**1. Introduction**

"STEM," an acronym for science, technology, engineering, and mathematics, which was initially proposed by National Science Foundation (NSF) of the USA in the 1990s with the purpose of emphasizing the importance of these four disciplines in the education community and society at large [1, 2]. In a more specific sense, educators have often used it to describe the inherent interconnectedness between the four disciplines and create curricula and pedagogy as well that link them together within one period (e.g., years, semesters or units) or classroom [1]. Since the beginning of the twenty-first century, the notion of STEM has attracted great attention globally and has been regarded as one of the primary foci of educational and curricular policy. However, STEM is not a fixed curriculum. It neither does intend to replace national curriculum frameworks or state curriculum standards, nor does it mean to be a quick fix for education problems [3]. Rather, the STEM education provides an approach to teaching and learning that removes or relieves the traditional barriers of disciplines to foster students' abilities.
