Early approach to theoretical thinking: gears in primary school

Gears are part of everyday experience from very early childhood. This paper analyses a teaching experiment conducted with 4th graders in the field of experience of gears. The aim is to identify the characteristics which, given a suitable sequence of tasks and proper teacher guidance, have enabled the pupils to approach theoretical thinking, and in particular mathematical theorems. We have focused on the relationships between the epistemological analysis of some pieces of mathematical knowledge brought into play in tasks concerning gears, cognitive analysis of pupil construction of those pieces of mathematical knowledge, and didactic analysis of the teacher's role in designing tasks and in offering cultural mediation. This paper presents the early findings of the teaching experiments, both at the external level of interpersonal classroom processes and at the inner level of individual mental processes. This revised version was published online in July 2006 with corrections to the Cover Date.     

African Universities and the African Heritage

This article deals with the role of the universities in Africa. What are the challenges for educators who want to root African education in African traditions? After a brief look at pre- colonial and colonial education the article goes on to describe the situation after independence and especially the effects on higher education of a concentration of resources on basic education. To what extent do the link arrangements built up between universities in the North and the South perpetuate a colonial situation? What can be done to restore the dignity and heritage of the African people through university training? Examples are mostly taken from Tanzania, the country in Africa the author knows best.     

Effects of learning cycle and traditional text on comprehension of science concepts by students at differing reasoning levels

Research has found the learning cycle to be effective for science instruction in hands‐on laboratories and interactive discussions. Can the learning cycle, in which examples precede the introduction of new terms, also be applied effectively to science text? A total of 123 high school students from two suburban schools were tested for reasoning ability, then randomly assigned to read either a learning cycle or traditional text passage. Immediate and delayed posttests provided concept comprehension scores that were analyzed by type of text passage and by reasoning level. Students who read the learning cycle passage earned higher scores on concept comprehension questions than those who read the traditional passage, at all reasoning levels. This result supports the hypothesis that reading comprehension and scientific inquiry involve similar information‐processing strategies and confirms the prediction that science text presented in the learning cycle format is more comprehensible for readers at all reasoning levels. © 1999 John Wiley & Sons, Inc. J Res Sci Teach 36: 23–37, 1999.     

Scientific discovery and topological transitions in collaboration networks

We analyze the advent and development of eight scientific fields from their inception to maturity and map the evolution of their networks of collaboration over time, measured in terms of co-authorship of scientific papers. We show that as a field develops it undergoes a topological transition in its collaboration structure between a small disconnected graph to a much larger network where a giant connected component of collaboration appears. As a result, the number of edges and nodes in the largest component undergoes a transition between a small fraction of the total to a majority of all occurrences. These results relate to many qualitative observations of the evolution of technology and discussions of the “structure of scientific revolutions”. We analyze this qualitative change in network topology in terms of several quantitative graph theoretical measures, such as density, diameter, and relative size of the network's largest component.To analyze examples of scientific discovery we built databases of scientific publications based on keyword and citation searches, for eight fields, spanning experimental and theoretical science, across areas as diverse as physics, biomedical sciences, and materials science. Each of the databases was vetted by field experts and is the result of a bibliometric search constructed to maximize coverage, while minimizing the occurrence of spurious records. In this way we built databases of publications and authors for superstring theory, cosmic strings and other topological defects, cosmological inflation, carbon nanotubes, quantum computing and computation, prions and scrapie, and H5N1 influenza. We also built a database for a classical example of “pathological” science, namely cold fusion. All these fields also vary in size and in their temporal patterns of development, with some showing explosive growth from an original identifiable discovery (e.g. carbon nanotubes) while others are characterized by a slow process of development (e.g. quantum computers and computation).We show that regardless of the detailed nature of their developmental paths, the process of scientific discovery and the rearrangement of the collaboration structure of emergent fields is characterized by a number of universal features, suggesting that the process of discovery and initial formation of a scientific field, characterized by the moments of discovery, invention and subsequent transition into “normal science” may be understood in general terms, as a process of cognitive and social unification out of many initially separate efforts. Pathological fields, seemingly, never undergo this transition, despite hundreds of publications and the involvement of many authors.     

Student trajectories in physics: the need for analysis through a socio-cultural lens

An analysis of student connections through time and space relative to the core discipline of physics is attempted, as viewed through the lens of actor-network-theory, by Antonia Candela. Using lenses of cultural realities, networks, and perceived power in the discourse of one specific university in the capital city of Mexico and one undergraduate physics classroom, the trajectories and itineraries of students are analyzed, relative to a physics professor’s pedagogical practices. This ethnographic study then yields comparisons between Mexican undergraduate students and students from the United States. Actor network theory recognizes that the symbiotic relationship existing between an actor and a continuum of space and time is defined by the symbiotic yet interdependent relationships and networks of practice (Lemke in Downward causation: Minds, bodies, and matter 2000). As part of this study and in line with actor-network-theory, human actors and non-human participants were viewed in relation to how subjects acted and were acted upon within networks of practice. Through this forum I reflect on this work with particular focus on the issues of situatedness of actors from a sociocultural perspective and how established networks viewed within this perspective frame and subsequently impact student trajectories and itineraries. In essence I argue for a need to look at a myriad of further complexities driving the symbiotic relationships being analyzed.     

Research and policy on the language of instruction issue in Africa

Since 1995 I have been engaged in consultancies and since 2001 in research dealing with the language of instruction policies in Africa. To what extent are the policies being implemented? What is the role of research and consultancy when it comes to language policy? What happens when researchers or consultants come up with recommendations which do not please donors or the people of power? My paper builds on a consultancy on the language policy of Namibia from 1995, the stock-taking exercise of ADEA/GTZ/UIL of 2006, as well as on research results and experiences gathered within the LOITASA (Language of Instruction in Tanzania and South Africa) project. In the first part of the article I give two examples where the policy recommendations by the consultants/researchers have not been followed up. I give an example of a consultancy that has had some impact on the policy formulation in some African countries. Recommendations from only one of the four studies/consultancies looked at have been thoroughly followed up. These recommendations were in line with what the donors wanted, but did not logically follow from the research done. In the second part of the article I deal with the challenge of making policy research relevant for those most greatly affected by the policy. This means working for a paradigm shift in the research and consultancy on language policies in Africa. It also means looking at the power of misconceptions held by lay people. Towards the end of the article I discuss changing a belief system which has become common knowledge. I show examples of how Tanzanian colleagues in the LOITASA project are trying to do this.     

Equivalence of Population Variances: Synchronizing the Objective and Analysis

Researchers are often interested in establishing equivalence of population variances. Traditional difference-based procedures are appropriate to answer questions about differences in some statistic (e.g., variances, etc.). However, if a researcher is interested in evaluating the equivalence of population variances, it is more appropriate to use a procedure designed to determine equivalence. A simulation study was used to compare novel equivalence-based tests to traditional variance homogeneity tests under common data conditions. Results demonstrated that traditional difference-based tests assess equality of variances from the wrong perspective and that the proposed Levene-Wellek-Welch test for equivalence of group variances the best performing test for detecting equivalence. An R function is provided in order to facilitate use of this test for equivalence of population variances.