1.
Ultramarine
–
Ultramarine is a deep blue color and a pigment which was originally made by grinding lapis lazuli into a powder. The name comes from the Latin ultramarinus, literally beyond the sea, Ultramarine was the finest and most expensive blue used by Renaissance painters. It was often used for the robes of the Virgin Mary and it remained an extremely expensive pigment until a synthetic ultramarine was invented in 1826. The pigment consists primarily of a mineral containing small amounts of polysulfides. It occurs in nature as a component of lapis lazuli containing a blue cubic mineral called lazurite. The pigment color code is P, the major component of lazurite is a complex sulfur-containing sodium-silicate, which makes ultramarine the most complex of all mineral pigments. Some chloride is present in the crystal lattice as well. The blue color of the pigment is due to the S−3 radical anion, the preparation is typically made in steps. The first part of the takes place at 700 to 750 °C in a closed furnace, so that sulphur, carbon. This yields a yellow-green product sometimes used as a pigment, in the second step air or sulphur dioxide at 350 to 450 °C is used to oxidise sulphide sulphur in the intermediate product to S2 and Sn chromophore molecules, resulting in the blue pigment. The mixture is heated in a kiln, sometimes in brick-sized amounts, the resultant solids are then ground and washed as per any other insoluble pigment manufacturing process. The chemical reaction produces large amounts of sulfur dioxide, meaning that flue-gas desulfurization is an part of its manufacture to comply with pollution regulations. Large chimneys were used to disperse sulfur dioxide produced in the process, resulting in ultramarine tinting the surrounding ground surfaces, Ultramarine poor in silica is obtained by fusing a mixture of soft clay, sodium sulfate, charcoal, sodium carbonate and sulfur. The product is at first white, but soon turns green green ultramarine when it is mixed with sulfur, the sulfur burns, and a fine blue pigment is obtained. Ultramarine rich in silica is obtained by heating a mixture of pure clay, very fine white sand, sulfur. A blue product is obtained at once, but a red tinge often results, the different ultramarines—green, blue, red and violet—are finely ground and washed with water. Its color is unaffected by light nor by contact with oil or lime as used in painting, hydrochloric acid immediately bleaches it with liberation of hydrogen sulfide. Even a small addition of oxide to the reddish varieties especially causes a considerable diminution in the intensity of the color
Ultramarine
–
Synthetic ultramarine
pigment
Ultramarine
–
Lapis lazuli specimen (rough), Afghanistan
Ultramarine
–
Natural ultramarine
Ultramarine
–
Synthetic ultramarine violet
2.
Color
–
Color or colour is the characteristic of human visual perception described through color categories, with names such as red, yellow, purple, or blue. This perception of color derives from the stimulation of cells in the human eye by electromagnetic radiation in the spectrum of light. Color categories and physical specifications of color are associated with objects through the wavelength of the light that is reflected from them and this reflection is governed by the objects physical properties such as light absorption, emission spectra, etc. By defining a color space, colors can be identified numerically by coordinates, there may also be more than three color dimensions in other color spaces, such as in the CMYK color model, wherein one of the dimensions relates to a colours colorfulness). The photo-receptivity of the eyes of species also varies considerably from our own. Honeybees and bumblebees for instance have trichromatic color vision sensitive to ultraviolet but is insensitive to red, papilio butterflies possess six types of photoreceptors and may have pentachromatic vision. The most complex color vision system in the kingdom has been found in stomatopods with up to 12 spectral receptor types thought to work as multiple dichromatic units. The science of color is sometimes called chromatics, colorimetry, or simply color science and it includes the perception of color by the human eye and brain, the origin of color in materials, color theory in art, and the physics of electromagnetic radiation in the visible range. Electromagnetic radiation is characterized by its wavelength and its intensity, when the wavelength is within the visible spectrum, it is known as visible light. Most light sources emit light at different wavelengths, a sources spectrum is a distribution giving its intensity at each wavelength. Although the spectrum of light arriving at the eye from a given direction determines the color sensation in that direction, in each such class the members are called metamers of the color in question. The table at right shows approximate frequencies and wavelengths for various pure spectral colors, the wavelengths listed are as measured in air or vacuum. A common list identifies six main bands, red, orange, yellow, green, blue, Newtons conception included a seventh color, indigo, between blue and violet. It is possible that what Newton referred to as blue is nearer to what today is known as cyan, the color of an object depends on both the physics of the object in its environment and the characteristics of the perceiving eye and brain. Some objects not only light, but also transmit light or emit light themselves. This effect is known as color constancy, opaque objects that do not reflect specularly have their color determined by which wavelengths of light they scatter strongly. If objects scatter all wavelengths with roughly equal strength, they appear white, if they absorb all wavelengths, they appear black. Opaque objects that reflect light of different wavelengths with different efficiencies look like mirrors tinted with colors determined by those differences
Color
–
Colored pencils
3.
Light
–
Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum. The word usually refers to light, which is visible to the human eye and is responsible for the sense of sight. Visible light is defined as having wavelengths in the range of 400–700 nanometres, or 4.00 × 10−7 to 7.00 × 10−7 m. This wavelength means a range of roughly 430–750 terahertz. The main source of light on Earth is the Sun, sunlight provides the energy that green plants use to create sugars mostly in the form of starches, which release energy into the living things that digest them. This process of photosynthesis provides virtually all the used by living things. Historically, another important source of light for humans has been fire, with the development of electric lights and power systems, electric lighting has effectively replaced firelight. Some species of animals generate their own light, a process called bioluminescence, for example, fireflies use light to locate mates, and vampire squids use it to hide themselves from prey. Visible light, as all types of electromagnetic radiation, is experimentally found to always move at this speed in a vacuum. In physics, the term sometimes refers to electromagnetic radiation of any wavelength. In this sense, gamma rays, X-rays, microwaves and radio waves are also light, like all types of light, visible light is emitted and absorbed in tiny packets called photons and exhibits properties of both waves and particles. This property is referred to as the wave–particle duality, the study of light, known as optics, is an important research area in modern physics. Generally, EM radiation, or EMR, is classified by wavelength into radio, microwave, infrared, the behavior of EMR depends on its wavelength. Higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths, when EMR interacts with single atoms and molecules, its behavior depends on the amount of energy per quantum it carries. There exist animals that are sensitive to various types of infrared, infrared sensing in snakes depends on a kind of natural thermal imaging, in which tiny packets of cellular water are raised in temperature by the infrared radiation. EMR in this range causes molecular vibration and heating effects, which is how these animals detect it, above the range of visible light, ultraviolet light becomes invisible to humans, mostly because it is absorbed by the cornea below 360 nanometers and the internal lens below 400. Furthermore, the rods and cones located in the retina of the eye cannot detect the very short ultraviolet wavelengths and are in fact damaged by ultraviolet. Many animals with eyes that do not require lenses are able to detect ultraviolet, by quantum photon-absorption mechanisms, various sources define visible light as narrowly as 420 to 680 to as broadly as 380 to 800 nm
Light
–
An example of refraction of light. The straw appears bent, because of refraction of light as it enters liquid from air.
Light
–
A triangular prism dispersing a beam of white light. The longer wavelengths (red) and the shorter wavelengths (blue) get separated.
Light
–
A
cloud illuminated by
sunlight
Light
–
A
city illuminated by
artificial lighting
4.
Wavelength
–
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the waves shape repeats, and thus the inverse of the spatial frequency. Wavelength is commonly designated by the Greek letter lambda, the concept can also be applied to periodic waves of non-sinusoidal shape. The term wavelength is also applied to modulated waves. Wavelength depends on the medium that a wave travels through, examples of wave-like phenomena are sound waves, light, water waves and periodic electrical signals in a conductor. A sound wave is a variation in air pressure, while in light and other electromagnetic radiation the strength of the electric, water waves are variations in the height of a body of water. In a crystal lattice vibration, atomic positions vary, wavelength is a measure of the distance between repetitions of a shape feature such as peaks, valleys, or zero-crossings, not a measure of how far any given particle moves. For example, in waves over deep water a particle near the waters surface moves in a circle of the same diameter as the wave height. The range of wavelengths or frequencies for wave phenomena is called a spectrum, the name originated with the visible light spectrum but now can be applied to the entire electromagnetic spectrum as well as to a sound spectrum or vibration spectrum. In linear media, any pattern can be described in terms of the independent propagation of sinusoidal components. The wavelength λ of a sinusoidal waveform traveling at constant speed v is given by λ = v f, in a dispersive medium, the phase speed itself depends upon the frequency of the wave, making the relationship between wavelength and frequency nonlinear. In the case of electromagnetic radiation—such as light—in free space, the speed is the speed of light. Thus the wavelength of a 100 MHz electromagnetic wave is about, the wavelength of visible light ranges from deep red, roughly 700 nm, to violet, roughly 400 nm. For sound waves in air, the speed of sound is 343 m/s, the wavelengths of sound frequencies audible to the human ear are thus between approximately 17 m and 17 mm, respectively. Note that the wavelengths in audible sound are much longer than those in visible light, a standing wave is an undulatory motion that stays in one place. A sinusoidal standing wave includes stationary points of no motion, called nodes, the upper figure shows three standing waves in a box. The walls of the box are considered to require the wave to have nodes at the walls of the box determining which wavelengths are allowed, the stationary wave can be viewed as the sum of two traveling sinusoidal waves of oppositely directed velocities. Consequently, wavelength, period, and wave velocity are related just as for a traveling wave, for example, the speed of light can be determined from observation of standing waves in a metal box containing an ideal vacuum. In that case, the k, the magnitude of k, is still in the same relationship with wavelength as shown above
Wavelength
–
Wavelength is decreased in a medium with slower propagation.
Wavelength
–
Wavelength of a
sine wave, λ, can be measured between any two points with the same
phase, such as between crests, or troughs, or corresponding
zero crossings as shown.
Wavelength
–
Various local wavelengths on a crest-to-crest basis in an ocean wave approaching shore
Wavelength
–
A wave on a line of atoms can be interpreted according to a variety of wavelengths.
5.
Fluorescence
–
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence, in most cases, the emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation. Fluorescent materials cease to glow immediately when the radiation source stops, unlike phosphorescence, Fluorescence also occurs frequently in nature in some minerals and in various biological states in many branches of the animal kingdom. An early observation of fluorescence was described in 1560 by Bernardino de Sahagún and it was derived from the wood of two tree species, Pterocarpus indicus and Eysenhardtia polystachya. The chemical compound responsible for this fluorescence is matlaline, which is the product of one of the flavonoids found in this wood. The name was derived from the fluorite, some examples of which contain traces of divalent europium. In a key experiment he used a prism to isolate ultraviolet radiation from sunlight, the specific frequencies of exciting and emitted light are dependent on the particular system. S0 is called the state of the fluorophore, and S1 is its first excited singlet state. A molecule in S1 can relax by various competing pathways and it can undergo non-radiative relaxation in which the excitation energy is dissipated as heat to the solvent. Excited organic molecules can also relax via conversion to a triplet state, relaxation from S1 can also occur through interaction with a second molecule through fluorescence quenching. Molecular oxygen is an extremely efficient quencher of fluorescence just because of its unusual triplet ground state, in most cases, the emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation, this phenomenon is known as the Stokes shift. The emitted radiation may also be of the wavelength as the absorbed radiation. Molecules that are excited through light absorption or via a different process can transfer energy to a second sensitized molecule, the fluorescence quantum yield gives the efficiency of the fluorescence process. It is defined as the ratio of the number of photons emitted to the number of photons absorbed, Φ = Number of photons emitted Number of photons absorbed The maximum fluorescence quantum yield is 1.0, each photon absorbed results in a photon emitted. Compounds with quantum yields of 0.10 are still considered quite fluorescent, thus, if the rate of any pathway changes, both the excited state lifetime and the fluorescence quantum yield will be affected. Fluorescence quantum yields are measured by comparison to a standard, the quinine salt quinine sulfate in a sulfuric acid solution is a common fluorescence standard. The fluorescence lifetime refers to the time the molecule stays in its excited state before emitting a photon. This is an instance of exponential decay, various radiative and non-radiative processes can de-populate the excited state
Fluorescence
–
Fluorescent minerals emit visible light when exposed to
ultraviolet light
Fluorescence
–
Lignum nephriticum cup made from the wood of the narra tree (
Pterocarpus indicus), and a flask containing its fluorescent
solution
Fluorescence
–
Matlaline, the fluorescent substance in the wood of the tree Eysenhardtia polystachya
Fluorescence
–
Aequoria victoria, biofluorescent jellyfish known for GFP.
6.
Phosphorescence
–
Phosphorescence is a type of photoluminescence related to fluorescence. Unlike fluorescence, phosphorescent material does not immediately re-emit the radiation it absorbs, the slower time scales of the re-emission are associated with forbidden energy state transitions in quantum mechanics. As these transitions occur very slowly in certain materials, absorbed radiation is re-emitted at an intensity for up to several hours after the original excitation. Typically, the glow slowly fades out, sometimes within a few minutes or up to a few hours in a dark room, the study of phosphorescent materials led to the discovery of radioactivity in 1896. In simple terms, phosphorescence is a process in which energy absorbed by a substance is released relatively slowly in the form of light and this is in some cases the mechanism used for glow-in-the-dark materials which are charged by exposure to light. Most photoluminescent events, in which a chemical substrate absorbs and then re-emits a photon of light, are fast, light is absorbed and emitted at these fast time scales in cases where the energy of the photons involved matches the available energy states and allowed transitions of the substrate. In the special case of phosphorescence, the photon energy undergoes an unusual intersystem crossing into an energy state of higher spin multiplicity. As a result, the energy can become trapped in the state with only forbidden transitions available to return to the lower energy state. These transitions, although forbidden, will occur in quantum mechanics but are kinetically unfavored. Most phosphorescent compounds are relatively fast emitters, with triplet lifetimes on the order of milliseconds. However, some compounds have triplet lifetimes up to minutes or even hours, if the phosphorescent quantum yield is high, these substances will release significant amounts of light over long time scales, creating so-called glow-in-the-dark materials. S0 + h ν → S1 → T1 → S0 + h ν ′ where S is a singlet, transitions can also occur to higher energy levels, but the first excited state is denoted for simplicity. Some examples of glow-in-the-dark materials do not glow by phosphorescence, for example, glow sticks glow due to a chemiluminescent process which is commonly mistaken for phosphorescence. In chemiluminescence, a state is created via a chemical reaction. The light emission tracks the progress of the underlying chemical reaction. The excited state will then transfer to a dye molecule, also known as a sensitizer or fluorophor, common pigments used in phosphorescent materials include zinc sulfide and strontium aluminate. Use of zinc sulfide for safety related products dates back to the 1930s, however, the development of strontium aluminate, with a luminance approximately 10 times greater than zinc sulfide, has relegated most zinc sulfide based products to the novelty category. Strontium aluminate based pigments are now used in signs, pathway marking
Phosphorescence
–
Phosphorescent, Europium-doped strontium silicate-aluminate oxide powder under visible light, long-wave UV light, and in total darkness
Phosphorescence
Phosphorescence
–
An extremely intense pulse of UV light in a
flashtube produced this blue phosphorescence in the
fused silica envelope.
