Two Square Tetrahedron | English | Fun with Maths
Channel: Arvind Gupta
Date: 2015-05-25

With two different color squares of the same size we will make an interlocking Tetrahedron. With slightly different modules we will be able to make Tetrahedrons of various shapes.
Take a 15-cm square. Bring two opposite edges together to fold the midline. Now place the corner on the midline and fold such that the crease passes through the top right corner. Similarly fold the other side. Upturn the model. Bring both corners together and fold. Fold the small blue triangle inwards. Reverse the model and fold the small triangle in a similar manner. This will make one complete MODULE. We will need to fold another similar Module. Now the two Modules can be assembled into a Tetrahedron. The sharp flaps of one will go into the pockets of the other. Similarly, insert the corners of the second into the pockets of the other. This will lock the two units into a beautiful Tetrahedron. This will be a REGULAR Tetrahedron where all the angles will be 60-degrees.
Variations: Now we will increase the size of the folded triangle as shown. Increase the size of the other triangle too. Bring both corners together and fold. You will make an Isosceles Triangle – where the base angles will be bigger and the apex angle will be smaller than the previous Module. Again assemble the two units to make a Tetrahedron. This Tetrahedron will have a different shape as compared to the previous one.
Now by changing the size of the folded triangle you can make Tetrahedrons of various shapes. This work was supported by IUCAA and Tata Trust. This film was made by Ashok Rupner TATA Trust: Education is one of the key focus areas for Tata Trusts, aiming towards enabling access of quality education to the underprivileged population in India. To facilitate quality in teaching and learning of Science education through workshops, capacity building and resource creation, Tata Trusts have been supporting Muktangan Vigyan Shodhika (MVS), IUCAA's Children’s Science Centre, since inception. To know more about other initiatives of Tata Trusts, please visit www.tatatrusts.org