A major change from the National Science Education Standards [23] to the Next Generation Science Standards [2] is the shift from teaching science as inquiry to teaching science as practices. This shift was driven by the criticism that the concept of teaching science through inquiry creates “a confusion of the goal of science—to discover new knowledge about the material world—with the goal of learning science—to build an understanding of the existing ideas that contemporary culture has built about the natural and living world that surround us” [24] (p. 178). That is, there is a conflation of the two activities, doing science and learning science, which are characterized by their different goals [24,25]. Anderson [26] also identified three variations of inquiry: scientific inquiry (the various ways in which scientists investigate the natural world), inquiry learning (a process by which students acquire scientific knowledge), and inquiry teaching (the pedagogical approach by which teachers engage students in inquiry). In addition, there has been a lack of agreement on what it means to teach science through inquiry [24]. For example, many teachers and students interpret that inquiry equates to using hands-on activities. In this case, scientific inquiry is seen as a means of verifying the scientific explanation offered by the teacher [3,27]. Simply using science process skills with no testable questions or target scientific concepts is also counted as inquiry-based teaching.

Considering that the idea of teaching science as inquiry is inadequately articulated and communicated, NGSS replaces the term inquiry with engaging students in eight science practices, emphasizing that students should understand science as a set of ongoing practices that build upon a body of scientific knowledge [2]. With the launch of the NGSS, science education communities have sought to move US science education away from teaching isolated concepts and processes toward student engagement in science practices [11]. By engaging in essential science practices, students can understand not only science concepts but also improve critical thinking skills that empower them to become lifelong learners of science [3,28]. Students can also develop their understanding of how science works and how scientific knowledge is developed as well as the epistemic basis of science [6,29].

The epistemology of science is a complex and multi-faceted construct that describes how scientific knowledge is developed, validated, and communicated as well as the practices engaged by the scientific community to continually build and refine the body of scientific knowledge [9,30]. Teachers’ epistemic understanding of science requires that the educator understands “for what purposes and to what ends the practices are” [8] (p. 2). For example, science educators should not only understand that scientists analyze and interpret data, but also that scientists using the same procedures might get different results; that analytic procedures can influence conclusions; and that data produced by investigations must be analyzed to derive meaning [31]. As another example, consider that the NGSS practice of engaging in argument from evidence makes clear that teachers should understand that scientific data are different from scientific evidence [31]. By emphasizing the integration of practices, disciplinary core ideas, and crosscutting concepts, the NGSS requires significant epistemological and pedagogical shifts on the part of teachers [11]. Particularly, teachers’ understanding of both how to perform science practices appropriately and why they are doing what they are doing is critical to the successful engagement of students in science practices as a means to learn disciplinary core ideas and crosscutting concepts [6]. Park et al. [31] demonstrate that secondary science teachers’ understanding of the epistemic nature of the science practices as well as their epistemic orientations predict their implementation of science practices. Hence, in order to create learning environments for their students to develop both scientific knowledge and scientific processes concurrently, teachers need a deep understanding of the epistemic nature of the science practices in addition to strong conceptual and procedural knowledge of the sciences [3,10]. The importance of incorporating epistemic knowledge of science into science curricula has been widely advocated by many science educators in the form of explicit instruction on the nature of science, ideas about science, etc. [32,33,34]. However, few studies have investigated teachers’ epistemic understanding of science practices specifically, especially with pre-service teachers.

Achievement motivation theorists have attempted to explain how motivation influences individuals’ choice, persistence, and performance of achievement tasks [35,36]. Motivation predicts academic achievement beyond cognitive ability [37]. A widely accepted approach to motivation is the expectancy-value theory [22,38]. In this theory, expectations of success and subjective task value are identified as the two major components that influence individuals’ effort, choices, and achievement in a variety of contexts, including academic achievement on different educational levels [38,39,40,41]. In other words, individuals’ choice of achievement tasks, persistence in those tasks, and performance in them can be explained by their beliefs about how well they will do on the activity and the extent to which they value the activity [20,21,42].

According to the expectancy-value model, expectations for success and personal efficacy is the main factor that influences individuals’ task, activity, or behavior choices [35,43,44]. Subjective task value is the second major component of the expectancy-value model of achievement-related choices. Eccles et al. [20] explain that life-defining choices are influenced by the subjective task value individuals attach to the various achievement-related options. In the longitudinal study with approximately 1000 high school seniors, Eccles [38] examined the relationship among personal expectation/efficacy for success, subjective task values, and occupational choice. They report that students’ expectations for success and personal efficacy predict their occupational choice, but they are not the only factor. Students’ decisions to enter particular occupations appear to depend on the value they attach to various occupational characteristics.

The defined components of the subjective task value beliefs are Attainment value or Importance, Intrinsic value or Interest, Utility value or Usefulness, and Cost [20,21,22,38,45]. According to Eccles et al. [20], Attainment value is defined as the personal importance ascribed to succeeding in a given task. Attainment value can be related to personal or collective identities individuals develop as they grow up by performing well in a task [38]. Intrinsic value is defined as the enjoyment an individual experiences when engaging in a task or the subjective interest in a task. When individuals perform tasks that are intrinsically valued, positive psychological consequences are the reward [22]. Utility value describes the perceived personal usefulness of engaging in a task or how a task fits into an individual’s future plans. For example, taking a math class to fulfill a requirement for a science degree. While Intrinsic value is similar to intrinsic motivation, Utility value can be viewed as extrinsic motivation as described in the self-determination theory [38,45,46,47]. Cost refers to the cost of participating in the activity, which is influenced by many factors such as anticipated anxiety, fear of failure, fear of the social consequences of success, and the loss of time and energy, etc. [38]. Cost also includes the amount of perceived effort that has to be utilized in order to succeed [20].