2 (two) is a number, numeral, and glyph. It is the natural number following 1 and preceding 3. It is the smallest and only even prime number. Because it forms the basis of a duality, it has religious and spiritual significance in many cultures.
Black is the darkest color, the result of the absence or complete absorption of visible light. It is an achromatic color, a color without hue, like white and gray. It is often used symbolically or figuratively to represent darkness, while white represents light. Black and white have often been used to describe opposites such as good and evil, the Dark Ages versus Age of Enlightenment, and night versus day. Since the Middle Ages, black has been the symbolic color of solemnity and authority, and for this reason is still commonly worn by judges and magistrates.
Black was one of the first colors used by artists in neolithic cave paintings. In the 14th century, it was worn by royalty, clergy, judges and government officials in much of Europe. It became the color worn by English romantic poets, businessmen and statesmen in the 19th century, and a high fashion color in the 20th century. In the Roman Empire, it became the color of mourning, and over the centuries it was frequently associated with death, evil, witches and magic. According to surveys in Europe and North America, it is the color most commonly associated with mourning, the end, secrets, magic, force, violence, evil, and elegance.
Black ink is the most common color used for printing books, newspapers and documents, as it provides the highest contrast with white paper and thus the easiest color to read. Similarly, black text on a white screen is the most common format used on computer screens.
Plastics are a wide range of synthetic or semi-synthetic organic compounds that are malleable and so can be molded into solid objects.
Plasticity is the general property of all materials which can deform irreversibly without breaking but, in the class of moldable polymers, this occurs to such a degree that their actual name derives from this specific ability.
Plastics are typically organic polymers of high molecular mass and often contain other substances. They are usually synthetic, most commonly derived from petrochemicals, however, an array of variants are made from renewable materials such as polylactic acid from corn or cellulosics from cotton linters.
In developed economies, about a third of plastic is used in packaging and roughly the same in buildings in applications such as piping, plumbing or vinyl siding. Other uses include automobiles (up to 20% plastic), furniture, and toys. In the developing world, the applications of plastic may differ—42% of India's consumption is used in packaging. Worldwide, about 50 kg of plastic is produced annually per person, with production doubling every ten years.
Plastics have many uses in the medical field as well, with the introduction of polymer implants and other medical devices derived at least partially from plastic. The field of plastic surgery is not named for use of plastic materials, but rather the meaning of the word plasticity, with regard to the reshaping of flesh.
The world's first fully synthetic plastic was bakelite, invented in New York in 1907, by Leo Baekeland who coined the term 'plastics'. Many chemists have contributed to the materials science of plastics, including Nobel laureate Hermann Staudinger who has been called "the father of polymer chemistry" and Herman Mark, known as "the father of polymer physics".
The success and dominance of plastics starting in the early 20th century led to environmental concerns regarding its slow decomposition rate after being discarded as trash due to its composition of large molecules. Toward the end of the century, one approach to this problem was met with wide efforts toward recycling.
Packaging is the science, art and technology of enclosing or protecting products for distribution, storage, sale, and use. Packaging also refers to the process of designing, evaluating, and producing packages. Packaging can be described as a coordinated system of preparing goods for transport, warehousing, logistics, sale, and end use. Packaging contains, protects, preserves, transports, informs, and sells. In many countries it is fully integrated into government, business, institutional, industrial, and personal use.
The peach (Prunus persica) is a deciduous tree native to the region of Northwest China between the Tarim Basin and the north slopes of the Kunlun Mountains, where it was first domesticated and cultivated. It bears an edible juicy fruit called a peach or a nectarine.
The specific name persica refers to its widespread cultivation in Persia (modern-day Iran), from where it was transplanted to Europe. It belongs to the genus Prunus which includes the cherry, apricot, almond and plum, in the rose family. The peach is classified with the almond in the subgenus Amygdalus, distinguished from the other subgenera by the corrugated seed shell. Due to their close relatedness, the inside of a peach stone tastes remarkably similar to almond, and peach stones are often used to make a cheap version of marzipan, known as persipan.
Peaches and nectarines are the same species, even though they are regarded commercially as different fruits. The skin of nectarines lacks the fuzz (fruit-skin trichomes) that peach-skin has; it is thought that a mutation in a single gene (MYB25) is responsible for the hair or no-hair difference between the two.
In 2018, China produced 62% of the world total of peaches and nectarines.