Phosphorescence
–
Phosphorescence of the quartz ignition tube of an
air-gap flash
7.
Luminescence
–
Luminescence is emission of light by a substance not resulting from heat, it is thus a form of cold-body radiation. It can be caused by chemical reactions, electrical energy, subatomic motions, or stress on a crystal and this distinguishes luminescence from incandescence, which is light emitted by a substance as a result of heating. Historically, radioactivity was thought of as a form of radio-luminescence, the term luminescence was introduced in 1888 by Eilhard Wiedemann. The dials, hands, scales, and signs of aviation and navigational instruments and this property of these minerals can be used during the process of mineral identification at rock outcrops in the field, or in the laboratory. Fluorophores. org A database of luminescent dyes
Luminescence
–
Luminol and
haemoglobin, an example of chemiluminescence
8.
Tint
–
In color theory, a tint is the mixture of a color with white, which increases lightness, and a shade is the mixture of a color with black, which reduces lightness. A tone is produced either by the mixture of a color with gray, mixing a color with any neutral color reduces the chroma, or colorfulness, while the hue remains unchanged. When mixing colored light, the mixture of spectrally balanced red, green and blue is always white. When we mix colorants, such as the pigments in paint mixtures and this moves the mixed color toward a neutral color—a gray or near-black. Lights are made brighter or dimmer by adjusting their brightness, or energy level, in painting, lightness is adjusted through mixture with white, black or a colors complement. It is common among some painters to darken a paint color by adding black paint—producing colors called shades—or to lighten a color by adding white—producing colors called tints. However, this is not always the best way for representational painting, for instance, darkening a color by adding black can cause colors such as yellows, reds and oranges, to shift toward the greenish or bluish part of the spectrum. Lightening a color by adding white can cause a shift towards blue when mixed with reds and oranges. When lightening a color this hue shift can be corrected with the addition of an amount of an adjacent color to bring the hue of the mixture back in line with the parent color
Tint
–
"Tint" redirects here. For other uses, see
Tint (disambiguation).
9.
Paint
–
Paint is any liquid, liquefiable, or mastic composition that, after application to a substrate in a thin layer, converts to a solid film. It is most commonly used to protect, color, or provide texture to objects, Paint can be made or purchased in many colors—and in many different types, such as watercolor, synthetic, etc. Paint is typically stored, sold, and applied as a liquid, in 2001 and 2004, South African archeologists reported finds in Blombos Cave of a 100, 000-year-old human-made ochre-based mixture that could have been used like paint. Further excavation in the cave resulted in the 2011 report of a complete toolkit for grinding pigments. Cave paintings drawn with red or yellow ochre, hematite, manganese oxide, ancient colored walls at Dendera, Egypt, which were exposed for years to the elements, still possess their brilliant color, as vivid as when they were painted about 2,000 years ago. The Egyptians mixed their colors with a substance, and applied them separately from each other without any blending or mixture. They appear to have used six colors, white, black, blue, red, yellow and they first covered the area entirely with white, then traced the design in black, leaving out the lights of the ground color. They used minium for red, and generally of a dark tinge, pliny mentions some painted ceilings in his day in the town of Ardea, which had been done prior to the foundation of Rome. He expresses great surprise and admiration at their freshness, after the lapse of so many centuries, Paint was made with the yolk of eggs and therefore, the substance would harden and adhere to the surface it was applied to. Pigment was made from plants, sand, and different soils, Most paints used either oil or water as a base. The process was done by hand by the painters and exposed them to lead poisoning due to the white-lead powder, in 1718, Marshall Smith invented a Machine or Engine for the Grinding of Colours in England. It is not known precisely how it operated, but it was a device that increased the efficiency of pigment grinding dramatically. By the proper onset of the Industrial Revolution, paint was being ground in steam-powered mills, interior house painting increasingly became the norm as the 19th century progressed, both for decorative reasons and because the paint was effective in preventing the walls rotting from damp. Linseed oil was also used as an inexpensive binder. In 1866, Sherwin-Williams in the United States opened as a large paint-maker and it was not until the stimulus of World War II created a shortage of linseed oil in the supply market that artificial resins, or alkyds, were invented. Cheap and easy to make, they held the color well. The vehicle is composed of the binder, or, if it is necessary to thin the binder with a diluent like solvent or water, it is the combination of binder + diluent. In this case, once the paint has dried or cured very nearly all of the diluent has evaporated, thus, an important quantity in coatings formulation is the vehicle solids, sometimes called the resin solids of the formula
Paint
–
Dried green paint
Paint
–
A charcoal and ochre cave painting of
Megaloceros from
Lascaux, France.
Paint
–
A piece of
Giant clam shell used to hold ochre paint in
pre-dynastic ancient Egypt
Paint
–
Watercolors as applied with a
brush
10.
Ink
–
Ink is a liquid or paste that contains pigments or dyes and is used to color a surface to produce an image, text, or design. Ink is used for drawing or writing with a pen, brush, thicker inks, in paste form, are used extensively in letterpress and lithographic printing. Ink can be a medium, composed of solvents, pigments, dyes, resins, lubricants, solubilizers, surfactants, particulate matter, fluorescents. The components of inks serve many purposes, the carrier, colorants. Pigments are solid, opaque particles suspended in ink to provide color, pigment molecules typically link together in crystalline structures that are 0. 1–2 µm in size and comprise 5–30 percent of the ink volume. Qualities such as hue, saturation, and lightness vary depending on the source, dye-based inks are generally much stronger than pigment-based inks and can produce much more color of a given density per unit of mass. However, because dyes are dissolved in the phase, they have a tendency to soak into paper, making the ink less efficient. To circumvent this problem, dye-based inks are made with solvents that dry rapidly or are used with quick-drying methods of printing, other methods include harder paper sizing and more specialized paper coatings. The latter is particularly suited to inks used in non-industrial settings, another technique involves coating the paper with a charged coating. If the dye has the charge, it is attracted to and retained by this coating. Cellulose, the material most paper is made of, is naturally charged. Such a compound is used in ink-jet printing inks. A more recent development in dye-based inks are dyes that react with cellulose to permanently color the paper, such inks are not affected by water, alcohol, and other solvents. As such, their use is recommended to prevent frauds that involve removing signatures and this kind of ink is most commonly found in gel inks and in certain fountain pen inks. Many ancient cultures around the world have discovered and formulated inks for the purposes of writing and drawing. The knowledge of the inks, their recipes and the techniques for their production comes from archaeological analysis or from written text itself. Evidence for the earliest Chinese inks, similar to modern inksticks, is around 256 BC in the end of the Warring States period and produced from soot, the best inks for drawing or painting on paper or silk are produced from the resin of the pine tree. They must be between 50 and 100 years old, the Chinese inkstick is produced with a fish glue, whereas Japanese glue is from cow or stag
Ink
–
Bottles of ink from
Germany.
Ink
–
Magnified line drawn by a
fountain pen.
Ink
–
Ink drawing of
Ganesha under an umbrella (early 19th century). Ink, called masi, an admixture of several chemical components, has been used in India since at least the 4th century BC. The practice of writing with ink and a sharp pointed needle was common in early
South India. Several
Jain sutras in India were compiled in ink.
Ink
–
Chinese
inkstick; carbon-based and made from
soot and
animal glue.
11.
Plastic
–
Plastic is a material consisting of any of a wide range of synthetic or semi-synthetic organic compounds that are malleable and can be molded into solid objects. Plastics are typically organic polymers of high mass, but they often contain other substances. They are usually synthetic, most commonly derived from petrochemicals, due to their relatively low cost, ease of manufacture, versatility, and imperviousness to water, plastics are used in an enormous and expanding range of products, from paper clips to spaceships. They have already displaced many traditional materials, such as wood, stone, horn and bone, leather, paper, metal, glass, and ceramic, in most of their former uses. In developed countries, about a third of plastic is used in packaging, other uses include automobiles, furniture, and toys. In the developing world, the ratios may be different - for example, the worlds first fully synthetic plastic was bakelite, invented in New York in 1907 by Leo Baekeland who coined the term plastics. Toward the end of the century, one approach to this problem was met with wide efforts toward recycling, the word plastic is derived from the Greek πλαστικός meaning capable of being shaped or molded, from πλαστός meaning molded. The common word plastic should not be confused with the technical adjective plastic, used for insulating parts in electrical fixtures, paper laminated products, thermally insulation foams. Problems include the probability of moldings naturally being dark colors, One of the most expensive commercial polymers. It forms the basis of artistic and commercial acrylic paints when suspended in water with the use of other agents, polytetrafluoroethylene – Heat-resistant, low-friction coatings, used in things like non-stick surfaces for frying pans, plumbers tape and water slides. It is more known as Teflon. Urea-formaldehyde – One of the aminoplasts and used as an alternative to phenolics. Used as an adhesive and electrical switch housings. Early plastics were bio-derived materials such as egg and blood proteins, in 1600 BC, Mesoamericans used natural rubber for balls, bands, and figurines. Treated cattle horns were used as windows for lanterns in the Middle Ages, materials that mimicked the properties of horns were developed by treating milk-proteins with lye. In the 1800s, as industrial chemistry developed during the Industrial Revolution, the development of plastics also accelerated with Charles Goodyears discovery of vulcanization to thermoset materials derived from natural rubber. Parkesine is considered the first man-made plastic, the plastic material was patented by Alexander Parkes, In Birmingham, UK in 1856. It was unveiled at the 1862 Great International Exhibition in London, parkesine won a bronze medal at the 1862 Worlds fair in London
Plastic
–
Household items made of various types of plastic
Plastic
–
A chair made with a polypropylene seat
Plastic
–
Plastic (LDPE) bowl, by GEECO, Made in England, c1950.
Plastic
–
Molded plastic food replicas on display outside a restaurant in
Japan
12.
Cloth
–
A textile or cloth is a flexible material consisting of a network of natural or artificial fibres. Yarn is produced by spinning raw fibres of wool, flax, cotton, hemp, Textiles are formed by weaving, knitting, crocheting, knotting, or felting. The words fabric and cloth are used in textile assembly trades as synonyms for textile, however, there are subtle differences in these terms in specialized usage. Textile refers to any material made of interlacing fibres, a fabric is a material made through weaving, knitting, spreading, crocheting, or bonding that may be used in production of further goods. Cloth may be used synonymously with fabric but is often a piece of fabric used for a specific purpose. The word textile is from Latin, from the adjective textilis, meaning woven, from textus, the word cloth derives from the Old English clað, meaning a cloth, woven or felted material to wrap around one, from Proto-Germanic kalithaz. The discovery of dyed flax fibres in a cave in the Republic of Georgia dated to 34,000 BCE suggests textile-like materials were made even in prehistoric times. The production of textiles is a craft whose speed and scale of production has been altered almost beyond recognition by industrialization, however, for the main types of textiles, plain weave, twill, or satin weave, there is little difference between the ancient and modern methods. Textiles have an assortment of uses, the most common of which are for clothing and for such as bags. In the household they are used in carpeting, upholstered furnishings, window shades, towels, coverings for tables, beds, and other flat surfaces, in the workplace they are used in industrial and scientific processes such as filtering. Textiles are used in traditional crafts such as sewing, quilting. Textiles for industrial purposes, and chosen for other than their appearance, are commonly referred to as technical textiles. Technical textiles include textile structures for applications, medical textiles, geotextiles, agrotextiles. In all these applications stringent performance requirements must be met, woven of threads coated with zinc oxide nanowires, laboratory fabric has been shown capable of self-powering nanosystems using vibrations created by everyday actions like wind or body movements. Fashion designers commonly rely on textile designs to set their fashion collections apart from others, armani, the late Gianni Versace, and Emilio Pucci can be easily recognized by their signature print driven designs. Textiles can be made from many materials and these materials come from four main sources, animal, plant, mineral, and synthetic. In the past, all textiles were made from natural fibres, including plant, animal, in the 20th century, these were supplemented by artificial fibres made from petroleum. Textiles are made in various strengths and degrees of durability, from the finest gossamer to the sturdiest canvas, microfibre refers to fibres made of strands thinner than one denier
Cloth
–
Sunday textile market on the sidewalks of
Karachi, Pakistan
Cloth
–
Simple textile (magnified)
Cloth
–
A small fabric shop in
Al-Mukalla, Yemen
Cloth
–
Late antique textile,
Egyptian, now in the
Dumbarton Oaks collection
13.
Cosmetics
–
Cosmetics, also known as make-up, are substances or products used to enhance or alter the appearance or fragrance of the body. Many cosmetics are designed for use of applying to the face and they are generally mixtures of chemical compounds, some being derived from natural sources, and some being synthetics. Common cosmetics include lipstick, mascara, eye shadow, foundation, rouge, skin cleansers and skin lotions, shampoo, hairstyling products, perfume and this broad definition includes any material intended for use as a component of a cosmetic product. The FDA specifically excludes soap from this category, Egyptian women and men also used makeup. They were very fond of eyeliner and eyeshadows in dark colors including blue, red, Ancient Sumerian men and women were possibly the first to invent and wear lipstick, about 5,000 years ago. They crushed gemstones and used them to decorate their faces, mainly on the lips, also around 3000 BC to 1500 BC, women in the ancient Indus Valley Civilization applied red tinted lipstick to their lips for face decoration. Ancient Egyptians extracted red dye from fucus-algin,0. 01% iodine, and some bromine mannite, lipsticks with shimmering effects were initially made using a pearlescent substance found in fish scales. Six thousand year old relics of the hollowed out tombs of the Ancient Egyptian pharaohs are discovered, according to one source, early major developments include, Kohl used by ancient Egypt as a protective of the eye kohl Castor oil used by ancient Egypt as a protective balm. Skin creams made of beeswax, olive oil, and rose water, vaseline and lanolin in the nineteenth century. The Ancient Greeks also used cosmetics as the Ancient Romans did, Cosmetics are mentioned in the Old Testament, such as in 2 Kings 9,30, where Jezebel painted her eyelids—approximately 840 BC—and in the book of Esther, where beauty treatments are described. One of the most popular traditional Chinese medicines is the fungus Tremella fuciformis, used as a beauty product by women in China, the fungus reportedly increases moisture retention in the skin and prevents senile degradation of micro-blood vessels in the skin, reducing wrinkles and smoothing fine lines. Cosmetic use was frowned upon at many points in Western history, for example, in the 19th century, Queen Victoria publicly declared make-up improper, vulgar, and acceptable only for use by actors. During the sixteenth century, the attributes of the women who used make-up created a demand for the product among the upper class. As of 2016, the worlds largest cosmetics company is LOréal, the market was developed in the US during the 1910s by Elizabeth Arden, Helena Rubinstein, and Max Factor. These firms were joined by Revlon just before World War II, during the 18th century, there was a high number of incidences of lead-poisoning because of the fashion for red and white lead makeup and powder. This led to swelling and inflammation of the eyes, attacked tooth enamel, heavy use was known to lead to death. Concealer is commonly used by men, Cosmetics brands release products especially tailored for men, and men are increasingly using them. Cosmetics are intended to be applied externally, a subset of cosmetics is called make-up, refers primarily to products containing color pigments that are intended to alter the users appearance
Cosmetics
–
Effects include light
foundation,
rouge on
cheekbones,
eyebrow plucking, simple black
eye liner
Cosmetics
–
Woman wearing several forms of cosmetics, including
lipstick,
eye liner, eye shadow and
hair dye
Cosmetics
–
Make up by an artist himself for an Indian classical dance
Cosmetics
–
Assorted cosmetics and tools
14.
