Infants have expectations about physical properties of solid objects. However, evidence on infants’ understanding of nonsolid substances (e.g., water or sand) is sparse and equivocal. We conducted four habituation/dishabituation experiments demonstrating that 5-month-olds have distinct expectations for how objects and substances behave. Experiment 1 found that infants use motion cues from the surface of a contained liquid or solid to predict whether it would pass through or rest on a grid when the container was upended. Experiment 2 extended these findings to show that motion cues led to different expectations about whether a new object will pass through or remain on the top surface of a liquid or solid. Experiments 3 and 4 replaced the liquid with sand. We found that infants expected sand, like liquid, to go through a grid, but did not expect another object to pass through it. These findings begin to characterize infants’ understanding of substances.