What you need:
Matchsticks and bits of a cycle valve tube
What you do:
a) Square
1. Make a square out of the matchsticks and bits of the cycle valve tube.
2. Press the opposite corners of the square.
b) Triangle
1. Make a triangle out of the matchsticks and bits of cycle valve tube.
2. Now, try pressing or shaking the triangle.
What happens?
a. The square is unable to resist the pressure. Its right angles give way and distort into a rhombus or a diamond shape.
b. The triangle’s shape remains intact. The triangle is the only rigid shape. All other shapes like hexagons, pentagons, squares and rectangles are wobbly and shaky.
Can you make the square rigid?
Yes. Insert a long babool thorn (or a long needle) through two diagonally opposite valve tube joints of the square. The thorn divides the square into two triangles which make the square rigid. Similarly, the structural members of railway bridges and electric towers are divided into triangles which make them rigid.
The roofs of village houses are made of bamboos and wooden beams that are always arranged in triangles.
Picture Credit : Google
