GEOMETRIC SOLIDS
The Geometric Solids are a key part of the sensorial curriculum area, allowing children to understand 3D shapes by making them tangible objects. The Geometric Solids comprised of ten solid wooden shapes that are colored in a bright blue.
Age
3 1/2 years onwards
MATERIALS
– A basket large enough to contain ten geometric wooden solids in blue:
A triangular prism
A rectangular prism
A cube
A cylinder
A cone
A triangular pyramid
A square pyramid
A sphere
An ellipsoid
An ovoid
Plane surfaces – cube, rectangular prism, triangular prism, pyramid
Curved surface – sphere, ovoid, ellipsoid
Flat and curved surfaces – cone, cylinder
Presentation 1
This is an individual exercise done at the table. This is a sensorial exploration of the shapes. Lay a mat on the table and place the solids in it. Select three solids, preferably one from each family. That is, one curved solid, one plane solid and one plane/curved solid.
Pick up the solid, feel it and pass it on to the child to feel. Experiment with the solids. See which ones roll and which ones do not roll. Place the curved solid in the base, indirectly drawing the child’s attention as to which are curved and which are angular.
Presentation 2
Take out all the bases and place them on the mat. Take out all the solids and place them correctly on their bases. When all are correctly placed, select a square base and see how many solids will fit correctly on it. Try placing a curved solid on it so that the child will see the difference.
Presentation 3
The names of the different solids are introduced by the Three Period Lesson. The child should already know a cube from working with the Pink Tower, a prism from working with the Broad Stair, and a cylinder from the Knobless Cylinders. To begin with start with a shape they can already name.
Exercise
The child chooses 3 – 4 solids. Place these in a separate basket and cover it with a scarf. Reach your hand under the scarf, feel one of the solids underneath, and say out loud what solid you believe you have in your hands. Take out the solid form under the scarf to reveal the solid you have. Allow the child to do as you have shown. This allows the names of the solids to be reinforced for the child. Work in this manner until the child can place a scarf over all of the solids and still feel and guess correctly.
OBJECTIVES:
To make the child familiar with, and to teach him the appropriate mathematical names for the various geometric solids.
To make the child aware of the geometric solids that are found in the everyday environment.
IDEAS
The sphere rolls in every direction; the cylinder rolls in one direction only; the cone rolls round itself; the prism and the pyramid, however, stand still, but the prism falls over more easily than the pyramid.
PURPOSE
Direct
To refine the stereognostic sense.
To make the child aware of the solid shapes that surround him.
Indirect
Preparation for geometry.
Control of Error
Visual.
LANGUAGE
The names of the geometric solids: sphere, prism, pyramid, cube, cone, cylinder, etc.
“The most attractive way of teaching a child to recognize this form is for him to touch them with closed eyes and to guess their names. After an exercise of this kind the child observes the forms when his eyes are open with a much more lively interest.” Maria Montessori in Dr. Montessori’s Own Handbook.