The study employed clinical interview to investigate 60 young children's (5-year old) conceptions about light and shadow. The major findings were as follows: (1) Light is equated to its source (or things that glow), or the shinning effect of light, or both; (2) More than half children hold alternative views about shadow especially in that light plays positive role on shadow. Based on above findings, the suggestions are: (1) increase the amount of research on scientific concepts development and on early Science teaching; (2) Scaffold children's learning by guiding skill of observing and thinking.