Updates

• i have redone my experimentation by applying extreme pressure not through hitting metal with a hammer but now with dropping a 25lb weight from a fixed height of 2.5ft
• i also redid the measurement in a quantified manner by putting weights in a bucket and adding weight until the bucket fell from the metal upon which it was hanging
• i redid my results presentation completely as well as the procedure part of my presentation
• all of this was done before city wide science fair, in preparation for said event.

updates

• i changed my slide show to the comments made
• i added pictures
• fixed typos
• added more information about metal

research paper

Metals are an important component of everyday life. Metals are used in every electricat device we have, every appliance, every vehicle and every building we use. Man has used metal since 7000B.C.E.ca. Metals comprise a great majority of the periodic table and have their own type of bonding system and structure. Metals can be worked and hardened, shaped, and broken. Metals can be malleable, ductile, or brittle. Metals conduct heat and electricity. There are 86 known metals. Earth’s crust is 24.1% metal.

To fully understand metals one must start at the very fundamentals, their atomic structure, physical properties, and chemical properties, in short, chemistry. Chemically metals are defined as atoms being shiny and being good conductors, conductive of heat, and conductive of electricity. To the human eye metals are not individual atoms but a tightly metallic bonded group. Metallic bonds are formed from the electromagnetic interaction between delocalized electrons, called conduction electrons and gathered in an electron sea, which is the group of electrons in metal. Metallic bonds are the bonds between metals that share electrons in a community fashion due to their positive charge (lack of valence electrons). This strong metallic form of bondage makes for high melting and boiling points. Metals are dense matter due to their tightly packed structure in which as many atoms as can possibly fit are assembled together. As a result of the community sharing property of metallic bonds and their close proximity to each other electrons have quite free tri-dimensional movement capabilities, which allow for high conductibility of heat and electricity, which may be transferred in the same way. As long as atoms in a metallic bond are making contact electrons may be transferred, which does not exclude liquid metals such as Mercury (Hg).

Metals are generally formed in one of two structures, 12 and 8-coordinated. In 12-coordinated metallic structures each atom is surrounded by six atoms on each layer, 3 on the left, 3 on the right, and smashed between two layers. In 8-coordinated metallic structures there are four atoms on each layer, 2 on the left 2 on the right, and the atom is again smashed between two layers. This is the ideal structure of metals and is not always true as, due to the sharing rather than ridged, structure of metals they may be deformed and changed before breaking apart like more brittle substances, as a result of deformity there are frequent irregularities in a metals structure. This same aspect that allows for structural irregularities, this sliding of the atoms over each other, allows for malleability, capable of being shaped or bent, and ductility, capable of being drawn out. Minor amounts of stress may allow metals to even retain their shape.

Grains are the groups of regularly structured metallic atoms in a piece of metal. When moving or being deformed a lack of regularity in grain size prohibits the sliding of atoms thus causing more irregularities in deformation. Stress and pressure increase the amount of grains by breaking down large grains. The more individual grains there are the more likely there are to be irregularities and thus the more hard, or resistant to plastic deformation, change in the shape or size of an object due to an applied force, the metal is. The harder a metal is the more brittle, easily cracked or fractured, it becomes. The heating of metal resets the grains by invigorating the metallic atoms into a more regular shape, thus restoring malleability. Cold working makes metal harder by breaking up metal grains and producing smaller, more irregular ones. Work hardening is the increasing brittleness and hardness due to strain beyond a metal's yield point, or plastic deformation.

Now that we know what metals are, we know their atomic and microscopic structure, and how they move, we should look to who uses and used them. Humanity has made use of this amazingly versatile substance for thousands of years, and its existence has helped humanity to master his environment to the fullest. Much like fire, however, the discovery of this substance and its use is shrouded in mystery and a lack of knowledge. It is most likely that the discovery of metal, like fire, was an accident. One person noticed that a rock turned red in the fire more quickly than the others and that, through tedious experimentation, it could be shaped by being beaten with a stone into a crude blade or spear tip. The advantages of such a blade are obvious over its simple flint counter-part. Firstly, metal does not crack or chip with use, it only bends and thus is not completely ruined and can be repaired which is much less difficult than fashioning a completely new stone blade. Metal can also be honed into a sharper tip with much less skill. Metal can also be shaped with less than a fraction of the skill required to shape a flint blade.

