Silver is a chemical element with symbol Ag and atomic number 47. A soft, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, reflectivity of any metal; the metal is found in the Earth's crust in the pure, free elemental form, as an alloy with gold and other metals, in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold and zinc refining. Silver has long been valued as a precious metal. Silver metal is used in many bullion coins, sometimes alongside gold: while it is more abundant than gold, it is much less abundant as a native metal, its purity is measured on a per-mille basis. As one of the seven metals of antiquity, silver has had an enduring role in most human cultures. Other than in currency and as an investment medium, silver is used in solar panels, water filtration, ornaments, high-value tableware and utensils, in electrical contacts and conductors, in specialized mirrors, window coatings, in catalysis of chemical reactions, as a colorant in stained glass and in specialised confectionery.
Its compounds are used in X-ray film. Dilute solutions of silver nitrate and other silver compounds are used as disinfectants and microbiocides, added to bandages and wound-dressings and other medical instruments. Silver is similar in its physical and chemical properties to its two vertical neighbours in group 11 of the periodic table and gold, its 47 electrons are arranged in the configuration 4d105s1 to copper and gold. This distinctive electron configuration, with a single electron in the highest occupied s subshell over a filled d subshell, accounts for many of the singular properties of metallic silver. Silver is an soft and malleable transition metal, though it is less malleable than gold. Silver crystallizes in a face-centered cubic lattice with bulk coordination number 12, where only the single 5s electron is delocalized to copper and gold. Unlike metals with incomplete d-shells, metallic bonds in silver are lacking a covalent character and are weak; this observation explains the low high ductility of single crystals of silver.
Silver has a brilliant white metallic luster that can take a high polish, and, so characteristic that the name of the metal itself has become a colour name. Unlike copper and gold, the energy required to excite an electron from the filled d band to the s-p conduction band in silver is large enough that it no longer corresponds to absorption in the visible region of the spectrum, but rather in the ultraviolet. Protected silver has greater optical reflectivity than aluminium at all wavelengths longer than ~450 nm. At wavelengths shorter than 450 nm, silver's reflectivity is inferior to that of aluminium and drops to zero near 310 nm. High electrical and thermal conductivity is common to the elements in group 11, because their single s electron is free and does not interact with the filled d subshell, as such interactions lower electron mobility; the electrical conductivity of silver is the greatest of all metals, greater than copper, but it is not used for this property because of the higher cost.
An exception is in radio-frequency engineering at VHF and higher frequencies where silver plating improves electrical conductivity because those currents tend to flow on the surface of conductors rather than through the interior. During World War II in the US, 13540 tons of silver were used in electromagnets for enriching uranium because of the wartime shortage of copper. Pure silver has the highest thermal conductivity of any metal, although the conductivity of carbon and superfluid helium-4 are higher. Silver has the lowest contact resistance of any metal. Silver forms alloys with copper and gold, as well as zinc. Zinc-silver alloys with low zinc concentration may be considered as face-centred cubic solid solutions of zinc in silver, as the structure of the silver is unchanged while the electron concentration rises as more zinc is added. Increasing the electron concentration further leads to body-centred cubic, complex cubic, hexagonal close-packed phases. Occurring silver is composed of two stable isotopes, 107Ag and 109Ag, with 107Ag being more abundant.
This equal abundance is rare in the periodic table. The atomic weight is 107.8682 u. Both isotopes of silver are produced in stars via the s-process, as well as in supernovas via the r-process. Twenty-eight radioisotopes have been characterized, the most stable being 105Ag with a half-life of 41.29 days, 111Ag with a half-life of 7.45 days, 112Ag with a half-life of 3.13 hours. Silver has numerous nuclear isomers, the most stable being 108mAg, 110mAg and 106mAg. All of the remaining radioactive isotopes have half-lives of less than an hour, the majority of these have half-lives of less than three minutes. Isotopes of silver range in relative atomic mass from 92.950 u
Benjamin Franklin was an American polymath and one of the Founding Fathers of the United States. Franklin was a leading author, political theorist, freemason, scientist, humorist, civic activist and diplomat; as a scientist, he was a major figure in the American Enlightenment and the history of physics for his discoveries and theories regarding electricity. As an inventor, he is known for the lightning rod and the Franklin stove, among other inventions, he founded many civic organizations, including the Library Company, Philadelphia's first fire department and the University of Pennsylvania. Franklin earned the title of "The First American" for his early and indefatigable campaigning for colonial unity as an author and spokesman in London for several colonies; as the first United States Ambassador to France, he exemplified the emerging American nation. Franklin was foundational in defining the American ethos as a marriage of the practical values of thrift, hard work, community spirit, self-governing institutions, opposition to authoritarianism both political and religious, with the scientific and tolerant values of the Enlightenment.
