In 1907 Montessori finally found a way to test her materials and methods on “normal” children. She began working with a group of 50 children in the San Lorenzo slums at the Casa dei Bambini, or House of Children. The children were too young to attend public school and were left alone while their parents worked.
Montessori approached the students as a doctor and scientist. She viewed the classroom as a laboratory where she could observe them interacting with her materials and discover how they learned. She developed letters made from sandpaper to give the children the feel of letter shapes. She introduced chairs, tables and sinks scaled to fit children aged 3 to 6. Children were encouraged to explore materials and develop their own sense-based experiences. Adults were only permitted to serve as guides, not lecturers.
Montessori’s experiments met with tremendous success. She found that learning was the natural state for children in an encouraging environment. The children in her care enjoyed learning. They did not need to be lectured or forcibly taught in order to perform well. In her “classroom,” the children taught themselves to read and write at ages younger than children in public schools taught with traditional methods of instruction.
Montessori’s success attracted international attention. She shared the results of her work in writings and through lectures. In the following decades, hundreds of Montessori-inspired schools opened in Europe and the United States.
In 1913 Montessori traveled to America at the behest of Mr. and Mrs. Alexander Graham Bell and magazine owner Sam McClure. She spoke to a sold-out Carnegie Hall audience of more than 5,000 people. Montessori also accepted an invitation to create a classroom at the Panama-Pacific Exposition in San Francisco where visitors were able to watch 21 children through a glass wall for four months. The classroom attracted enormous attention and was seen as a brilliant and convincing demonstration of Montessori’s principles.