Merdeka Belajar Curriculum. However, the problem-solving skills of students in Indonesia are still low. Therefore, an effective learning model is needed to improve problem-solving skills, one of which is through the development of teaching modules. This study aims to develop teaching modules based on Problem-Based Learning (PBL) assisted by e-books to improve the problem-solving skills of grade X high school students based on content, construct, and language feasibility. This research uses a development approach with the 4D model, which includes the stages of Define, Design, Develop, and Disseminate. However, this research only focuses on the development stage (Develop) by conducting module validation. The validation was conducted by three validators, namely educational expert lecturers and material expert lecturers. The results showed that the PBL-based teaching module to improve problem-solving skills had met the validity criteria regarding content, construct, and language. By using the mode value, a value of 4 and a validity percentage of 100% were obtained with a very valid category. Therefore, the teaching module developed is suitable for use in trials on students in the learning process to improve problem-solving skills.


Introduction
Education in Indonesia has undergone curriculum changes and improvements over the past few decades.These changes were made to face the challenges and needs of education that continue to evolve and to ensure that Indonesian learners receive quality and relevant education [1][2][3][4][5].Since its independence in 1945, Indonesia has launched several education curricula to fulfill the national goal of improving the quality of education [6][7][8].Each curriculum change seeks to correct the shortcomings found in the previous curriculum, integrate educational innovations, and keep up with global education trends [1,9,10].Until 2021, there have been about ten curriculum changes and improvements in Indonesia.Each change sought to improve learning approaches and methods, integrate local values with global needs, and support the holistic development of student competencies [11,12].The latest curriculum has been formed, known as the Merdeka Belajar curriculum [13][14][15].This curriculum aims to give students greater freedom in determining their learning paths, encouraging active participation, and developing learners' creativity and interests [16][17][18].
Indonesia implemented the Merdeka Belajar Curriculum (KMB) to change the world of education to be active and creative while fostering 21st-century skills [19,20].Learning in the 21st century reflects the importance of developing 4C skills, namely critical thinking and problem-solving skills, creativity and innovation, communication, and collaboration [21].Based on Sudhirta et al. [22], it is said that the 4C concept applied in RTC has a significant impact on the nation's next generation in facing the challenges of life in the 21st century era.One important aspect of 21st-century learning is learning, which requires students to have problem-solving skills.Problem-solving is the ability possessed by someone to be able to solve problems and be able to apply them in everyday life [23].Therefore, problem-solving skills have an essential role in education so that students can overcome various problems by using their skills and knowledge and applying them in everyday life [24].
In an era of ever-evolving education, Merdeka Belajar Curriculum in Indonesia has emerged as the latest change in learning approaches.This curriculum aims to make the learning process more relevant, in-depth, and fun for students [25,26].The concept of the independent learning curriculum is the formation of independence in thinking [27].Freedom of thought is determined by the teacher, meaning that the teacher is the most essential role in supporting the success of education [28].One crucial aspect of implementing the Independent Learning Curriculum is the development of teaching modules [4,29].Teaching modules are teaching materials arranged systematically and thoroughly, paying attention to the learning principles teachers apply to students.The teaching module includes opening, material content, and closing, thus assisting the teacher in delivering material in a structured manner [30,31].Teaching modules are an essential component in implementing the Merdeka Belajar Curriculum at the Senior High School (SMA or MA) level because they can increase teaching effectiveness and provide complete guidance for teachers [2,8,32].
For the effectiveness of learning, a strategy is needed in implementing the Merdeka Belajar Curriculum at the SMA/MA level.One of the strategies that can be used in implementing ETC is using the Problem-Based Learning (PBL) learning model supported by using E-Book-based teaching modules.The PBL learning model aims to develop students' problem-solving skills [33] per the Merdeka Belajar Curriculum concept, which prioritizes independence of thought.On the other hand, TPACK (Technological Pedagogical Content Knowledge) is a framework that integrates an understanding of technology, pedagogy, and content in the learning process [34,35].In this context, the use of PBL-based teaching modules assisted by E-Books connects the learning content presented in the module with the use of digital technology as a learning tool.Teachers who implement this teaching module need to have a strong understanding of TPACK, namely how to use technology appropriately to teach learning content with a PBL approach.By utilizing E-Books as a learning tool, students can access materials digitally and interactively [36,37].Teaching modules contain teaching materials that have been systematically arranged in E-Books, providing easy access and flexibility for students in learning [38].In addition, E-Books can also provide additional resources such as videos, images, and links relevant to the learning material, enriching students' learning experience [39].
By integrating E-Book-assisted PBL-based teaching modules with TPACK, teachers can create an innovative and engaging learning environment [40].They can combine digital technology with the PBL approach so that students are engaged in solving real problems relevant to everyday life [41,42].Through this combination, students gain knowledge of learning materials and develop problemsolving skills and technology utilization in the context of the Merdeka Belajar Curriculum.
The PBL model is an approach that involves students actively in the process of solving and solving real problems [43].Physics is a subject that studies natural phenomena related to everyday life [44].Physics learning is also closely related to the problem-solving process, so the problems given can require students to be able to think critically in finding solutions to the problems faced [45,46] because this physics material is identical to various problem situations in everyday life [47,48].One of the problems that exist in everyday life is the dwindling fossil energy crisis.Therefore, renewable energy material is very suitable to be implemented in the PBL model because it can help students develop problem-solving skills and understand the importance of renewable energy in sustainably meeting energy needs.This is because, in PBL, students must be able to develop and practice problem-solving skills through the stages of problem identification, information gathering, analysis, and evaluation [49].
Based on this description, it is necessary to develop a physics teaching module based on Problembased learning to improve problem-solving skills in students on renewable energy material.Therefore, researchers developed this teaching module to improve students' problem-solving skills.