Food
–
Food is any substance consumed to provide nutritional support for an organism. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, the substance is ingested by an organism and assimilated by the organisms cells to provide energy, maintain life, or stimulate growth. Historically, humans secured food through two methods, hunting and gathering and agriculture, today, the majority of the food energy required by the ever increasing population of the world is supplied by the food industry. They address issues such as sustainability, biological diversity, climate change, nutritional economics, population growth, water supply, most food has its origin in plants. Some food is obtained directly from plants, but even animals that are used as sources are raised by feeding them food derived from plants. Cereal grain is a food that provides more food energy worldwide than any other type of crop. Corn, wheat, and rice – in all of their varieties – account for 87% of all grain production worldwide, most of the grain that is produced worldwide is fed to livestock. Some foods not from animal or plant sources include various edible fungi, fungi and ambient bacteria are used in the preparation of fermented and pickled foods like leavened bread, alcoholic drinks, cheese, pickles, kombucha, and yogurt. Another example is blue-green algae such as Spirulina, inorganic substances such as salt, baking soda and cream of tartar are used to preserve or chemically alter an ingredient. Many plants and plant parts are eaten as food and around 2,000 plant species are cultivated for food, many of these plant species have several distinct cultivars. Seeds of plants are a source of food for animals, including humans, because they contain the nutrients necessary for the plants initial growth, including many healthful fats. In fact, the majority of food consumed by human beings are seed-based foods, edible seeds include cereals, legumes, and nuts. Oilseeds are often pressed to produce rich oils - sunflower, flaxseed, rapeseed, sesame, seeds are typically high in unsaturated fats and, in moderation, are considered a health food, although not all seeds are edible. Large seeds, such as those from a lemon, pose a choking hazard, fruits are the ripened ovaries of plants, including the seeds within. Many plants and animals have coevolved such that the fruits of the former are a food source to the latter. Fruits, therefore, make up a significant part of the diets of most cultures, some botanical fruits, such as tomatoes, pumpkins, and eggplants, are eaten as vegetables. Vegetables are a type of plant matter that is commonly eaten as food. These include root vegetables, bulbs, leaf vegetables, stem vegetables, animals are used as food either directly or indirectly by the products they produce
Food
–
Various foods
Food
–
Foods from plant sources
Food
–
Various raw
meats
Food
–
Tractor and
Chaser bin
15.
Manufacturing
–
Manufacturing is the value added to production of merchandise for use or sale using labour and machines, tools, chemical and biological processing, or formulation. Manufacturing engineering or manufacturing process are the steps through which raw materials are transformed into a final product, the manufacturing process begins with the product design, and materials specification from which the product is made. These materials are modified through manufacturing processes to become the required part. Manufacturing takes turns under all types of economic systems, in a free market economy, manufacturing is usually directed toward the mass production of products for sale to consumers at a profit. In a collectivist economy, manufacturing is more directed by the state to supply a centrally planned economy. In mixed market economies, manufacturing occurs under some degree of government regulation, modern manufacturing includes all intermediate processes required the production and integration of a products components. Some industries, such as semiconductor and steel manufacturers use the term fabrication instead, the manufacturing sector is closely connected with engineering and industrial design. Examples of major manufacturers in North America include General Motors Corporation, General Electric, Procter & Gamble, General Dynamics, Boeing, Pfizer, examples in Europe include Volkswagen Group, Siemens, and Michelin. Examples in Asia include Sony, Huawei, Lenovo, Toyota, Samsung, in its earliest form, manufacturing was usually carried out by a single skilled artisan with assistants. In much of the world, the guild system protected the privileges. Before the Industrial Revolution, most manufacturing occurred in rural areas, entrepreneurs organized a number of manufacturing households into a single enterprise through the putting-out system. Toll manufacturing is an arrangement whereby a first firm with specialized equipment processes raw materials or semi-finished goods for a second firm, manufacturing provides important material support for national infrastructure and for national defense. On the other hand, most manufacturing may involve significant social and environmental costs, the clean-up costs of hazardous waste, for example, may outweigh the benefits of a product that creates it. Hazardous materials may expose workers to health risks and these costs are now well known and there is effort to address them by improving efficiency, reducing waste, using industrial symbiosis, and eliminating harmful chemicals. The negative costs of manufacturing can also be addressed legally, developed countries regulate manufacturing activity with labor laws and environmental laws. Across the globe, manufacturers can be subject to regulations and pollution taxes to offset the costs of manufacturing activities. Labor unions and craft guilds have played a role in the negotiation of worker rights. Environment laws and labor protections that are available in developed nations may not be available in the third world, tort law and product liability impose additional costs on manufacturing
Manufacturing
–
Textile factory (
Germany, circa 1975).
Manufacturing
Manufacturing
–
Assembly of Section 41 of a
Boeing 787 Dreamliner
Manufacturing
–
A female industrial
worker amidst heavy steel semi-products (KINEX BEARINGS,
Bytča,
Slovakia, c. 1995–2000)
16.
Visual arts
–
The visual arts are art forms such as ceramics, drawing, painting, sculpture, printmaking, design, crafts, photography, video, filmmaking, literature, and architecture. Many artistic disciplines involve aspects of the arts as well as arts of other types. Also included within the arts are the applied arts such as industrial design, graphic design, fashion design, interior design. Current usage of the visual arts includes fine art as well as the applied, decorative arts and crafts. The distinction was emphasized by artists of the Arts and Crafts Movement, Art schools made a distinction between the fine arts and the crafts, maintaining that a craftsperson could not be considered a practitioner of the arts. The increasing tendency to painting, and to a lesser degree sculpture. The Western hierarchy of genres reflected similar attitudes, training in the visual arts has generally been through variations of the apprentice and workshop systems. Visual arts have now become a subject in most education systems. Drawing is a means of making an image, using any of a variety of tools. Digital tools that simulate the effects of these are also used, the main techniques used in drawing are, line drawing, hatching, crosshatching, random hatching, scribbling, stippling, and blending. An artist who excels in drawing is referred to as a draftsman or draughtsman, drawing goes back at least 16,000 years to Paleolithic cave representations of animals such as those at Lascaux in France and Altamira in Spain. In ancient Egypt, ink drawings on papyrus, often depicting people, were used as models for painting or sculpture, drawings on Greek vases, initially geometric, later developed to the human form with black-figure pottery during the 7th century BC. Painting taken literally is the practice of applying pigment suspended in a carrier, like drawing, painting has its documented origins in caves and on rock faces. The finest examples, believed by some to be 32,000 years old, are in the Chauvet, in shades of red, brown, yellow and black, the paintings on the walls and ceilings are of bison, cattle, horses and deer. Paintings of human figures can be found in the tombs of ancient Egypt, in the great temple of Ramses II, Nefertari, his queen, is depicted being led by Isis. The Greeks contributed to painting but much of their work has been lost, one of the best remaining representations are the hellenistic Fayum mummy portraits. Another example is mosaic of the Battle of Issus at Pompeii, Greek and Roman art contributed to Byzantine art in the 4th century BC, which initiated a tradition in icon painting. Apart from the manuscripts produced by monks during the Middle Ages
Visual arts
–
Vincent van Gogh:
The Church at Auvers (1890)
Visual arts
–
Mosaic of Battle of Issus
Visual arts
–
Nefertari with Isis
Visual arts
–
Raphael:
Spasimo (1514-1516)
17.
Powder (substance)
–
A powder is a dry, bulk solid composed of a large number of very fine particles that may flow freely when shaken or tilted. Powders are a special sub-class of granular materials, although the terms powder, in particular, powders refer to those granular materials that have the finer grain sizes, and that therefore have a greater tendency to form clumps when flowing. Granulars refers to the coarser granular materials that do not tend to form clumps except when wet, many manufactured goods come in powder form, such as flour, sugar, ground coffee, powdered milk, copy machine toner, gunpowder, cosmetic powders, and some pharmaceuticals. In nature, dust, fine sand and snow, volcanic ash, typically, a powder can be compacted or loosened into a vastly larger range of bulk densities than can a coarser granular material. When deposited by sprinkling, a powder may be very light, when vibrated or compressed it may become very dense and even lose its ability to flow. The bulk density of coarse sand, on the other hand, the clumping behavior of a powder arises because of the molecular Van der Waals force that causes individual grains to cling to one another. Actually, this force is present not just in powders, but in sand and gravel, only when the grains are very small and lightweight does the Van der Waals force become predominant, causing the material to clump like a powder. The cross-over size between flow conditions and stick conditions can be determined by simple experimentation, many other powder behaviors are common to all granular materials. These include segregation, stratification, jamming and unjamming, fragility, loss of energy, frictional shearing, compaction. Powders are transported in the atmosphere differently from a coarse granular material, for one thing, tiny particles have little inertia compared to the drag force of the gas that surrounds them, and so they tend to go with the flow instead of traveling in straight lines. For this reason, powders may be an inhalation hazard, larger particles cannot weave through the bodys defenses in the nose and sinus, but will strike and stick to the mucous membranes. The body then moves the mucous out of the body to expel the particles, the smaller particles on the other hand can travel all the way to the lungs from which they cannot be expelled. Serious and sometimes fatal diseases such as silicosis are a result from working with certain powders without adequate respiratory protection, also, if powder particles are sufficiently small, they may become suspended in the atmosphere for a very long time. Random motion of the air molecules and turbulence provide upward forces that may counteract the force of gravity. Coarse granulars, on the hand, are so heavy that they fall immediately back to the ground. Once disturbed, dust may form huge dust storms that cross continents and this actually explains why there is relatively little hazardous dust in the natural environment. Once aloft, the dust is likely to stay aloft until it meets water in the form of rain or a body of water. Then it sticks and is washed downstream to settle as mud deposits in a lake or sea
Powder (substance)
–
Iron powder
18.
Adhesion
–
Adhesion is the tendency of dissimilar particles or surfaces to cling to one another. The forces that cause adhesion and cohesion can be divided into several types, the intermolecular forces responsible for the function of various kinds of stickers and sticky tape fall into the categories of chemical adhesion, dispersive adhesion, and diffusive adhesion. In addition to the magnitudes of these intermolecular forces, there are certain emergent mechanical effects. Surface energy is defined as the work that is required to build an area of a particular surface. Another way to view the energy is to relate it to the work required to cleave a bulk sample. If the new surfaces are identical, the surface energy γ of each surface is equal to half the work of cleavage, W, γ = W11. If the surfaces are unequal, the Young-Dupré equation applies, W12 = γ1 + γ2 – γ12 and this methodology can also be used to discuss cleavage that happens in another medium, γ12 = W121 = W212. These two energy quantities refer to the energy that is needed to one species into two pieces while it is contained in a medium of the other species. Likewise for a three species system, γ13 + γ23 – γ12 = W12 + W33 – W13 – W23 = W132, there is no single theory covering adhesion, and particular mechanisms are specific to particular material scenarios. Five mechanisms of adhesion have been proposed to explain why one material sticks to another, Adhesive materials fill the voids or pores of the surfaces, other interlocking phenomena are observed on different length scales. Sewing is an example of two forming a large scale mechanical bond, velcro forms one on a medium scale. Two materials may form a compound at the joint, the strongest joints are where atoms of the two materials swap or share electrons. A weaker bond is formed if an atom in one molecule is attracted to an atom of nitrogen, oxygen, or fluorine in another molecule. Chemical adhesion occurs when the atoms of two separate surfaces form ionic, covalent, or hydrogen bonds. The engineering principle behind chemical adhesion in this sense is fairly straightforward, if surface molecules can bond and it bears mentioning that these attractive ionic and covalent forces are effective over only very small distances – less than a nanometer. In surface science, the term adhesion almost always refers to dispersive adhesion, in a typical solid-liquid-gas system the contact angle is used to evaluate adhesiveness indirectly, while a Centrifugal Adhesion Balance allows for direct quantitative adhesion measurements. Generally, cases where the angle is low are considered of higher adhesion per unit area. This approach assumes that the contact angle corresponds to a higher surface energy
Adhesion
–
Dew drops adhering to a
spider web
Adhesion
–
Diagram of various cases of cleavage, with each unique species labeled. A: γ = (1/2)W 11 B: W 12 = γ 1 + γ 2 – γ 12 C: γ 12 = (1/2)W 121 = (1/2)W 212 D: W 12 + W 33 – W 13 – W 23 = W 132.
Adhesion
–
Cohesion causes water to form
drops, surface tension causes them to be nearly spherical, and adhesion keeps the drops in place.
Adhesion
–
Water droplets are flatter on a
Hibiscus flower which shows better adhesion.
19.
Insoluble
–
Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent. The solubility of a substance depends on the physical and chemical properties of the solute and solvent as well as on temperature, pressure. The solubility of a substance is a different property from the rate of solution. Most often, the solvent is a liquid, which can be a substance or a mixture. One may also speak of solid solution, but rarely of solution in a gas, the extent of solubility ranges widely, from infinitely soluble such as ethanol in water, to poorly soluble, such as silver chloride in water. The term insoluble is often applied to poorly or very poorly soluble compounds, a common threshold to describe something as insoluble is less than 0.1 g per 100 mL of solvent. Under certain conditions, the solubility can be exceeded to give a so-called supersaturated solution. Metastability of crystals can also lead to apparent differences in the amount of a chemical that dissolves depending on its form or particle size. A supersaturated solution generally crystallises when seed crystals are introduced and rapid equilibration occurs, phenylsalicylate is one such simple observable substance when fully melted and then cooled below its fusion point. Solubility is not to be confused with the ability to dissolve a substance, for example, zinc dissolves in hydrochloric acid as a result of a chemical reaction releasing hydrogen gas in a displacement reaction. The zinc ions are soluble in the acid, the smaller a particle is, the faster it dissolves although there are many factors to add to this generalization. Crucially solubility applies to all areas of chemistry, geochemistry, inorganic, physical, organic, in all cases it will depend on the physical conditions and the enthalpy and entropy directly relating to the solvents and solutes concerned. By far the most common solvent in chemistry is water which is a solvent for most ionic compounds as well as a range of organic substances. This is a factor in acidity/alkalinity and much environmental and geochemical work. According to the IUPAC definition, solubility is the composition of a saturated solution expressed as a proportion of a designated solute in a designated solvent. Solubility may be stated in units of concentration such as molarity, molality, mole fraction, mole ratio, mass per volume. Solubility occurs under dynamic equilibrium, which means that solubility results from the simultaneous and opposing processes of dissolution, the solubility equilibrium occurs when the two processes proceed at a constant rate. The term solubility is used in some fields where the solute is altered by solvolysis
Insoluble
–
Diving medicine:
Insoluble
–
"Soluble" redirects here. For the algebraic object called a "soluble group", see
Solvable group.
