ELEMENTS OF SYMMETRY IN ACTION - DODECAHEDRON GAME

Last Update 11/ 09/ 2002

in English/ in Esperanto/ in French/ in Portuguese

The figure shows a set of dodecahedron edges represented mainly in a dark colour in perspective projection with convenient distortion, constituting an instructive application game of elements of symmetry. It works by clicking in the right sequence, the buttons with the respective element of symmetry in such orientation to turn the colour of the edges blue.

The application presents randomly a blue edge as starting point. Seven buttons at the right side of the figure may be used to operate the centre of inversion, 2 planes of symmetry and 4 axis of rotation oriented as shown in Table 1.

Table 1. The seven buttons of the interactive picture.
Buttons I m m 2 2 3 3
Orientation at origin contains 

2 e 3

perpendicular 

to m

intersection 

of m and m

perpendicular 

to 2

contained 

in m

contains 

(100; 150) 

(243; 150)

In Table 1, symbol I means centre of symmetry, m (any colour) indicates reflection plane and 3 and 2 are three fold and binary rotation axes respectively.

A scheme with the orientation of the axes and planes cited in table 1 is shown after a click on the grey background at the right side of the figure on the application, after the column of buttons. Symmetry elements coloured white in the scheme are coloured black in the buttons.

Each symmetry operation acts over all blue edges present at the time.

Answer with this game or with the aid of a three-dimensional model:

1) What is the minimum number of clicks on the buttons to solve the task?

2) The buttons that solved the task are always the same?

3) Commuting the symmetry operations gives always the same results?

Try to obtain:

1) Only 18 blue edges connected in a cycle.

2) Two independent cycles of 9 blue edges each.

The time spent can be checked at the end of the game, when the application shows the initial date (related to GMT) at the top of the figure and the final date at the bottom.

Click in the dodecahedron to start another game.

Please send your comments.

Table of subjects.
Presentation
Chemistry Analytical Chromatography
Elemental organic analysis
Volumetric analysis, simulation
Crystallography 3 fold screw axis
4 fold inversion axis on tetrahedron
5 fold rotation axis absent in crystallography
Binary axis and reflection plane in stereographic projection
Bravais lattices
Conic sections under symmetry operators
Converting from spherical coordinates to stereographic projection
Crystal lattice and unit cell
Determination of unit cell
Elements of symmetry in action - animation
Elements of symmetry in action - cube game
Elements of symmetry in action - dodecahedron game
Elements of symmetry in action - icosahedron game
Elements of symmetry in action - octahedron game
Elements of symmetry in action - tetrahedron game
Ewald sphere and crystal measurements
Extinctions
Five classes in the cubic system
Five classes in the rhombohedral system
From tetrahedron to prism
Gnomonic projection
Improper symmetry axis
Miller indices
Miller indices - animation
Miller indices - cube game
Miller indices - octahedron game
Miller indices - rhombic dodecahedron game
Miller indices - tetrahedron game
Mirror plane
Orientations of the cube
Plane symmetry groups
Question on point group
Rotation axis in octahedron and Werner compounds
Rotation axis on tetrahedron and organic molecules
Rotation of the parallel and stereographic projections of the cube
Seven faces in stereographic projection
Seven classes in the hexagonal system
Seven classes in the tetragonal system
Six elements of symmetry in seven orientations
Spherical projection of the octahedron
Stereographic projection
Stereographic projection of six polyhedra in different orientations
Straight line equations and symmetry elements
Symmetry, 2 fold axis
Symmetry, 2, 3 and 6 fold axis in benzene
Symmetry, 3 fold axis in the cube
Symmetry, 4 fold axis in the cube
Symmetry, 4 fold axis in the unit cell of gold
Symmetry elements and Miller indices game
Symmetry elements and Miller indices game - octahedron
Symmetry in art and in crystallography
Three classes in the monoclinic system
Three classes in the orthorhombic system
Twin crystals
Two classes in the triclinic system
Unit cell in hexagonal net
General Butane conformations
Density
Electrochemical cell
Ethane conformations
Resources of chemical-ICT: water, health and symmetry
Solid and liquid gold