GAM Brown Stair

The stair is a series of prisms that changes in width, or breadth, while the length stays constant. Building it, the child sees breadth grow step by step and develops visual discrimination of size in three dimensions.

The prisms are crafted in precise progressions from 1 by 1 by 20 cm up to 10 by 10 by 20 cm. Each prism keeps the same length but grows in width and height, so the difference between neighbours is regular and clear to the eye and hand.

Practice with the brown stair indirectly prepares the child for concepts in plane geometry, area and volume. By handling a set that changes in a fixed, measured way, the child builds a physical sense of dimension that later mathematical work can draw on.

The purpose of the brown stair is to educate the hand to perceive differences in size, shape and weight. Lifting and comparing the prisms, the child refines both sight and touch and learns to read three dimensional differences with growing accuracy.

Yes, the material has a built in control of error. If the stair is badly built the child can usually see the uneven steps, so the mistake is visible and can be corrected by the child without an adult pointing it out.

The prisms are solid wood and are handled often, so wipe them with a dry or barely damp cloth and keep them away from water and strong sun. Stored together on a low shelf, the set stays ready for the child to carry out and build.

The brown stair is a three to six sensorial material, used in the years when children compare and order their world by size. It often sits alongside other graded sensorial work as the child refines dimension, and younger children may explore it with guidance.