20.
Dye
–
A dye is a colored substance that has an affinity to the substrate to which it is being applied. The dye is applied in an aqueous solution, and may require a mordant to improve the fastness of the dye on the fiber. Both dyes and pigments are colored because they absorb some wavelengths of light more than others, in contrast to dyes, pigments are insoluble and have no affinity for the substrate. Some dyes can be precipitated with a salt to produce a lake pigment. The majority of natural dyes are from plant sources, roots, berries, bark, leaves, and wood, fungi, textile dyeing dates back to the Neolithic period. Throughout history, people have dyed their textiles using common, locally available materials, scarce dyestuffs that produced brilliant and permanent colors such as the natural invertebrate dyes Tyrian purple and crimson kermes were highly prized luxury items in the ancient and medieval world. Plant-based dyes such as woad, indigo, saffron, and madder were raised commercially and were important trade goods in the economies of Asia, across Asia and Africa, patterned fabrics were produced using resist dyeing techniques to control the absorption of color in piece-dyed cloth. Dyes from the New World such as cochineal and logwood were brought to Europe by the Spanish treasure fleets, dyed flax fibers have been found in the Republic of Georgia in a prehistoric cave dated to 36,000 BP. Archaeological evidence shows that, particularly in India and Phoenicia, dyeing has been carried out for over 5,000 years. The dyes were obtained from animal, vegetable or mineral origin, by far the greatest source of dyes has been from the plant kingdom, notably roots, berries, bark, leaves and wood, but only a few have ever been used on a commercial scale. The discovery of synthetic dyes late in the 19th century ended the large-scale market for natural dyes. These dyes are made from synthetic resources such as petroleum by-products, the first human-made organic aniline dye, mauveine, was discovered serendipitously by William Henry Perkin in 1856, the result of a failed attempt at the total synthesis of quinine. Other aniline dyes followed, such as fuchsine, safranine, many thousands of synthetic dyes have since been prepared. These may be natural or synthetic, other than pigmentation, they have a range of applications including organic dye lasers, optical media and camera sensors. This is the basic classification Dyes are classified according to their solubility, acid dyes are water-soluble anionic dyes that are applied to fibers such as silk, wool, nylon and modified acrylic fibers using neutral to acid dye baths. Attachment to the fiber is attributed, at least partly, to salt formation between anionic groups in the dyes and cationic groups in the fiber, acid dyes are not substantive to cellulosic fibers. Most synthetic food colors fall in this category, basic dyes are water-soluble cationic dyes that are mainly applied to acrylic fibers, but find some use for wool and silk. Usually acetic acid is added to the dye bath to help the uptake of the dye onto the fiber, basic dyes are also used in the coloration of paper
Dye
–
Yarn drying after being dyed in the early American tradition, at
Conner Prairie living history museum.
Dye
–
Dyeing wool cloth, 1482: from a French translation of
Bartolomaeus Anglicus
Dye
–
Historical collection of over 10,000 dyes at Technical University Dresden,
Germany
Dye
–
RIT brand dye from mid-20th century Mexico, part of the permanent collection of the
Museo del Objeto del Objeto
21.
Liquid
–
A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a constant volume independent of pressure. As such, it is one of the four states of matter. A liquid is made up of tiny vibrating particles of matter, such as atoms, water is, by far, the most common liquid on Earth. Like a gas, a liquid is able to flow and take the shape of a container, most liquids resist compression, although others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, a distinctive property of the liquid state is surface tension, leading to wetting phenomena. The density of a liquid is usually close to that of a solid, therefore, liquid and solid are both termed condensed matter. On the other hand, as liquids and gases share the ability to flow, although liquid water is abundant on Earth, this state of matter is actually the least common in the known universe, because liquids require a relatively narrow temperature/pressure range to exist. Most known matter in the universe is in form as interstellar clouds or in plasma form within stars. Liquid is one of the four states of matter, with the others being solid, gas. Unlike a solid, the molecules in a liquid have a greater freedom to move. The forces that bind the molecules together in a solid are only temporary in a liquid, a liquid, like a gas, displays the properties of a fluid. A liquid can flow, assume the shape of a container, if liquid is placed in a bag, it can be squeezed into any shape. These properties make a suitable for applications such as hydraulics. Liquid particles are bound firmly but not rigidly and they are able to move around one another freely, resulting in a limited degree of particle mobility. As the temperature increases, the vibrations of the molecules causes distances between the molecules to increase. When a liquid reaches its point, the cohesive forces that bind the molecules closely together break. If the temperature is decreased, the distances between the molecules become smaller, only two elements are liquid at standard conditions for temperature and pressure, mercury and bromine. Four more elements have melting points slightly above room temperature, francium, caesium, gallium and rubidium, metal alloys that are liquid at room temperature include NaK, a sodium-potassium metal alloy, galinstan, a fusible alloy liquid, and some amalgams
Liquid
–
The formation of a spherical
droplet of liquid water minimizes the
surface area, which is the natural result of
surface tension in liquids.
Liquid
–
Thermal image of a sink full of hot water with cold water being added, showing how the hot and the cold water flow into each other.
Liquid
–
Surface waves in
water
22.
Precipitation (chemistry)
–
Precipitation is the creation of a solid from a solution. When the reaction occurs in a solution, the solid formed is called the precipitate. The chemical that causes the solid to form is called the precipitant, without sufficient force of gravity to bring the solid particles together, the precipitate remains in suspension. After sedimentation, especially when using a centrifuge to press it into a compact mass, Precipitation can be used as a medium. The precipitate-free liquid remaining above the solid is called the supernate or supernatant, powders derived from precipitation have also historically been known as flowers. When the solid appears in the form of fibers which have been through chemical processing. Sometimes the formation of a precipitate indicates the occurrence of a chemical reaction, if silver nitrate solution is poured into a solution of sodium chloride, a chemical reaction occurs forming a white precipitate of silver chloride. When potassium iodide solution reacts with lead nitrate solution, a precipitate of lead iodide is formed. Precipitation may occur if the concentration of a compound exceeds its solubility, Precipitation may occur rapidly from a supersaturated solution. Precipitation in solids is routinely used to synthesize nanoclusters, an important stage of the precipitation process is the onset of nucleation. The creation of a solid particle includes the formation of an interface, which requires some energy based on the relative surface energy of the solid. If this energy is not available, and no suitable nucleation surface is available, Precipitation reactions can be used for making pigments, removing salts from water in water treatment, and in classical qualitative inorganic analysis. Precipitation is also useful to isolate the products of a reaction during workup, ideally, the product of the reaction is insoluble in the reaction solvent. Thus, it precipitates as it is formed, preferably forming pure crystals, an example of this would be the synthesis of porphyrins in refluxing propionic acid. Thereafter, the precipitate may easily be separated by filtration, decanting, an example would be the synthesis of chromic tetraphenylporphyrin chloride, water is added to the DMF reaction solution, and the product precipitates. Precipitation is also useful in purifying products, crude bmim-Cl is taken up in acetonitrile, and dropped into ethyl acetate, another important application of an antisolvent is in ethanol precipitation of DNA. In metallurgy, precipitation from a solution is also a useful way to strengthen alloys. An example of a reaction, Aqueous silver nitrate is added to a solution containing potassium chloride
Precipitation (chemistry)
–
Crystals of meso -tetratolylporphyrin from a
reflux of
propanoic acid precipitate on cooling
Precipitation (chemistry)
–
Chemical Precipitation
Precipitation (chemistry)
–
Copper from a wire
displaces silver in a silver nitrate solution it is dipped into, and solid silver precipitates out.
23.
Lake pigment
–
A lake pigment is a pigment manufactured by precipitating a dye with an inert binder, or mordant, usually a metallic salt. Unlike vermilion, ultramarine, and other pigments made from ground minerals, manufacturers and suppliers to artists and industry frequently omit the lake designation in the name. Many lake pigments are fugitive because the involved are not lightfast. Red lakes were important in Renaissance and Baroque paintings, they were often used as translucent glazes to portray the colors of rich fabrics. This sense of lake is unconnected with lake meaning body of water and it has the same root as the word lacquer, and comes originally from the Hindi word lakh, through the Arabic word lakk and the Persian word lak. Many lake pigments are azo dyes and they characteristically have sulfonate and sometimes carboxylate substituents, which confer negative charge to the chromophore. The metallic salt or binder used must be inert and insoluble in the vehicle, the organic component of the dye determines which wavelengths are absorbed and reflected by the resulting precipitate. In ancient times chalk, white clay, and crushed bones were used as sources of the calcium salts. The salts that are used today include barium sulfate, calcium sulfate, aluminium hydroxide. Lake pigments have a history in decoration and the arts. Some have been produced for thousands of years and traded over long distances. The red lakes were important in the history of art, because they were translucent, they were often used in layers of glazes over a more opaque red to create a deep. They were very often used by Titian and other Venetian artists of the 16th century to depict fine draperies, indigo lake was originally produced from the leaves of woad, and was known in ancient Egypt. In the late Middle Ages, a fashion for woad as a textile dye led to overplanting, after trade routes opened to the east, indigo was imported from India as a substitute for woad, and the cultivation of woad became uneconomical in Europe. Today, the blue dye known as indigo once produced from woad. The dye and pigment are both fugitive, rose madder lake, originally from the root of the madder plant, is also known as alizarin crimson in its synthetic form. Since rose madder is fugitive when exposed to light, its use has largely superseded, even in synthetic form. Carmine lake was produced from the cochineal insect, native to Central
Lake pigment
–
Titian used glazes of red lake to create the vivid crimson of the robes in "The Vendramin Family Venerating a Relic of the True Cross", completed 1550-60 (detail).
Lake pigment
–
A typical lake pigment is
Lithol Rubine BK.
24.
Biological pigment
–
Biological pigments, also known simply as pigments or biochromes, are substances produced by living organisms that have a color resulting from selective color absorption. Biological pigments include plant pigments and flower pigments, many biological structures, such as skin, eyes, feathers, fur and hair contain pigments such as melanin in specialized cells called chromatophores. For example, butterfly wings typically contain structural color, although many butterflies have cells that contain pigment as well, see conjugated systems for electron bond chemistry that causes these molecules to have pigment. Other functions of pigments in plants include attracting insects to flowers to encourage pollination, plant pigments include a variety of different kinds of molecule, including porphyrins, carotenoids, anthocyanins and betalains. All biological pigments selectively absorb certain wavelengths of light while reflecting others, the principal pigments responsible are, Chlorophyll is the primary pigment in plants, it is a chlorin that absorbs yellow and blue wavelengths of light while reflecting green. It is the presence and relative abundance of chlorophyll that gives plants their green color, all land plants and green algae possess two forms of this pigment, chlorophyll a and chlorophyll b. Kelps, diatoms, and other photosynthetic heterokonts contain chlorophyll c instead of b, all chlorophylls serve as the primary means plants use to intercept light in order to fuel photosynthesis. Carotenoids are red, orange, or yellow tetraterpenoids, during the process of photosynthesis, they have functions in light-harvesting, in photoprotection, and also serve as protein structural elements. In higher plants, they serve as precursors to the plant hormone abscisic acid. Plants, in general, contain six ubiquitous carotenoids, neoxanthin, violaxanthin, antheraxanthin, zeaxanthin, lutein, lutein is a yellow pigment found in fruits and vegetables and is the most abundant carotenoid in plants. Lycopene is the red pigment responsible for the color of tomatoes, other less common carotenoids in plants include lutein epoxide, lactucaxanthin, and alpha carotene. In cyanobacteria, many other carotenoids exist such as canthaxanthin, myxoxanthophyll, synechoxanthin, algal phototrophs such as dinoflagellates use peridinin as a light harvesting pigment. Anthocyanins are water-soluble flavonoid pigments that appear red to blue, according to pH and they occur in all tissues of higher plants, providing color in leaves, plant stem, roots, flowers, and fruits, though not always in sufficient quantities to be noticeable. Anthocyanins are most visible in the petals of flowers of many species, betalains are red or yellow pigments. Like anthocyanins they are water-soluble, but unlike anthocyanins they are synthesized from tyrosine and this class of pigments is found only in the Caryophyllales, and never co-occur in plants with anthocyanins. Betalains are responsible for the red color of beets. Chlorophylls degrade into colorless tetrapyrroles known as nonfluorescent chlorophyll catabolites, as the predominant chlorophylls degrade, the hidden pigments of yellow xanthophylls and orange beta-carotene are revealed. These pigments are present throughout the year, but the red pigments, pigmentation is used by many animals for protection, by means of camouflage, mimicry, or warning coloration
Biological pigment
–
The
budgerigar gets its yellow color from a
psittacofulvin pigment and its green color from a combination of the same yellow pigment and blue
structural color. The blue and white bird in the background lacks the yellow pigment. The dark markings on both birds are due to the black pigment
eumelanin.
Biological pigment
–
Anthocyanin gives these
pansies their purple pigmentation.
Biological pigment
–
Bougainvillea bracts get their color from
betalains
25.
Inorganic chemistry
–
Inorganic chemistry deals with the synthesis and behavior of inorganic and organometallic compounds. This field covers all chemical compounds except the myriad organic compounds, the distinction between the two disciplines is far from absolute, as there is much overlap in the subdiscipline of organometallic chemistry. It has applications in every aspect of the industry, including catalysis, materials science, pigments, surfactants, coatings, medications, fuels. Many inorganic compounds are compounds, consisting of cations and anions joined by ionic bonding. Examples of salts are magnesium chloride MgCl2, which consists of magnesium cations Mg2+ and chloride anions Cl−, or sodium oxide Na2O, in any salt, the proportions of the ions are such that the electric charges cancel out, so that the bulk compound is electrically neutral. The ions are described by their state and their ease of formation can be inferred from the ionization potential or from the electron affinity of the parent elements. Important classes of compounds are the oxides, the carbonates, the sulfates. Many inorganic compounds are characterized by high melting points, inorganic salts typically are poor conductors in the solid state. Other important features include their high meilting point and ease of crystallization, where some salts are very soluble in water, others are not. The simplest inorganic reaction is double displacement when in mixing of two salts the ions are swapped without a change in oxidation state, in redox reactions one reactant, the oxidant, lowers its oxidation state and another reactant, the reductant, has its oxidation state increased. The net result is an exchange of electrons, electron exchange can occur indirectly as well, e. g. in batteries, a key concept in electrochemistry. When one reactant contains hydrogen atoms, a reaction can take place by exchanging protons in acid-base chemistry, as a refinement of acid-base interactions, the HSAB theory takes into account polarizability and size of ions. Inorganic compounds are found in nature as minerals, soil may contain iron sulfide as pyrite or calcium sulfate as gypsum. Inorganic compounds are also found multitasking as biomolecules, as electrolytes, the first important man-made inorganic compound was ammonium nitrate for soil fertilization through the Haber process. Inorganic compounds are synthesized for use as such as vanadium oxide and titanium chloride. Subdivisions of inorganic chemistry are organometallic chemistry, cluster chemistry and bioinorganic chemistry and these fields are active areas of research in inorganic chemistry, aimed toward new catalysts, superconductors, and therapies. Inorganic chemistry is a highly practical area of science, traditionally, the scale of a nations economy could be evaluated by their productivity of sulfuric acid. The manufacturing of fertilizers is another application of industrial inorganic chemistry
Inorganic chemistry
–
Inorganic compounds show rich variety: A:
Diborane features
unusual bonding B:
Caesium chloride has an archetypal
crystal structure C:
Fp2 is an
organometallic complex D:
Silicone 's uses range from
breast implants to
Silly Putty E:
Grubbs' catalyst won the
2005 Nobel Prize for
its discoverer F:
Zeolites find extensive use as
molecular sieves G:
Copper(II) acetate surprised
theoreticians with its
diamagnetism
Inorganic chemistry
–
The structure of the ionic framework in
potassium oxide, K 2 O
26.
