Nancy Nguyen

WATCHES

Origin of watches

A watch is a portable timepiece that is usually worn around the wrist or attached to a chain. Watches appeared in the 15th century in Europe. They were not commonly worn until the 17th century. The watch evolved from the invention underline text by clockmaker Peter Henlein who invented the mainspring in 1511. In the 1920s wristwatches became more popular as they became more practical. In World War I pocket watches were found to be impractical on the battlefield because they had a tendency to get caught on objects and clothing.1

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The Evolution of Watches

Year Event Details
1500-1600 Clock-watches The first timepieces were made in the German city of Nuremburg and Augsburg, attached on a chain made out of brass, iron, steel and tapered pins. It only had an hour hand and did not have a glass covered face.
1600-1657 Pocket watches Men began to wear these instead of pendants. They were round and flat with glass covered faces. A spring was introduced into the manufacturing of the watches however the force provided by the spring was not constant.
1657-1765 The balance spring The addition of the balance spring to the balance wheel limited the force of the back and forth motion of the balance wheel. This increased the accuracy enormously, reducing errors from several hours per day to 10 minutes per day.
1765-1800 Temperature compensation and chronometers Watches took a turn from telling time to scientific uses. Watches were altered to become scientific instruments that determine the longitude during sea voyages. The arms where made of bimetallic (material to convert a temperature change into mechanical displacement) which when heated causes the arms to slightly bend inward allowing the balance wheel to rotate back and forth faster. This also reduced errors.
1800-1850 Lever escapement The lever escapement was invented by Thomas Mudge but was then later improved by Josiah Emery and was then adopted by Swiss watchmakers (who are now the leading supplier of watches). The lever allows the balance wheel to swing completely free during most of its cycle causing to function precisely.
1850-1900 Mass production From 1850 watches have taken the world by storm. Watches became more of use and the mass production of watches inspired watchmakers to improve the technology.
1900-1920 Better materials The use of better materials improved the production methods of watches. It was found that alloys of invar and elinvar used for the balance where unaffected by temperature. The introduction of using artificial sapphire made watches cheap and more affordable.
1920-1950 Wrist watch Wrist watches were originally created by Patek Philippe but the concept was developed by Constant Girard. The development of the wrist watch was found to be more practical as it keeps your hands free.
1950-1969 Electric watches Electric-powered watches were then developed with a balance wheel powered by a solenoid which is a coil wound into tightly packed helix and produces magnetic field when an electric current is passed through.
1969 Quartz watches The quartz watch was is a revolutionary improvement in watch technology. It increased the accuracy and eliminated moving parts hence making it more shock-resistant. The introduction of LED display was also then developed.
1990 Radio controlled The radio-controlled watch’s quartz oscillator is set to the correct time daily by coded radio time signals broadcasted by the government operator time station. This allows the watch to have the long-term accuracy as atomic clocks.2

Manufacturing of Watches

Watches nowadays quartz digital watches with LED displays are available. The heart of quartz watch is a tiny silver quartz which is synthetically produced by cutting with a diamond saw and shipped to watchmaker to use. Though quartz in their natural form is firstly loaded into a giant kettle or autoclave. An alkaline material is then pumped into the bottom of the autoclave and is heated to approximately 400 degrees celsius. This then results to seeds or tiny particles of quartz appear hanging from the top of the autoclave. The pieces of quartz are then sealed ina vacuum chamber with wires attached to both ends that connects to a circuit board.

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Mircochips are manufacured similar to quartz but are more extensive and complex. Microchips involve chemical and x-ray engraving of microscopic electronic circuits onto a piece of silion dioxide.

When assemblying a watch, a entire set of crystals and microships is set onto a circuit board. the battery is then installed and generates the electricity for the quartz crystal and provides power for the LED display. The time setting mechanisms are connected by using two specific pins. One pins the counter circuit (seconds, minutes, hours) while the other pushes the number of times to bring the display. Then is finally closed into a case and attached to a wrist strap.4

Chemical Compostion

Gold Cyanide

Gold
Gold is a chemical element with dense, soft, shiny, malleable and ductile properties. It is bright yellow colour and lustereous which is traditionally considered attractive and maintains its lustereous state without oxidizing in air or water.
Symbol: Au
Atomic Number: 79
Group/Period: XI/VI
Electron Configuration: 2, 8, 18, 32, 18, 1

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Gold cyanide is a compostion of gold, sodium cyanide, water, oxygen and may often react with other metals such as zinc and copper. It is mainly used for making jewellery.

Gold cyanide is produced by going through various of industrial steps. Simply, gold(Au) reacts with the sodium cyanide solution(NaCN) in presents of oxygen and water. The oxygen plays an important role as it speeds up the reaction allowing the gold combining with the cyanide solution. Thus forming gold cyanide and sodium hydroxide.

