# Montessori Geometric Solids Presentation

MATERIALS:

Geometric Solids – cube, ellipsoid, ovoid, two pyramids, one square based and one triangular based, cone, rectangular prism, triangular prism, cylinder and a set of bases for the solids.

Plane surfaces – cube, rectangular prism, triangular prism, pyramid

Curved surface – sphere, ovoid, ellipsoid

Flat and curved surfaces – cone, cylinder

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 every day environment

AGE:

3 plus years.

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 on 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 1:

The child is asked to sort the solids. E.g., those with straight sides (plane) or those with curved sides or those containing both.

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Exercise 2:

The child is asked to experiment with the solids and place them together to try to form other solids. This should be followed by a discussion.

Exercise 3:

Using the set of bases, the child is asked to place each on its solid base, using the appropriate language. The child is helped to discover which solids have the same bases. The language used is important so that the child realises the importance of the number of straight edges and curves.

Exercise 4:

Place all the solids in a basket and cover the basket with a cloth. Ask one child to find a cone, another to find a sphere, another a cube etc.

Exercise 5:

Invite the child to feel one of the solids in the covered basket and to name the solid before he withdraws it from the basket.

NOTE:

It is important that the Montessori Directress should help make the children aware of geometric shapes found in the every day environment. This can be done informally or as a class project where children are asked to collect such items as empty cardboard boxes, tins etc. that correspond in shape to the solids.