One area explored in the second (in-depth) phase of the Learning in Science Project was "children's science," defined as views of the world and the meanings for words that children have and bring with them to science lessons. The investigation reported focuses on the concept of "energy" held by 52 Form 1 to 6 students. Data were obtained by the "interview-about-instances" procedure in which students were shown diagrams on cards which represented different instances (exemplars) and non-instances (non-exemplars) of the concept. Section 1 discusses methodology. Section 2 considers important aspects of scientists' views of energy, including energy conservation, heat and work, and internal energy. Section 3 details various aspects of students' views about energy, while section 4 examines other aspects of students' answers to interview questions and their implications for teaching. Section 5 considers scientific perspectives that some students do have. Section 6 offers several suggestions, based on the finding that children have and tend to retain the everyday use of the word, for modifying/qualifying children's views to make them more scientific. Included in appendices are interview cards used (with a scientific description of the energy involved in each situation) and selected answers to the question "Where does energy come from?" (JN)