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Structural Colouration
Structural coloration in animals, and a few plants, is the production of colour by microscopically structured surfaces fine enough to interfere with visible light instead of pigments, although some structural coloration occurs in combination with pigments. For example, peacock tail feathers are pigmented brown, but their microscopic structure makes them also reflect blue, turquoise, and green light, and they are often iridescent. Structural coloration was first observed by English scientists Robert Hooke and Isaac Newton, and its principle – wave interference – explained by Thomas Young a century later. Young described iridescence as the result of interference between reflections from two or more surfaces of thin films, combined with refraction as light enters and leaves such films. The geometry then determines that at certain angles, the light reflected from both surfaces interferes constructively, while at other angles, the light interferes destructively. Different colo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peacock Feathers Closeup
Peafowl is a common name for three bird species in the genera ''Pavo (genus), Pavo'' and ''Afropavo'' within the tribe Pavonini of the family Phasianidae, the pheasants and their allies. Male peafowl are referred to as peacocks, and female peafowl are referred to as peahens, although peafowl of either sex are often referred to colloquialism, colloquially as "peacocks." The two Asiatic species are the blue or Indian peafowl originally of the Indian subcontinent, and the green peafowl of Southeast Asia; the one African species is the Congo peafowl, native only to the Congo Basin. Male peafowl are known for their piercing calls and their extravagant plumage. The latter is especially prominent in the Asiatic species, which have an eye-spotted "tail" or "train" of covert feathers, which they display as part of a courtship ritual. The functions of the elaborate iridescent Animal coloration, colouration and large "train" of peacocks have been the subject of extensive scientific debat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffraction Grating
In optics, a diffraction grating is an optical component with a periodic structure that diffracts light into several beams travelling in different directions (i.e., different diffraction angles). The emerging coloration is a form of structural coloration. The directions or diffraction angles of these beams depend on the wave (light) incident angle to the diffraction grating, the spacing or distance between adjacent diffracting elements (e.g., parallel slits for a transmission grating) on the grating, and the wavelength of the incident light. The grating acts as a dispersive element. Because of this, diffraction gratings are commonly used in monochromators and spectrometers, but other applications are also possible such as optical encoders for high precision motion control and wavefront measurement. For typical applications, a reflective grating has ridges or ''rulings'' on its surface while a transmissive grating has transmissive or hollow slits on its surface. Such a grating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Particle Theory Of Light
In the physical sciences, a particle (or corpuscule in older texts) is a small localized object which can be described by several physical or chemical properties, such as volume, density, or mass. They vary greatly in size or quantity, from subatomic particles like the electron, to microscopic particles like atoms and molecules, to macroscopic particles like powders and other granular materials. Particles can also be used to create scientific models of even larger objects depending on their density, such as humans moving in a crowd or celestial bodies in motion. The term ''particle'' is rather general in meaning, and is refined as needed by various scientific fields. Anything that is composed of particles may be referred to as being particulate. However, the noun ''particulate'' is most frequently used to refer to pollutants in the Earth's atmosphere, which are a suspension of unconnected particles, rather than a connected particle aggregation. Conceptual properties The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opticks
''Opticks: or, A Treatise of the Reflexions, Refractions, Inflexions and Colours of Light'' is a book by English natural philosopher Isaac Newton that was published in English in 1704 (a scholarly Latin translation appeared in 1706). (''Opticks'' was originally published in 1704). The book analyzes the fundamental nature of light by means of the refraction of light with prisms and lenses, the diffraction of light by closely spaced sheets of glass, and the behaviour of color mixtures with spectral lights or pigment powders. ''Opticks'' was Newton's second major book on physical science and it is considered one of the three major works on optics during the Scientific Revolution (alongside Kepler's ''Astronomiae Pars Optica'' and Huygens' ''Traité de la Lumière''). Newton's name did not appear on the title page of the first edition of ''Opticks''. Overview The publication of ''Opticks'' represented a major contribution to science, different from but in some ways rivalling the ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nacre
Nacre ( , ), also known as mother of pearl, is an organicinorganic composite material produced by some molluscs as an inner shell layer; it is also the material of which pearls are composed. It is strong, resilient, and iridescent. Nacre is found in some of the most ancient lineages of bivalves, gastropods, and cephalopods. However, the inner layer in the great majority of mollusc shells is porcellaneous, not nacreous, and this usually results in a non-iridescent shine, or more rarely in non-nacreous iridescence such as ''flame structure'' as is found in conch pearls. The outer layer of cultured pearls and the inside layer of pearl oyster and freshwater pearl mussel shells are made of nacre. Other mollusc families that have a nacreous inner shell layer include marine gastropods such as the Haliotidae, the Trochidae and the Turbinidae. Physical characteristics Structure and appearance Nacre is composed of hexagonal platelets of aragonite (a form of calcium carbonate) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micrographia
