This paper describes a pilot study of a computer simulation called WIIS, which is designed to extend students' learning experience of the sizes of the objects beyond human vision. By interacting with a simulation that incorporates temporal, aural, and visual representation (TAVR), students are expected to refine their mental model of the sizes of the objects too small to see with human eyes (called submacroscopic objects). The goals of the study are to explore whether middle school students can understand TAVR in a simulation and how they use their experience of interacting with TAVRs to refine their mental model of the sizes of submacroscopic objects. Keywords Learning technologies, multimodal representations, simulations ACM Classification Keywords H.5.1 Multimedia Information Systems, K.3.1 Computer uses in education