This paper argues that the metaphorical representation of concepts and the appropriation of language-based construals can be hypothesized as additional sources of conceptual change alongside those previously proposed. Analyses of construals implicit in the lay and scientific use of the noun "energy" from the perspective of the theory of conceptual metaphor are summarized. The experientially grounded metaphorical construals identified in both uses help conceptualize the shift from the concrete, naive to the abstract, scientific understanding of energy. The case of the concept of energy motivates the more general hypothesis that an important part of learning a highly abstract (even mathematical) concept is the appropriation of experientially grounded metaphorical construals implicit in scientific discourse. Pedagogical implications of this proposal are discussed.