News tagged with diameter
Thousands of invisibility cloaks trap a rainbow
Many people anticipating the creation of an invisibility cloak might be surprised to learn that a group of American researchers has created 25 000 individual cloaks.
May 24, 2012 |
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Study shows subway systems develop in remarkably similar ways
(Phys.org) -- Visitors to major cities in the world might disagree, but a small group of French and British researchers has found that regardless of city density, structure and other factors, subway systems ...
May 22, 2012 |
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The most profitable asteroid is...
With the recent announcement of the asteroid mining company, Planetary Resources, some of the most-asked questions about this enticing but complex endeavor include, what asteroids do we mine? Which are the ...
Space & Earth / Space Exploration
May 17, 2012 |
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Size matters - even for molecules
Two electrons that are emitted from a large molecule by a single photon may originate from far apart within that molecule. In a recent study on hydrocarbon molecules consisting of one to five fused benzene ...
Apr 11, 2012 |
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Apollo 16: What young really means on the moon
(PhysOrg.com) -- One of the main goals of the Apollo 16 mission was to explore and sample a young bright-rayed crater aptly named North Ray crater (890 m diameter). Its high reflectivity is due to its young ...
Space & Earth / Space Exploration
Mar 09, 2012 |
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A study describes liquid water diffusion at molecular level
An article published in Physical Review E and conducted by Spanish researchers at the universities of Granada and Barcelona might lead to a revolutionary change in water desalination and filtration methods.
Feb 24, 2012 |
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'Smart' microcapsules in a single step
(PhysOrg.com) -- A new, single-step method of fabricating microcapsules, which have potential commercial applications in industries including medicine, agriculture and diagnostics, has been developed by researchers ...
Nanotechnology / Nanomaterials
Feb 13, 2012 |
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Faraway Eris is Pluto's twin: Dwarf planet sized up accurately as it blocks light of faint star
(PhysOrg.com) -- Astronomers have measured the diameter of the dwarf planet Eris by catching it as it passed in front of a faint star. This was seen by telescopes in Chile, including the TRAPPIST telescope ...
Oct 26, 2011 |
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Shining light on the elusive carbon nanotube
Michael Blades shakes a small bottle of liquid and watches as tiny black specks swirl around. Each speck represents a cluster of millions of carbon nanotubes (CNTs).
Nanotechnology / Nanomaterials
Oct 20, 2011 |
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Slowest crystal growth ever measured
(PhysOrg.com) -- Deep within a silver and lead mine in Naica, Mexico, scientists discovered what is now known as Cueva de los Cristales, or Cave of Crystals, close to a decade ago. The gypsum crystals found ...
Sep 13, 2011 |
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No small measure: Origins of nanorod diameter discovered
(PhysOrg.com) -- A new study answers a key question at the very heart of nanotechnology: Why are nanorods so small?
Mar 19, 2009 |
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Diameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle. The word "diameter" derives from Greek διάμετρος (diametros), "diagonal of a circle", from δια- (dia-), "across, through" + μέτρον (metron), "a measure").
In more modern usage, the length of a diameter is also called the diameter. In this sense one speaks of the diameter rather than a diameter, because all diameters of a circle have the same length, this being twice the radius.
For a convex shape in the plane, the diameter is defined to be the largest distance that can be formed between two opposite parallel lines tangent to its boundary, and the width is defined to be the smallest such distance. For a curve of constant width such as the Reuleaux triangle, the width and diameter are the same because all such pairs of parallel tangent lines have the same distance. See also Tangent lines to circles.
For more information about Diameter, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
