As teachers adopt technology in their classrooms and develop the pedagogical models that will allow them to make use of the affordances of the technology, we are seeing improved learning outcomes and high-quality learning demonstrated. The pedagogical models that are showing the most promise come from ideas about how designers can implement the class of theories referred to as constructivism. Designers of technology-based learning environments can draw on the work of the many writers who have sought to develop guidelines and heuristics to support new modes of learning (see for example, Grabinger, 1996; Hannafin & Land, 1997; Squires, 1996). Constructivist frameworks are based upon the argument for learners being placed in authentic environments that incorporate sophisticated representations of context through such constructs as virtual "worlds". Learning experiences, which adopt these approaches, designed around bounded resources, such as CD-ROM technologies, are now well documented and many teachers have been making extensive use of these environments for some time. One such project, Exploring the Nardoo, which has been developed within constructivist frameworks as a virtual world has been acclaimed for its illustration of these concepts. The product displays varying degrees of fidelity of representation, learner immersion and active participation and has been shown to offer learning advantages for users. However, teachers need to continue to address the constantly changing nature of the capability of the technology, and potential learning opportunities offered by these changes. Unbounded environments, such as the World Wide Web, have offered a new set of affordances and now the concept of learning objects is set to again require teachers to re-conceptualise learning experiences for their students. The concept of a 'learning object' has developed from the movement to create reusable learning resources. Significant investment in content, described in terms of standards, which can be reused and re-purposed in education settings, is becoming a priority nationally (The Le@rning Federation, http://socci.edna.edu.au/newcms/view-page.asp) and internationally (Ariadne: http://ariadne.unil.ch/. Merlot: http://taste.merlot.org/, LRX: http://www.lrx.com.au/). Teachers are now seeking tools to make effective use of the myriad of learning objects that are now being developed, in such entities as digital libraries, to construct meaningful learning environments. This paper will review the changes in pedagogy which ICT based learning environments have been able to facilitate, report on research findings on learning outcomes for a series of innovative bounded CD-ROM learning environments, and review the potential of learning object technologies to again challenge teachers striving for high quality learning from their students.