Piaget's constructivism argues that learning is an active process where individuals construct new knowledge from experiences through processes of assimilation and accommodation. The role of the teacher is as a facilitator who supports developmentally-appropriate, learner-initiated learning. Papert's constructionism builds on Piaget's ideas and sees learning as an active process where students construct mental models through creative experimentation and making social objects. The teacher takes a mediating role and stresses the importance of tools, media, and context in how knowledge is formed and transformed.