This chapter examines the historical development of science education in India, beginning with the policy context in pre-independence India to the present day, with a specific focus on school science education and teacher education. Specifically, this study examines the pedagogical orientation of pre-service science teachers, who had been a part of two-year Bachelor of Education teacher education program in India. They had taught middle grades science during their school internship program in different genres of schools, ranging from state-funded to private-funded during internship. Assessment items in Pedagogy of Science Teaching Test (POSTT) were used to identify their pedagogical orientations, and reasons for their specific orientations were probed through interviews. It comes out that pre-service teachers develop varying pedagogical orientations, ranging from direct instruction to open inquiry, emerging from several school-related factors like class size, availability of resources, leadership guidance; discrepancies between professional development and school culture, and other personal constraints.

Science curricula and teaching methods vary greatly, depending in part on which facets of science are emphasized, e.g., core disciplinary ideas or science practices and process skills, and perspectives differ considerably on desirable pedagogies. Given the multi-faceted nature of science and the variety of teaching methods found in practice, it is no simple task to determine what teaching approaches might be most effective and for what purposes. Research into relative efficacy faces considerable challenges, with confounding factors, ambiguities, conflations, and lack of controls being threats to validity. We provide a conceptual framework characterizing the many teaching strategies found in practice as being variants of two fundamental contrasting epistemic modes, and we disentangle conflations of terms and confusions of constructs in both teaching practice and research. Instructional units for two science topics were developed in parallel in the alternative epistemic modes, differing in concept learning paths but otherwise equivalent. We conducted a randomized controlled study of the comparative efficacy of the two modes for learning core disciplinary ideas, using operationally defined active-direct and guided-inquiry teaching methods. Five middle school teachers taught each unit in both modes over 4 years of classroom trials in an 8-day summer program for eighth grade students. Student understanding of core ideas was assessed using pre- and post-tests, and learning gains were analyzed by mode, teacher, topic, and trial year. Although routes to concept understanding were very different in the two modes, eventual student learning gains were similar, within statistical variation. Efficacy variations between and within teachers were greater than between modes, indicating the importance of teacher effects on student achievement. Findings suggest that teachers need not be bound to one mode throughout and can flexibly decide on the pedagogical approach for each concept and situation, on several grounds other than efficacy of core content acquisition alone.

Language ambiguities in concept meanings can exacerbate student learning difficulties and conceptual understanding of physics concepts. This is especially true for the concept of “weight,” which has multiple meanings in both scientific and everyday usage. The term weight has been defined in several different ways, with nuances, but in textbooks and teaching the term is almost always defined in one of two ways: operationally either as the contact force between an object and a measuring scale or as the gravitational force on an object due to some other body such as Earth. The use of the same name for different concepts leads to much confusion, especially in accelerating situations, and to conflicting notions of “weightlessness” in free fall situations. In the present paper, we share an innovative approach that initially avoids the term weight entirely while teaching the physics of each situation, and then teaches the language ambiguities explicitly. We developed an instructional module with this approach and implemented it over two terms in three sections of an introductory physics course for preservice elementary teachers. Learning gains for content understanding were assessed using pretests and post-tests. Participants achieved remarkably high gains for both static and accelerating situations. Surveys preand postinstruction showed substantially improved appreciation of language issues and ambiguities associated with weight, weightlessness, and free fall. Interviews with instructors teaching the module provided additional insight into the advantages and teaching demands of the new approach.

The term “weight” has multiple related meanings in both scientific and everyday usage. Even among experts and in textbooks, weight is ambiguously defined as either the gravitational force on an object or operationally as the magnitude of the force an object exerts on a measuring scale. This poses both conceptual and language difficulties for learners, especially for accelerating objects where the scale reading is different from the gravitational force. But while the underlying physical constructs behind the two referents for the term weight (and their relation to each other) are well understood scientifically, it is unclear how the concept of weight should be introduced to students and how the language ambiguities should be dealt with. We investigated treatments of weight in a sample of twenty introductory college physics textbooks, analyzing and coding their content based on the definition adopted, how the distinct constructs were dealt with in various situations, terminologies used, and whether and how language issues were handled. Results indicate that language-related issues, such as different, inconsistent, or ambiguous uses of the terms weight, “apparent weight,” and “weightlessness,” were prevalent both across and within textbooks. The physics of the related constructs was not always clearly presented, particularly for accelerating bodies such as astronauts in spaceships, and the language issue was rarely addressed. Our analysis of both literature and textbooks leads us to an instructional position which focuses on the physics constructs before introducing the term weight, and which explicitly discusses the associated language issues.