In the words of historian Henry Steele Commager, "In a Franklin could be merged the virtues of Puritanism without its defects, the illumination of the Enlightenment without its heat." To Walter Isaacson, this makes Franklin "the most accomplished American of his age and the most influential in inventing the type of society America would become."Franklin became a successful newspaper editor and printer in Philadelphia, the leading city in the colonies, publishing the Pennsylvania Gazette at the age of 23. He became wealthy publishing this and Poor Richard's Almanack, which he authored under the pseudonym "Richard Saunders". After 1767, he was associated with the Pennsylvania Chronicle, a newspaper, known for its revolutionary sentiments and criticisms of British policies, he pioneered and was first president of Academy and College of Philadelphia which opened in 1751 and became the University of Pennsylvania. He organized and was the first secretary of the American Philosophical Society and was elected president in 1769.
Franklin became a national hero in America as an agent for several colonies when he spearheaded an effort in London to have the Parliament of Great Britain repeal the unpopular Stamp Act. An accomplished diplomat, he was admired among the French as American minister to Paris and was a major figure in the development of positive Franco-American relations, his efforts proved vital for the American Revolution in securing shipments of crucial munitions from France. He was promoted to deputy postmaster-general for the British colonies in 1753, having been Philadelphia postmaster for many years, this enabled him to set up the first national communications network. During the revolution, he became the first United States Postmaster General, he was active in community affairs and colonial and state politics, as well as national and international affairs. From 1785 to 1788, he served as governor of Pennsylvania, he owned and dealt in slaves but, by the 1750s, he argued against slavery from an economic perspective and became one of the most prominent abolitionists.
His colorful life and legacy of scientific and political achievement, his status as one of America's most influential Founding Fathers, have seen Franklin honored more than two centuries after his death on coinage and the $100 bill and the names of many towns, educational institutions, corporations, as well as countless cultural references. Benjamin Franklin's father, Josiah Franklin, was a soaper and candlemaker. Josiah was born at Ecton, England on December 23, 1657, the son of blacksmith and farmer Thomas Franklin, Jane White. Benjamin's father and all four of his grandparents were born in England. Josiah had seventeen children with his two wives, he married his first wife, Anne Child, in about 1677 in Ecton and immigrated with her to Boston in 1683. Following her death, Josiah was married to Abiah Folger on July 9, 1689 in the Old South Meeting House by Samuel Willard. Benjamin, their eighth child, was Josiah Franklin's fifteenth tenth and last son. Abiah Folger was born in Nantucket, Massachusetts, on August 15, 1667, to Peter Folger, a miller and schoolteacher, his wife, Mary Morrell Folger, a former indentured servant.
She came from a Puritan family, among the first Pilgrims to flee to Massachusetts for religious freedom, when King Charles I of England began persecuting Puritans. They sailed for Boston in 1635, her father was "the sort of rebel destined to transform colonial America." As clerk of the court, he was jailed for disobeying the local magistrate in defense of middle-class shopkeepers and artisans in conflict with wealthy landowners. Ben Franklin followed in his grandfather's footsteps in his battles against the wealthy Penn family that owned the Pennsylvania Colony. Benjamin Franklin was born on Milk Street, in Boston, Massachusetts, on January 17, 1706, baptized at Old South Meeting House, he was one of seventeen children born to Josiah Franklin, one of ten born by Josiah's second wife, Abiah Folger. Among Benjamin's siblings were his older brother James and his younger sister Jane. Josiah wanted Ben to attend school with the clergy, but only had enough money to send him to school for two years, he did not graduate.
