The Implementation of STEM-Integrated Project-Based Learning Model on Renewable Energy Topic Through a Windmill Simulation

The depletion of conventional energy sources requires human innovations related to renewable energy. Unfortunately, learning about renewable energy, especially in Indonesia, is only theoretical with teacher-centered learning. The learning should be student-centered as a future generation must be ready for all the changes and demands of the 21st-century era. This study aims to describe the process of implementing the STEM-integrated PjBL model on renewable energy issues through windmill simulation. The research was conducted in a High School in Jember Regency. This type of research is descriptive qualitative with a single case study approach. The results showed that the stages in STEM-integrated PjBL, including teacher introduction, objectives, connections, well-defined outcomes, materials, engagement, exploration, explanation, extension, and evaluation, are very suitable for implementation in high school, especially renewable energy. STEM-integrated PjBL can be conducted to make students more active in the learning process.


Introduction
Conventional energy is still the basis for Indonesia's primary energy supply [1].However, in reality, Indonesia's conventional energy sources are increasingly approaching a crisis point due to the rapid increase in population and their uneconomical and efficient use [2].These conditions require innovation to supply energy in the long term.Renewable energy is an innovative energy source that is environmentally friendly and can guarantee the sustainability of energy sources for the future [3].Indonesia has abundant potential renewable energy sources, including geothermal, wind, water, ocean currents, solar, bioenergy, and even nuclear energy, so it can be used as an energy source on a large scale [4].
Utilization of potential renewable energy sources requires adequate quality human resources.The role of education is the main foundation of an effort to form quality Indonesian human resources in overcoming current and future challenges [5].One of the benchmarks for a quality educational process is reflected in the learning process [6].A good learning process is closely related to students' activeness in the learning process.One model that emphasizes the role of students in the learning process is Project Based Learning [7].The PjBL model is designed so students are active, creative, innovative, and think critically in solving a problem [8].
The PjBL model will run optimally when integrated with the Science, Technology, Engineering, and Mathematics (STEM) approach, especially in science lessons [9].Many studies describe the positive impact of the STEM-integrated PjBL model.The first study stated that the STEM-integrated PjBL model would provide meaningful learning for students [10].An in-depth explanation of the results of the second study stated that the STEM-integrated PjBL model trains students to think critically, creatively, analytically, and scientifically literate, improving higher-order thinking skills to provide challenges and motivate students [11].Implementation of the STEM-integrated PjBL model on renewable energy material is also needed because by using this model, students are expected to be able to solve the problem of large and environmentally friendly energy needs [9].Unfortunately, no literature explains the STEM-integrated PjBL model syntax.Capraro's research merely explains the indicators that must be included in the STEM-integrated PjBL model, including teacher introduction, objectives, connections, well-defined outcomes, materials, engagement, exploration, explanation, extension, and evaluation [12].As for other research, it only combines the syntax of the PjBL model with STEM indicators according to the needs of the learning process.Therefore, this study aims to describe implementing the STEM-integrated PjBL model according to Capraro's research on renewable energy material through windmill simulation.Hopefully, this research can find a good syntax formula and be used as a syntax reference for the STEM-integrated PjBL learning model.

Method
This research is a type of qualitative descriptive research.Qualitative descriptive research emphasizes that reality has multiple dimensions, is interactive, and is an exchange of social experiences by individuals or groups.Yin's case study uses the research design, which includes planning, designing, collecting, analyzing, and sharing [13].The flow of the case study formulated by Yin is in Figure 1.The case study design was chosen because it is suitable for research that aims to understand the background of a problem or individual interactions within a social unit in a profound, holistic, intensive, and natural way [14].This research was conducted at a High School in Jember Regency, with the research subjects being students of XD class, totaling 32 students divided into six groups.The data collection method in this study uses observation.In addition, observations were also carried out, assisted by three observers in each process of implementing the STEM-integrated PjBL model.

Results and Discussion
The implementation process of the STEM-integrated PjBL model on renewable energy material is divided into four meetings, each lasting 2x45 minutes.The first renewable energy material was presented by presenting national energy consumption data, national fossil energy reserves, and the percentage of renewable energy utilization in Indonesia.After that, it was continued with students discussing and making windmill prototype projects.In the process of implementing the STEMintegrated PjBL model, three people were observed.Table 1. is a recap of the observed data.Students answer the trigger questions given by the teacher.9 9 9 9 9 9 Students listen to the news presenting energy needs.9 9 9 9 9 9

