Science literacy is an increasingly important skill in the 21st century. With engagement and motivation as vital precursors to learning science, we believe introducing children to playful interactions with scientific phenomena would improve their motivations and attitudes towards science. To investigate this, we developed a tablet application where children journey in a story-driven game to capture virtual creatures by manipulating the sound measured using the built-in microphone. This game was designed with feedback from 16 children and 10 parents. In this paper, we describe the iterative design process and findings in a multi-day study with 11 more children aged between 8 and 12. Children were motivated by the game, demonstrated a strong association between sound and its behaviour in the physical world, and expressed enthusiasm to learn more in the classroom.