Exploration of questions leads to more questions. Depending upon students' response, the teacher encourages abstract as well as concrete, poetic as well as practical, creations of new knowledge. Students have ideas that later they may see were invalid, incorrect, or insufficient to explain new experiences. These ideas are temporary steps in the integration of knowledge. For instance, a child may believe that all trees lose their leaves in the fall, until she visits an evergreen forest.
Constructivist teaching takes into account students' current conceptions and builds from there.
It may take some work, but it's just a matter of finding the right fit, as with a puzzle piece. The student has to change her previous understanding to find a fit for the information. This can be harder work. Rejected bits of information may just not be absorbed by the student. Or they may float around, waiting for the day when the student's understanding has developed and permits a fit.