Archimedean Polyhedra and the Boundary: the Missing Link
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Volumes of Prisms and Cylinders 625
11-4 11-4 Volumes of Prisms and 11-4 Cylinders 1. Plan Objectives What You’ll Learn Check Skills You’ll Need GO for Help Lessons 1-9 and 10-1 1 To find the volume of a prism 2 To find the volume of • To find the volume of a Find the area of each figure. For answers that are not whole numbers, round to prism a cylinder the nearest tenth. • To find the volume of a 2 Examples cylinder 1. a square with side length 7 cm 49 cm 1 Finding Volume of a 2. a circle with diameter 15 in. 176.7 in.2 . And Why Rectangular Prism 3. a circle with radius 10 mm 314.2 mm2 2 Finding Volume of a To estimate the volume of a 4. a rectangle with length 3 ft and width 1 ft 3 ft2 Triangular Prism backpack, as in Example 4 2 3 Finding Volume of a Cylinder 5. a rectangle with base 14 in. and height 11 in. 154 in. 4 Finding Volume of a 6. a triangle with base 11 cm and height 5 cm 27.5 cm2 Composite Figure 7. an equilateral triangle that is 8 in. on each side 27.7 in.2 New Vocabulary • volume • composite space figure Math Background Integral calculus considers the area under a curve, which leads to computation of volumes of 1 Finding Volume of a Prism solids of revolution. Cavalieri’s Principle is a forerunner of ideas formalized by Newton and Leibniz in calculus. Hands-On Activity: Finding Volume Explore the volume of a prism with unit cubes. -
On the Archimedean Or Semiregular Polyhedra
ON THE ARCHIMEDEAN OR SEMIREGULAR POLYHEDRA Mark B. Villarino Depto. de Matem´atica, Universidad de Costa Rica, 2060 San Jos´e, Costa Rica May 11, 2005 Abstract We prove that there are thirteen Archimedean/semiregular polyhedra by using Euler’s polyhedral formula. Contents 1 Introduction 2 1.1 RegularPolyhedra .............................. 2 1.2 Archimedean/semiregular polyhedra . ..... 2 2 Proof techniques 3 2.1 Euclid’s proof for regular polyhedra . ..... 3 2.2 Euler’s polyhedral formula for regular polyhedra . ......... 4 2.3 ProofsofArchimedes’theorem. .. 4 3 Three lemmas 5 3.1 Lemma1.................................... 5 3.2 Lemma2.................................... 6 3.3 Lemma3.................................... 7 4 Topological Proof of Archimedes’ theorem 8 arXiv:math/0505488v1 [math.GT] 24 May 2005 4.1 Case1: fivefacesmeetatavertex: r=5. .. 8 4.1.1 At least one face is a triangle: p1 =3................ 8 4.1.2 All faces have at least four sides: p1 > 4 .............. 9 4.2 Case2: fourfacesmeetatavertex: r=4 . .. 10 4.2.1 At least one face is a triangle: p1 =3................ 10 4.2.2 All faces have at least four sides: p1 > 4 .............. 11 4.3 Case3: threefacesmeetatavertes: r=3 . ... 11 4.3.1 At least one face is a triangle: p1 =3................ 11 4.3.2 All faces have at least four sides and one exactly four sides: p1 =4 6 p2 6 p3. 12 4.3.3 All faces have at least five sides and one exactly five sides: p1 =5 6 p2 6 p3 13 1 5 Summary of our results 13 6 Final remarks 14 1 Introduction 1.1 Regular Polyhedra A polyhedron may be intuitively conceived as a “solid figure” bounded by plane faces and straight line edges so arranged that every edge joins exactly two (no more, no less) vertices and is a common side of two faces. -
Archimedean Solids
University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln MAT Exam Expository Papers Math in the Middle Institute Partnership 7-2008 Archimedean Solids Anna Anderson University of Nebraska-Lincoln Follow this and additional works at: https://digitalcommons.unl.edu/mathmidexppap Part of the Science and Mathematics Education Commons Anderson, Anna, "Archimedean Solids" (2008). MAT Exam Expository Papers. 4. https://digitalcommons.unl.edu/mathmidexppap/4 This Article is brought to you for free and open access by the Math in the Middle Institute Partnership at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in MAT Exam Expository Papers by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Archimedean Solids Anna Anderson In partial fulfillment of the requirements for the Master of Arts in Teaching with a Specialization in the Teaching of Middle Level Mathematics in the Department of Mathematics. Jim Lewis, Advisor July 2008 2 Archimedean Solids A polygon is a simple, closed, planar figure with sides formed by joining line segments, where each line segment intersects exactly two others. If all of the sides have the same length and all of the angles are congruent, the polygon is called regular. The sum of the angles of a regular polygon with n sides, where n is 3 or more, is 180° x (n – 2) degrees. If a regular polygon were connected with other regular polygons in three dimensional space, a polyhedron could be created. In geometry, a polyhedron is a three- dimensional solid which consists of a collection of polygons joined at their edges. The word polyhedron is derived from the Greek word poly (many) and the Indo-European term hedron (seat). -
Math 366 Lecture Notes Section 11.4 – Geometry in Three Dimensions
