The construction of the child's intellect and personality takes place as the child relates to the environment.  The environment provides both the stimulus and the material with which the child will develop intellect, will, and personality.  There is a constant exchange between the child and the environment in which the child chooses to attend to certain stimuli, based on the inner drives of the sensitive periods.  The efforts the child makes in adapting to the environment accomplish the child's self-construction.

"The child has a different relation to his environment from ours.  Adults admire . . . remember . . . and think about it; but the child absorbs it.  The things he sees are not just remembered; they form a part of his soul.(Montessori, The Absorbent Mind)

It is through the senses that the child both experiences the world and relates to it.  The world is full of sensorial impressions.  The work of the child in developing the intellect involves the ability to distinguish the differences and similarities in the objects of the environment, classify, organize, and grade the characteristics of these objects and to formulate abstract ideas front them.  

"There is nothing in the intellect which was not first in the senses. (Aristotle)

Dr. Montessori believed that the development of the senses precluded higher levels of intellectual activity.  The senses must be refined, trained, and perfected so that they will perceive information accurately and be skilled in careful observation.  The benefits of well-trained senses is not limited to the development of the intellect and the practical aspects of life as they relate to being of service to the individual in occupations and hobbies but extend to being able to appreciate and enjoy beauty in the world.

"The beautiful harmonies of nature and art escape those whose senses are dull." (Montessori, The Discovery of the Child)

From the age of two and one-half to six the child not only seeks out sensory experiences but also seeks to refine and perfect the use of the senses.  The sensorial materials help bring to order the sensory experiences of the child and assist in deriving abstractions from them.  The materials provide the child with specific experiences that help the child to classify and order mental images.  Each material isolates one concept such as color, length, weight, size, shape, texture, or volume through a series of gradations, contrasts, or identities.  The objects in an activity are identical among themselves with the except of the one essential and variable quality