ABSTRACT
The development of language and understanding are closely interwoven, as studies by Piaget, Vygotsky, Bruner and many others have shown. Understanding is a constructive process in which the reader interacts with the text. Science educators in many countries, therefore, attach greater importance to the role of written and spoken language in effective science teaching than before. They are more aware of the part language plays in the growth of ideas. Important books have been written on this topic (Prestt, 1980; Vollmer, 1980; Bulman, 1985; White and Welford, 1988).