In recent years, inquiry-based science instruction has become widely advocated in science education standards in many countries and, hence, in teacher preparation programmes. Nevertheless, in practice, one finds a wide variety of science instructional approaches. In South Africa, as in many countries, there is also a great disparity in school demographic situations, which can also affect teaching practices. This study investigated the pedagogical orientations of in-service physical sciences teachers at a diversity of schools in South Africa. Assessment items in a Pedagogy of Science Teaching Test (POSTT) were used to identify teachers’ science teaching orientations, and reasons for pedagogical choices were probed in interviews. The findings reveal remarkable differences between the orientations of teachers at disadvantaged township schools and teachers at more privileged suburban schools. We found that teachers at township schools have a strong ‘active direct’ teaching orientation overall, involving direct exposition of the science followed by confirmatory practical work, while teachers at suburban schools exhibit a guided inquiry orientation, with concepts being developed via a guided exploration phase. The study identified contextual factors such as class size, availability of resources, teacher competence and confidence, time constraints, student ability, school culture and parents’ expectations as influencing the methods adopted by teachers. In view of the recent imperative for inquiry-based learning in the new South African curriculum, this study affirms the context specificity of curriculum implementation (Bybee 1993) and suggests situational factors beyond the curriculum mandate that need to be addressed to achieve successful inquiry-based classroom instruction in science.

A critical aspect of teacher education is gaining pedagogical content knowledge of how to teach science for conceptual understanding. Given the time limitations of college methods courses, it is difficult to touch on more than a fraction of the science topics potentially taught across grades K-8, particularly in the context of relevant pedagogies. This research and development work centers on constructing a formative assessment resource to help expose pre-service teachers to a greater number of science topics within teaching episodes using various modes of instruction. To this end, 100 problem-based, science pedagogy assessment items were developed via expert group discussions and pilot testing. Each item contains a classroom vignette followed by response choices carefully crafted to include four basic pedagogies (didactic direct, active direct, guided inquiry, and open inquiry). The brief but numerous items allow a substantial increase in the number of science topics that pre-service students may consider. The intention is that students and teachers will be able to share and discuss particular responses to individual items, or else record their responses to collections of items and thereby create a snapshot profile of their teaching orientations. Subsets of items were piloted with students in pre-service science methods courses, and the quantitative results of student responses were spread sufficiently to suggest that the items can be effective for their intended purpose.

Planning and implementing successful classroom science instruction for concept learning is a demanding task for teachers, requiring several kinds of knowledge: content knowledge, pedagogy knowledge, and knowledge of inquiry. Together this knowledge is the Pedagogical Content Knowledge of Science Instruction. Science teacher education programs routinely include science content courses where knowledge of science is assessed. Much less attention has been given to the assessment of knowledge pertaining to the pedagogies of science content instruction as typically taught in science teaching methods courses. Our assessment items are for this purpose. Each item begins with a classroom teaching vignette followed by a question asking either for an evaluation of what was done in the vignette or preference for what should be done. Although the items were designed with formative assessment in mind, sets of items can also be compiled for summative or research purposes, with versions for different science subjects and grade levels. The instruments can be used to identify science teaching orientations and pedagogical content knowledge of science instruction. This paper describes the development and testing of the items, concluding with comments on applications for instruction and future research. Example items of different types are provided and illustrative results discussed.

Planning and implementing successful classroom science instruction for concept learning is a demanding task for teachers, requiring several kinds of knowledge: content knowledge, pedagogy knowledge, and knowledge of inquiry. Together this knowledge is the Pedagogical Content Knowledge of Science Instruction. Science teacher education programs routinely include science content courses where knowledge of science is assessed. Much less attention has been given to the assessment of knowledge pertaining to the pedagogies of science content instruction as typically taught in science teaching methods courses. Our assessment items are for this purpose. Each item begins with a classroom teaching vignette followed by a question asking either for an evaluation of what was done in the vignette or preference for what should be done. Although the items were designed with formative assessment in mind, sets of items can also be compiled for summative or research purposes, with versions for different science subjects and grade levels. The instruments can be used to identify science teaching orientations and pedagogical content knowledge of science instruction. This paper describes the development and testing of the items, concluding with comments on applications for instruction and future research. Example items of different types are provided and illustrative results discussed.

There are continuing educational and political debates about 'inquiry' versus 'direct' teaching of science. Traditional science instruction has been largely direct but in the US, recent national and state science education standards advocate inquiry throughout K‐12 education. While inquiry‐based instruction has the advantage of modelling aspects of the nature of real scientific inquiry, there is little unconfounded comparative research into the effectiveness and efficiency of the two instructional modes for developing science conceptual understanding. This research undertook a controlled experimental study comparing the efficacy of carefully designed inquiry instruction and equally carefully designed direct instruction in realistic science classroom situations at the middle school grades. The research design addressed common threats to validity. We report on the nature of the instructional units in each mode, research design, methods, classroom implementations, monitoring, assessments, analysis and project findings.