Method
This type of research is descriptive quantitative, which aims to describe the results of the validity assessment by three validators on the learning devices that have been developed [50,51].Assessment is based on three aspects: content, construct, and language.This is development research with the 4D model and refers to the Merdeka Belajar Curriculum.Based on Thiagarajan [52], there are four stages of the 4D model (Define, Design, Develop, and Disseminate).However, this study is limited to the development stage without the dissemination stage.Figure 1 are the stages carried out in this study.

Define
At the Define Stage, curriculum analysis, learning outcomes analysis, learning objectives, and material analysis are carried out before designing the teaching module.

Design
The Design Stage aims to design the teaching module design that researchers will develop.The preparation of the Teaching Module design draft will produce a draft, which the supervisor will then review.After that, ATP, RPP, and LKPD are adjusted to the PBL model, and the preparation of tests is adjusted to the indicators of problem-solving skills.

Develop
The results of this study are the development and validation of PBL-based teaching modules to improve problem-solving skills on renewable energy material.The data collection method used is the teaching module validation method conducted by three validators: educational expert lecturers and material expert lecturers.The instrument used is the teaching module validation sheet.The results of the validator's score are taken as the mode value, with the data obtained as a criterion score using a Likert scale as Table 1.Based on the results of the assessment by the expert validators, it was then analyzed descriptively and quantitatively using the Equation (1).

Percentage (%) =
Total score obtained total score x 100% (1) After obtaining the percentage value, results will be analyzed descriptively quantitatively based on the interpretation criteria [53] as in Table 2.In calculating the percentage of validation scores, the calculation takes the mode value of the score given by the validator.Because each aspect in validation has a different weight, we need to find out the validity category of each aspect instead of using the average value [54].The mode score obtained from the validator is then divided by the maximum number of scores on the validation sheet so that the percentage of validity scores on devices and instruments is obtained.

Results and Discussion
This study aims to develop and produce PBL-based teaching modules to improve problem-solving skills on renewable energy material that is feasible and valid so that it can be used in the learning process at school.This teaching module contains module identity, learning objectives (ATP) flow, Pancasila Learner Profile, Target Learners, learning models, and learning activity plans.This teaching module is adapted to the Problem-Based Learning model on renewable energy material with the achievement of indicators and learning objectives as well as steps from PBL and problem-solving indicators.
The content of this teaching module is information on learning objectives and lesson plans oriented toward learning activities to analyze information and solve problems to improve problem-solving skills.In line with research from [55] argues that problem-solving skills are the ability to identify problems to be able to solve the problems faced.That way, someone can find a solution to be able to solve the problem clearly, coherently, and systematically [56].
The image of the initial appearance and content of the developed teaching module is shown in Figure 2. In Figure 2, there is an attractively designed teaching module cover page.On this cover, there is a title, agency logo, and identity of the class phase level used for grade 10 SMA / MA equivalent, namely Phase E in the independent learning curriculum.The teaching module content section contains school identities, initial competencies, Pancasila student profiles, facilities and infrastructure that will be used in learning activities, and learning objectives that students will achieve after applying this teaching module.This teaching module consists of several components that contain success indicators, learning objectives, subject matter, lesson plans, material descriptions, evaluations, and bibliographies.The development of this teaching module uses the Problem-Based Learning model and indicators of problem-solving skills in learning activities.In the PBL learning syntax section using 5 phases based on Arends [43], the first phase is problem orientation to learners, where students are introduced to the problems they will solve.The second phase involves organizing learners to deal with the problem, including forming working groups if needed.The third phase is individual and group investigation, where students research, gather information and seek solutions to the problem.The fourth phase involves developing and presenting work, where students present their solutions to the group or class.Finally, the fifth phase analyzes and evaluates the problem-solving process and results, where students reflect on their learning experience and get feedback for self-development.
Developing teaching modules using the Problem-Based Learning (PBL) learning model is the right approach to improving students' problem-solving skills.PBL involves students actively in the process of solving and resolving real problems [57].Several essential components in the developed teaching module help achieve learning objectives and facilitate students' problem-solving skills.These components include success indicators and clear learning objectives, subject matter relevant to renewable energy material, lesson plans that follow the PBL model, in-depth material descriptions according to student needs, evaluations that include problem-solving aspects, and a bibliography that is a reference source to enrich student understanding.By using the PBL model and indicators of problem-solving skills, this teaching module allows students to develop critical thinking skills, analysis, collaboration, and communication skills [42,58] in the context of solving renewable energy problems.Thus, this teaching module supports the implementation of the Merdeka Belajar Curriculum, which emphasizes relevance, depth, and excitement in the learning process.Figure 3 is the content of learning activities using the syntax of the PBL model.This learning activity is designed using the PBL approach, which aims to improve students' understanding of energy and its changes in everyday life.Through a video of the phenomenon of problems that exist in everyday life, namely micro hydropower plants for remote villages that are still not reached by electricity supply and the fuel oil crisis, learners are invited to observe, formulate problems, and identify energy changes that occur.Furthermore, learners are given the opportunity to gather information, conduct experiments, and present the results of their investigations in the form of group presentations.
The following is an explanation of the stages carried out in the content of the teaching module in learning activities.

