Despite Singapore's excellent science achievements in international benchmark tests such as the Trends in International Mathematics and Science Study (TIMSS) and Programme for International Student Assessment (PISA), little is known about Singaporean children's (aged 4-8) emerging science conceptions as formal science schooling begins at Grade 3 (aged 9). This paper builds on the well-established literature on preschool children's emerging conceptions and play to illuminate children's ideas about floating and sinking. Using narratives of a 90-minute activity involving a group of Singaporean children aged 6, we surfaced emerging conceptions that an object floats or sinks due to its weight, and that objects sink because water is "soft"--a conception that has not been reported in previous literature. We also observed a shift from binary discourse about floating and sinking to more graded descriptions (e.g. "sink a bit") as the children played more. The play-based activity provided opportunities for the children's emerging conceptions to be elicited because it was conceptually-oriented and created opportunities for social interactions. It allowed children who were not proficient in standard English to express their thinking in actions. In sum, this paper illustrates how play-based contexts could be used to identify children's emerging conceptions.