Interesting thread on discovery learning, with notes from Alan Siegel’s study of videotaped Japanese Math lessons:

Discovery learning is fashionable in math reform circles, writes Seebach. The Japanese are supposed to be the models. But the Japanese teach traditionally — with “beautifully designed and superbly executed” lessons.
The videotape shows, Siegel says, that “a master teacher can present every step of a solution without divulging the answer, and can, by so doing, help students learn to think deeply. In such circumstances, the notion that students might have discovered the ideas on their own becomes an enticing mix of illusion intertwined with threads of truth.”