Organic chemistry
–
Study of structure includes many physical and chemical methods to determine the chemical composition and the chemical constitution of organic compounds and materials. In the modern era, the range extends further into the table, with main group elements, including, Group 1 and 2 organometallic compounds. They either form the basis of, or are important constituents of, many products including pharmaceuticals, petrochemicals and products made from them, plastics, fuels and explosives. Before the nineteenth century, chemists generally believed that compounds obtained from living organisms were endowed with a force that distinguished them from inorganic compounds. According to the concept of vitalism, organic matter was endowed with a vital force, during the first half of the nineteenth century, some of the first systematic studies of organic compounds were reported. Around 1816 Michel Chevreul started a study of soaps made from various fats and he separated the different acids that, in combination with the alkali, produced the soap. Since these were all compounds, he demonstrated that it was possible to make a chemical change in various fats, producing new compounds. In 1828 Friedrich Wöhler produced the chemical urea, a constituent of urine, from inorganic starting materials. The event is now accepted as indeed disproving the doctrine of vitalism. In 1856 William Henry Perkin, while trying to manufacture quinine accidentally produced the organic dye now known as Perkins mauve and his discovery, made widely known through its financial success, greatly increased interest in organic chemistry. A crucial breakthrough for organic chemistry was the concept of chemical structure, ehrlich popularized the concepts of magic bullet drugs and of systematically improving drug therapies. His laboratory made decisive contributions to developing antiserum for diphtheria and standardizing therapeutic serums, early examples of organic reactions and applications were often found because of a combination of luck and preparation for unexpected observations. The latter half of the 19th century however witnessed systematic studies of organic compounds, the development of synthetic indigo is illustrative. The production of indigo from plant sources dropped from 19,000 tons in 1897 to 1,000 tons by 1914 thanks to the methods developed by Adolf von Baeyer. In 2002,17,000 tons of indigo were produced from petrochemicals. In the early part of the 20th Century, polymers and enzymes were shown to be large organic molecules, the multiple-step synthesis of complex organic compounds is called total synthesis. Total synthesis of natural compounds increased in complexity to glucose. For example, cholesterol-related compounds have opened ways to synthesize complex human hormones, since the start of the 20th century, complexity of total syntheses has been increased to include molecules of high complexity such as lysergic acid and vitamin B12
Organic chemistry
–
Friedrich Wöhler
Organic chemistry
–
Methane, CH 4, in line-angle representation, showing four carbon-hydrogen single (σ) bonds in black, and the
3D shape of such
tetrahedral molecules, with ~109° interior
bond angles, in green. Methane is the simplest
organic chemical and simplest
hydrocarbon, and molecules can be built up conceptually from it by exchanging up to all 4 hydrogens with carbon or other atoms.
Organic chemistry
–
This swimming board is made of
polystyrene, an example of a polymer.
27.
White
–
White is an achromatic color, a color without hue. An incoming light to the eye that stimulates all its three types of color sensitive cone cells in nearly equal amounts results in white. White is one of the most common colors in nature, the color of sunlight, snow, milk, chalk, limestone, in many cultures white represents or signifies purity, innocence, and light, and is the symbolic opposite of black, or darkness. According to surveys in Europe and the United States, white is the color most often associated with perfection, the good, honesty, cleanliness, the beginning, the new, neutrality, and exactitude. In ancient Egypt and ancient Rome, priestesses wore white as a symbol of purity, in the Middle Ages and Renaissance a white unicorn symbolized chastity, and a white lamb sacrifice and purity, the widows of kings dressed in white rather than black as the color of mourning. It was also used in 20th century modern architecture as a symbol of modernity, simplicity. White is an important color for almost all world religions, the Pope, the head of the Roman Catholic Church, has worn white since 1566, as a symbol of purity and sacrifice. In Islam, and in the Shinto religion of Japan, it is worn by pilgrims, in Western cultures and in Japan, white is the most common color for wedding dresses, symbolizing purity and virginity. In many Asian cultures, white is also the color of mourning, the white color on television screens and computer monitors is created with the RGB color model by mixing red, green and blue light at equal intensities. The word white continues Old English hwīt, ultimately from a Common Germanic *χwītaz also reflected in OHG wîz, ON hvítr, the root is ultimately from Proto-Indo-European language *kwid-, surviving also in Sanskrit śveta to be white or bright and Slavonic světŭ light. The Icelandic word for white, hvítur, is derived from the Old Norse form of the word hvítr. Common Germanic also had the word *blankaz, borrowed into Late Latin as *blancus, the antonym of white is black. Some non-European languages have a variety of terms for white. The Inuit language has seven different words for seven different nuances of white, Japanese has six different words, depending upon brilliance or dullness, or if the color is inert or dynamic. White was one of the first colors used in art, the Lascaux Cave in France contains drawings of bulls and other animals drawn by paleolithic artists between 18,000 and 17,000 years ago. Paleolithic artists used calcite or chalk, they sometimes as a background, sometimes as a highlight, along with charcoal and red, in ancient Egypt, white was connected with the goddess Isis. The priests and priestesses of Isis dressed only in white linen, in Greece and other ancient civilizations, white was often associated with mothers milk. In Greek mythology, the chief god Zeus was nourished at the breast of the nymph Amalthea, in the Talmud, milk was one of four sacred substances, along with wine, honey, and the rose
White
White
White
White
28.
Absorption (electromagnetic radiation)
–
In physics, absorption of electromagnetic radiation is the way in which the energy of a photon is taken up by matter, typically the electrons of an atom. Thus, the energy is transformed into internal energy of the absorber. The reduction in intensity of a wave propagating through a medium by absorption of a part of its photons is often called attenuation. The mass attenuation coefficient, also called mass extinction coefficient, which is the absorption coefficient divided by density, the absorption cross section and scattering cross-section are closely related to the absorption and attenuation coefficients, respectively. Extinction in astronomy is equivalent to the attenuation coefficient, absorbance and optical depth are two related measures All these quantities measure, at least to some extent, how well a medium absorbs radiation. However, practitioners of different fields and techniques tend to use different quantities drawn from the list above. The absorbance of an object quantifies how much of the incident light is absorbed by it and this may be related to other properties of the object through the Beer–Lambert law. A few examples of absorption are ultraviolet–visible spectroscopy, infrared spectroscopy, understanding and measuring the absorption of electromagnetic radiation has a variety of applications. Here are a few examples, In meteorology and climatology, global and local temperatures depend in part on the absorption of radiation by gases and land. In medicine, X-rays are absorbed to different extents by different tissues, for example, see computation of radiowave attenuation in the atmosphere used in satellite link design. In chemistry and materials science, because different materials and molecules will absorb radiation to different extents at different frequencies, in optics, sunglasses, colored filters, dyes, and other such materials are designed specifically with respect to which visible wavelengths they absorb, and in what proportions. In physics, the D-region of Earths ionosphere is known to significantly absorb radio signals that fall within the electromagnetic spectrum. Optical Propagation in Linear Media, Atmospheric Gases and Particles, Solid-State Components, physics Archive - Ask a scientist
Absorption (electromagnetic radiation)
29.
Azo dye
–
Azo compounds are compounds bearing the functional group R–N=N–R′, in which R and R′ can be either aryl or alkyl. IUPAC defines azo compounds as, Derivatives of diazene, HN=NH, the more stable derivatives contain two aryl groups. The N=N group is called an azo group, the name azo comes from azote, the French name for nitrogen that is derived from the Greek ἀ- + ζωή. Most colored textile and leather articles are treated with azo dyes, as a consequence of п-delocalization, aryl azo compounds have vivid colors, especially reds, oranges, and yellows. Therefore, they are used as dyes, and are known as azo dyes. Some azo compounds, e. g. methyl orange, are used as acid-base indicators due to the different colors of their acid, most DVD-R/+R and some CD-R discs use blue azo dye as the recording layer. The development of azo dyes was an important step in the development of the chemical industry, azo pigments consist of colorless particles colored using an azo compound. Azo pigments are important in a variety of paints including artists paints and they have excellent coloring properties, again mainly in the yellow to red range, as well as good lightfastness. The lightfastness depends not only on the properties of the azo compound. Aryl azo compounds are stable, crystalline species. Azobenzene is the prototypical aromatic azo compound and it exists mainly as the trans isomer, but upon photolysis, converts to the cis isomer. The oxidation of hydrazines also gives azo compounds, typical aniline partners are shown below. Illustrative azo compounds that are precursors to dyes Aliphatic azo compounds are commonly encountered than the aryl azo compounds. A commercially important alkyl azo compound is azobisisobutyronitrile, which is used as an initiator in free radical polymerizations. A simple dialkyl diazo compound is diethyldiazene, EtN=NEt, because of their instability, aliphatic azo compounds pose the risk of explosion. Likewise, several studies have linked azo pigments with basal cell carcinoma. Azo dyes derived from benzidine are carcinogens, exposure to them has classically been associated with bladder cancer, accordingly, the production of benzidine azo dyes was discontinued in the 1980s in the most important western industrialized countries. Certain azo dyes can break down under reductive conditions to any of a group of defined aromatic amines
Azo dye
–
General chemical formula of azo compounds
30.
Phthalocyanine
–
Phthalocyanine is an intensely blue-green-coloured aromatic macrocyclic compound that is widely used in dyeing. Phthalocyanines form coordination complexes with most elements of the periodic table and these complexes are also intensely colored and also are used as dyes or pigments. Unsubstituted phthalocyanine, abbreviated H 2Pc, and many of its complexes have low solubility in organic solvents. Benzene at 40 °C dissolves less than a milligram of H 2Pc or CuPc per litre, H 2Pc or CuPc dissolve easily in sulfuric acid due to the protonation of the nitrogen atoms bridging the pyrrole rings. Many phthalocyanine compounds are very stable, do not melt but can be sublimed. Substituted phthalocyanine complexes often have higher solubility. They are less stable and often can not be sublimed. Unsubstituted phthalocyanines strongly absorb light between 600 and 700 nm, thus these materials are blue or green, substitution can shift the absorption towards longer wavelengths, changing the color from pure blue to green to colorless. Phthalocyanines are structurally related to other macrocyclic pigments, especially the porphyrins, both feature four pyrrole-like subunits linked to form a 16-membered ring. The pyrrole-like rings within H 2Pc are closely related to isoindole, both porphyrins and phthalocyanines function as planar tetradentate dianionic ligands that bind metals through four inwardly projecting nitrogen centers. Such complexes are formally derivatives of Pc2−, the base of H 2Pc. An unidentified blue compound, which is now known to be metal-free phthalocyanine, was first reported in 1907 and they remarked on the enormous stability of these complexes but did not further characterize these blue complexes. In the same year, copper phthalocyanine was also discovered at Scottish Dyes, Phthalocyanine forms upon heating phthalic acid derivatives that contain nitrogen functional groups. Classical precursors are phthalonitrile and diiminoisoindole, in the presence of urea, the heating of phthalanhydride is a useful route to H2Pc. These reactions are more efficient in the presence of metal salts, other precursors include o-cyanobenzamide and phthalimide. Several of these materials are shown in the figure below. Using such methods, approximately 57000 tonnes of various phthalocyanines were produced in 1985, halogenated and sulfonated derivatives of copper phthalocyanines are commercially important. Such compounds are prepared by treating CuPc with chlorine, bromine or oleum, approximately 25% of all artificial organic pigments are phthalocyanine derivatives
Phthalocyanine
–
STM images of individual phthalocyanine molecules recorded at a bias of −2 V (left) and +1 V (right). Note that STM probes density of electrons in the
HOMO/LUMO bands rather than atomic profiles.
Phthalocyanine
–
Phthalocyanine
31.
Conjugated system
–
Lone pairs, radicals or carbenium ions may be part of the system. The compound may be cyclic, acyclic, linear or mixed, conjugation is the overlap of one p-orbital with another across an intervening σ bond. A conjugated system has a region of overlapping p-orbitals, bridging the interjacent single bonds and they allow a delocalization of pi electrons across all the adjacent aligned p-orbitals. The pi electrons do not belong to a bond or atom. The largest conjugated systems are found in graphene, graphite, conductive polymers, conjugation is possible by means of alternating single and double bonds. As long as each contiguous atom in a chain has an available p-orbital, for example, furan is a five-membered ring with two alternating double bonds and an oxygen in position 1. Oxygen has two pairs, one of which occupies a p-orbital on that position, thereby maintaining the conjugation of that five-membered ring. The presence of a nitrogen in the ring or groups α to the ring like a group, an imine group. There are also types of conjugation. Homoconjugation is an overlap of two separated by a non-conjugating group, such as CH2. For example, the molecule CH2=CH–CH2–CH=CH2 is homoconjugated because the two C=C double bonds are separated by one CH2 group, cyclic compounds can be partly or completely conjugated. Annulenes, completely conjugated monocyclic hydrocarbons, may be aromatic, non-aromatic or anti-aromatic, conjugated, planar, cyclic compounds that follow Hückels rule are aromatic and exhibit an unusual stability. The classic example benzene has a system of 6 π-electrons, which forms the ring along the planar σ-ring with its 12 electrons. Not all compounds with alternating double and single bonds are aromatic, cyclooctatetraene, for example, possesses alternating single and double bonds. The molecule typically adopts a tub conformation, because the p-orbitals of the molecule do not align themselves well in this non-planar molecule, the electrons are not as easily shared between the carbon atoms. The molecule can be considered conjugated, but is neither aromatic. Many pigments make use of conjugated electron systems to absorb visible light, for example, the long conjugated hydrocarbon chain in beta-carotene leads to its strong orange color. When an electron in the system absorbs a photon of light of the right wavelength, in this model the lowest possible absorption energy corresponds to the energy difference between the highest occupied molecular orbital and the lowest unoccupied molecular orbital
Conjugated system
–
Cinnamaldehyde, a type of
phenolic compound with a conjugated system
32.
