Tetrahedral-dodecahedral honeycomb

Regular polyhedra

This shows a 3d print of a mathematical sculpture I produced using shapeways.com. This model is available at http://shpws.me/q0PF.

From playlist 3D printing

Canonical structures inside the Platonic solids III | Universal Hyperbolic Geometry 51

The dodecahedron is surely one of the truly great mathematical objects---revered by the ancient Greeks, Kepler, and many mathematicians since. Its symmetries are particularly rich, and in this video we look at how to see the five-fold and six-fold symmetries of this object via internal str

From playlist Universal Hyperbolic Geometry

How to construct a Tetrahedron

How the greeks constructed the first platonic solid: the regular tetrahedron. Source: Euclids Elements Book 13, Proposition 13. In geometry, a tetrahedron also known as a triangular pyramid, is a polyhedron composed of four triangular faces, six straight edges, and four vertex corners. Th

From playlist Platonic Solids

How to Construct a Dodecahedron

How the greeks constructed the Dodecahedron. Euclids Elements Book 13, Proposition 17. In geometry, a dodecahedron is any polyhedron with twelve flat faces. The most familiar dodecahedron is the regular dodecahedron with regular pentagons as faces, which is a Platonic solid. A regular dode

From playlist Platonic Solids

The geometry of the regular tetrahedron | Universal Hyperbolic Geometry 45 | NJ Wildberger

We look at the geometry of the regular tetrahedron, from the point of view of rational trigonometry. In particular we re-evaluate an important angle for chemists formed by the bonds in a methane molecule, and obtain an interesting rational spread instead. Video Content: 00:00 Introduction

From playlist Universal Hyperbolic Geometry

How do ceramic crystal structures differ from metal crystal structures?

Metal crystal structures are much simpler than ceramic structures. This is due to two reasons. First, ceramics have positive and negative charged ions. Cations and ions must maintain charge neutrality. Second, the size of cations and anions are very different! Structures with multiple diff

From playlist Materials Sciences 101 - Introduction to Materials Science & Engineering 2020

Hyperbolic honeycombs

These sculptures are joint work with Roice Nelson. They are available from shapeways.com at http://shpws.me/oNgi, http://shpws.me/oqOx and http://shpws.me/orB8.

From playlist 3D printing

Rhombofoam in Zome – Scott Vorthmann

Rhombofoam is a pattern that fills 3D space in all the ways that a golden rhombohedron does, while forming dodecahedral and 16-sided cells that have the topology of foam: three cells around each edge, and four around each vertex. The result is a foam model that has the symmetries of a quas

From playlist G4G12 Videos

review midterm 2

mse 3310 spring 2017 midterm 2 review

From playlist Introduction to Ceramics Spring 2017

Day 14 ceramic crystal structures

0:00 reading quiz 5:25 HCP structure and close-packing 10:27 theoretical density calculation 15:00 difference between observed and theoretical densities 18:16 ceramic crystal structures and using rc/ra ratio to determine coordination 23:26 rock salt (NaCl) structure 29:28 cesium chloride (

From playlist Introduction to Materials Science and Engineering Fall 2017

ceramic crystal structures

0:00 coordination of hexagonal close-packed HCP structure 4:40 theoretical density 21:37 structure of ceramics using cation/anion ratio 30:65 NaCl rock salt structure 33:05 CsCl structure 35:18 ZnS zinc blende structure 39:00 solving for lattice parameter in terms of cation and anion radii

From playlist Introduction to Materials Science & Engineering Fall 2019

Unique way to divide a tetrahedron in half

This is an interesting geometry volume problem using tetrahedrons. We use the volume of a tetrahedron and Cavalieri's principle in 3D.

From playlist Platonic Solids

Henry Segerman - 3D Shadows: Casting Light on the Fourth Dimension - 02/11/17

Henry Segerman "3D Shadows: Casting Light on the Fourth Dimension" February 11, 2017 Wesier Hall Ann Arbor, Michigan

From playlist 3D printing

Coordination Compounds: Geometry and Nomenclature

We have been learning a lot about a wide variety of compounds, but we haven't really looked much at the transition metals. These also form compounds called coordination compounds, and the types of bonds involved in these compounds is quite a bit different from what we are used to, as are t

From playlist General Chemistry

Reaching for Infinity Through Honeycombs – Roice Nelson

Pick any three integers larger than 2. We describe how to understand and draw a picture of a corresponding kaleidoscopic {p,q,r} honeycomb, up to and including {∞,∞,∞}.

From playlist G4G12 Videos

Mod-15 Lec-36 Magnetic Ceramics (Contd. )

Advanced ceramics for strategic applications by Prof. H.S. Maiti,Department of Metallurgy and Material Science,IIT Kharagpur.For more details on NPTEL visit http://nptel.ac.in

From playlist IIT Kharagpur: Advanced Ceramics for Strategic Applications | CosmoLearning.org Materials Science

Cardboard Tetrahedron Pyramid Perfect Circle Solar How to make a pyramid out of cardboard

How to make a pyramid out of cardboard. A tetrahedron is a polyhedron composed of four triangular faces, three of which meet at each vertex.

From playlist HOME OF GREENPOWERSCIENCE SOLAR DIY PROJECTS

The remarkable Platonic solids II: symmetry | Universal Hyperbolic Geometry 48 | NJ Wildberger

We look at the symmetries of the Platonic solids, starting here with rigid motions, which are essentially rotations about fixed axes. We use the normalization of angle whereby one full turn has the value one, and also connect the number of rigid motions with the number of directed edges.

From playlist Universal Hyperbolic Geometry

Canonical structures inside the Platonic solids I | Universal Hyperbolic Geometry 49 | NJ Wildberger

Each of the Platonic solids contains somewhat surprising addition structures that shed light on the symmetries of the object. Here we look at the tetrahedron, and investigate a remarkable three-fold symmetry which is contained inside the obvious four-fold symmetry of the object. We connect

From playlist Universal Hyperbolic Geometry

Combinatorics and Geometry to Arithmetic of Circle Packings - Nakamura

Speaker: Kei Nakamura (Rutgers) Title: Combinatorics and Geometry to Arithmetic of Circle Packings Abstract: The Koebe-Andreev-Thurston/Schramm theorem assigns a conformally rigid fi-nite circle packing to a convex polyhedron, and then successive inversions yield a conformally rigid infin

From playlist Mathematics