SEEING IS NOT UNDERSTANDING: Vygotsky, Halliday and Metaphor in Forming and Forgetting Middle School Science Concepts.

When teachers explain science concepts-for example, the solar wind, or plasma waves-some methods seem to be quick-acting and others long-lasting. Still others pose as many problems as they seem to solve. How, for example, does a parent explain how there can be solar wind without any air in space? How does a teacher explain how there can be plasma waves without any water? Locating metaphor between thinking and speech rather than within one or the other, we work out a single scheme to analyze two conversations with adult Koreans. These suggest that a text studied some ten years ago in middle school science class, replete with striking visual images, has left little more than everyday concepts. Instead of trying to use the striking visual images to refill gaps in the memory, however, the questions asked by a skilled science teacher suggest ways in which thinking could be freed from the middle school dogma of only three matter phases (solid, liquid, gas). To understand a metaphor like "solar wind", we need to replace fixed matters of fact with some more elusive facts of matter.