Abstract
The rapid growth of the Internet, coupled with improved multimedia capabilities in computing, has expanded the options for using technology to support collaborative learning. Asynchronous electronic conferencing is commonly used to support distributed discourse-based learning. Mind Bridges is a Web-based threaded discussion forum with support for embedded multimedia content. This paper describes the Mind Bridges system as well as an empirical study of its use to support science learning. We monitored the pattern of usage and the trajectory of collaborative discourse manifested by participants. We found a shift in the percentage of shallow comments and learned facts towards independent thinking statements over time. However, improvement in students? conceptual understanding was hindered by their weak reasoning abilities.