Since around 7000-6000b.c.e. tribesmen in Anatolia have been using crudely fashioned copper tools. This is probably the first place people started using copper because of its abundance. Metals are found very rarely in a pure state, most are found as ores, a minerals that contain metal, ores look similar to rocks and are lumpy and impure, being mixed with minerals. Copper is commonly found as one of two ores azurite, or malachite. Copper is a rather soft metal and has a low melting point in comparision with other metals, as a result ores could be smelted, or separated from minerals by heat, this is evidenced as early as 3800b.c.e. by smelted copper objects found in Iran. As metal’s use became more wide spread it was sought by more and more people. Cyprus, an island in the Mediterranean sea off the coast of modern day Syria, became a wealthy center of trade as a result of its huge copper deposits around 3000b.c.e.

The year 2800b.c.e. brings about another concept that must be defined and explained and that is alloys, a mixture containing two or more metallic elements or metallic and nonmetallic elements usually fused together or dissolving into each other when molten. Alloys are created in one of two ways, the first way being substitutional, and the second way being interstitutional. Interstitutional is the type of alloy formed when atoms of a smaller size are inserted into the gaps between metal atoms, making for a more dense, stronger compound, like bronze and steel. Substitutional is the second type of alloy and it is formed when atoms of a similar size replace metallic atoms in the metallic structure, such as sterling silver, brass, and pewter; this type of alloy is much harder to make. Alloys allow the combining of two or more substances with metal to create a substance with desired properties. Bronze is the first alloy discovered by man and remained the dominant material for tools in the Mediterranean, Egypt, Mesopotamia, and China for thousands of years.

Bronze, an interstitutional alloy, is made from the mixing of tin and copper, two soft metals that combine to form a significantly harder metal with the durability for much more diverse and extreme work. Bronze tools were first discovered in Sumer, a Mesopotamian civilization, in Ur, a city state of said civilization, around the year 2800b.c.e. Bronze spread to the Indus river valley civilization known as the Harrapan civilization (named after one of its cities) by the year 2500b.c.e. Bronze spread to west and central Europe to the predecessors of the Celts around the year 2000b.c.e.. The lack of production and avability of bronze limited its use to the wealthy and thus was mainly used as luxury items or weapons instead of tools. The Chinese discovered bronze around 1500b.c.e. completely separate from the nations of north Africa and Mesopotamia and Europe.

The creation of bronze required the finding of two rather rare metals in most parts of the world and was especially expensive. Iron was the solution to this problem as it was strong enough to be useful by itself. The only problem with iron is that it is found very imnpure in nature and could not be separated from ore by smelting due to the lack of means present. Copper and tin melt at 1300 degrees Celsius whereas iron melts only at 1528 degrees Celsius. The furnaces used to smelt bronze just couldn’t produce enough heat to smelt iron. As a result of the lack of means necessary to melt out the impurities of iron, the impurities had to be beaten out of the metal, which required a lot of time and energy and was dreadfully inefficient.

As a result of the ineffiecency of iron processing there was a five hundred year gap between when iron was discovered and used around 2000b.c.e. and when it was widely used around 1500b.c.e. The Hittites of Anatolia were the first to use iron as their artifacts indicate. Iron, like copper, was quickly replaced by its better alloy form known as steel.

Steel is an interstitutional alloy formed when iron is super heated with charcoal or some other high carbon fuel and then quickly cooled. During heating the iron atoms separate slightly and the carbon from the burning fuel is turned into gas, as the gas escapes some is caught between the expanded iron atoms, like fish in a net, and when the iron is cooled the carbon atoms are locked in and the iron is now steel. Steel is harder, less brittle, and thus better to use and easier to work with than iron. Thus steel was highly prized over iron but was not widely used until it could be effieciently produced.

Around the 11^th century b.c.e. the iron age began in the middle east and spread out from Anatolia and the Middle east. Around this same time steel was discovered. In China the first furnace hot enough to melt iron was invented around 513b.c.e. and shortly afterward the Chinese iron age began. Iron soon spread to Japan and by this time the Eastern Asians had a firm knowledge of metal working as well as a knowledge of steel. Japan begun the making of swords by folding metal over itself and re-forging it over and over again and thus took advantage of the structure of grains and metallic crystal structure and their effects on metal and how it is deformed.