Although "his parents talked of the church as a career" for Franklin, his schooling e
The Nova Constellatio coins are the first coins struck under the authority of the United States of America. These pattern coins were struck in early 1783, are known in three silver denominations, one copper denomination. All known examples bear the legend "NOVA CONSTELLATIO" with the exception of a unique silver 500-Unit piece; the Nova Constellatio patterns were the culmination of two years of work on the part of Robert Morris, the Founding Father credited with financing the Revolutionary War. Morris was unanimously elected the Nation’s first Superintendent of Finance in 1781; the financier’s plan, developed with his assistant, Gouverneur Morris, was ambitious: he hoped to unite the fledgling Nation with a monetary unit that would allow for easy conversion from British, Portuguese, or State currencies to U. S. funds. More Morris’s proposal would be the first system of coinage in Western Europe or the Americas to use decimal accounting – an innovation, adopted by every nation on earth in the last two centuries.
Due to the new government’s precarious financial situation, Congress did not put Morris’s plan into effect. S. Dollar. Both men became champions of the decimal concept after examining Morris’s coins. While Thomas Jefferson was in possession of the Nova Constellatio coins, he wrote a report entitled “Notes on the Establishment of a Money Unit and of Coinage for the United States”. If we adopt the Dollar for our Unit, we should strike four coins, one of gold, two of silver, one of copper, viz.: 1. A golden piece, equal in value to ten dollars: 2; the Unit or Dollar itself, of silver: 3. The tenth of a Dollar, of silver also: 4; the hundredth of a Dollar, of copper. This is the first written description of the monetary system adopted by the United States illustrating the historical importance of Morris's patterns. There are records of seven coins associated with Morris's plan: 1. A single silver coin of indeterminate denomination delivered to Morris on April 2nd, 1783. Upon its receipt, Morris recorded in his diary: I sent for Mr. Dudley who delivered me a Piece of Silver Coin being the first, struck as an American Coin.2.
A set of silver coins comprising a 1,000-Unit piece, a 500-Unit piece, three 100-Unit pieces. These coins were struck after Alexander Hamilton visited the Treasury, initiating correspondence “On the Subject of the Coin” between Morris and Hamilton, culminating in the decision to strike a set of coins “to lay before Congress”; these coins were sent to Thomas Jefferson, who composed his “Notes on the Establishment of a Money Unit and of Coinage for the United States” while examining the set. Jefferson recorded the value of the set at $1.8, or 1,800-Units, indicating that its composition was one 1,000-Unit piece, one 500-Unit piece, three 100-Unit pieces. This is the precise composition of the known silver examples bearing the legend "Nova Constellatio".3. A 5-Unit copper piece bearing the legend "Nova Constellatio", sent to London prior to Jefferson’s receipt of the set. After being returned to Congress, the coins were dispersed. In the mid-1840s, the 1,000-unit and 500-Unit piece from the set bearing the Legend NOVA CONSTELLATIO were discovered by a descendent of longtime Secretary of Congress, Charles Thomson.
From this point forward, Morris’s coins would be called the Nova Constellatios. Twenty-five years would pass. A second silver 500-Unit piece was uncovered in 1870. Collectors dubbed this coin the “Type-2”, because its design differed from the Congressional set’s 500-Unit piece. In 2017, the designation for this piece was changed to "Plain Obverse" in A Guide Book of United States Coins 2017: The Official Red Book, when forensic evidence demonstrated that it was struck prior to the example from the set, sent to Congress. By 1900, three silver 100-Unit coins - all bearing the NOVA CONSTELLATIO inscription – would be located, leaving only the copper 5-Unit piece unaccounted for. In 1979, this coin bearing the NOVA CONSTELLATIO legend, was discovered in Europe. Nova Constellatio patterns
Nickel (United States coin)
A nickel, in American usage, is a five-cent coin struck by the United States Mint. Composed of 75% copper and 25% nickel, the piece has been issued since 1866, its diameter is.835 inches and its thickness is.077 inches. Due to inflation, the purchasing power of the nickel continues to drop and the coin represents less than 1% of the federal hourly minimum wage. In 2015, over 1.5 billion nickels were produced at the Denver mints. The silver half dime, equal to five cents, had been issued since the 1790s; the American Civil War caused economic hardship, driving silver from circulation. In 1865, Congress abolished the five-cent fractional currency note after Spencer M. Clark, head of the Currency Bureau, placed his own portrait on the denomination. After the successful introduction of two-cent and three-cent pieces without precious metal, Congress authorized a five-cent piece consisting of base metal; the initial design of the Shield nickel was struck from 1866 until 1883 was replaced by the Liberty Head nickel.
