Categorizing organisms as living or nonliving things may seem to be intuitive by nature. Yet, it is regulated by scientific criteria. Students come to school with rules already in place. Their categorizing criteria have already been influenced by their personal experiences, also known as observations and inferences. They believe that all things are alive in some way or another--either it can move on its own, have feelings, or can think for itself. The authors developed a series of lessons to address the topic of living versus nonliving. In building these lessons, the authors maintained an awareness of the effect of their own cultural influences and developmentally appropriate responses for six- to seven-year-olds. The lessons were designed to help first-grade students develop their observational skills, their ability to articulate their own thinking to others, and the skill of asking themselves provocative questions. (Contains 1 figure and 1 online resource.)