Many popular hands-on science activities, as traditionally implemented, fail to support inquiry-based science instruction, because the activities direct teachers to terminate lessons prematurely. This paper presents a model describing one approach for extending seemingly limited hands-on activities into full-inquiry science lessons. The strategy involves (a) discrepant events to engage students in direct inquiry; (b) teacher-supported brainstorming activities to facilitate students in planning investigations; (c) effective written job performance aids to provide structure and support; (d) requirements that students provide a product of their research, which usually includes a class presentation and a graph; and (e) class discussion and writing activities to facilitate students in reflecting on their activities and learning. The paper presents the model as a tool for facilitating science teachers' efforts to understand and implement the type of powerful, effective, and manageable inquiry-based science instruction called for in the National Science Education Standards.Extending Hands-On Science: 3 With paternal compassion, the guru of classroom management, Harry Wong, urged educators to give novice teachers permission to engage their students in pedagogically questionable textbook-and worksheet-driven activities (Wong, 1998;Wong & Wong, 1998).Such activities, according to Wong, are relatively harmless, provided that teachers eventually move beyond them. Wong contended that novice teachers rely on textbooks and worksheets as their "primary survival tools," and they should be given them permission to do what they must do to survive. Research on teaching practices suggests that Wong's advice is well founded. Both novice and experienced teachers appear to rely heavily upon textbooks when making decisions about what and how to teach (Bellen, Bellen & Blank, 1992;Roth, Roffie, Lucas & Boutonné, 1997;Sánchez & Valcarcel, 1999). For example, in a survey of experienced and novice teachers in Spain, researchers Sánchez and Valcarcel, (1999) found almost all of the teachers (92%) used textbooks as a basic reference for their planning units.Textbooks served as the only guide for 33% of the teachers, and for most of the teachers (59%), textbooks served as the "basic pillar of the lesson" (p. 499).Unfortunately, hands-on activities recommended by many science textbooks and worksheets are typically presented as step-by-step instructions. As discussed in the National Science Education Standards (National Research Council, 1996), when science teachers move beyond worksheets and step-by-step procedures in order to engage students in inquiry, they must constantly struggle to guide student inquiry toward curriculum goals. As pointed out by Crawford (1999), this ongoing demand for improvisation during teaching can be expected to create a substantial stumbling block for novice science teachers. Concerns about the substantial challenges inherent in implementing inquiry-based science instruction, as Extending Hands-On Science: 4 ...