Section 11-4 Math 366 Lecture Notes Section 11.4 – Geometry in Three Dimensions Simple Closed Surfaces A simple closed surface has exactly one interior, no holes, and is hollow. A sphere is the set of all points at a given distance from a given point, the center . A sphere is a simple closed surface. A solid is a simple closed surface with all interior points. (see p. 726) A polyhedron is a simple closed surface made up of polygonal regions, or faces . The vertices of the polygonal regions are the vertices of the polyhedron, and the sides of each polygonal region are the edges of the polyhedron. (see p. 726-727) A prism is a polyhedron in which two congruent faces lie in parallel planes and the other faces are bounded by parallelograms. The parallel faces of a prism are the bases of the prism. A prism is usually names after its bases. The faces other than the bases are the lateral faces of a prism. A right prism is one in which the lateral faces are all bounded by rectangles. An oblique prism is one in which some of the lateral faces are not bounded by rectangles. To draw a prism: 1) Draw one of the bases. 2) Draw vertical segments of equal length from each vertex. 3) Connect the bottom endpoints to form the second base. Use dashed segments for edges that cannot be seen. A pyramid is a polyhedron determined by a polygon and a point not in the plane of the polygon. The pyramid consists of the triangular regions determined by the point and each pair of consecutive vertices of the polygon and the polygonal region determined by the polygon. -
A Congruence Problem for Polyhedra
A congruence problem for polyhedra Alexander Borisov, Mark Dickinson, Stuart Hastings April 18, 2007 Abstract It is well known that to determine a triangle up to congruence requires 3 measurements: three sides, two sides and the included angle, or one side and two angles. We consider various generalizations of this fact to two and three dimensions. In particular we consider the following question: given a convex polyhedron P , how many measurements are required to determine P up to congruence? We show that in general the answer is that the number of measurements required is equal to the number of edges of the polyhedron. However, for many polyhedra fewer measurements suffice; in the case of the cube we show that nine carefully chosen measurements are enough. We also prove a number of analogous results for planar polygons. In particular we describe a variety of quadrilaterals, including all rhombi and all rectangles, that can be determined up to congruence with only four measurements, and we prove the existence of n-gons requiring only n measurements. Finally, we show that one cannot do better: for any ordered set of n distinct points in the plane one needs at least n measurements to determine this set up to congruence. An appendix by David Allwright shows that the set of twelve face-diagonals of the cube fails to determine the cube up to conjugacy. Allwright gives a classification of all hexahedra with all face- diagonals of equal length. 1 Introduction We discuss a class of problems about the congruence or similarity of three dimensional polyhedra. -
Can Every Face of a Polyhedron Have Many Sides ?
Can Every Face of a Polyhedron Have Many Sides ? Branko Grünbaum Dedicated to Joe Malkevitch, an old friend and colleague, who was always partial to polyhedra Abstract. The simple question of the title has many different answers, depending on the kinds of faces we are willing to consider, on the types of polyhedra we admit, and on the symmetries we require. Known results and open problems about this topic are presented. The main classes of objects considered here are the following, listed in increasing generality: Faces: convex n-gons, starshaped n-gons, simple n-gons –– for n ≥ 3. Polyhedra (in Euclidean 3-dimensional space): convex polyhedra, starshaped polyhedra, acoptic polyhedra, polyhedra with selfintersections. Symmetry properties of polyhedra P: Isohedron –– all faces of P in one orbit under the group of symmetries of P; monohedron –– all faces of P are mutually congru- ent; ekahedron –– all faces have of P the same number of sides (eka –– Sanskrit for "one"). If the number of sides is k, we shall use (k)-isohedron, (k)-monohedron, and (k)- ekahedron, as appropriate. We shall first describe the results that either can be found in the literature, or ob- tained by slight modifications of these. Then we shall show how two systematic ap- proaches can be used to obtain results that are better –– although in some cases less visu- ally attractive than the old ones. There are many possible combinations of these classes of faces, polyhedra and symmetries, but considerable reductions in their number are possible; we start with one of these, which is well known even if it is hard to give specific references for precisely the assertion of Theorem 1. -
BY S. RAMASESHAN Number of Diffaent Kinds of Planes Permitted By