In 1161b.c.e the Celts of Britannia built the first European iron foundry in England. Soon after Rome was mass producing and equipping its legions with arms and armor made of steel. Metal continued to be used in the dark ages and medieval world in Afroeurasia. In the Americas, however, there was little to no use or knowledge of metal and its working. American peoples remained without great use of metal until the Europeans brought it to them through trade and warfare.

Europe and China continued to advance in metallurgy and chemistry and metal working and by 1709 Abraham Darby discovered that iron could be brought to smelting temperature by coke, a gray, hard porous substance formed from the solid carbonaceous material derived from destructive distillation of low-ash, low-sulfur bituminous coal, instead of coal. This discovery greatly advanced the production of steel by making fuel use more efficient and thus more steel could be made with less fuel. Europe further advanced in metal working and metals uses in engineering and in 1779 the first iron bridge was constructed. In 1784 a steel producer named Cort discovered the method of steel production known as puddling, a means of making iron and steel by stirring molten iron in a reverberatory furnace with iron rods, which were consumed in the process. Cort also created the system of a rolling mill, steel mill where metal is rolled into sheets and bars between two huge cylinders when hot and cut into desirable shapes in the process. Rolling mills soon became the center of the steel producing industry.

Our knowledge of metals has greatly increased since 1784 and is far more comprehensive than need calls for to mention, but it is safe to say that humanity does not yet know everything about metals. Metals have been and will most likely always be a huge part of human life and an understanding of them is important for everyone.

earths crust composition from: http://mistupid.com/geology/earthcrust.htm

• Oxygen 46.6%
• Silicon 27.8%
• Aluminum 8.1%
• Iron 5.0%
• Calcium 3.6%
• Sodium 2.8%
• Potassium 2.6%
• Magnesium 2.0%
• others 1.6%

Metallic bonds from:http://www.tpub.com/content/doe/h1015v1/css/h1015v1_49.htm, and from: http://dl.clackamas.cc.or.us/ch104-08/metallic.htm

• a metallic bond is a bond in which an atom acheives a more stable state by having contact with and thus sharing valence electrons with multiple surrounding atoms
• the atoms involved in the stability of one given atom are called a metallic crystal
• in a metallic bond all atoms share electrons with all other atoms in the metallic crystal
• the sharing of electrons holds atoms together in a tightly packed bundle
• electrons move easily through metallic bonds
• 
  

Structures of Metal from: http://www.chemguide.co.uk/atoms/structures/metals.html

• metals are large groups of metallic bonded atoms
• most metals are densely packed with as many atoms as will fit
• each atom is surrounded by 12 other atoms (6 on each layer)
• 3 atoms below and 3 above
• some metals have only 8 adjacent neighbors
• this is the perfect world scenario
• there are irregularities
• due to the strength of metallic bonds metals have high melting and boiling points
• metallic structure allows for tri-demensional electron movement
• liquid metals coduct electricity as well
• as long as atoms are touching electrons may be transfered
• thermal conductivity is the same as electric conductivity
• malleability and ductility are possible due to the ability of metallic atoms to slide over eachother
• minor amounts of stress may be resisted to the point of metal retaining its shape
• a lack of regularity in grain boundries prohibits the sliding of atoms
• the more individual grains their are the more likely there is to be irregularities and thus the harder the metal
• stress and pressure increase the amount of grains by breaking down large grains thus making metals harder
• harder the metal the more brittle
• heating of metal resets the grains and sets them into a more regular shape thus restoring malleability
• cold working makes metal harder by breaking up metal grains and producing smaller ones
• 
  

Work Hardening from: http://www.tpub.com/content/doe/h1017v2/css/h1017v2_88.htm

• Work hardneing is the appearent hardening of metal due to plastic deformation, changing the shape or size of an object due to applied force.
• makes metal more resistant to change in form
• makes metal more brittle
• requires more stress to deform as metal hardens
• smaller grain size makes for harder metal
• larger grain size makes for more malleable metal