Objectives
The teacher conveys and explains the purpose of learning.9 9 9 9 9 9 Connections Teachers make devices and interconnected teaching materials.9 9 9 9 9 9 Well-Defined Outcome Students search for relevant literature regarding energy conversion in windmills.9 9 9 9 9 9 In the previous meeting, students answered the teacher's questions regarding the project's progress.9 9 9 9 9 9

Materials
Students make a project requirement plan that will be implemented in the worksheet based on the group agreement.9 9 9 9 9 9 Engagement Each group of students makes windmill products from the results of the designs made 9 9 9 9 9 9

Exploration
Each group assembles a prototype and takes data on the electrical energy produced by the windmills that are made.9 9 9 9 9 9 Students observe and analyze data and constraints on experiments.9 9 9 9 9 9

Explanation
In groups, students discuss design solutions to existing constraints.9 9 9 9 9 9 Made repairs to the blade of the windmill that was made 9 9 9 9 9 9

Extension
Students answer questions given by the teacher regarding the concepts and prototypes designed.9 9 9 9 9 9

Evaluation
Students make presentations about windmill products and the resulting data.9 9 9 9 9 9 Table 1 shows the ten stages of the STEM-integrated PjBL model that can be implemented.In-depth, the STEM-integrated PjBL stages are as follows:

Teacher Introductions
In the first stage, the teacher gave a trigger problem to determine the student's initial knowledge.Students are directed to be sensitive to social problems, especially in the energy sector.The issues raised included the scarcity and increasing fuel prices, the government's discourse on using electric stoves, and the switch from motorized to electric vehicles.Then, students analyze the problems presented, answer questions posed by the teacher, and discuss the causes of these problems with their classmates.After students find the cause of the problem, the teacher continues to provide an introduction in the form of important information about energy sources.The information provided includes the amount of national energy consumption, national fossil energy reserves, and the percentage of national energy utilization.This information aims to make students more aware that renewable energy is needed.Students pay close attention to the information conveyed to enrich their initial knowledge.The information provided includes the amount of Indonesia and the world's fossil energy reserves, the amount of renewable energy potential, and the percentage of renewable energy utilization in Indonesia.This information is essential because it will make it easier for students to solve a problem [15].
The teacher introduction process positively impacts students because students are directed to be sensitive to the conditions around them by identifying problems.Identifying problems forms the character of high curiosity and careful observation of problems [16].Then, the teacher explains the identification results in more depth so that students' initial knowledge is vital before entering into project work.

Objectives
After the teacher introduction stage, proceed to the objectives stage.At this stage, the teacher identifies the objectives of the learning process that will be carried out and conveys them in the learning process.This stage is helpful to make the learning process more directed and systematic.In the independent curriculum, teachers must write learning objectives when planning lessons.Still, it is also crucial that the teacher outlines the objectives of the learning process to students.The delivery of these learning objectives is instrumental so that students and teachers have the same vision and mission in the learning process for the next few meetings.In this research, the objectives of the renewable energy learning process are that students understand the utilization of renewable energy and can design and make prototypes of renewable energy power plants.

Connections
After the first two stages have been carried out, it can be seen that the teacher's role is quite dominating in the learning process.Additional teaching materials are needed that are interconnected with lesson plans.Teaching materials include books, modules, worksheets, and handouts [17].This research uses worksheets to direct students to work on their projects.Worksheets are learning guides, evaluation tools, and teaching material media that prioritize students' role in providing individual and group learning experiences [18].The worksheet contains several questions about the energy problem presented, and then students are directed to identify the problem and determine the type of power plant following the information presented.In addition to questions, students are also given directions to create a power plant project according to their creativity so that the project runs systematically and all group members have roles according to their skills in working together.Worksheets in this study effectively maintain the connection with students to match the learning objectives.Other research also states that the worksheets contain detailed instructions and procedures to train thinking and science process skills in completing tasks under the learning indicators to be achieved [19].

Well-Defined Outcome
The product as the project's final result must be well-defined and concrete.Excellent and detailed product definitions can direct students' imagination and creativity in completing projects so that the results of student projects do not come out of the critical points of learning objectives.Products can be prototypes, videos, crafts, or other things that can be applied or have practical value.The final product of implementing the STEM-integrated PjBL model in this study was a prototype of a wind power plant, so students were directed to make a prototype in the form of a windmill blade.Figure 2 is an example of a student-made windmill blade prototype.

Figure 2. Example of a student-made windmill blade prototype
Figure 2 shows the different shapes and details of the student project results.This is because, in manufacturing, students can determine the shape, size, and number of blades to be made.Still, a limit that students must pay attention to is the maximum diameter of the blade so that it can be paired with the tools provided.This is so that the prototype can be tested and assessed for effectiveness.The selection of blade shapes and details is based on the results of student literature studies, both from books, YouTube videos, the web, and journals.The results of this literature review are then reprocessed by conducting discussions with their respective groups-at every meeting, the teacher continuously checks and asks about the project's progress.Students must answer honestly and be able to take responsibility for every decision made.