BY S. RAMASESHAN (From thy Department ef Physics, Indian Institute of Science, Bangalore) Received for publication June 20, 1916 (Communicated by Sir C. V. Raman, ~t.,F. R.s., N.L.) number of diffaent kinds of planes permitted by the law of rational indices to appear as faces on a crystal is practically unlimited. The number of "forms " actually observed, however, is limited and there is a decided preference for a few amongst them. This is one of the most striking facts of geometric crystallography and its explanation is obviously of importance. Pierre Curie (1885) stressed the role played by the surface energy of the faces in determining the " forms " of the crystal. According to him, the different faces of a crystal have different surface energies and the form of the crystal as a whole is determined by the condition that the total surface energy of the crystal should be a minimum. According to W. Gibbs (1877), on the other hand, it is the velocity of growth in different directions which is the determining factor, while the surface energy of the crystal plays a subordi- nate role and is only effective in the case of crystals of submicroscopic size, We have little direct knowledge as to how diamond is actually formed in nature. It is necessary, therefore, to rely upon the indications furnished by the observed forms of the crystals. One of the most remarkable facts about diamond is the curvature of the faces which is a very common and marked feature. This is particularly noticeable in the case of the diamonds found in the State of Panna in Central India. -
How Platonic and Archimedean Solids Define Natural Equilibria of Forces for Tensegrity
How Platonic and Archimedean Solids Define Natural Equilibria of Forces for Tensegrity Martin Friedrich Eichenauer The Platonic and Archimedean solids are a well-known vehicle to describe Research Assistant certain phenomena of our surrounding world. It can be stated that they Technical University Dresden define natural equilibria of forces, which can be clarified particularly Faculty of Mathematics Institute of Geometry through the packing of spheres. [1][2] To solve the problem of the densest Germany packing, both geometrical and mechanical approach can be exploited. The mechanical approach works on the principle of minimal potential energy Daniel Lordick whereas the geometrical approach searches for the minimal distances of Professor centers of mass. The vertices of the solids are given by the centers of the Technical University Dresden spheres. Faculty of Geometry Institute of Geometry If we expand this idea by a contrary force, which pushes outwards, we Germany obtain the principle of tensegrity. We can show that we can build up regular and half-regular polyhedra by the interaction of physical forces. Every platonic and Archimedean solid can be converted into a tensegrity structure. Following this, a vast variety of shapes defined by multiple solids can also be obtained. Keywords: Platonic Solids, Archimedean Solids, Tensegrity, Force Density Method, Packing of Spheres, Modularization 1. PLATONIC AND ARCHIMEDEAN SOLIDS called “kissing number” problem. The kissing number problem is asking for the maximum possible number of Platonic and Archimedean solids have systematically congruent spheres, which touch another sphere of the been described in the antiquity. They denominate all same size without overlapping. In three dimensions the convex polyhedra with regular faces and uniform vertices kissing number is 12. -
Fundamental Principles Governing the Patterning of Polyhedra
FUNDAMENTAL PRINCIPLES GOVERNING THE PATTERNING OF POLYHEDRA B.G. Thomas and M.A. Hann School of Design, University of Leeds, Leeds LS2 9JT, UK. [email protected] ABSTRACT: This paper is concerned with the regular patterning (or tiling) of the five regular polyhedra (known as the Platonic solids). The symmetries of the seventeen classes of regularly repeating patterns are considered, and those pattern classes that are capable of tiling each solid are identified. Based largely on considering the symmetry characteristics of both the pattern and the solid, a first step is made towards generating a series of rules governing the regular tiling of three-dimensional objects. Key words: symmetry, tilings, polyhedra 1. INTRODUCTION A polyhedron has been defined by Coxeter as “a finite, connected set of plane polygons, such that every side of each polygon belongs also to just one other polygon, with the provision that the polygons surrounding each vertex form a single circuit” (Coxeter, 1948, p.4). The polygons that join to form polyhedra are called faces, 1 these faces meet at edges, and edges come together at vertices. The polyhedron forms a single closed surface, dissecting space into two regions, the interior, which is finite, and the exterior that is infinite (Coxeter, 1948, p.5). The regularity of polyhedra involves regular faces, equally surrounded vertices and equal solid angles (Coxeter, 1948, p.16). Under these conditions, there are nine regular polyhedra, five being the convex Platonic solids and four being the concave Kepler-Poinsot solids. The term regular polyhedron is often used to refer only to the Platonic solids (Cromwell, 1997, p.53). -
The Crystal Forms of Diamond and Their Significance
