1. Introduction
K-12 science education in the US has been criticized for not providing students with engaging opportunities to experience how science is actually carried out
[1]. This assertion underpins the design of the Next Generation Science Standards (NGSS), which emphasize engaging students in learning experiences crafted around asking fundamental questions about the world and learning about how scientists have pursued answers to those questions
[2]. To guide the creation of these learning experiences, the NGSS outlines eight essential science practices through which students should learn disciplinary core ideas and crosscutting concepts as well as the nature of science: (1) Asking questions, (2) Developing and using models, (3) Planning and carrying out investigations, (4) Analyzing and interpreting data, (5) Using mathematics and computational thinking, (6) Constructing explanations, (7) Engaging in argument from evidence, and (8) Obtaining, evaluating, and communicating information
[2]. The NGSS explicitly states that “students in grades K-12 should engage in all eight practices over each grade band”
[2] (p. 2), and suggests these practices should be interwoven into instruction in a coherent learning progression.
To attain the goals of the NGSS, the fundamental paradigm of science education needs to shift from presenting final-form science to students as facts toward emphasizing science as an ongoing process and practice. However, this paradigm shift places significant demands on teachers
[3], as they should understand how to engage students in science practices through which students not only develop a conceptual understanding of scientific knowledge but also learn how scientific knowledge is constructed, communicated, and validated. Given the centrality of teachers in educational processes and student learning
[4[4][5],
5], the extent to which students are engaged in these science practices depends on teachers providing rich learning opportunities to their students. That is, science teachers are required to provide guidance on how to effectively participate in the practice, how to use them to make sense of the world, and how to apprentice into the scientific community
[6,7][6][7]. This new emphasis necessitates science teachers’ deep understanding of the epistemic nature of science practices
[8]. In short, teachers should know “for what purposes and to what ends each science practice is engaged in”
[8] (p. 393). Only when teachers are confident that they know what the epistemic nature and goals of the eight practices are and understand them as interdependent epistemic procedures for building knowledge can they create learning environments to engage their students in the essential practices of science proposed by the NGSS
[6,9,10][6][9][10].
In this regard, examining teachers’ epistemic understanding of the eight NGSS practices can be a stepping stone for supporting science teachers’ implementation of reform-oriented science teaching. Kite and his colleagues
[11] conducted a qualitative study to examine the characteristics of secondary science teachers’ understanding of the epistemic nature of the eight science practices. The researchers highlight the need for teacher education initiatives that explicitly target teachers’ epistemic understandings that promote effective implementation of the science practices that are critical to student learning of cognitive, epistemic, and social aspects of science. However, few studies have been conducted to examine pre-service teachers’ understanding of the science practices. Preservice teacher education programs or professional development programs for in-service teachers should be the places where teachers can improve their understanding of the NGSS science practices. Considering that, this study aimed to examine elementary preservice teachers’ understanding of the NGSS science practices and the impact of science teaching methods courses on their understanding. A number of studies have repeatedly reported that elementary teachers do not provide the desired level of science lessons in an inquiry-based, science practice-centered way
[12,13][12][13].
In addition to teacher knowledge, research has shown that teachers’ beliefs and values affect their instructional choices and efforts to change their pedagogical practice
[14,15,16][14][15][16]. Although teacher beliefs are difficult to define clearly and the relationship between beliefs and practices is not always apparent, many researchers have highlighted that teacher beliefs play a critical role in implementing reform initiatives in the science classroom
[17,18,19][17][18][19]. In particular, task value beliefs that individuals place on an activity, along with their expectations for success, affect their choice and persistence to engage in as well as performance in the activity
[20,21][20][21]. In their expectancy-value theory, Wigfield and Eccles
[21,22][21][22] identify four major task value beliefs: Attainment value or Importance, Intrinsic value or Interest, Utility value or Usefulness, and Cost. Bearing this in mind,
wresearche
rs expect that when preservice elementary teachers value the eight science practices outlined by the NGSS, they are more likely to implement them in their future classrooms. Stated differently, students may not be exposed to the practices that their teachers do not value or that they deem to be less important. Thus, it is imperative to understand the value preservice elementary teachers place on each of the science practices and their underlying reasoning for their valuation. From this understanding, science educators could gain implications for potential interventions to change preservice teachers’ beliefs about science practices in a way that will promote their effective implementation of the science practices.
2. NGSS Science Practices
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][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][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][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][6][29].
3. Teachers’ Epistemic Understanding of Science Practices
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][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][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][32][33][34]. However, few studies have investigated teachers’ epistemic understanding of science practices specifically, especially with pre-service teachers.
4. Task Value Beliefs and Teaching Practice
Achievement motivation theorists have attempted to explain how motivation influences individuals’ choice, persistence, and performance of achievement tasks
[35,36][35][36]. Motivation predicts academic achievement beyond cognitive ability
[37]. A widely accepted approach to motivation is the expectancy-value theory
[22,38][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][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][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][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][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][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].