this link tells about Montessori school system http://en.wikipedia.org/wiki/Montessori_education
Montessori education is characterized by an emphasis on independence, freedom within limits, and respect for a child’s natural psychological development, as well as technological advancements in society. Although a range of practices exists under the name "Montessori", the Association Montessori Internationale (AMI) and the American Montessori Society (AMS) cite these elements as essential:
Mixed age classrooms, with classrooms for children aged 2½ or 3 to 6 years old by far the most common
Student choice of activity from within a prescribed range of options
Uninterrupted blocks of work time
A Constructivism or "discovery" model, where students learn concepts from working with materials, rather than by direct instruction
Specialized educational materials developed by Montessori and her collaborators
In addition, many Montessori schools design their programs with reference to Montessori’s model of human development from her published works, and use pedagogy, lessons, and materials introduced in teacher training derived from courses presented by Montessori during her lifetime.