"Discovery Learning is a method of inquiry-based instruction, discovery learning believes that it is best for learners to discover facts and relationships for themselves."
see http://www.learning-theories.com/discovery-learning-bruner.html

"Discovery Learning is a method of inquiry-based instruction and is considered a constructivist based approach to education. It is supported by the work of learning theorists and psychologists Jean Piaget, Jerome Bruner, and Seymour Papert. Although this form of instruction has great popularity, there is some debate in the literature concerning its efficacy (Mayer, 2004)."
see http://en.wikipedia.org/wiki/Discovery_learning

If you would like to know why minimal guidance during instruction does not work go to http://projects.ict.usc.edu/dlxxi/materials/clark/Constructivism_EP_05_Kirschner_Sweller_Clark_Ss.pdf