"Montessori material" is a general name for the teaching aids and activities within the classroom; which include a combination of specific Montessori apparatus and teacher made materials. Montessori designed her didactic apparatus by observing children, realizing that children need the comfort of using things their own size. The Montessori apparatus is introduced to children as they become ready for the 'next step' in their learning process. All activities are presented on a 1:1 basis; this way individual progress can be assessed and recorded enabling staff to track children's progression in attaining their early learning goals.
Each material teaches a single skill or concept at a time—for example, the various “dressing frames” help toddlers learn to button, zip, and tie; 3-dimensional grammar symbols help primary students analyze sentence structure and style. And, built into many of the materials is a mechanism (“control of error”) for providing the student with some way of assessing her progress and correcting her mistakes, independent of the teacher.
The concrete materials provide passages to abstraction, and introduce concepts that become increasingly complex. As students progress, the teacher replaces some materials with others, ensuring that the level of challenge continues to meets their needs.