Constructivism in a Nutshell

"Constructivism is a model in psychology that characterizes learning as a process of actively constructing knowledge.  Individuals create meaning for themselves or make sense of new information by selecting, organizing, and integrating information with other knowledge, often in the context of social interactions." (EdPsych Modules, 2nd Edition)

There have been multiple occasions throughout my graduate studies in which the theories of Piaget and Vygotsky were mentioned when discussing students and their cognitive development.  But what are these theories and how can they be applied or observed in the classrooms? 

While both individuals may have different approaches when it comes to cognitive development, both would agree that 1) learning is a process of actively constructing knowledge, 2) cognitive development is an interaction between heredity and environment, 3) a symbolic system is needed for development, 4) internalized language is needed for conscious thought, promotes reflection, and helps plan, and 5) play is important.