The Buffalo nickel was introduced in 1913 as part of a drive to increase the beauty of American coinage. In 2004 and 2005, special designs in honor of the bicentennial of the Lewis and Clark Expedition were issued. In 2006, the Mint reverted to using Jefferson nickel designer Felix Schlag's original reverse, although a new obverse, by Jamie Franki, was substituted; as of the end of FY 2013, it cost more than nine cents to produce a nickel. The silver half disme was one of the denominations prescribed by the Mint Act of 1792; the first pieces under federal authority were half dimes, struck in 1792 in the cellar of John Harper, a saw maker. The dies were engraved by Adam Eckfeldt, who a half-century recalled that the silver for the half dimes was supplied by President George Washington, that the 1,500 coins struck from the bullion were given to Washington's Secretary of State, Thomas Jefferson, for distribution to important people, both in the US and overseas. By legend, President Washington supplied silverware from his home, Mount Vernon, to provide bullion for the coins.
In his annual message to Congress in late 1792, Washington noted the ongoing construction of a mint building and stated: "There has been a small beginning in the coinage of half dimes, the want of small coins in circulation calling the first attention to them."In 1793, the newly established Philadelphia Mint began striking cents and half cents. Coinage of precious metal was delayed. In 1794, Congress lowered the chief coiner's bond to $5,000, the assayer's to $1,000. Subsequently, silver coinage began that year; the half dime was struck from 1794 until 1805, though none were dated 1798, 1799, or 1804. By 1804, silver US coins were exported, as they could be exchanged at par in the West Indies with heavier Spanish coins, which were imported as bullion and deposited at the Mint for melting and restriking. In response, in 1804 the US stopped striking silver dollars. In 1807, mint Director Robert Patterson in a letter explained to Jefferson "nearly the whole of our Silver Bullion come through the Banks, it is seldom that they will consent to take any coin less than half dollars."Beginning in 1829, the silver five-cent piece was again struck.
In 1837, the half dime's obverse design changed from one by William Kneass, depicting a bust of Liberty, to one that featured a seated Liberty by Christian Gobrecht. In 1851, it ceased to be the smallest US silver coin; the Civil War caused most American coins to vanish from circulation, with the gap filled by such means as merchant tokens, encased postage stamps, United States fractional currency, issued in denominations as low as three cents. Although specie was hoarded or exported, the copper-nickel cent the only base metal denomination being struck vanished. In 1864, Congress began the process of restoring coins to circulation by abolishing the three-cent note and authorizing bronze cents and two-cent pieces, with low intrinsic values, to be struck; these new coins proved popular, though the two-cent piece soon faded from circulation. On March 3, 1865, Congress passed legislation authorizing the Mint to strike three-cent pieces of 75% copper and 25% nickel. In 1864, Congress authorized a third series of fractional currency notes.
The five-cent note was to bear a depiction of "Clark", but Congress was appalled when the issue came out not with a portrait of William Clark, the explorer, but Spencer M. Clark, head of the Currency Bureau. According to numismatic historian Walter Breen, Congress's "immediate infuriated response was to pass a law retiring the five-cent denomination, another to forbid portrayal of any living person on federal coins or currency." Clark kep
The Buffalo nickel or Indian Head nickel is a copper-nickel five-cent piece, struck by the United States Mint from 1913 to 1938. It was designed by sculptor James Earle Fraser; as part of a drive to beautify the coinage, five denominations of US coins had received new designs between 1907 and 1909. In 1911, Taft administration officials decided to replace Charles E. Barber's Liberty Head design for the nickel, commissioned Fraser to do the work, they were impressed by Fraser's designs showing an American bison. The designs were approved in 1912, but were delayed several months because of objections from the Hobbs Manufacturing Company, which made mechanisms to detect slugs in nickel-operated machines; the company was not satisfied by changes made in the coin by Fraser, in February 1913, Treasury Secretary Franklin MacVeagh decided to issue the coins despite the objections. Despite attempts by the Mint to adjust the design, the coins proved to strike indistinctly, to be subject to wear—the dates were worn away in circulation.
