We propose a new perspective, seeing interactivity that is the immaterial part of an interactive artifact as something concretely describable and perceivable as we do with physical materials. In order to examine the validity of this proposal, we extracted a set of interactivity attributes to be used as a design language for thinking and describing interactivity in a new way, and conducted an online survey with 14 Flash prototypes representing pairs of values of 7 interactivity attributes we extracted. The result showed that all the interactivity attributes were significant, and participants experienced distinctive and meaningful emotional effects for different interactivity attributes. Author Keywords Interaction design, interactivity, design language, emotion ACM Classification Keywords H.5.2 [User Interfaces]: Theory and methods, User-centered design.