Materials
Making a product requires many materials to complete.Materials here are not only tools and materials but essential information about the project so that it can run effectively is also included in the category of materials.Students can find reference sources and choose tools and materials according to the project's needs.All information, tools, and materials needed are written in the worksheet.Most students make windmill blades with plastic as it is lightweight and easy to shape.This follows the information obtained that making windmill blades requires a lightweight material so that the wind quickly moves it.Besides that, plastic is a material that is easily shaped to create an aerodynamic effect from the blade.Tools needed include scissors, a ruler, a bow, and a pencil.

Engagement
The process of creating the project is entirely in the control of the students.Students are allowed to conduct discussions to choose the best design.The teacher's role at this stage is only as a facilitator who ensures the discussion process is on topic and involves all group members.Each group member must have a role according to their skills in working on the project.This aims to create communication and collaboration between students in the group.So, 21 st -century skills are very well honed, considering that communication and collaboration activities increase problem-solving [20].At this stage, the technology indicator appears when students combine the concept of dynamic fluid on the blade and energy conversion on the dynamo to produce electrical energy.Engineering indicators can also be seen when students design the blade and provide details so it can work optimally.The blade design is carefully measured and calculated to appropriately capture the wind's kinetic energy.

Exploration
Exploration is the initial stage of checking the product after completion.Exploration aims to check whether the product is following the plan.Exploration results are written down to become reference data for the next stage.This study's exploratory stage was seen when students tested the windmill blade prototype.Student activity while testing the prototype is shown in Figure 3.

Figure 3. Students conduct prototype testing
The first step is for students to assemble windmill blades with the generator provided so that a windmill simulation is formed and connected to a multimeter to measure the voltage generated, as shown in Figure 3.To create a constant wind using the help of a fan with three-speed variations.The resulting voltage data and product constraints in the trial process are then recorded in the worksheet.Product testing aims to evaluate the prototype design by looking at the results of observations and data, which are then used as a reference to identify parts needing improvement [21].

Explanation
Students are directed to be able to provide explanations after analyzing the results of the exploration of the products they make.The explanation must be logical and based on scientific concepts.If some students' explanations are unsatisfactory or misconceptions occur, the teacher can help explain before students continue to modify the product.The explanations made by students this time were about the constraints and solutions that would be carried out to improve the prototype's performance.Most of the students' explanations relate to the aerodynamic forces that occur on the prototype and make improvements to maximize them.In detail, students wrote down the improvements on the worksheet as follows: "What needs to be improved is the angle of inclination of the blade so that the wind lifting force is used more."(ATH, group 1) "The diameter and length of the blade are enlarged, and given a bend on the side of the blade" (NND, group 4) "Make the blade more pointed and slimmer so that the aerodynamic force is maximized" (RVL, group 5).
From these quotes, it can be seen that each group has its obstacles and solutions, but in general, the improvements made are in the category of size, shape, and details on the blade, such as bending and tilt.

Extension
Extension is an additional assignment given to students.This task can be applied to groups that have finished first.The tasks given are more straightforward and remain within the topic being studied.This study only gave questions to the group that had finished while waiting for the other groups.Questions about the science concepts contained in the windmill simulation to ensure students obtain the concepts properly and holistically.

Evaluation
The evaluation or assessment stage is the stage to provide feedback on the prototype made.Evaluation can be in the form of appreciation and correction from the teacher or other groups when making presentations.Teacher evaluation can be in the form of verbal and grades according to the assessment indicators that have been made.The evaluation process can begin with one group presenting the results of their group's work, starting from identifying the energy problem presented, the materials chosen, and information on the science concepts underlying the prototype design they made.Furthermore, other students ask questions about the results presented, such as details of the test results and the improvements made.In addition to questions, other students can provide input based on the results of their project, such as additional information that other groups have not received in making windmills.During this interaction process, the teacher can assess student understanding.From how students explain the product and the process of working on the project, it can be seen to what extent students understand the concept.As the results of other studies state, students are said to have understood the concept if they can explain the material in their language without being fixated on the book [15].

Conclusion
Based on the description of the implementation stages of the STEM-integrated PjBL model above, it can be seen that the indicators of the STEM-integrated PjBL model initiated by Capraro can be carried out sequentially.They include teacher introduction, objectives, connections, well-defined outcomes,

Figure 1 .
Figure 1.The flow of case study research.

Table 1 .
Observation data on the implementation of the STEM-integrated PjBL model