Implementation of science technology engineering and mathematics approach in learning to critical thinking skills of fifth-grade elementary school students in Lampung Province

21st-century skills in the world of education are skills that must be mastered by every student and even become essential to the progress of education in Indonesia. These skills are being able to think critically and problem-solving, learning and innovating skills, collaboration, communicating effectively, analyzing information, and having life skills (Widana et al., 2018; Wijaya et al., 2016; Zubaidah, 2016). Various skills are pursued by all elements of education so that students can compete with other countries and are ready to face life's challenges (Astutik & Hariyati, 2021; Nuryanti et al., 2018). Students in elementary schools need to be supported to have 21st-century skills such as critical thinking skills.

Critical thinking skills play an important role in today's life aspects (Erikson & Erikson, 2019; Halpern, 2014; Prajapati et al., 2017). Every problem that students encounter will be easily overcome if they can think critically. Critical thinking skills is a person's ability to think that is fundamental, reasonable, and reflective which includes activities to analyze, synthesize, create, identify questions, and be able to make logical conclusions and characterize 21st-century learning (Asyari et al., 2016; Butterworth & Thwaites, 2013; Ennis, 2011; Mahanal et al., 2019; Mardliyah, 2018; Schmaltz et al., 2017). Critical thinking skills are also part of the mental process that teaches how to understand the events and conditions of environment as well as to acquire new knowledges (Doleck et al., 2017; Zubaidah et al., 2018). Students with critical thinking skills looked different compared to others since their curiousity is high. Critical thinking skills are actually required for students to conceptualize themselves being active, skilled, easy to solve problems, able to collect data and make hypotheses, and applying all their learned knowledges (Changwong et al., 2018; Cintamulya, 2019).

Having critical thinking skills, the students can transfer knowledge from one domain to another. Furthermore, the educators teach them how these abilities can develop efficiently and contribute to every field (Zohar et al., 1994). The effectiveness of a person's critical thinking skills needs an indicator to determine the achievement of a predetermined target. There are six indicators of critical thinking skills i.e., Focus, Reason, Inference, Situation, Clarity, Overview (FRISCO) (Ennis, 2011). The six indicators of critical thinking skills provide a broad and useful range of knowledge for students. So, by the six indicators, they are expected to be a reference in measuring students' critical thinking skills.

In fact, the conditions that occur in elementary schools today are that the students have low critical thinking skills. This problem is appeared because the learning activity is still oriented to educators as the center of attention (teacher centered mode). So far, educators have not been able to handle it properly. However, it is already known that critical thinking skills have become a curriculum demand in elementary schools to prepare the students dealing with complex life (Rachmadtullah, 2015; Septikasari & Frasandy, 2018; Sukmana, 2018).

The integration STEM approach into Project Based Learning (PjBL) can be applied to overcome the low critical thinking skills of fifth-grade elementary school students in Lampung Province. Knowledge learned through the STEM approach is most useful in the daily lives of students and gives different meanings in its implementation (Ritz & Fan, 2014). The STEM approach is a learning approach that integrates knowledge of STEM in a student-centered learning environment and teach the student how to investigate engineering-related problems and find solutions and then build evidence-based on explanations relating to real-world phenomena (Changpetch & Seechaliao, 2020; Crotty et al., 2017; Shernoff et al., 2017).

The implementation of the STEM approach is the best way to learn in elementary schools to improve children's critical thinking skills (Yaki et al., 2019). This is because the STEM approach can foster active, meaningful, and creative learning where the four scientific aspects are simultaneously acquire to solve daily life problems. The implementation of learning is under the steps of the STEM approach which consists of reflection, research, discovery, application, communication (Khairiyah, 2019). The STEM approach can create quality learning in student-centered schools so that the output produced is under the learning objectives.

In addition, STEM also implemented in developed countries such as USA has a real impact on the development of students to be active, innovative, creative, productive, and excelling in schools (Kocakaya & Ensari, 2018; Oktapiani & Hamdu, 2020; Permanasari, 2016; Wang & Chiang, 2020). Furthermore, students who get learning with the STEM approach will form a sense of confidence to always contribute to the development of technological literacy (Prismasari et al., 2019; Salar, 2021). The purpose of the STEM approach in learning in elementary schools is to develop cognitive, affective, psychomotor skills and to form awareness of STEM disciplines that create intellectual intelligence and human culture (Haryanti & Suwarma, 2018; Jauhariyyah et al., 2017).

Learning with the STEM approach can be applied to mathematics subjects. Mathematics has an important role in the growth of children's critical thinking skills through learning activities (Hidayati, 2017). The benefits obtained from learning mathematics are that it can form a systematic, logical, critical, and careful mathematical mindset (Acar et al., 2018; Azizah et al., 2018; Karso et al., 2010). When students learn mathematics, they also learn how to construct their thoughts. Based on this, students need to be trained to think highly, namely critical thinking.

The previous research on critical thinking skills, such as the research by (Putranta et al., 2019) shows a difference with our research which lies in the use of PhET simulations to improve critical thinking skills. The results of increasing students' critical thinking skills are obtained an average N-gain value of 0.61 (medium category). In addition, research by (Parno et al., 2021) shows that 7E LC and STEM-Based 7E LC models significantly affect the improvement of participants' critical thinking skills. Furthermore, research by (Selisne et al., 2019) shows that using modules with the STEM approach effectively increases student competence consisting of knowledge, attitudes, and skills. This study aims to determine the implementation of the STEM approach to the critical thinking skills of fifth-grade elementary school students in Lampung Province.