Modeling a Tetrahedron and Parallelepiped
This material is suitable for older school-age children. It can be used for a creative lesson aimed at developing spatial thinking.
Objective of the practical task: Learning to model geometric objects.
Materials needed for the task: juice straws, matches, glue, scissors, toothpicks, modeling clay.
If a visually impaired student has a complete and correct understanding of the object being studied, they can quickly perform various constructions and calculations. Modeling is one of the ways to develop spatial imagination.
Task: Think about how you can use 6 matches to form 4 equilateral triangles, ensuring that each side equals 1 matchstick. You are not allowed to break the matches. (photo from the internet). Assemble the base from three matches, then place three matches at the corners of the triangle and connect the upper ends at a single point. The result is a tetrahedron—the simplest three-dimensional figure. It is a solid figure with 4 faces and six edges. Each face is an equilateral triangle. We explain to the children that when talking about triangles on a single plane, it is impossible to form four triangles with six matches. However, by using three dimensions, we can construct a pyramid-like figure. This model can demonstrate the shape of a polyhedron, and it’s convenient to show the surface development of a solid using these models.
When modeling polyhedrons, the leading method involves using modeling clay and toothpicks. Small balls of clay are rolled, and toothpicks are inserted into them step by step to form a figure. Afterward, the model is placed in the fridge to harden the clay. This method of construction is very engaging and fun.
Another option is to create polyhedron models using a 3D pen. A 3D pen is a tool that allows drawing in the air. Children show great interest in this creative activity. The pen is loaded with a plastic filament, which melts at high temperatures and is extruded. The molten plastic is soft and can be shaped into a 3D figure. This method creates convenient models because it allows viewing the solid figure from different angles, revealing the internal structure. Transparent models make it easy to visualize sections of the solid.
Model of a Rectangular Parallelepiped: In the parallelepiped, skew lines are drawn. Drawing with a 3D pen helps develop spatial thinking and creative perception.
How to construct a tetrahedron: Use the pen to draw the base, then sequentially build the lateral edges, connecting them to the base and the common vertex.
How to construct a rectangular parallelepiped: Draw the top and bottom bases, then build the side edges, connecting the upper and lower bases step by step.
Using polyhedron models in lessons helps students grasp and understand material in stereometry.