In 1938, after the expiration of the minimum 25-year period during which the design could not be replaced without congressional authorization, it was replaced by the Jefferson nickel, designed by Felix Schlag. Fraser's design is admired today, has been used on commemorative coins and the gold American Buffalo series. In 1883, the Liberty Head nickel was issued. After the coin was released, it was modified to add the word "CENTS" to the reverse because the similarity in size with the half eagle allowed criminals to gild the new nickels and pass them as five dollar coins. An Act of Congress, passed into law on September 26, 1890 required that coinage designs not be changed until they had been in use 25 years, unless Congress authorized the change; the act made silver dollar exceptions to the twenty-five year rule. However, the Mint continued to strike the Liberty Head nickel in large numbers through the first decade of the 20th century. President Theodore Roosevelt in 1904 expressed his dissatisfaction with the artistic state of the American coinage, hoped to hire sculptor Augustus Saint-Gaudens to redesign all the coins.
Constrained by the 1890 act, the Mint only hired Saint-Gaudens to redesign the cent and the four gold pieces. Saint-Gaudens, before his 1907 death, designed the eagle and double eagle, which entered circulation that year. By that time, the Liberty Head nickel had been in circulation for more than 25 years, was eligible for redesign regardless of the special provision. In 1909, Mint Director Frank Leach instructed Barber to make pattern coins for new nickels. Most of these coins featured George Washington; the press found out about the pieces, speculated they would be released into circulation by the end of the year. The Mint received orders from banks in anticipation of the "Washington nickel". However, the project was discontinued when Leach left office on November 1, 1909, to be replaced by Abram Andrew. Andrew was dissatisfied with the just-issued Lincoln cent, considered seeking congressional authorization to replace the cent with a design by sculptor James Earle Fraser. While the change in the cent did not occur, according to numismatic historian Roger Burdette, "Fraser's enthusiasm led to adoption of the Buffalo nickel in December 1912".
On May 4, 1911, Eames MacVeagh, son of Treasury Secretary Franklin MacVeagh wrote to his father: A little matter that seems to have been overlooked by all of you is the opportunity to beautify the design of the nickel or five cent piece during your administration, it seems to me that it would be a permanent souvenir of a most attractive sort. As you are aware, it is the only coin the design of which you can change during your administration, as I believe there is a law to the effect that the designs must not be changed oftener than every twenty-five years. I should think it might be the coin of which the greatest numbers are in circulation. Soon after the MacVeagh letter, Andrew announced that the Mint would be soliciting new designs for the nickel. Fraser, an assistant to Saint-Gaudens, approached the Mint, produced concepts and designs; the new Mint director, George Roberts, who had replaced Andrew favored a design featuring assassinated President Abraham Lincoln, but Fraser soon developed a design featuring a Native American on one side and a bison on the other.
Andrew and Roberts recommended Fraser to MacVeagh, in July 1911, the Secretary approved hiring Fraser to design a new nickel. Official approval was slow in coming. MacVeagh wrote, "Tell him that of the three sketches which he submitted we would like to use the sketch of the head of the Indian and the sketch of the buffalo." Roberts transmitted the news followed up with a long list of instructions to the sculptor, in which he noted, "The motto,'In God We Trust', is not required upon this coin and I presume we are agreed that nothing should be upon it, not required." Fraser completed the models by June 1912, prepared coin-size electrotypes. He brought the models and electrotypes to Washington on July 10, where they met with the enthusiastic agreement of Secretary MacVeagh. In July 1912, word of the new design became publicly known, coin-operated machine manufacturers sought information. Replying to the inquiries, MacVeagh wrote that there would be no change in the diameter, thickness, or weight of the nickel.
This satisfied mos
A sundial is a device that tells the time of day when there is sunlight by the apparent position of the Sun in the sky. In the narrowest sense of the word, it consists of a flat plate and a gnomon, which casts a shadow onto the dial; as the Sun appears to move across the sky, the shadow aligns with different hour-lines, which are marked on the dial to indicate the time of day. The style is the time-telling edge of the gnomon, though nodus may be used; the gnomon casts a broad shadow. The gnomon may be wire, or elaborately decorated metal casting; the style must be parallel to the axis of the Earth's rotation for the sundial to be accurate throughout the year. The style's angle from horizontal is equal to the sundial's geographical latitude. In a broader sense, a sundial is any device that uses the Sun's altitude or azimuth to show the time. In addition to their time-telling function, sundials are valued as decorative objects, literary metaphors, objects of mathematical study, it is common for inexpensive, mass-produced decorative sundials to have incorrectly aligned gnomons and hour-lines, which cannot be adjusted to tell correct time.
