This study aims to explore how to use an AI chatbot pedagogically in scientific inquiry by developing a guided-inquiry activity using an AI chatbot and applying it. The developed guided-inquiry activity consisted of designing and doing inquiry activities using the transmission of sound as the topic. In this activity, a chatbot, which was given the name Inquirybot, was designed with conversation flow and scripts for guiding the inquiry design process. By applying the developed inquiry activities and Inquirybot to fifth- and sixth-grade gifted students, we found several practical possibilities and challenges for using an AI chatbot in scientific inquiry. Based on the results, future tasks and educational implications are discussed in terms of efficiently adapting AI chatbots in scientific-inquiry activities.