Typically used in K-12 science classes, this model offers a simple way to incorporated inquiry-based learning into a higher ed. course. The initial 'enagagement' activity creates in the learners a need to know. They then "define questions, issues or problems that relate to his/her world."
See also http://mlab.uiah.fi/fle/research/enable.html for a model of the inquiry learning process where all students and tutors are sharing and distributing their existing knowledge for each other.
Via Sue Hellman