There are several different types of sundials. Some sundials use a shadow or the edge of a shadow while others use a line or spot of light to indicate the time; the shadow-casting object, known as a gnomon, may be a long thin rod or other object with a sharp tip or a straight edge. Sundials employ many types of gnomon; the gnomon may be moved according to the season. It may be oriented vertically, aligned with the Earth's axis, or oriented in an altogether different direction determined by mathematics. Given that sundials use light to indicate time, a line of light may be formed by allowing the Sun's rays through a thin slit or focusing them through a cylindrical lens. A spot of light may be formed by allowing the Sun's rays to pass through a small hole or by reflecting them from a small circular mirror. Sundials may use many types of surfaces to receive the light or shadow. Planes are the most common surface, but partial spheres, cylinders and other shapes have been used for greater accuracy or beauty.
Sundials differ in their need for orientation. The installation of many dials requires knowing the local latitude, the precise vertical direction, the direction to true North. Portable dials are self-aligning: for example, it may have two dials that operate on different principles, such as a horizontal and analemmatic dial, mounted together on one plate. In these designs, their times agree only. Sundials may indicate the local solar time only. To obtain the national clock time, three corrections are required: The orbit of the Earth is not circular and its rotational axis is not perpendicular to its orbit; the sundial's indicated solar time thus varies from clock time by small amounts that change throughout the year. This correction – which may be as great as 15 minutes – is described by the equation of time. A sophisticated sundial, with a curved style or hour lines, may incorporate this correction; the more usual simpler sundials sometimes have a small plaque that gives the offsets at various times of the year.
The solar time must be corrected for the longitude of the sundial relative to the longitude of the official time zone. For example, an uncorrected sundial located west of Greenwich, England but within the same time-zone, shows an earlier time than the official time, it may show "11:45" at official noon, will show "noon" after the official noon. This correction can be made by rotating the hour-lines by a constant angle equal to the difference in longitudes, which makes this is a possible design option. To adjust for daylight saving time, if applicable, the solar time must additionally be shifted for the official difference; this is a correction that can be done on the dial, i.e. by numbering the hour-lines with two sets of numbers, or by swapping the numbering in some designs. More this is ignored, or mentioned on the plaque with the other corrections, if there is one; the principles of sundials are understood most from the Sun's apparent motion. The Earth rotates on its axis, revolves in an elliptical orbit around the Sun.
An excellent approximation assumes that the Sun revolves around a stationary Earth on the celestial sphere, which rotates every 24 hours about its celestial axis. The celestial axis is the line connecting the celestial poles. Since the celestial axis is aligned with the axis about which the Earth rotates, the angle of the axis with the local horizontal is the local geographical latitude. Unlike the fixed stars, the Sun changes its position on the celestial sphere, being - on north hemisphere - at a positive declination in spring and summer, at a negative declination in autumn and winter, having zero declination at the equinoxes; the Sun's celestial longitude varies, changing by one complete revolution per year. The path of the Sun on the celestial sphere is called the ecliptic; the ecliptic passes through the twelve constellations of the zodiac in the course of a year. This model of the Sun's motion helps to understand sundials. If the shadow-casting gnomon is aligned with the celestial poles, its shadow will revolve at a constant rate, this rotation will not change with the seasons.