''Micrographia: or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses. With Observations and Inquiries Thereupon.'' is a historically significant book by Robert Hooke about his observations through various lenses. It was the first book to include illustrations of insects and plants as seen through microscopes. Published in January 1665, the first major publication of the Royal Society, it became the first scientific best-seller, inspiring a wide public interest in the new science of microscopy. The book originated the biological term ''cell''. Observations Hooke most famously describes a fly's eye and a plant cell (where he coined that term because plant cells, which are walled, reminded him of the cells in a honeycomb"... I could exceedingly plainly perceive it to be all perforated and porous, much like a Honey-comb, but that the pores of it were not regular .these pores, or cells, .were indeed the first microscopical pores I ever saw, and perhaps, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micrographia Title Page
''Micrographia: or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses. With Observations and Inquiries Thereupon.'' is a historically significant book by Robert Hooke about his observations through various lenses. It was the first book to include illustrations of insects and plants as seen through microscopes. Published in January 1665, the first major publication of the Royal Society, it became the first scientific best-seller, inspiring a wide public interest in the new science of microscopy. The book originated the biological term ''cell''. Observations Hooke most famously describes a fly's eye and a plant cell (where he coined that term because plant cells, which are walled, reminded him of the cells in a honeycomb"... I could exceedingly plainly perceive it to be all perforated and porous, much like a Honey-comb, but that the pores of it were not regular .these pores, or cells, .were indeed the first microscopical pores I ever saw, and perhaps, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camouflage
Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the battledress of a modern soldier, and the leaf-mimic katydid's wings. A third approach, motion dazzle, confuses the observer with a conspicuous pattern, making the object visible but momentarily harder to locate, as well as making general aiming easier. The majority of camouflage methods aim for crypsis, often through a general resemblance to the background, high contrast disruptive coloration, eliminating shadow, and countershading. In the open ocean, where there is no background, the principal methods of camouflage are transparency, silvering, and countershading, while the ability to produce light is among other things used for counter-illumination on the undersides of cephalopods such as squid. Some animals, such as chameleons and o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biomimicry
Biomimetics or biomimicry is the emulation of the models, systems, and elements of nature for the purpose of solving complex human problems. The terms "biomimetics" and "biomimicry" are derived from grc, βίος (''bios''), life, and μίμησις ('' mīmēsis''), imitation, from μιμεῖσθαι (''mīmeisthai''), to imitate, from μῖμος (''mimos''), actor. A closely related field is bionics. Living organisms have evolved well-adapted structures and materials over geological time through natural selection. Biomimetics has given rise to new technologies inspired by biological solutions at macro and nanoscales. Humans have looked at nature for answers to problems throughout their existence. Nature has solved engineering problems such as self-healing abilities, environmental exposure tolerance and resistance, hydrophobicity, self-assembly, and harnessing solar energy. History One of the early examples of biomimicry was the study of birds to enable human flight. Alt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buttercup
''Ranunculus'' is a large genus of about almost 1700 to more than 1800 species of flowering plants in the family Ranunculaceae. Members of the genus are known as buttercups, spearworts and water crowfoots. The genus is distributed in Europe, North America and South America. The familiar and widespread buttercup of gardens throughout Northern Europe (and introduced elsewhere) is the creeping buttercup ''Ranunculus repens'', which has extremely tough and tenacious roots. Two other species are also widespread, the bulbous buttercup ''Ranunculus bulbosus'' and the much taller meadow buttercup ''Ranunculus acris''. In ornamental gardens, all three are often regarded as weeds. Buttercups usually flower in the spring, but flowers may be found throughout the summer, especially where the plants are growing as opportunistic colonizers, as in the case of garden weeds. The water crowfoots (''Ranunculus'' subgenus ''Batrachium''), which grow in still or running water, are sometimes tre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bragg's Law
In physics and chemistry , Bragg's law, Wulff–Bragg's condition or Laue–Bragg interference, a special case of Laue diffraction, gives the angles for coherent scattering of waves from a crystal lattice. It encompasses the superposition of wave fronts scattered by lattice planes, leading to a strict relation between wavelength and scattering angle, or else to the wavevector transfer with respect to the crystal lattice. Such law had initially been formulated for X-rays upon crystals. However, It applies to all sorts of quantum beams, including neutron and electron waves at atomic distances, as well as visible light at artificial periodic microscale lattices. History Bragg diffraction (also referred to as the Bragg formulation of X-ray diffraction) was first proposed by Lawrence Bragg and his father, William Henry Bragg, in 1913 in response to their discovery that crystalline solids produced surprising patterns of reflected X-rays (in contrast to that of, say, a liquid). They ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollia Condensata
''Pollia condensata'', sometimes called the marble berry, is a perennial herbaceous plant with stoloniferous stems and hard, dry, shiny, round, metallic blue fruit. It is found in forested regions of Africa. The blue colour of the fruit, created by structural coloration, is the most intense of any known biological material. Description The plant was originally described from Angola, in southern Africa. It has large, smooth, narrow leaves, and pale pink or whitish flowers on a stem about 60 cm high. The fruit capsule is about 4 mm in diameter. Structural coloration The surface of the ''Pollia'' fruit has an especially smooth and transparent cuticle which reflects light as a mirror does (specular reflection). Beneath this glossy surface lies a special layer of cells which have an elaborate but unpigmented microstructure, whose function is to reflect light within a narrow range of wavelengths. This structural coloration is created by Bragg reflection from spirally stacke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