Double bond
–
A double bond in chemistry is a chemical bond between two chemical elements involving four bonding electrons instead of the usual two. The most common double bond, that is two carbon atoms, can be found in alkenes. Many types of double bonds exist between two different elements, for example, in a carbonyl group with a carbon atom and an oxygen atom. Other common double bonds are found in azo compounds, imines and sulfoxides, in skeletal formula the double bond is drawn as two parallel lines between the two connected atoms, typographically, the equals sign is used for this. Double bonds were first introduced in chemical notation by prominent Russian chemist Alexander Butlerov, double bonds involving carbon are stronger than single bonds and are also shorter. Double bonds are also electron-rich, which makes them reactive, the type of bonding can be explained in terms of orbital hybridization. In ethylene each carbon atom has three sp2 orbitals and one p-orbital, the three sp2 orbitals lie in a plane with ~120° angles. The p-orbital is perpendicular to this plane, when the carbon atoms approach each other, two of the sp2 orbitals overlap to form a sigma bond. At the same time, the two p-orbitals approach and together form a pi-bond. For maximum overlap, the p-orbitals have to parallel, and, therefore. This property gives rise to cis-trans isomerism, double bonds are shorter than single bonds because p-orbital overlap is maximized. With 133 pm, the ethylene C=C bond length is shorter than the C−C length in ethane with 154 pm. The double bond is stronger,636 kJ mol−1 versus 368 kJ mol−1. In an alternative representation, the double bond results from two overlapping sp3 orbitals as in a bent bond, in molecules, with alternating double bonds and single bonds, p-orbital overlap can exist over multiple atoms in a chain, giving rise to a conjugated system. Conjugation can be found in such as dienes and enones. In cyclic molecules, conjugation can lead to aromaticity, in cumulenes, two double bonds are adjacent. Double bonds are common for period 2 elements carbon, nitrogen, and oxygen, metals, too, can engage in multiple bonding in a metal ligand multiple bond. Double bonded compounds, alkene homologs, R2E=ER2 are now known for all of the heavier group 14 elements, unlike the alkenes these compounds are not planar but adopt twisted and/or trans bent structures
Double bond
–
Chemical compounds with double bonds
33.
Vermilion
–
Vermilion is a brilliant red or scarlet pigment originally made from the powdered mineral cinnabar, and is also the name of the resulting color. The word vermilion came from the Old French word vermeillon, which was derived from vermeil, from the Latin vermiculus and it has the same origin as the English word vermin. The name originated because it had a color to the natural red dye made from an insect, the Kermes vermilio. The words for the color in Portuguese, Galician and Catalan have the same origin, the first recorded use of vermilion as a color name in English was in 1289. The term cinnabar was used interchangeably with vermilion until the 17th century, by the late 18th century cinnabar applied to the unground natural mineral only. Vermilion is a dense, opaque pigment with a clear, brilliant hue, the pigment was originally made by grinding a powder of cinnabar, which contains mercury. The chemical formula of the pigment is HgS, like most mercury compounds, Vermilion is not one specific hue, Mercuric sulfides make a range of warm hues – from bright orange-red to a duller reddish-purple that resembles fresh duck liver. Differences in hue are caused by the size of the particles of pigment. Larger crystals produce duller and less-orange hue, Cinnabar pigment was a side-product of the mining of mercury, and mining cinnabar was difficult, expensive and dangerous, because of the toxicity of mercury. The Greek philosopher Theophrastus of Eresus described the process in De Lapidibus, efforts began early to find a better way to make the pigment. The Chinese were probably the first to make a synthetic vermilion as early as the 4th century BC, the Greek alchemist Zosimus of Panopolis wrote that such a method existed. In the early ninth century the process was described by the Arab or Persian alchemist Jabir ibn Hayyan in his book of recipes of colors. The process described by Jabir ibn Hayyan was fairly simple, Mercury and sulfur were mixed together, forming a black compound of sulphide of mercury, called Aethiopes mineralis. This was then heated in a flask, the compound vaporized, and recondensed in the top of the flask. The flask was broken, the vermilion was taken out, when first created the pigment was almost black, but as it was ground the red color appeared. The longer the color was ground, the finer the color became, the Italian Renaissance artist Cennino Cennini wrote, if you were to grind it every day even for twenty years it would keep getting better and more perfect. During the 17th century a new method of making the pigment was introduced, Mercury and melted sulfur were mashed to make black mercury sulfide, then heated in retort, producing vapors condensing as a bright, red mercury sulfide. To remove the sulfur these crystals were treated with an alkali, washed
Vermilion
–
The bright vermilion murals in the Villa of Mysteries in
Pompeii (before 79 AD) were painted with ground and powdered
cinnabar, the most expensive red pigment of the time.
Vermilion
Vermilion
–
A page of the Roman de Girart de Roussillon (1450). Both vermilion and
minium, or red lead, were used in Medieval manuscripts. Vermilion, as expensive as gilding, was usually reserved for the most important illustrations or designs.
Vermilion
–
A "Chinese red" lacquerware roundbox from the Qing dynasty (1736-1795), from the National Museum of China in Beijing.
34.
Cadmium yellow
–
Cadmium pigments are a class of pigments that have cadmium as one of the chemical components. The principal pigments are a family of yellow/orange/red cadmium sulfides and sulfoselenides as well as compounds with other than cadmium. Their greatest use is in the coloring of plastics and specialty paints which must resist processing or service temperatures up to 3,000 °C, the color-fastness or permanence of cadmium requires protection from a tendency to slowly form carbonate salts with exposure to air. Most paint vehicles accomplish this, but cadmium colors will fade in fresco or mural painting, the following are commonly used as pigments in artists paints, Cadmium yellow is cadmium sulfide. Pigment Yellow 37 Cadmium sulfoselenide is a solution of CdS. Depending on the S/Se ratio, C. I, zinc cadmium sulfide is a greenish, solid solution of CdS and ZnS. Cadmium yellow is sometimes mixed with viridian to give a bright, when first introduced, there were hardly any stable pigments in the yellow to red range, with orange and bright red being very troublesome. The cadmium pigments eventually replaced compounds such as mercury sulfide with greatly improved light-fastness, Cadmium pigments are known for excellent light-fastness, although the lighter shades can fade in sunlight. Cadmium sulfide is not very toxic when used as a pigment, the cadmium pigments have been partially replaced by azo pigments. These have significantly inferior lightfastness, but still good, and they have the advantage of both being cheaper and non-toxic, list of inorganic pigments Fiedler, I. Bayard, M. A. Cadmium Yellows, Oranges and Reds, a Handbook of Their History and Characteristics, Vol.1, Feller, R. L. Oxford University Press 1986, p.65 –108 National Pollutant Inventory - Cadmium and compounds Cadmium yellow. Why are cinnabar, vermilion, and cadmium orange colored, Cadmium yellow, ColourLex Cadmium orange, ColourLex Cadmium red, ColourLex
Cadmium yellow
–
Red cadmium pigment
Cadmium yellow
–
Yellow cadmium pigment
Cadmium yellow
–
Cadmium-rich hemimorphite crusted on smithsonite
Cadmium yellow
–
Cadmium sulfide
35.
Charge-transfer complex
–
The resulting electrostatic attraction provides a stabilizing force for the molecular complex. The source molecule from which the charge is transferred is called the electron donor, the nature of the attraction in a charge-transfer complex is not a stable chemical bond, and is thus much weaker than covalent forces. Many such complexes can undergo a transition into an excited electronic state. The excitation energy of this occurs very frequently in the visible region of the electromagnetic spectrum. These optical absorption bands are referred to as charge-transfer bands. Optical spectroscopy is a technique to characterize charge-transfer bands. Charge-transfer complexes exist in many types of molecules, inorganic as well as organic, and in solids, liquids, a well-known example is the complex formed by iodine when combined with starch, which exhibits an intense blue charge-transfer band. In inorganic chemistry, most charge-transfer complexes involve electron transfer between metal atoms and ligands, if the transfer occurs from the MO with ligand-like character to the metal-like one, the complex is called a ligand-to-metal charge-transfer complex. If the electronic charge shifts from the MO with metal-like character to the ligand-like one, thus, a MLCT results in oxidation of the metal center, whereas a LMCT results in the reduction of the metal center. Resonance Raman spectroscopy is also a technique to assign and characterize charge-transfer bands in these complexes. Charge-transfer complexes are formed by association of molecules or molecular subgroups, one acting as an electron donor. The association does not constitute a strong covalent bond and is subject to significant temperature, concentration, the formation of the dative state is an electronic transition giving rise to the colorful absorption bands. The intensity of charge-transfer bands in the spectrum is strongly dependent upon the degree of this association reaction. The methods were first described for the association of iodine dissolved in aromatic hydrocarbons, the procedure is called the Benesi-Hildebrand method, named after the authors of the study. The absorption wavelength of charge-transfer bands, i. e. the charge-transfer transition energy, is characteristic of the type of donor and acceptor entities. The electron donating power of a molecule is measured by its ionization potential. The electron accepting power of the electron acceptor is determined by its electron affinity, the overall energy balance is the energy gained in a spontaneous charge transfer. Charge-transfer complexes are identified by Color, The color of CT complexes is reflective of the energy balance resulting from the transfer of electronic charge from donor to acceptor
Charge-transfer complex
–
Fig. 1 I 2 •
PPh3 charge-transfer complexes in
CH2Cl2. From left to right: (1) I 2 dissolved in dichloromethane - no CT complex. (2) A few seconds after excess PPh 3 was added - CT complex is forming. (3) One minute later after excess PPh 3 was added, the CT complex [Ph 3 PI] + I − has been formed. (4) Immediately after excess I 2 was added, which contains [Ph 3 PI] + [I 3] −.
36.
Absorption band
–
According to quantum mechanics, atoms and molecules can only hold certain defined quantities of energy, or exist in specific states. An absorption band is a range of wavelengths, frequencies or energies in the spectrum which are characteristic of a particular transition from initial to final state in a substance. According to quantum mechanics, atoms and molecules can only hold certain defined quantities of energy, when electromagnetic radiation is absorbed by an atom or molecule, the energy of the radiation changes the state of the atom or molecule from an initial state to a final state. The number of states in an energy range is discrete for gaseous or diluted systems. Condensed systems, like liquids or solids, have a density of states distribution. In order for a substance to change its energy it must do so in a series of steps by the absorption of a photon and this absorption process can move a particle, like an electron, from an occupied state to an empty or unoccupied state. It can also move a whole vibrating or rotating system, like a molecule, when a photon is absorbed, the electromagnetic field of the photon disappears as it initiates a change in the state of the system that absorbs the photon. Energy, momentum, angular momentum, magnetic moment and electric dipole moment are transported from the photon to the system. Because there are laws, that have to be satisfied. This results in a series of selection rules and it is not possible to make any transition that lies within the energy or frequency range that is observed. The strength of an electromagnetic absorption process is determined by two factors. Second, not all transitions have the transition matrix element. For some types of bands or spectroscopic disciplines temperature and statistical mechanics plays an important role, for other energy ranges thermal motion effects, like Doppler broadening may determine the linewidth. A wide variety of band and line shapes exist. In many cases it is convenient to assume that a spectral line is a Lorentzian or Gaussian. Analysis of the density and the intensities, width and shape of spectral lines sometimes can yield a lot of information about the observed system like it is done with Mössbauer spectra. In systems with a large number of states like macromolecules. If the line broadening mechanism is known and the shape of spectral density is clearly visible in the spectrum
Absorption band
–
Absorptions bands in the
Earth's atmosphere created by
greenhouse gases and the resulting effects on transmitted radiation.
37.
Subtractive color
–
The color that a surface displays depends on which parts of the visible spectrum are not absorbed and therefore remain visible. Subtractive color systems start with light, presumably white light, colored inks, paints, or filters between the watchers and the light source or reflective surface subtract wavelengths from the light, giving it color. If the incident light is other than white, our visual mechanisms are able to compensate well, conversely, additive color systems start with darkness. Light sources of various wavelengths are added in proportions to produce a range of colors. Usually, three colors are combined to stimulate humans’ trichromatic color vision, sensed by the three types of cone cells in the eye, giving an apparently full range. RYB is the standard set of subtractive primary colors used for mixing pigments. It is used in art and art education, particularly in painting and it predated modern scientific color theory. Red, yellow, and blue are the colors of the standard color wheel. The secondary colors, violet, orange, and green make up another triad, formed by mixing equal amounts of red and blue, red and yellow, in color printing, the usual primary colors are cyan, magenta and yellow. Cyan is the complement of red, meaning that the cyan serves as a filter that absorbs red, the amount of cyan applied to a white sheet of paper controls how much of the red in white light will be reflected back from the paper. Ideally, the cyan is completely transparent to green and blue light and has no effect on those parts of the spectrum, magenta is the complement of green, and yellow the complement of blue. Combinations of different amounts of the three can produce a range of colors with good saturation. In inkjet color printing and typical mass production photomechanical printing processes, additive color Color mixing Color motion picture film Color space Color theory Primary color Berns, Roy S. Billmeyer and Saltzmans Principles of Color Technology, 3rd edition. Stroebel, Leslie, John Compton, Ira Current, and Richard Zakia, basic Photographic Materials and Processes, 2nd edition. CS1 maint, Multiple names, authors list Wyszecki, Günther & W. S. Stiles, colour Science, Concept and Methods, Quantitative Data and Formulae. Stanford University CS178 interactive Flash demo comparing additive and subtractive color mixing
Subtractive color
–
An 1877 color photo by
Louis Ducos du Hauron, a French pioneer of
color photography. The overlapping subtractive yellow, cyan and red (magenta) image elements can be seen clearly along the edges of the image.
Subtractive color
–
Subtractive color mixing
38.
Color temperature
–
The color temperature of a light source is the temperature of an ideal black-body radiator that radiates light of comparable color to that of the light source. Color temperature is a characteristic of light that has important applications in lighting, photography, videography, publishing, manufacturing, astrophysics, horticulture. Color temperature is conventionally expressed in kelvins, using the symbol K, Color temperatures over 5000 K are called cool colors, while lower color temperatures are called warm colors. The fact that warm lighting in this sense actually has a color temperature often leads to confusion. The color temperature of the radiation emitted from an ideal black body is defined as its surface temperature in kelvins. This permits the definition of a standard by which light sources are compared, to the extent that a hot surface emits thermal radiation but is not an ideal black-body radiator, the color temperature of the light is not the actual temperature of the surface. An incandescent lamps light is thermal radiation, and the bulb approximates an ideal black-body radiator and this means that the emitted radiation does not follow the form of a black-body spectrum. These sources are assigned what is known as a color temperature. CCT is the temperature of a black-body radiator which to human color perception most closely matches the light from the lamp. Because such an approximation is not required for incandescent light, the CCT for an incandescent light is simply its unadjusted temperature, the Sun closely approximates a black-body radiator. The effective temperature, defined by the radiative power per square unit, is about 5780 K. The color temperature of sunlight above the atmosphere is about 5900 K, as the Sun crosses the sky, it may appear to be red, orange, yellow or white depending on its position. The changing color of the Sun over the course of the day is mainly a result of scattering of light and is not due to changes in black-body radiation. The blue color of the sky is caused by Rayleigh scattering of the sunlight from the atmosphere, some early morning and evening light has a lower color temperature due to increased low-wavelength light scattering by the Tyndall effect. Daylight has a similar to that of a black body with a correlated color temperature of 6500 K or 5500 K. For colors based on theory, blue occurs at higher temperatures. This is the opposite of the cultural associations attributed to colors, in red is hot. For lighting building interiors, it is important to take into account the color temperature of illumination
Color temperature
–
The house above appears a light cream during the midday, but seems a bluish white here in the dim light before full sunrise. Note the different color temperature of the sunrise in the background.
