Cardboard, Rubber Bands, and Polyhedron Models

Young children's pre chool years are filled with three-dimensional objects as the children come to understand spatial and topological idea. These idea, such a nearness order or enclosure are based on the child's experiences and sensory impressions of shape and solids. However. too often early school experience with geometric concepts are limited to plane figure. This is because solid are difficult to represent on paper or the blackboard and young children have difficulty constructing model of three-dimensional figure with cardboard and paste. The “cut and paste” method of constructsion also produces permanent figures that are difficult to store.

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Marshmallows Toothpicks and Geodesic Domes

The Arithmetic Teacher ◽

10.5951/at.25.3.0039 ◽

1977 ◽

Vol 25 (3) ◽

pp. 39-42

Author(s):

M. Stoessel Wahl

Keyword(s):

Young Children ◽

Three Dimensional ◽

Three Dimensional Objects ◽

Early School ◽

Geodesic Domes

Young children grow up in and Patterns for Domes adapt to a world of three-dimensional objects. Solids. however, are difficult to show on textbook pages and in chalkboard drawings, with the result that there is a tendency to limit early school geometric experiences to recognition of plane figures.

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Tabletowe dzieci. Ile zła wyrządza małym dzieciom tablet reklamowany jako najlepsza zabawka dla twojego dziecka. Ku rozwadze dorosłym, którzy temu ulegają

Special School ◽

10.5604/01.3001.0010.8327 ◽

2018 ◽

Vol LXXVIII (5) ◽

pp. 325-334

Author(s):

Edyta Gruszczyk-Kolczyńska

Keyword(s):

Young Children ◽

Virtual World ◽

Mental Representations ◽

Three Dimensional ◽

Three Dimensional Objects ◽

Number Of Children ◽

The World ◽

Real Objects ◽

To Come ◽

Insight Into

In the article, I present the findings of scientific insight into issues that I call tablet children. I provide alarming data on the number of children aged 6 months and a little bit older who are given access to tablets and smartphones by adults. I quote the most important findings included in the theory of representation by Jerome S. Bruner to explain the following: – What makes babies and toddlers use tablets and smartphones in a remarkably efficient way; – Adverse differences in representations created by children based on experiences gathered in the world of real objects and in the virtual world; – Distortions in the outlines of mental representations formed by young children when they watch images on tablet and smartphone screens too frequently. Being given access to these devices is particularly dangerous for young children, who have not yet created the outlines of the representations of three-dimensional objects and three-dimensional qualities of space in their minds. Distortions in the outlines of representations are difficult to fix as subsequent experiences only complement and expand the existing representations. Since the existing representations take part in creating new representations, the new ones are not fully correct either. I also argue the need for serious research that should aim to determine the far-reaching results of tablets and smartphones being available to babies and young children. This will help to come to terms with these devices educationally and also to determine when and for how long they can be made available to children so that they are safe for children's mental development.

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convergent-beam diffraction from surfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100125208 ◽

1987 ◽

Vol 45 ◽

pp. 30-33

Author(s):

J. A. Eades ◽

A. E. Smith ◽

D. F. Lynch

Keyword(s):

Reciprocal Lattice ◽

Three Dimensional ◽

Grazing Incidence ◽

Three Dimensions ◽

Plane Figure ◽

Transmission Electron ◽

Convergent Beam ◽

Beam Patterns ◽

Beam Diffraction

It is quite simple (in the transmission electron microscope) to obtain convergent-beam patterns from the surface of a bulk crystal. The beam is focussed onto the surface at near grazing incidence (figure 1) and if the surface is flat the appropriate pattern is obtained in the diffraction plane (figure 2). Such patterns are potentially valuable for the characterization of surfaces just as normal convergent-beam patterns are valuable for the characterization of crystals.There are, however, several important ways in which reflection diffraction from surfaces differs from the more familiar electron diffraction in transmission.GeometryIn reflection diffraction, because of the surface, it is not possible to describe the specimen as periodic in three dimensions, nor is it possible to associate diffraction with a conventional three-dimensional reciprocal lattice.

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Fast Overlap Detection between Hard-Core Colloidal Cuboids and Spheres. The OCSI Algorithm

Algorithms ◽

10.3390/a14030072 ◽

2021 ◽

Vol 14 (3) ◽

pp. 72

Author(s):

Luca Tonti ◽

Alessandro Patti

Keyword(s):

Colloidal Particles ◽

Dynamic Properties ◽

Wide Spectrum ◽

Three Dimensional ◽

Hard Core ◽

Detection Algorithm ◽

Three Dimensional Objects ◽

Aggregation Behaviour ◽

Sphere Radius ◽

User Friendly

Collision between rigid three-dimensional objects is a very common modelling problem in a wide spectrum of scientific disciplines, including Computer Science and Physics. It spans from realistic animation of polyhedral shapes for computer vision to the description of thermodynamic and dynamic properties in simple and complex fluids. For instance, colloidal particles of especially exotic shapes are commonly modelled as hard-core objects, whose collision test is key to correctly determine their phase and aggregation behaviour. In this work, we propose the Oriented Cuboid Sphere Intersection (OCSI) algorithm to detect collisions between prolate or oblate cuboids and spheres. We investigate OCSI’s performance by bench-marking it against a number of algorithms commonly employed in computer graphics and colloidal science: Quick Rejection First (QRI), Quick Rejection Intertwined (QRF) and a vectorized version of the OBB-sphere collision detection algorithm that explicitly uses SIMD Streaming Extension (SSE) intrinsics, here referred to as SSE-intr. We observed that QRI and QRF significantly depend on the specific cuboid anisotropy and sphere radius, while SSE-intr and OCSI maintain their speed independently of the objects’ geometry. While OCSI and SSE-intr, both based on SIMD parallelization, show excellent and very similar performance, the former provides a more accessible coding and user-friendly implementation as it exploits OpenMP directives for automatic vectorization.

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The Effect of Material Properties on the Perceived Shape of Three-Dimensional Objects

i-Perception ◽

10.1177/2041669520982317 ◽

2020 ◽

Vol 11 (6) ◽

pp. 204166952098231

Author(s):

Masakazu Ohara ◽

Juno Kim ◽

Kowa Koida

Keyword(s):

Material Properties ◽

Regional Variation ◽

Three Dimensional ◽

Mean Square ◽

Viewing Condition ◽

Three Dimensional Objects ◽

Transparent Objects ◽

Dimensional Shape ◽

Local Root ◽

Three Dimensional Shape

Perceiving the shape of three-dimensional objects is essential for interacting with them in daily life. If objects are constructed from different materials, can the human visual system accurately estimate their three-dimensional shape? We varied the thickness, motion, opacity, and specularity of globally convex objects rendered in a photorealistic environment. These objects were presented under either dynamic or static viewing condition. Observers rated the overall convexity of these objects along the depth axis. Our results show that observers perceived solid transparent objects as flatter than the same objects rendered with opaque reflectance properties. Regional variation in local root-mean-square image contrast was shown to provide information that is predictive of perceived surface convexity.

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