Constructivism is a learning theory that emphasizes active learning through hands-on experiences and collaboration. Key contributors include Piaget, Bruner, Vygotsky, and Dewey. According to constructivism, learning occurs as students actively construct new knowledge based on their previous knowledge and experiences. In the classroom, teachers should facilitate hands-on projects, problem solving activities, and discussions to help students build upon what they already know. Technology can also be incorporated to enhance constructivist learning through virtual experiences, educational videos, and online collaboration.