The brown stairs are ten wooden brown prisms that are all the same length, but vary in breadth and height.
The student scatters the ten prisms on a mat and then proceeds to place them in their right order of graduation upon the same mat. These kinds of activities help the student to develop a trained eye in observation techniques when discriminating objects of dimensions.
Other skills developed are the ability to compare, to form judgments, and to reason and make precious decisions between objects. The students are introduced to the concepts of broad and narrow and their variations of these concepts.
The Brown Stairs Extensions
The students are then shown extensions of the brown stairs after working with them extensively. They are introduced to the language associated with the pieces: broad, broader, broadest or thick, thicker, and thickest.
In another seating, they are invited to take out the pink tower and brown stairs together and are shown that the biggest cube of the pink tower has the same thickness as the thickest rectangular prism of the brown stairs. This is done with each graduating piece as they are laid side by side so that the child can notice their relationship. They are then invited to explore building and arranging the pink tower and brown stairs in different formations in order to notice different patterns and/or relationships. As the children explore, they are also making dimensional connections which indirectly prepares their minds for mathematics. They will develop a strong impression of what volume looks like because they have felt it and explored it.