The document discusses constructivist learning theory, which emphasizes active learning through group activities, constructing knowledge rather than acquiring it, debates, and reflecting on experiences. Key theorists who developed constructivism include John Dewey, Piaget, George Kelly, and Lev Vygotsky. Constructivism is used in classrooms by having teachers act as facilitators rather than lecturers, utilizing group work, Socratic discussions, and collaborative projects to help students construct their own understanding.