Preschool children (aged 5-6 years) in Singapore learn science by discovering, inquiring, and investigating things that interest them in their daily lives. One approach involves learning science through building and exploring robots based on the Artec robotics curriculum, developed by an established Japanese education provider, Artec Co., Ltd. This paper presents the findings from a research project that aimed to observe and identify the learning of a group of six preschool children (5 years) in science through an hour-long Artec robotics lesson, The Catch of the Day; this involved building a robotic fishing rod that mimics a real fishing rod. In terms of learning outcomes, the preschool children built, explored, and examined the science concepts and principles behind a real fishing rod by exploring the robotic version. This qualitative and quantitative research incorporates the research methods of documentary analysis and classroom observation. The results indicate that through the inquiry and investigation of the robotic fishing rod, the preschool children discovered the science concepts and principles of the spool, reel, and handle. The children learned that each fishing rod has a reel-to-reel fishing line to catch a fish. The preschool children observed that the reel's handle and spool were connected by the spool's gears, and upon turning the handle, the spool would spin to reel in the fishing line. The study demonstrates that it is productive for preschool children to learn science concepts and principles by building, exploring, and examining robots. The Artec robotic curriculum comprises various robotic themes for children to learn science and is a useful learning platform for preschool children in Singapore.