4Au+8(NaCN)+O2+2H2O→4NaAu(CN)2+4NaOH
Once the gold has dissolved in the cyanide, and the ore body has been depleted of its gold, which then follows by one of the two main processes for recovering the gold from cyanide solution. First one being the Merrill-Crowe zinc precipitation process and the other is the adsorption of the gold onto activated carbon. And other method, Merrill Crowe, involves first removing the oxygen from the solution, then mixing a fine zinc powder with it and recovering the very fine gold precipitate on a precoat filter, since the gold precipitate is very fine.5

2Au(CN)+Zn→2Au+Zn(CN)4

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Gallium Arsenide

Gallium
Gallium is a chemical element that does not exist nature. It is a soft silvery metallic poor metal; which means it has a low boiling/melting point and a higher electronegativity.
Symbol: As
Atomic Number: 33
Group/Period: XV/IV
Electron Configuration: 2, 8, 18, 3

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Arsenic
Arsenic is a chemical element that is a metalloid. It exists in minerals in conjuction with with sulfur and metals, and also as a pure elemental crystal.
Symbol: Ga
Atomic Number: 31
Group/Period: XIII/IV
Electron Configuration: 2, 8, 18, 5

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Gallium arsenide (GaAs) is a compound of the elements gallium and arsenic. It is a semiconductor and is used in the manufacturing of microchips, microwave frequency intergrated circuits, solar cells and optical windows. Wet engraving of Gallium Arsenide (GaAs) industrially uses an oxidizing agent such as hydrogen peroxide or bromine water, and the same strategy has been described in a patent relating to processing scrap components containing GaAs where the Ga3+ is complexed with a hydroxamic acid ("HA")6

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Gallium arsenide reacts with hydrogen peroxide and hydromamic acid to form a complex Gallium arsenide with hydromamic acid and arsenic acid and water.
GaAs + H2O2+NH2-OH + → "GaA" complex + H3AsO4 + 4 H2O

Enviromental Impact

When manufacturing products there will always be enviromental consequences. In watch making there are highly toxic chemical being use that secrete gases to the atmosphere. Also when making stainless steel and moulding metals, fossil fuel is used. In factories, especially when making metals, a large amount of electricity is required for the factory to operate. Fossil fuel is used to generate electricity in factories which causes pollution to the earth's atmosphere as the gas carbon dioxide is given off from the burning fossil fuel.7

In the mining industry parts of the earth is being extracted for our use. In mining operations a lot of chemical proccesses are being used which causes pollution and harms the enviroment as it leaks or spills. In addition erosion of cleared land surface and dumped waste material results to sediment loadings into the adjacent water bodies, particularly during rainfall.8

Properties

Parts Material9 Properties Definiton Use
Case Stainless steel Hard, durable, malleable Hardness is a measure of how resistant solid matter is to various kinds of permanent shape change when a force is applied. Stainless steel is use for the case of the watch due to it's hard properties, therefore being preventing the clock from breaking.
Microchip Silicon, LED (gallium arsenide, gallium phosphide) high electron velocity, electron mobility, durable Durability is theability to endure and resist wear and decay. Silicon is a durable material therefore allowing it to last which is important as the mirochip functions the watch. Which then relates to conductivity as the mircoship must be able to generate electricity for the watch to function.
Face LCD (liquid crystals), glass Transparent, hard Transparency is the physical property of allowing light to pass through the material without being scattered. The glass and LCD is use to cover the face of the watch. Glass and LCD is used because it is transparent which allows us to tell the time.
Pillar plate Gold Malleable, conductive Malleability is the ability to deform under compressive pressure and to form thin sheets usually by hammering or rolling. The pillar plate is a thin plate inserted into watch which allows the watch to function. Gold is frequently used for the pillar plate as it is malleable therefore being able to form thin sheets. Gold is also conductive material which allows to generate electricity through the watch.
Wristband Gold, copper, steel Malleable, durable, flexible Flexibility is the ability to bend without occasionally breaking. It is important for the material of the wristband to be flexiable so it is comfortable to wear around the wrist. Not only that they also have to be malleable to actually form the shape of the wristband and be durable so it resists to wearing which is why materials such as gold, copper and steel are used.
Battery zinc, lithium, manganese dioxide, silver oxide conductive Conductivity is ability to conduct an electric current. The most important property of the battery is that it must be conductive as it is the power source of the whole entire watch. Materials like zinc, lithium, manganese dioxide, silver oxide are used because they have conductive properties and are appropriate for creating batteries.
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