Color temperature
–
The
CIE 1931 x,y chromaticity space, also showing the chromaticities of black-body light sources of various temperatures (
Planckian locus), and lines of constant correlated color temperature.
39.
Lab color space
–
The Lab color space describes mathematically all perceivable colors in the three dimensions L for lightness and a and b for the color opponents green–red and blue–yellow. Other, less common examples of spaces with Lab representations make use of the CIE1994 color difference. The Lab color space exceeds the gamuts of the RGB and CMYK color models, one of the most important attributes of the Lab model is device independence. This means that the colors are defined independent of their nature of creation or the device they are displayed on, the Lab color space is used when graphics for print have to be converted from RGB to CMYK, as the Lab gamut includes both the RGB and CMYK gamut. Also it is used as an interchange format between different devices as for its device independency, the space itself is a three-dimensional real number space, that contains an infinite number of possible representations of colors. The lightness, L*, represents the darkest black at L* =0, the color channels, a* and b*, will represent true neutral gray values at a* =0 and b* =0. The red/green opponent colors are represented along the a* axis, with green at negative a* values, the yellow/blue opponent colors are represented along the b* axis, with blue at negative b* values and yellow at positive b* values. The scaling and limits of the a* and b* axes will depend on the implementation of Lab color, as described below. Perceptually uniform means that a change of the amount in a color value should produce a change of about the same visual importance. When storing colors in limited precision values, this can improve the reproduction of tones, both Lab spaces are relative to the white point of the XYZ data they were converted from. Lab values do not define absolute colors unless the point is also specified. Often, in practice, the point is assumed to follow a standard and is not explicitly stated. The lightness correlate in CIELAB is calculated using the root of the relative luminance. Unlike the RGB and CMYK color models, Lab color is designed to approximate human vision and it aspires to perceptual uniformity, and its L component closely matches human perception of lightness, although it does not take the Helmholtz–Kohlrausch effect into account. Thus, it can be used to make accurate color balance corrections by modifying output curves in the a and b components, or to adjust the lightness contrast using the L component. In the 1990s, when computer hardware and software were limited to storing and manipulating mostly 8-bit/channel bitmaps, converting an RGB image to Lab, with 16-bit/channel and floating-point support now common, the loss due to quantization is negligible. A big portion of the Lab coordinate space cannot be generated by spectral distributions, it falls outside the human vision. Some specific uses of the abbreviation in software, literature etc, in Adobe Photoshop, image editing using Lab mode is CIELAB D50
Lab color space
–
An example of color enhancement using LAB colorspace in Photoshop. The left side of the photo is enhanced, while the right side is normal.
40.
Ochre
–
Ochre (/ˈoʊkər/ OH-kər, from Greek, ὠχρός, ōkhrós, or ocher, is a natural earth pigment containing hydrated iron oxide, which ranges in color from yellow to deep orange or brown. It is also the name of the produced by this pigment. A variant of ochre containing an amount of hematite, or dehydrated iron oxide, has a reddish tint known as red ochre. Ochre is a family of pigments, which includes yellow ochre, red ochre, purple ochre, sienna. The major ingredient of all the ochres is iron oxide-hydroxide, known as limonite, which gives them a yellow color. Yellow ochre, FeO·nH 2O, is a hydrated iron hydroxide also called gold ochre Red ochre, Fe 2O3, takes its color from the mineral hematite. Purple ochre, is identical to red ochre chemically but of a different hue caused by different light diffraction properties associated with an average particle size. Brown ochre, also FeO, is a hydrated iron oxide. Sienna contains both limonite and an amount of manganese oxide, which makes it darker than ochre. Umber pigments contain a proportion of manganese which make them a dark brown. When natural sienna and umber pigments are heated, they are dehydrated and some of the limonite is transformed into hematite, giving them more reddish colors, called burnt sienna and burnt umber. Ochres are non-toxic, and can be used to make an oil paint that dries quickly, modern ochre pigments often are made using synthetic iron oxide. Pigments which use natural ochre pigments indicate it with the name PY-43 on the label, pieces of ochre engraved with abstract designs have been found at the site of the Blombos Cave in South Africa, dated to around 75,000 years ago. In Wales, the paleolithic burial called the Red Lady of Paviland from its coating of red ochre has been dated to around 33,000 years before present. Paintings of animals made with red and yellow ochre pigments have been found in sites at Pech Merle in France. The cave of Lascaux has an image of a horse colored with yellow estimated to be 17,300 years old. In Ancient Egypt, yellow was associated with gold, which was considered to be eternal, the skin and bones of the gods were believed to be made of gold. The Egyptians used yellow extensively in tomb painting, though occasionally they used orpiment
Ochre
–
Ochre- pigment
Ochre
Ochre
–
Yellow ochre (Goldochre)- pigment
Ochre
–
Limonite, a mineraloid containing iron hydroxide, is the main ingredient of all the ochre pigments.
41.
Iron oxide
–
Iron oxides are chemical compounds composed of iron and oxygen. All together, there are sixteen known iron oxides and oxyhydroxides, common rust is a form of iron oxide. Iron oxides are used as inexpensive, durable pigments in paints, coatings. Colors commonly available are in the end of the yellow/orange/red/brown/black range. When used as a coloring, it has E number E172. Limonite Iron oxide nanoparticles List of inorganic pigments Information from Nano-Oxides, http, //chemed. chem. purdue. edu/demos/demosheets/12.3. html http, //minerals. usgs. gov/minerals/pubs/commodity/iron_oxide/ CDC - NIOSH Pocket Guide to Chemical Hazards de
Iron oxide
–
Iron oxide pigment
42.
Cave
–
A cave is a hollow place in the ground, specifically a natural underground space large enough for a human to enter. Caves form naturally by the weathering of rock and often extend deep underground, the word cave can also refer to much smaller openings such as sea caves, rock shelters, and grottos. A cavern is a type of cave, naturally formed in soluble rock with the ability to grow speleothems. Speleology is the science of exploration and study of all aspects of caves, visiting or exploring caves for recreation may be called caving, potholing, or spelunking. The formation and development of caves is known as speleogenesis, which can occur over the course of millions of years, caves are formed by various geologic processes and can be variable sizes. These may involve a combination of processes, erosion from water, tectonic forces, microorganisms, pressure. Isotopic dating techniques can be applied to cave sediments, in order to determine the timescale when geologic events may have occurred to help form and it is estimated that the maximum depth of a cave cannot be more than 3,000 metres due to the pressure of overlying rocks. For karst caves the maximum depth is determined on the basis of the limit of karst forming processes. Most caves are formed in limestone by dissolution, solutional caves or karst caves are the most frequently occurring caves and such caves form in rock that is soluble. Most occur in limestone, but they can form in other rocks including chalk, dolomite, marble, salt. Rock is dissolved by acid in groundwater that seeps through bedding planes, faults, joints. Over geological epochs cracks expand to become caves and cave systems, the largest and most abundant solutional caves are located in limestone. Limestone dissolves under the action of rainwater and groundwater charged with H2CO3, the dissolution process produces a distinctive landform known as karst, characterized by sinkholes and underground drainage. Limestone caves are often adorned with calcium carbonate formations produced through slow precipitation and these include flowstones, stalactites, stalagmites, helictites, soda straws and columns. These secondary mineral deposits in caves are called speleothems, the portions of a solutional cave that are below the water table or the local level of the groundwater will be flooded. Lechuguilla Cave in New Mexico and nearby Carlsbad Cavern are now believed to be examples of type of solutional cave. They were formed by H2S gas rising from below, where reservoirs of oil give off sulfurous fumes and this gas mixes with ground water and forms H2SO4. The acid then dissolves the limestone from below, rather than from above, caves formed at the same time as the surrounding rock are called primary caves
Cave
–
Lechuguilla Cave,
New Mexico, USA
Cave
–
Speleothems in Hall of the Mountain King of
Ogof Craig a Ffynnon, a solutional cave in
South Wales.
Cave
–
Exploring a
lava tube in
Hawaii.
Cave
–
Painted Cave, a large
sea cave,
Santa Cruz Island,
California
43.
Lusaka
–
Lusaka is the capital and largest city of Zambia. One of the cities in southern Africa, Lusaka is in the southern part of the central plateau at an elevation of about 1,279 metres. As of 2010, the population was about 1.7 million. Lusaka is the centre of commerce and government in Zambia and connects to the countrys four main highways heading north, south. English is the language of the city, but Nyanja. Lusaka was the site of a named after its headman Lusaka. In the Nyanja language, Manda means graveyard, the area was expanded by European settlers in 1905 with the building of the railway. After the federation of Northern and Southern Rhodesia in 1953, it was a centre of the movement amongst some of the educated elite that led to the creation of the Republic of Zambia. In 1964, Lusaka became the capital of the newly independent Zambia, in recent years, Lusaka has become a popular urban settlement for Zambians and tourists alike. Its central nature and fast growing infrastructure sector have increased confidence and as such Zambians are seeing signs of development in the form of job creation, housing. Consequently, it is thought that with proper and effective economic reforms, Lusaka is home to a diverse community of foreign nationals, many of whom work in the aid industry as well as diplomats, representatives of religious organizations and some business people. The Parliament is situated at the Parliament complex, which features a 15-story building, the city is also the capital of Lusaka Province, the smallest and most populous of the countrys nine provinces, and forms an administrative district run by Lusaka City Council. In 2007, the mayor was Steven Chilatu, and the deputy mayor was Mary Phiri, mwewa up to 1982 List of Governors Simon C. Mwewa 1982 to 1983 Donald C, the children of the late President, Levy Mwanawasa as well as the children of Vice-President George Kunda, attend the Rhodes Park School. The city is home to the University of Zambia. The city centre includes several blocks west of Cairo Road, around which lie the New City Market and Kamwala Market, further east lies the government area, including the State House and the various ministries, around Cathedral Hill and Ridgeway neighborhoods. One of the streets and points of interest upon business is Cairo Road. Cairo Road was a section of the Great North Road and was so named because it is a link in Cecil Rhodes then dream of a Cape to Cairo Road through British colonies in Africa
Lusaka
–
Downtown Lusaka
Lusaka
–
Supreme Court of Zambia
Lusaka
–
Freedom statue
Lusaka
–
Government House, built for the
Governor of Northern Rhodesia
44.
Zambia
–
The capital city is Lusaka, in the south-central part of Zambia. The population is concentrated mainly around Lusaka in the south and the Copperbelt Province to the northwest, originally inhabited by Khoisan peoples, the region was affected by the Bantu expansion of the thirteenth century. After visits by European explorers in the century, Zambia became the British protectorate of Northern Rhodesia towards the end of the nineteenth century. For most of the period, Zambia was governed by an administration appointed from London with the advice of the British South Africa Company. On 24 October 1964, Zambia became independent of the United Kingdom, Kaundas socialist United National Independence Party maintained power from 1964 until 1991. Kaunda played a key role in diplomacy, cooperating closely with the United States in search of solutions to conflicts in Rhodesia, Angola. From 1972 to 1991 Zambia was a one-party state with the UNIP as the legal political party under the motto One Zambia. Kaunda was succeeded by Frederick Chiluba of the social-democratic Movement for Multi-Party Democracy in 1991, beginning a period of social-economic growth, after Mwanawasas death, Rupiah Banda presided as Acting President before being elected President in 2008. Holding office for three years, Banda stepped down after his defeat in the 2011 elections by Patriotic Front party leader Michael Sata. Sata died on 28 October 2014, the second Zambian president to die in office, Guy Scott served briefly as interim president until new elections were held on 20 January 2015, in which Edgar Lungu was elected as the sixth President. In 2010, the World Bank named Zambia one of the worlds fastest economically reformed countries, the Common Market for Eastern and Southern Africa is headquartered in Lusaka. The territory of what is now Zambia was known as Northern Rhodesia from 1911 and it was renamed Zambia at independence in 1964. The new name of Zambia was derived from the Zambezi river, the area of modern Zambia is known to have been inhabited by the Khoisan until around AD300, when migrating Bantu began to settle around these areas. These early hunter-gatherer groups were either annihilated or absorbed by subsequent more organised Bantu groups. Archaeological excavation work on the Zambezi Valley and Kalambo Falls show a succession of human cultures, in particular, ancient camping site tools near the Kalambo Falls have been radiocarbon dated to more than 36,000 year ago. The fossil skull remains of Broken Hill Man, dated between 300,000 and 125,000 years BC, further shows that the area was inhabited by pre-historic man. The early history of tribes of modern-day Zambia can only be gleaned from knowledge passed down by successive generations through word of mouth, in the 12th century, major waves of Bantu-speaking immigrants arrived during the Bantu expansion. Among them, the Tonga people were the first to settle in Zambia and are believed to have come from the east near the big sea, by the late 12th century, more advanced kingdoms and empires had been established in most regions of modern-day Zambia
Zambia
–
A statue of
Scottish explorer and missionary
David Livingstone on the Zambian side of
Victoria Falls.
Zambia
–
Flag
Zambia
–
Cecil Rhodes
Zambia
–
Mwata
Kazembe XVII Paul Kanyembo Lutaba, king of the Lunda people in Zambia in 1961.
45.
Industrial Revolution
–
The Industrial Revolution was the transition to new manufacturing processes in the period from about 1760 to sometime between 1820 and 1840. The Industrial Revolution began in Great Britain and most of the important technological innovations were British, aided by these legal and cultural foundations, an entrepreneurial spirit and consumer revolution drove industrialisation in Britain, which would be emulated in countries around the world. A change in marrying patterns to getting married later made able to accumulate more human capital during their youth. The Industrial Revolution marks a turning point in history, almost every aspect of daily life was influenced in some way. In particular, average income and population began to exhibit unprecedented sustained growth, mechanised textile production spread from Great Britain to continental Europe in the early 19th century, with important centres of textiles, iron and coal emerging in Belgium, and later in France. Since then industrialisation has spread throughout much of the world, the precise start and end of the Industrial Revolution is still debated among historians, as is the pace of economic and social changes. Economic historians are in agreement that the onset of the Industrial Revolution is the most important event in the history of humanity since the domestication of animals and plants. The term Industrial Revolution applied to change was becoming more common by the late 1830s. Friedrich Engels in The Condition of the Working Class in England in 1844 spoke of an industrial revolution, however, although Engels wrote in the 1840s, his book was not translated into English until the late 1800s, and his expression did not enter everyday language until then. Credit for popularising the term may be given to Arnold Toynbee, some historians, such as John Clapham and Nicholas Crafts, have argued that the economic and social changes occurred gradually and the term revolution is a misnomer. This is still a subject of debate among some historians, the commencement of the Industrial Revolution is closely linked to a small number of innovations, beginning in the second half of the 18th century. By the 1830s the following gains had been made in important technologies, Textiles – mechanised cotton spinning powered by steam or water greatly increased the output of a worker, the power loom increased the output of a worker by a factor of over 40. The cotton gin increased productivity of removing seed from cotton by a factor of 50, large gains in productivity also occurred in spinning and weaving of wool and linen, but they were not as great as in cotton. Steam power – the efficiency of steam engines increased so that they used between one-fifth and one-tenth as much fuel, the adaptation of stationary steam engines to rotary motion made them suitable for industrial uses. The high pressure engine had a power to weight ratio. Steam power underwent an expansion after 1800. Iron making – the substitution of coke for charcoal greatly lowered the fuel cost for pig iron, using coke also allowed larger blast furnaces, resulting in economies of scale. The cast iron blowing cylinder was first used in 1760 and it was later improved by making it double acting, which allowed higher furnace temperatures
Industrial Revolution
–
A
Watt steam engine. The
steam engine, made of iron and fueled primarily by
coal, became widely used in the
United Kingdom during the Industrial Revolution.