Opening Stage
The opening stage in PBL is a moment to create a pleasant learning atmosphere and motivate learners [59].The teacher opens the learning, motivates learners, and gives advice to increase the spirit of learning.This is important in the PBL approach because high motivation can increase learners' problem-solving involvement [60].Teachers encourage learners to participate in learning and develop their problem-solving skills actively.

Apperception Stage
In the apperception stage, learners are invited to engage directly with real problems or situations related to learning materials [61].In the context of PBL, the teacher uses a video of a problem phenomenon that exists in everyday life, such as a video about a water wheel, to introduce energy and its changes.Learners are asked to observe the video and respond with related questions.
This apperception aims to link the problems around learners with the material of energy and its changes and activate their critical thinking.Learners are invited to think about the energy changes that occur in the video and identify the basic forms of energy that exist in everyday life.In the context of PBL, apperception is the first step to arouse learners' interest and motivation [62] in solving problems related to energy and its changes.Through apperception, learners will understand the relevance of the material to everyday life and feel challenged to find solutions in the context of the problem [63].

Learner Problem Orientation Stage
This stage is the core of the PBL approach, where learners are invited to formulate problems based on their observations of the problem phenomenon video.The teacher provides contextual problems related to the waterwheel video, such as what causes the waterwheel to rotate, what energy changes occur in the video, and how to utilize the waterwheel as a source of electrical energy.
In this stage, learners are actively involved in critical thinking and analysis [64,65].They are invited to identify the energy changes before water can produce electricity through a waterwheel.Through this discussion, learners are introduced to the energy transformation concept and allowed to express their opinions on the issue.

Organizing Learners Stage
At this stage, learners gather information from handouts and e-books on renewable energy.They are also divided into small groups to work on the LKPD (Learner Worksheet) and conduct discussions.
In the PBL approach, group work is essential because it can improve learners' collaboration and problem-solving skills [66][67][68].Through group work, learners can share ideas, gather various points of view, and support each other in developing their understanding [69] of the problem of energy and its changes.The teacher acts as a facilitator and provides guidance to the groups [70].

Guiding the Investigation Stage
In this stage, the teacher guides learners in formulating hypotheses, determining experimental variables, and applying physics concepts related to energy changes [71,72].Learners conduct experiments and analyze the results.
In the PBL approach, experimentation becomes a vital tool to develop learners' problem-solving skills [70,73].Learners are invited to design experiments, collect data, and interpret the results.Teachers provide guidance and support in this process, including assisting learners in analyzing data and concluding their results [74].

Developing and Presenting Results Stage
After conducting experiments and analyzing data, learners use the information they have gathered to develop their understanding of energy and its changes.They do further exercises in problem-solving discussions to test their understanding and present the results of their experimental reports.
In the PBL approach, the ability to present research results and experimental reports is an essential skill that is developed [75].Learners are encouraged to communicate effectively, organize information well, and convey their research results clearly [76,77].Teachers provide constructive feedback and assist learners in improving their presentations.

