All young children meet the world around him/her through the constant use of all their senses. To examine a new object, a baby will look at it, hold it in their hands to feel the texture and weight, shake it, lick it or even try to bite it. Since he/she naturally uses all their powers of observation during their early years, Dr. Montessori felt that this was the ideal time to give the child equipment, which would sharpen their senses and enable them to understand the many impressions they receive through them.

Each of the sensorial materials isolates one defining quality, such as color, weight, shape, texture, size, sound, smell, etc ... The equipment emphasizes this particular quality by eliminating or minimizing other differences. Thus, the sound boxes are all the same size, shape, color and texture. They differ only in sounds, which are made when the child shakes them.