Motion is a topic that is taught from elementary grades through to university at various levels of sophistication. It is an area that can be challenging for learning in a conceptually meaningful way, and formal kinematics instruction can sometimes seem dry and boring. Thus, the nature of students' initial introduction to motion is important in sparking their interest, shaping their perspective, and developing conceptual understanding of motion. The kinematic concepts we want students to acquire for basic motions are: position, time, speed, direction, velocity, velocity change, change rate, and acceleration, all with respect to a frame of reference. In this article we describe a challenge game used as an “opener” to motion, in which students themselves essentially generate these concepts, in everyday language, from a perceived need for them.

We have investigated and analyzed the cognition of an expert tackling a qualitative conceptual physics problem of an unfamiliar type. Our goal was to elucidate the detailed cognitive processes and knowledge elements involved, irrespective of final solution form, and consider implications for instruction. The basic but non-trivial problem was to find qualitatively the direction of acceleration of a pendulum bob at various stages of its motion, a problem originally studied by Reif and Allen. Methodology included interviews, introspection, retrospection and self-reported metacognition. Multiple facets of cognition were revealed, with different reasoning strategies used at different stages and for different points on the path. An account is given of the zigzag thinking paths and interplay of reasoning modes and schema elements involved. We interpret the cognitive processes in terms of theoretical concepts that emerged, namely: case-based, principle-based, experiential-intuitive and practical-heuristic reasoning; knowledge elements and schemata; activation; metacognition and epistemic framing. The complexity of cognition revealed in this case study contrasts with the tidy principle-based solutions we present to students. The pervasive role of schemata, case-based reasoning, practical heuristic strategies, and their interplay with physics principles is noteworthy, since these aspects of cognition are generally neither recognized nor taught. The schema/reasoning-mode perspective has direct application in science teaching, learning and problem-solving.

We have investigated how students tackle problems in geometric optics involving ray construction, to try to understand the nature and origin Of the Surprisingly wide variety of students' solution attempts. We find that students use various reasoning, modes and knowledge elements in conjunction. Their thinking may usefully be described as an interplay of principle-based and case-based reasoning, drawing on a knowledge mixture of basic principles, procedures, specific cases and recalled result features. Even though we usually present Solutions and teach problem solving as a systematic application of principles, real cognition is more complex. Associative thinking in terms of prior cases seems to be a strong natural tendency of both novices and experts. However, novices are not easily able to discriminate the specific from the general. and tend to lack epistemic awareness and metacognitive skills. Our research findings will be illustrated by examples of student thinking on a basic reflection problem. Implications for learning and instruction are discussed.

We have used LabVIEW visual programming to build an interactive tutorial to promote conceptual understanding in physics problem solving. This programming environment is able to offer a web-accessible problem solving experience that enables students to work at their own pace and receive feedback. Intuitive graphical symbols, modular structures and die ability to create templates are just a few of the advantages this software has to offer. The architecture of an application can be designed in a way that allows instructors with little knowledge of LabVIEW to easily personalize it. Both the physics Solution and the interactive pedagogy can be Visually programmed in LabVIEW. Our physics pedagogy approach is that of cognitive apprenticeship, in that the tutorial guides students to develop conceptual understanding and physical insight into phenomena, rather than purely formula-based Solutions. We demonstrate how this model is reflected in the design and programming of the interactive tutorials.

Problem-solving is an important part of physics teaching, learning and assessment. It is widely assumed that the way that experts solve problems, and students should, is by systematic application of basic physics principles. Model solutions are laid out this way, and teaching of problem-solving usually consists of 'going over' such solutions step by step. However, while this does represent the physics structure of the final solution, it does not adequately reflect how people actually think when tackling problems. Real cognition is complex. This study was prompted by students trying to 'map across' result features recalled from previous cases instead of working from basics. Since our instruction emphasizes the power and generality of basic principles, our first response was to re-emphasize principles, but we found that experts in fact draw extensively and effectively on rich compiled case knowledge. We investigated cognition in detail for geometrical optics. Research methods included analysis of written solutions, reflections on thinking, and interviews. Cognitive modes emerged from the initial research stages, and were then used to code individuals' problem-solving pathways. Learners and experts alike used multiple modes of cognition, significantly principle-based reasoning, case-based reasoning and experiential-intuitive reasoning. Case-based reasoning using pre-compiled knowledge played a pervasive role in conjunction with, and sometimes in conflict with, principle-based reasoning. The implications for instruction are that it should reflect what we know about cognition and expertise, and hence include teaching case-based as well as principle-based reasoning. We are doing this in optics, by using cases and variations, identifying topic knowledge schema 'sub-assemblies', and modeling their use in problems.

The first and most compelling evidence of the universe's expansion was, and continues to be, the observed redshift of spectra from distant objects. This paper plays "devil's advocate" by providing an alternative explanation with elementary physics. I assume a steady-state universe that is infinite in both expanse and age, with the observed redshifts caused by particle interactions creating an overall index of refraction of the universe. The cumulative effects of these interactions over long distances cause not only the shifts that we observe, but also the monotonically increasing redshifts as more distant objects are observed. This is a novel explanation for the phenomenon known as "tired light" which has been discussed for decades.