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# Sensorial: Geometric Solids 3D shapes

The sensorial curriculum area is unique to Montessori education, encouraging the child to engage all five senses in their learning forming concrete ideas from the abstract in their environment. The Geometric Solids are a key part of the sensorial curriculum, allowing the child to understand 3D shapes by making them tangible objects.

The geometric solids compromise of ten wooden solid shapes that are coloured in blue. The shapes include:

· Cube

· Sphere

· Ellipsoid

· Ovoid

· Cylinder

· Cone

· Square-based pyramid

· Triangular-based pyramid

· Square-based prism

· Triangular-based prism

There are also bases for the solids: three squares, two circles, three equilateral triangles, two acute-angled triangles, two rectangles. These Geometric solids and their bases are usually kept in a basket or in a wooden box along with the bases of the solids.

The Geometric Solids are one of many Montessori materials that challenge and shape a child’s stereognosis sense, which is their ability to perceive and understand both the form and nature of objects through touch. This knowledge provides the foundation for future work in geometry, which falls into the Mathematics curriculum for older Montessori students.

When teaching the child the Geometric solids in the Montessori classroom, we follow the ‘three-period lesson’. During the first presentation, the teacher will invite the child to explore the 3D shapes. First, the child will lay out the mat and the teacher, taking two or three geometric solids, gives them to the child to feel and explore the shape. The teacher will then gradually introduce the other solids giving the names of the child shows interest. The teacher will then say: ‘Let’s explore what the shapes will do’ and they will build or roll the shapes. The first presentation, therefore, is simply for the child to get sensorial experience with the shapes and explore the properties of the individual pieces.

The second presentation will be the teacher explaining to the child ‘Today, you are going to sort the solids into groups’. The teacher then passes a solid to the child and asks him to feel or roll the solid then place it at the top of the mat. Then they will repeat with another solid and the teacher will ask the child if he/ she would like to place it in the first group or start a new group. The teacher and child will continue until all the solids are sorted then the teacher will lastly discuss the groups with the child. During this presentation, it is an ideal time to introduce and reinforce the names of the geometric solids.

During the third presentation, the teacher will ask the child to put the solids in a horizontal line in front of them on the mat as well as to place the bases in front of the solids and explore if there are any similarities between the shapes and the solids. The teacher may need to demonstrate one or two variations for the child to understand the exercise. For example, the cube can go on the solid square. Note: there are more bases than solids and some of the solids can go on different bases such as the triangular based pyramid can go on the equilateral triangle or on its side on the rectangle. Thus, the teacher will highlight to the child, that some shapes have more than one base.

Objectives when teaching the Geometric solids to the child: 1) To provide experiences of solid shapes in the environment and stimulate interest in discerning these shapes in the world around the child 2) To develop an understanding of the relationship between shapes 3) To develop vocabulary

“First the education of the senses, then the education of the intellect.” - Maria Montessori -