Closing Stage
The closing stage is a moment of reflection and evaluation of learning [78].The teacher asks questions to evaluate learners' understanding of energy and its changes.The teacher also assists students in summarizing the learning that has been done [79].
In the PBL approach, the closing stage is also an opportunity to plan the next learning steps.Teachers and learners together plan follow-up that is relevant to the learning material that has been learned.This reflection and evaluation process helps learners develop understanding and problemsolving skills [79].
Using the PBL approach in the design of learning activities as described, it can be expected that students' learning motivation will increase and their problem-solving skills will develop [59].In learning activities using the PBL approach, learners are invited to understand energy and its changes in everyday life through a video of the phenomenon of the electrical energy crisis in a remote village by utilizing alternative energy.They observe, formulate problems, and identify energy changes that occur.Furthermore, learners have the opportunity to gather information, conduct experiments, and present the results of the investigation in the form of group presentations.This design is expected to increase learners' learning motivation due to the relevant context and their active involvement in the learning process.In addition, through group collaboration, learners can develop social skills, critical thinking, and problem-solving [66].In this PBL approach, learners also receive feedback from the teacher to improve their understanding and strategies.The reflection stage also allows learners to identify the next steps.Thus, the PBL approach can effectively improve learners' problem-solving and motivate them to learn [80].
This PBL-based teaching module to improve students' problem-solving skills is validated to obtain input on the overall content contained in the teaching module.The validity of the module produced can be known by validating the module by three validators who are experts in their fields.The validation results were analyzed to determine the module in terms of content, construct, and language.The results of the validator's assessment for each component of the teaching module validity can be seen in Table 3.Based on Table 3, the physics teaching module based on Problem-Based Learning to improve problem-solving skills obtained a percentage value of 100% with a Very Valid category.Validity results from 3 expert lecturers showed that all aspects obtained a mode score of 4, with a percentage of 100%.This is because the content of the material presented is in accordance with the learning objectives, the learning model is in accordance with the syntax of the PBL model, the content of the material about renewable energy has the correct concept, and the language used is clear and in accordance with the understanding of students.Therefore, based on the results of this validation, the teaching module of the PBL model assisted by E-Book to improve problem-solving skills is considered to have reached the level of perfection and only requires further revision.This conclusion indicates that this teaching module has met the content, structure, and language eligibility standards.
The PBL-based teaching module developed to improve problem-solving skills has high content, construct, and language validity.The content validity of this module is guaranteed because it is in accordance with the indicators of achieving the learning objectives that have been set.This module integrates the concept of energy and its changes in everyday life by using videos of limited electrical energy by utilizing alternative energy such as micro hydropower plants (PLTM) and the problem of the fuel oil energy crisis problem as an authentic context.This ensures that the material presented is relevant to the lives of learners.The construct validity of this module is also guaranteed, as it is designed to develop learners' problem-solving skills.Through the PBL approach, learners are invited to observe, formulate problems, gather information, conduct experiments, and present the results of their investigations.This process effectively helps learners develop critical thinking, collaboration skills, and creativity in solving energy-related problems.The language validity of this module is also high.The language used in the module is clear, appropriate to the learners' level of understanding, and presented with good grammar.This makes it easier for learners to understand the material and carry out learning activities.With high validity in terms of content, construct, and language, this PBL-based teaching module can be effectively implemented in an independent learning curriculum.The module supports the achievement of the learning objectives set and engages learners in active and collaborative engagement.Aspects of the Pancasila learner profile, such as independence, global diversity, and mutual cooperation, are also fulfilled through the structured learning activities in this module.
In the context of an independent learning curriculum, this PBL-based teaching module provides flexibility for learners to learn independently, develop problem-solving skills [81], and improve their understanding of energy and its changes in everyday life.By using this module, learners can be active in learning, explore their potential, and face authentic problems that are relevant to their lives [59], [82].
Based on the results and discussion, overall, the content, construct, and language validation results state that the physics teaching module based on the PBL model is suitable for improving students' problem-solving skills.Where the overall average validation result is 100% with a valid category, this research concludes that the development of teaching modules based on problem-based learning to improve problem-solving skills can be used to improve problem-solving skills and can be implemented in accordance with the independent learning curriculum.

Conclusion
Based on the research results on the development of E-Book-assisted physics teaching modules to improve problem-solving skills on renewable energy material, a validation value of 100% was obtained with a very valid category in content, construction, and language.This shows that the physics teaching module based on the PBL model to improve problem-solving skills in students can be implemented for learning activities that are in accordance with the independent learning curriculum at school.The implementation of physics teaching modules based on the PBL model with the help of this E-Book is in accordance with the independent learning curriculum at school.Through the PBL approach, students are given the opportunity to be actively involved in solving real problems relevant to everyday life while gaining a deep understanding of renewable energy.With the support of digital technology in the form of E-Books, students can access learning materials flexibly and interactively, thus enriching their learning experience.

Figure 2 .
Initial appearance of teaching module design and teaching module content.

Figure 3 .
Problem-based learning model lesson plan.

Table 2 .
Interpretation criteria for the feasibility of teaching module validity.

Table 3 .
Recapitulation of data on teaching module validation results.