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The Platonic solids have been known since antiquity. It has been suggested that certain carved stone balls created by the late Neolithic people of Scotland represent these shapes; however, these balls have rounded knobs rather than being polyhedral, the numbers of knobs frequently differed from the numbers of vertices of the Platonic solids, there is no ball whose knobs match the 20 vertices ...
The most familiar dodecahedron is the regular dodecahedron with regular pentagons as faces, which is a Platonic solid. There are also three regular star dodecahedra, which are constructed as stellations of the convex form. All of these have icosahedral symmetry, order 120.
The Theory of Forms or Theory of Ideas, [1] [2] [3] also known as Platonic idealism or Platonic realism, is a philosophical theory widely credited to the Classical Greek philosopher Plato. A major concept in metaphysics , the theory suggests that the physical world is not as real or true as Forms.
Around the same time as the Pythagoreans, Plato described a theory of matter in which the five elements (earth, air, fire, water and spirit) each comprised tiny copies of one of the five regular solids. Matter was built up from a mixture of these polyhedra, with each substance having different proportions in the mix.
Timaeus links each of these elements to a certain Platonic solid: the element of earth would be a cube, of air an octahedron, of water an icosahedron, and of fire a tetrahedron. [8] Each of these perfect polyhedra would be in turn composed of triangular faces the 30-60-90 and the 45-45-90 triangles. The faces of each element could be broken ...
A solid crystalline substance, cubane is one of the Platonic hydrocarbons and a member of the prismanes. It was first synthesized in 1964 by Philip Eaton and Thomas Cole. [4] Before this work, Eaton believed that cubane would be impossible to synthesize due to the "required 90 degree bond angles".
Solid: A solid holds a definite shape and volume without the need of a container. The particles are held very close to each other. Amorphous solid: A solid in which there is no far-range order of the positions of the atoms. Crystalline solid: A solid in which atoms, molecules, or ions are packed in regular order.
In a solid, constituent particles (ions, atoms, or molecules) are closely packed together. The forces between particles are so strong that the particles cannot move freely but can only vibrate. As a result, a solid has a stable, definite shape, and a definite volume. Solids can only change their shape by an outside force, as when broken or cut.