• the constructivist theories of Jean Piaget arguing that human learning is no the result of a transmission of knowledge, but an active process of knowledge construction based on experiences gained from the real world and linked to personal, unique pre-knowledge (Piaget 1972).
• the constructionist educational philosophy of S. Papert adding that the construction of new knowledge is more effective when the learners are engaged in constructing products that are personally meaningful to them. Constructionism (Papert, 1992), is a natural extension of constructivism and emphasizes the hands-on aspect. The learners in a constructionist environment build something on their own, preferably a tangible object that they can both touch and find meaningful. The goal of constructionism is giving children good things to do so that they can learn by doing much better than they could before (Papert, 1980).

In this theoretical frame a socio-constructivist view is adopted, where learning is not an individual, but a particularly social and societal activity that means that learning always takes place in a social context. Under such a framework the use of educational technology could contribute to the realisation of

So, a first premise of this project concerns the implementation of constructivist -constructionist methods not only in classroom, but in teacher education as well. A second premise is referred to the technology-enhanced learning as occurred in the implementation of different kinds of curriculum innovation in the classrooms. A third is related with the emerging need for a teaching as a research-based profession and for the creation of a culture in which researchers and teachers can create a shared body of knowledge.

Research in science and technology education has made possible the development of learning strategies and materials that attempt to meet students' needs and address their learning difficulties, such as computer-based learning environments and microcomputer-based laboratory tools. Nowadays, increasing attention is paid to computer-based modelling activities. Computer-aided modelling in learning is considered to be a valuable learning tool that contributes to the enhancement of learning and the development of student thinking. Taking into consideration that students have a better understanding when they express themselves through invention and creation (Piaget, 1974), teachers need to provide students with the opportunity to design, build and program their own models. Programming as a general model-building and toolmaking learning environment has been shown to support constructionist learning across the curriculum (Papert, 1992). The LEGO robot, an outgrowth of Papert's LOGO programming language created in the 1960's, partners technology with constructionism ideas.

Under this framework, programmable robotic constructions have recently been proposed promising to enhance students' learning science and technology concepts. The Lego Mindstorms system (http://www.legomindstorms.com) provides a flexible medium for constructionist learning, offering opportunities for design and construction with limited time and small funds. It is comprised of building materials (regular blocks, gears, pulleys and axels) and the programming software Robolab (http://www.ceeo.tufts.edu/) offering a simple graphical interface for writing programs to create behaviours for the LEGO robots. The programmable constructions make possible new types of science experiments, in which children investigate everyday phenomena in their lives (both in and out of the classroom).

References

• Papert, S. (1980). Mindstorms: Children, Computers, and Powerful Ideas. N.Y.: Basic Books
• Papert, S. (1992). The Children's Machine. N.Y.: Basic Books.
• Piaget, J. (1972). The Principles of Genetic Epistemology. N. Y.: Basic Books.
• Piaget, J. (1974), To understand is to invent. N.Y.: Basic Books.