Teaching Size in Montessori
The Inital Sensorial Activities to Teach Size Relationships
Nov 12, 2008
The Sensorial activities in a Montessori classroom are designed to refine the child’s senses in order to better observe and appreciate her world. Using both the visual and tactile senses, the child learns about size through manipulation of the Pink Tower, Brown Prisms, and Knobbed Cylinders, and Knobless Cylinders.
The Pink Tower
Some also refer to the Pink Tower as the Pink Cubes. They are a series of ten graduation cubes. The smallest measures one cm cubed; the largest is ten cm cubed.
When the child is introduced to the Pink Tower, all ten are brought over, one at a time. Each cube is to be carried with both hands, so that the child feels each subsequent cube getting larger. The child is shown the two extremes, and they are named for her: largest and smallest. She is then shown how to place them in order from largest to smallest, in the form of a tower.
The Brown Prisms
The Brown Prisms can also be referred to as the Brown Stair or the Broad Stair. It consists of ten prisms of identical length. The bases are graduated in width, with the thinnest being one cm squared and the thickest being ten cm squared.
The procedure for the lesson is similar to that for the Pink Tower. Each prism is carried one at a time, with two hands, to feel the change in thickness. The extremes are set together for comparison, then named: thickest and thinnest. They are then laid across the rug in order from thickest to thinnest, resembling a flight of stairs.
The Red Rods
The Red Rods are a set of ten rods graduated in length from one decimeter (ten cm) to a full meter. They are all of the same thickness. The rods are carried one at a time, using two hands, so that the change in length is felt. Again, the two extremes are laid next to each other and named: shortest and longest. The rods are lined up flush against the left side of the rug. The hand is run down the length, left-to-right, to determine which is next in order. The rods are ordered from longest to shortest.
The Knobbed Cylinders
There are four sets of knobbed cylinders. Each consists of ten cylinders in a wooden block. In the first set, the cylinders are all the same height, but gradually decrease in width. In the second set, as each cylinder decreases in width, it also decreases in height. In the third set, as the width decreases, the height increases. In the fourth set, the diameter or all the cylinders is the same, but the height gradually decreases.
For the initial lesson, the first set is used. Emphasizing the use of only the thumb and first two fingers (the same ones used in a proper pencil grip), each cylinder is pulled out of the block, one at a time. They are then returned to the block, one at a time, held by the knob by the pincer grasp. Prior to reinsertion, the diameter of the cylinder and its corresponding hole are traced using two fingers on the opposite hand.
The Knobless Cylinders
The Knobless Cylinders are four sets of cylinders that are independent of a block. They have no knobs and are color-coded by set. The first set is red, second is yellow, third is green, and fourth is blue. Each set is ordered using appropriate vocabulary: largest to smallest, thickest to thinnest, tallest to shortest. Grading can be done horizontally on the rug, or built vertically, using the lid as a sturdy base.
As the child manipulates the Pink Tower, Brown Prisms, Red Rods, Knobbed and Knobless Cylinders, she will refine her visual and tactile senses as she learns to discriminate various measurements of size. This will lead to greater observations of the world around her.
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