Sisters, Lydia and Amelia sit comfortably together, playing in the sand. Amelia repeatedly pours sand on her sister’s leg. Why? Notice that Amelia does not look up at her sister as if she expects a reaction. She does not set the spoon directly on Lydia’s leg as if to deposit the sand in a particular location. Amelia does observe how the sand lands on Lydia’ leg. The color contrast allows her to see the effect of the falling sand. If she poured sand directly into the box, then the spatter would be undetectable. From these observations, we speculate that Amelia is most interested in how to vary the effect of the sand as it falls.