Let’s talk about free play: problem solving and imaginative experimentation.  Did you notice the words after the colon in the preceding sentence?  That explanatory phrase is one way of addressing a difficulty we face in approaching the subject of play: language.
The word “play” often implies, as www.dictionary.com says: “the opposite of work”.  Can’t be serious then, right?
The Miriam-Webster dictionary defines play as:
“Engaging in an activity for enjoyment or recreation rather than for a serious or useful purpose: the children were playing outside: their friends were playing with their dolls.”

Play that is  “purposeless”  – not oriented toward a particular end – allows freedom to experiment and learn some of the very serious lessons of life. It is also the crucial difference between free play and the sports, dance classes and other programmed events that dominate so many young children’s schedules.  It stands in stark contrast, as so many teachers tell me, to the formulaic ways in which children are playing with toys that are related to movies and television shows.
There is a science of play.  Stuart Brown, M.D. Founder of the National Institute for Play, sees play in its evolutionary terms.  He followed the trail of play in animals and humans. He states in his book  Play: How it Shapes the Brain, Opens the Imagination and Invigorates the Soul that brain imaging confirms that the period of play in each species is  tied to the size and rate of growth of the cerebellum, which research now shows is responsible for attention, language processing, sensing musical rhythm and more.
We need to get this straight: play is, as Vivian Gussin Paley says in Child’s Work: The Importance of Fantasy Play :“the work of childhood”.  We give lip service to children being “our future”, yet we underpay those who provide developmentally appropriate environments for them and undervalue their natural way of learning.  In Crisis in the Kindergarten:A New Report on the Disappearance of Play, the Alliance for Childhood reports:  “New research shows that many kindergartens spend 2 to 3 hours per day instructing and testing children in literacy and math—with only 30 minutes per day or less for play.”

Parents often approach me at workshops with the question: “Will my child be “behind” if we don’t let her have television, computer and video games until after she is eight?”  I answer: “No.  Let her form her own voice until eight or nine and then she can use all the media tools for articulating her own perceptions.”
This view is confirmed by Henry Jenkins, recently retired head of the  MIT Comparative Media Studies Program, and his colleagues in an occasional paper on digital media and learning: Confronting the Challenges of Participatory Culture: Media Education for the 21st Century, published in June, 2009. The first chapter of that study is “The Needed Skills in the New Media Culture”.  What is number one on the list of skills these MIT researchers, no Luddites, say is necessary to be able to use technology in the future?  “Play: The ability to experiment with one’s surroundings as a form of problem solving.”