This is the most common design. In such cases, the same hour lines may be used throughout the year; the hour-lines will be spaced uniformly if the surface receiving the shadow is either perpendicular or circular about the gnomon
Penny (United States coin)
The United States one-cent coin called the penny, is a unit of currency equaling one one-hundredth of a United States dollar. The cent's symbol is ¢, its obverse has featured the profile of President Abraham Lincoln since 1909, the centennial of his birth. From 1959 to 2008, the reverse featured the Lincoln Memorial. Four different reverse designs in 2009 honored Lincoln's 200th birthday and a new, "permanent" reverse – the Union Shield – was introduced in 2010; the coin is 0.75 inches in diameter and 0.0598 inches in thickness. Its weight has varied, depending upon the composition of metals used in its production; the U. S. Mint's official name for the coin is "cent" and the U. S. Treasury's official name is "one cent piece"; the colloquial term penny derives from the British coin of the same name, the pre-decimal version of which had a similar place in the British system. In American English, pennies is the plural form. In the early 2010s the price of metal used to make pennies rose to a noticeable cost to the mint which peaked at a $0.02 for $0.01 ratio.
This pushed the mint to look for alternative metals again for the coin, brought the penny debate into more focus. There are no firm plans to eliminate the penny as arguments for and against the coin continue to be debated. In honor of Lincoln's 200th anniversary, special 2009 cents were minted for collectors in the same composition as the 1909 coins; the isotope composition of early coins spanning the period 1828 to 1843 reflects the copper from Cornish ores from England, while coins after 1850 reflect the Keweenaw Peninsula, Michigan ores, a finding consistent with historical records. In 1943, at the peak of World War II, zinc-coated steel cents were made for a short time because of war demands for copper. A few copper cents from 1943 were produced from the 1942 planchets remaining in the bins; some 1944 steel cents have been confirmed. From 1944 to 1946, salvaged ammunition shells made their way into the minting process, it was not uncommon to see coins featuring streaks of brass or having a darker finish than other issues.
During the early 1970s, the price of copper rose to the point where the cent contained one cent's worth of copper. This led the Mint to test alternative metals, including aluminum and bronze-clad steel. Aluminum was chosen, over 1.5 million of these pennies were struck and ready for public release before being rejected. The proposed aluminum pennies were rejected for two reasons: vending machine owners complained the coins would cause mechanical problems. One aluminum cent was donated to the Smithsonian Institution; the cent's composition was changed in 1982 because the value of the copper in the coin started to rise above one cent. Some 1982 pennies used the 97.5% zinc composition, while others used the 95% copper composition. With the exception of 2009 bicentennial cents minted for collectors, United States cents minted after 1982 have been zinc with copper plating. In Fiscal Year 2013, the average one-cent piece minted cost the U. S. Mint 1.83 cents, down from 2.41 cents apiece in FY 2011. The bronze and copper cents can be distinguished from the newer zinc cents by dropping the coins on a solid surface.
The predominantly zinc coins make a lower-pitched "clunk", while the copper coins produce a higher-pitched ringing sound. In addition, a full 50-cent roll of pre-1982/3 coins weighs 5.4 oz compared to a post-1982–83 roll which weighs 4.4 oz. Mintage figures for the penny can be found at United States cent mintage figures; the coin has gone through several designs over its two-hundred-year time frame. Until 1857 it was about the size of the current U. S. dollar coins. The following types of cents have been produced: Large cents: Flowing Hair Chain 1793 Flowing Hair Wreath 1793 Liberty Cap 1793–1796 Draped bust 1796–1807 Classic Head 1808–1814 Coronet 1816–1839 Braided Hair 1839–1857, 1868 Small cents: Flying Eagle cent Indian Head cent Lincoln cent Lincoln Wheat Lincoln Memorial Lincoln Bicentennial 4 reverse designs Lincoln Union Shield Throughout its history, the Lincoln cent has featured several typefaces for the date, but most of the digits have been old-style numerals, except with the 4 and 8 neither ascending nor descending.
The only significant divergence is that the small 3 was non-descending in the early history, before switching to a descending, large 3 for just one year in 1934 and permanently in 1943. The digit 5 was small and non-descending up to 1945 from 1950 and on, it became a large descending 5. From 1959 until 2008, the Lincoln Memorial was shown on the reverse of the United States cent; because the Lincoln Memorial was shown in sufficient detail to discern the statue of Lincoln on the reverse of cent, Abraham Lincoln was at that time the only person to be depicted on both the obverse and reverse of the same United States coin. In 1999, the New Jersey state quarter was released, which depicts George Washington on both sides, crossing the Delaware River on the reverse side and in profile on the obverse. (The state quarter for South Dakota, released in 2006 features Washington on both sides: the typical profile on the obverse, Washington within Mount Rushmore on the re