In the current study, we focus on teacher-student discourse in Pre-K science activities, with particular attention to teacher questioning. Videotaped classroom observations and teacher interviews served as the corpus of data. Overall, teachers asked mostly closed-ended questions, but used more open-ended questions when experiments were being conducted. During experiments, teachers' questions were aimed at prediction and reasoning. In contrast, teachers used primarily closed-ended questions when science skills were being practiced and during science book readings, when their questions were oriented toward recognition and recall of factual information. The effects of the teachers' questions can be seen in the students' responses. When questions were open-ended, students employed a more varied vocabulary and more complex sentence structures. When teachers' questions were oriented toward prediction and reasoning, students practiced these higher level cognitive skills in responding. Based on these findings, we provide recommendations for teaching practice in early childhood science education.