THE CRYSTAL FORMS OF DIAMOND AND THEIR SIGNIFICANCE BY SIR C. V. RAMAN AND S. RAMASESHAN (From the Department of Physics, Indian Institute of Science, Bangalore) Received for publication, June 4, 1946 CONTENTS 1. Introductory Statement. 2. General Descriptive Characters. 3~ Some Theoretical Considerations. 4. Geometric Preliminaries. 5. The Configuration of the Edges. 6. The Crystal Symmetry of Diamond. 7. Classification of the Crystal Forros. 8. The Haidinger Diamond. 9. The Triangular Twins. 10. Some Descriptive Notes. 11. The Allo- tropic Modifications of Diamond. 12. Summary. References. Plates. 1. ~NTRODUCTORY STATEMENT THE" crystallography of diamond presents problems of peculiar interest and difficulty. The material as found is usually in the form of complete crystals bounded on all sides by their natural faces, but strangely enough, these faces generally exhibit a marked curvature. The diamonds found in the State of Panna in Central India, for example, are invariably of this kind. Other diamondsJas for example a group of specimens recently acquired for our studies ffom Hyderabad (Deccan)--show both plane and curved faces in combination. Even those diamonds which at first sight seem to resemble the standard forms of geometric crystallography, such as the rhombic dodeca- hedron or the octahedron, are found on scrutiny to exhibit features which preclude such an identification. This is the case, for example, witb. the South African diamonds presented to us for the purpose of these studŸ by the De Beers Mining Corporation of Kimberley. From these facts it is evident that the crystallography of diamond stands in a class by itself apart from that of other substances and needs to be approached from a distinctive stand- point. -
Sink Or Float? Thought Problems in Math and Physics
AMS / MAA DOLCIANI MATHEMATICAL EXPOSITIONS VOL AMS / MAA DOLCIANI MATHEMATICAL EXPOSITIONS VOL 33 33 Sink or Float? Sink or Float: Thought Problems in Math and Physics is a collection of prob- lems drawn from mathematics and the real world. Its multiple-choice format Sink or Float? forces the reader to become actively involved in deciding upon the answer. Thought Problems in Math and Physics The book’s aim is to show just how much can be learned by using everyday Thought Problems in Math and Physics common sense. The problems are all concrete and understandable by nearly anyone, meaning that not only will students become caught up in some of Keith Kendig the questions, but professional mathematicians, too, will easily get hooked. The more than 250 questions cover a wide swath of classical math and physics. Each problem s solution, with explanation, appears in the answer section at the end of the book. A notable feature is the generous sprinkling of boxes appearing throughout the text. These contain historical asides or A tub is filled Will a solid little-known facts. The problems themselves can easily turn into serious with lubricated aluminum or tin debate-starters, and the book will find a natural home in the classroom. ball bearings. cube sink... ... or float? Keith Kendig AMSMAA / PRESS 4-Color Process 395 page • 3/4” • 50lb stock • finish size: 7” x 10” i i \AAARoot" – 2009/1/21 – 13:22 – page i – #1 i i Sink or Float? Thought Problems in Math and Physics i i i i i i \AAARoot" – 2011/5/26 – 11:22 – page ii – #2 i i c 2008 by The -
THE INVENTION of ATOMIST ICONOGRAPHY 1. Introductory
THE INVENTION OF ATOMIST ICONOGRAPHY Christoph Lüthy Center for Medieval and Renaissance Natural Philosophy University of Nijmegen1 1. Introductory Puzzlement For centuries now, particles of matter have invariably been depicted as globules. These glob- ules, representing very different entities of distant orders of magnitudes, have in turn be used as pictorial building blocks for a host of more complex structures such as atomic nuclei, mole- cules, crystals, gases, material surfaces, electrical currents or the double helixes of DNA. May- be it is because of the unsurpassable simplicity of the spherical form that the ubiquity of this type of representation appears to us so deceitfully self-explanatory. But in truth, the spherical shape of these various units of matter deserves nothing if not raised eyebrows. Fig. 1a: Giordano Bruno: De triplici minimo et mensura, Frankfurt, 1591. 1 Research for this contribution was made possible by a fellowship at the Max-Planck-Institut für Wissenschafts- geschichte (Berlin) and by the Netherlands Organization for Scientific Research (NWO), grant 200-22-295. This article is based on a 1997 lecture. Christoph Lüthy Fig. 1b: Robert Hooke, Micrographia, London, 1665. Fig. 1c: Christian Huygens: Traité de la lumière, Leyden, 1690. Fig. 1d: William Wollaston: Philosophical Transactions of the Royal Society, 1813. Fig. 1: How many theories can be illustrated by a single image? How is it to be explained that the same type of illustrations should have survived unperturbed the most profound conceptual changes in matter theory? One needn’t agree with the Kuhnian notion that revolutionary breaks dissect the conceptual evolution of science into incommensu- rable segments to feel that there is something puzzling about pictures that are capable of illus- 2 THE INVENTION OF ATOMIST ICONOGRAPHY trating diverging “world views” over a four-hundred year period.2 For the matter theories illustrated by the nearly identical images of fig.