Introduction
Using match sticks and cycle valve tubes make the following structures  cube, tetrahedron and octahedron. Evaluate the stability of these structures.
Tools
Parts


Scrape the sulphur from the matchstick head and taper the match stick using a cutter.

Taper the opposite end as well.



Similarly taper the remaining match sticks.

Cut 2cm long valve tubes ( about 20 in number).

Push two matchsticks through the two ends of the valve tube. This is a jointoftwo.



Three matchsticks and three valve tubes can be looped to make an equilateral triangle.



Connect four matchsticks and valve tubes end to end and square it up.

Try making different shapes like parallelogram, rhombus etc by slightly pressing at the corners of the square.



Take a thick cardboard piece (about 12cm x 8cm).

Using a pen, trace the inner and outer perimeter of the square you'd made previously.

With the help of a cutter, carve out the area of the cardboard between the outer and the inner square to make a groove where the matchstick square fits perfectly.



The groove should look something like that!

Take four tapered matchsticks and erect them at the vertices of the square. This represents the tie beam structure.

Now place the tie beam structure into the groove. It has to fit in perfectly. Take four more tapered matchsticks and poke them at four adjacent corners next to the groove.



Shake the cardboard to induce tremor.

You will notice that the independent column structure collapses whereas the tie beam structure does not.



Add another stick and a valve tube to make a pentagon.

Work your hand around the pentagon to make an isosceles triangle and a star.



Take a joint of two and pierce a hole through the valve tube by poking it at right angle using a needle or a safety pin.

Drag the needle out from the opposite side.

Insert a third matchstick in this hole. This is a joint ofthree, or simply a Tjoint.



Make a hole at each vertex of the triangle using a needle/safety pin.

Take the joint of three matchsticks and insert them into the holes made at the triangle's vertices.



After inserting the joint of three matchsticks into the vertices of the triangle you get the tetrahedron.



Join two similar triangles with three matchsticks to make the model of a prism.

Join two similar squares with four matchsticks to make a cube.



Take two valve tubes. Weave the needle through one of the tubes.

Now pierce the needle through the centre of the other valve tube.

To widen the hole, pull either side of the valve tube.



Slide the second valve tube over the first one.

Now gently remove the cross i.e the joint offour out from the needle.



Insert matchsticks into the jointoffour valve tubes.

Poke the jointoffour matchsticks into the holed vertices(valve tube) of a square.

This makes a pyramid.



Make six jointoffour valve tubes.

Insert matchsticks into one of the six jointoffour valve tubes.

Now insert four jointoffour valve tubes onto the four open ends of matchsticks.



Now connect the jointoffour valve tubes of adjacent matchsticks.

This makes the base (square) and one half (pyramid) of the octahedron.

Make another joint of four matchsticks and connect it to the base.



Make eight jointofsix.

Connect the tapered matchsticks using the jointofsix to make a cube.

For the diagonals, you may use coconut sticks of appropriate length.



Besides an isosceles triangle and a star which is/are the other shape(s) you can make using the pentagon .

Make a hexagon, heptagon, octagon and as many 2D geometrical shapes as you can.

Put together the threedimensional objects you'd made to make different kinds of houses and other configurations.

Try making a joint of five and six and figure out the shapes/configurations you can make with the help of it.



Give a slight push along the sides of a cube. You will notice that the cube is not rigid enough to withstand the nudge. This implies that it is the quality of material at the joints and not the property of the structure itself that makes buildings with similar structural construction sturdier.

Take a tetrahedron, apply force along its edges. The structure remains unfaltered. Their stiff edges make them inherently rigid . Application of this structure in fields like structural engineering is due to this very property.

Similarly, apply force along the edges of the octahedron and the cube with face diagonals. Observe its stability.



Which is the most geometrically stable structure?

List the modern methods used to make earthquakeresistant buildings.

Literally, is it the earthquake that kills people or is it the buildings?