Industrial Revolution
–
Iron and Coal, 1855–60, by
William Bell Scott illustrates the rise of coal and iron working in the Industrial Revolution and the heavy engineering projects they made possible.
Industrial Revolution
–
Model of the
spinning jenny in a museum in
Wuppertal. Invented by
James Hargreaves in 1764, the spinning jenny was one of the innovations that started the revolution.
Industrial Revolution
–
The only surviving example of a
spinning mule built by the inventor
Samuel Crompton.
46.
Mineral
–
A mineral is a naturally occurring chemical compound, usually of crystalline form and abiogenic in origin. A mineral has one specific chemical composition, whereas a rock can be an aggregate of different minerals or mineraloids, the study of minerals is called mineralogy. There are over 5,300 known mineral species, over 5,070 of these have been approved by the International Mineralogical Association, the silicate minerals compose over 90% of the Earths crust. The diversity and abundance of species is controlled by the Earths chemistry. Silicon and oxygen constitute approximately 75% of the Earths crust, which translates directly into the predominance of silicate minerals, minerals are distinguished by various chemical and physical properties. Differences in chemical composition and crystal structure distinguish the various species, changes in the temperature, pressure, or bulk composition of a rock mass cause changes in its minerals. Minerals can be described by their various properties, which are related to their chemical structure. Common distinguishing characteristics include crystal structure and habit, hardness, lustre, diaphaneity, colour, streak, tenacity, cleavage, fracture, parting, more specific tests for describing minerals include magnetism, taste or smell, radioactivity and reaction to acid. Minerals are classified by key chemical constituents, the two dominant systems are the Dana classification and the Strunz classification, the silicate class of minerals is subdivided into six subclasses by the degree of polymerization in the chemical structure. All silicate minerals have a unit of a 4− silica tetrahedron—that is, a silicon cation coordinated by four oxygen anions. These tetrahedra can be polymerized to give the subclasses, orthosilicates, disilicates, cyclosilicates, inosilicates, phyllosilicates, other important mineral groups include the native elements, sulfides, oxides, halides, carbonates, sulfates, and phosphates. The first criterion means that a mineral has to form by a natural process, stability at room temperature, in the simplest sense, is synonymous to the mineral being solid. More specifically, a compound has to be stable or metastable at 25 °C, modern advances have included extensive study of liquid crystals, which also extensively involve mineralogy. Minerals are chemical compounds, and as such they can be described by fixed or a variable formula, many mineral groups and species are composed of a solid solution, pure substances are not usually found because of contamination or chemical substitution. Finally, the requirement of an ordered atomic arrangement is usually synonymous with crystallinity, however, crystals are also periodic, an ordered atomic arrangement gives rise to a variety of macroscopic physical properties, such as crystal form, hardness, and cleavage. There have been recent proposals to amend the definition to consider biogenic or amorphous substances as minerals. The formal definition of an approved by the IMA in 1995, A mineral is an element or chemical compound that is normally crystalline. However, if geological processes were involved in the genesis of the compound, Mineral classification schemes and their definitions are evolving to match recent advances in mineral science
Mineral
–
Amethyst, a variety of
quartz
Mineral
–
Schist is a
metamorphic rock characterized by an abundance of platy minerals. In this example, the rock has prominent
sillimanite porphyroblasts as large as 3 cm (1.2 in).
Mineral
–
Hübnerite, the manganese-rich end-member of the
wolframite series, with minor quartz in the background
Mineral
–
When minerals react, the products will sometimes assume the shape of the reagent; the product mineral is termed to be a pseudomorph of (or after) the reagent. Illustrated here is a pseudomorph of
kaolinite after
orthoclase. Here, the pseudomorph preserved the Carlsbad
twinning common in orthoclase.
47.
Insect
–
Insects are a class of hexapod invertebrates within the arthropod phylum that have a chitinous exoskeleton, a three-part body, three pairs of jointed legs, compound eyes and one pair of antennae. They are the most diverse group of animals on the planet, including more than a million described species, the number of extant species is estimated at between six and ten million, and potentially represent over 90% of the differing animal life forms on Earth. Insects may be found in all environments, although only a small number of species reside in the oceans. The life cycles of insects vary but most hatch from eggs, insect growth is constrained by the inelastic exoskeleton and development involves a series of molts. The immature stages can differ from the adults in structure, habit and habitat, Insects that undergo 3-stage metamorphosis lack a pupal stage and adults develop through a series of nymphal stages. The higher level relationship of the Hexapoda is unclear, fossilized insects of enormous size have been found from the Paleozoic Era, including giant dragonflies with wingspans of 55 to 70 cm. The most diverse insect groups appear to have coevolved with flowering plants, adult insects typically move about by walking, flying or sometimes swimming. As it allows for rapid yet stable movement, many insects adopt a tripedal gait in which they walk with their legs touching the ground in alternating triangles, Insects are the only invertebrates to have evolved flight. Many insects spend at least part of their lives under water, with adaptations that include gills. Some species, such as water striders, are capable of walking on the surface of water, Insects are mostly solitary, but some, such as certain bees, ants and termites, are social and live in large, well-organized colonies. Some insects, such as earwigs, show maternal care, guarding their eggs, Insects can communicate with each other in a variety of ways. Male moths can sense the pheromones of female moths over great distances, other species communicate with sounds, crickets stridulate, or rub their wings together, to attract a mate and repel other males. Lampyridae in the beetle order communicate with light, humans regard certain insects as pests, and attempt to control them using insecticides and a host of other techniques. Some insects damage crops by feeding on sap, leaves or fruits, a few parasitic species are pathogenic. Some insects perform complex ecological roles, blow-flies, for example, help consume carrion, Many other insects are considered ecologically beneficial as predators and a few provide direct economic benefit. Silkworms and bees have been used extensively by humans for the production of silk and honey, in some cultures, people eat the larvae or adults of certain insects. Insect first appears documented in English in 1601 in Hollands translation of Pliny, translations of Aristotles term also form the usual word for insect in Welsh, Serbo-Croatian, Russian, etc. The evolutionary relationship of insects to other animal groups remains unclear, in the Pancrustacea theory, insects, together with Entognatha, Remipedia, and Cephalocarida, make up a natural clade labeled Miracrustacea
Insect
Insect
–
Evolution has produced enormous variety in insects. Pictured are some of the possible shapes of
antennae.
Insect
–
The different forms of the male (top) and female (bottom)
tussock moth Orgyia recens is an example of
sexual dimorphism in insects.
48.
Mollusk
–
The molluscs compose the large phylum Mollusca of invertebrate animals. Around 85,000 extant species of molluscs are recognized, molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater and terrestrial habitats and they are highly diverse, not just in size and in anatomical structure, but also in behaviour and in habitat. The phylum is divided into 9 or 10 taxonomic classes. The gastropods are by far the most numerous molluscs in terms of classified species, the three most universal features defining modern molluscs are a mantle with a significant cavity used for breathing and excretion, the presence of a radula, and the structure of the nervous system. Other than these things, molluscs express great morphological diversity, so many textbooks base their descriptions on an ancestral mollusc. This has a single, limpet-like shell on top, which is made of proteins and chitin reinforced with calcium carbonate, the underside of the animal consists of a single muscular foot. Although molluscs are coelomates, the coelom tends to be small, the main body cavity is a hemocoel through which blood circulates, their circulatory systems are mainly open. The generalized mollusc has two paired nerve cords, or three in bivalves, the brain, in species that have one, encircles the esophagus. Most molluscs have eyes, and all have sensors to detect chemicals, vibrations, the simplest type of molluscan reproductive system relies on external fertilization, but more complex variations occur. All produce eggs, from which may emerge trochophore larvae, more complex veliger larvae, good evidence exists for the appearance of gastropods, cephalopods and bivalves in the Cambrian period 541 to 485.4 million years ago. Molluscs have, for centuries, also been the source of important luxury goods, notably pearls, mother of pearl, Tyrian purple dye and their shells have also been used as money in some preindustrial societies. Mollusc species can also represent hazards or pests for human activities, the bite of the blue-ringed octopus is often fatal, and that of Octopus apollyon causes inflammation that can last for over a month. Stings from a few species of large tropical cone shells can also kill, schistosomiasis is transmitted to humans via water snail hosts, and affects about 200 million people. Snails and slugs can also be serious pests, and accidental or deliberate introduction of some snail species into new environments has seriously damaged some ecosystems. The words mollusc and mollusk are both derived from the French mollusque, which originated from the Latin molluscus, from mollis, molluscus was itself an adaptation of Aristotles τα μαλακά, the soft things, which he applied to cuttlefish. The scientific study of molluscs is accordingly called malacology, as it is now known these groups have no relation to molluscs, and very little to one another, the name Molluscoida has been abandoned. The most universal features of the structure of molluscs are a mantle with a significant cavity used for breathing and excretion
Mollusk
Mollusk
–
Cornu aspersum (formerly Helix aspersa) – a common land
snail
Mollusk
–
About 80% of all known mollusc species are
gastropods (
snails and
slugs), including this
cowry (a sea snail).
Mollusk
–
The use of
love darts by the land snail
Monachoides vicinus is a form of
sexual selection
49.
Blue
–
Blue is the colour between violet and green on the optical spectrum of visible light. Human eyes perceive blue when observing light with a wavelength between 450 and 495 nanometres, which is between 4500 and 4950 ångströms. Blues with a frequency and thus a shorter wavelength gradually look more violet, while those with a lower frequency. Pure blue, in the middle, has a wavelength of 470 nanometers, in painting and traditional colour theory, blue is one of the three primary colours of pigments, along with red and yellow, which can be mixed to form a wide gamut of colours. Red and blue mixed together form violet, blue and yellow together form green, Blue is also a primary colour in the RGB colour model, used to create all the colours on the screen of a television or computer monitor. The clear sky and the sea appear blue because of an optical effect known as Rayleigh scattering. When sunlight passes through the atmosphere, the wavelengths are scattered more widely by the oxygen and nitrogen molecules. An optical effect called Tyndall scattering, similar to Rayleigh scattering, explains blue eyes, distant objects appear more blue because of another optical effect called atmospheric perspective. Blue has been used for art and decoration since ancient times and it is the most important color in Judaism. In the Middle Ages, cobalt blue was used to colour the stained glass windows of cathedrals, beginning in the 9th century, Chinese artists used cobalt to make fine blue and white porcelain. Blue dyes for clothing were made from woad in Europe and indigo in Asia, in 1828 a synthetic ultramarine pigment was developed, and synthetic blue dyes and pigments gradually replaced mineral pigments and vegetable dyes. Pierre-Auguste Renoir, Vincent van Gogh and other late 19th century painters used ultramarine and cobalt blue not just to depict nature, in the late 18th century and 19th century, blue became a popular colour for military uniforms and police uniforms. In the 20th century, because blue was associated with harmony, it was chosen as the colour of the flags of the United Nations. Surveys in the US and Europe show that blue is the colour most commonly associated with harmony, faithfulness, confidence, distance, infinity, the imagination, cold, and sometimes with sadness. In US and European public opinion polls it is the most popular colour, Blue is the colour of light between violet and green on the visible spectrum. Blues also vary in shade or tint, darker shades of blue contain black or grey, darker shades of blue include ultramarine, cobalt blue, navy blue, and Prussian blue, while lighter tints include sky blue, azure, and Egyptian blue. Today most blue pigments and dyes are made by a chemical process, the modern English word blue comes from Middle English bleu or blewe, from the Old French bleu, a word of Germanic origin, related to the Old High German word blao. In heraldry, the azure is used for blue
Blue
–
Sky blue or pale
azure, mid-way on the RBG colour wheel between blue and cyan.
Blue
–
Blue
Blue
–
Extract of natural
indigo, the most popular blue dye before the invention of synthetic dyes. It was the colour of the first
blue jeans.
Blue
–
A block of
lapis lazuli, originally used to make ultramarine.
50.
Purple
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Purple is a color intermediate between blue and red. It is similar to violet, but unlike violet, which is a color with its own wavelength on the visible spectrum of light, purple is a composite color made by combining red. According to surveys In Europe and the U. S. purple is the color most often associated with royalty, magic, mystery, when combined with pink, it is associated with eroticism, femininity and seduction. Purple was the color worn by Roman magistrates, it became the color worn by the rulers of the Byzantine Empire and the Holy Roman Empire. Similarly in Japan, the color is associated with the Emperor. The first recorded use of the purple in the English language was in the year 975 AD. In heraldry, the word purpure is used for purple, in the traditional color wheel used by painters, violet and purple are both placed between red and blue. Purple occupies the space closer to red, between crimson and violet, violet is closer to blue, and is usually less saturated than purple. While the two look similar, from the point of view of optics there are important differences. There is no such thing as the wavelength of purple light, monochromatic violet light cannot be produced by the red-green-blue color system, the method used to create colors on a television screen or computer display. This means that when light strikes the eye, the S-cone should be stimulated strongly. The resulting color has the same hue as pure violet, however, one curious psychophysical difference between purple and violet is their appearance with an increase in luminance. Violet, as it brightens, looks more and more blue, the same effect does not happen with purple. This is the result of what is known as the Bezold–Brücke shift, while the scientific definitions of violet and purple are clear, the cultural definitions are more varied. The color known in antiquity as Tyrian purple ranged from crimson to a deep bluish-purple, in France, purple is defined as a dark red, inclined toward violet. The color called purple by the French, pourpre, contains red and half the amount of blue of the color called purple in the United States. In German, this color is sometimes called Purpurrot to avoid confusion, Purple first appeared in prehistoric art during the Neolithic era. These works have been dated to between 16,000 and 25,000 BC, as early as the 15th century BC the citizens of Sidon and Tyre, two cities on the coast of Ancient Phoenicia, were producing purple dye from a sea snail called the spiny dye-murex
Purple
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Purple is the color of royalty. A ticket for the coronation of
Elizabeth II (1953)
Purple
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Purple
Purple
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In Catholicism purple is a
liturgical color representing piety
Purple
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Purple has become a popular color for
neckties; it is less aggressive than red, but more active than blue.
