Foreign language learning and science teaching can both be seen as examples of Davydov's "ascent to the concrete", because they begin from abstract definitions and proceed in the direction of concrete use. The microgenetic lessons that enable these ontogenetic processes can also be seen as examples of "ascent of the concrete" because they involve, in the case of foreign language teaching, first definition and then concrete use of language, and in the case of science teaching, first formulation of science concepts and then their concrete demonstration. The formulation of science concepts often involves what Halliday refers to as grammatical metaphor, a lexical condensation we shall refer to as grammatical reification. In our data, which involves teaching science through a foreign language, we find episodes of language teaching embedded in episodes concerned with science. We also observe that grammatical reification is denser early in the exchange, but late in the lesson. We claim that these differences in distribution are the result of deliberate decisions by the teacher, whose goal is not simply maintaining power but helping children to convert purely verbal knowledge into knowledge for use.