Copper Domes

Introduction

We as humans often take for granted the simple things in life. We live each day without taking time to appreciate the structure and beauty of objects around us. Copper domes are one of those simple objects that we often see but never really take the time to learn about. If we did, we would find that copper is one of the most reliable and remarkable elements known to man. It has a long history and many properties that make it an ideal candidate for the composition of domes. The process of creating copper and domes is a fascinating one, and the

end results can be seen everywhere from churches to theme parks.

History of Copper

Copper is one of the oldest elements known to man. The name Copper comes from the Latin word Cyprium (island of Cyprus), which is famous for its copper mines. Copper was probably first used along the Tigris and Euphrates Rivers around 8000 B.C. Three thousand years later, people learned how to heat copper. Middle Easterners learned how to heat and hammer the metal into sheets. These sheets were used to make larger tools, weapons, and ornaments. Around 3500 B.C., people discovered how to make bronze. Bronze is created by melting copper with arsenic. Around 1000 B.C., people learned the art of making brass. Brass is created my mixing zinc and copper. Brass coins began being used by the Romans around the 100s B.C. By the 1800s A.D., much advancement in copper had been made. The element was now used for electric lighting and for telephone and telegraph systems.

With all of this extra demand for copper, deposits with a high-grade ore were dwindling. Thus, geologists had to search for additional copper deposits. They located large ore deposits in the United States and Chile. The only problem was that the grade of the copper found was too low. However, Daniel C. Jackling found a solution to this problem in 1900. Jackling found that these low-grade copper ores could be cheaply processed. Thanks to Jackling's findings of processing such ore for consumption, no real copper shortage exists today. Every continent on the Earth has copper deposits. Most of world's copper comes from the mountain ranges between Alaska and South America. Chile is the current leader in copper production, producing nearly one-third of the Earth's copper. The United States comes in second, mining nearly one-tenth of the world's copper. The demand for this metal is substantial, and about fifteen million tons are mined throughout the world each year. Copper is recyclable, though. Therefore, scrap wire, motors, car radiators, and electronics--all made of copper--can be recycled and reused.

Properties of Copper

Copper is element number 29 on the periodic table of elements. It is a transition metal located in group eleven, period four. Its electron configuration is 1s22s2p63s2p6d104s1. Copper has a mass of 63.546, a boiling point of 2567 degrees Celsius, and a melting point of 1084.6 degrees Celsius. These properties help explain why copper is such a versatile element and why it is a practical choice for the construction of domes.

Metallic bonds help explain many of copper's properties. Metals, including copper, have lost their valence electrons and so are similar to cations, having a positive charge. They are known as kernels. Since the kernels are positively charged, they are attracted to the negative electrons around them. The larger the magnitude of positive charge and the more valence electrons that exist, the stronger the metallic bond will be. Metallic bonds are omni directional, meaning they are still present even when they are shifted around. This makes copper very flexible (malleable). It can be shaped either hot or cold, and it does not crack when hammered, stamped, or forged. This property is essential when making domes because the metal must be shaped and bent repetitively in order to get that rounded shape. Metallic bonds are also what make metals, like copper, ductile. Ductility is the ability to be drawn into a thin wire without breaking. Copper is so amazingly ductile that a one centimeter rod can be turned into a wire that is thinner than a human hair simply by heating the copper and rolling it. This is important when creating copper domes because it proves how malleable, strong, and durable the copper is. Additionally, metallic bonds help the metal conduct electricity with ease. All of the space where the electrons flow freely around the atom is sometimes called the electron sea. Since the electron sea is similar to a fluid, it makes the metal a good conductor of electricity because electricity can easily flow through it. Copper is also a very good conductor of heat due to these metallic bonds. When heat is added to one side of a piece of copper, it is transferred to the other side because the kernels start to vibrate since they are spread apart. In a domino effect, when one kernel starts to vibrate, it touches another which also starts to vibrate, sending the heat across the copper. Thus, during cold winter months, a copper dome would absorb the heat and help keep you warm inside. Because copper is cheaper than most metals, it makes for a very affordable dome.

Corrosion-resistance is another one of copper's many qualities. It has one of the highest nobilities of other common elements. Nobility is the measure of a metal's resistance to corrosion. Copper is more resistant than aluminum, steel, zinc, iron, stainless steel, tin, and lead. It doe not rust like most metals. When exposed to damp air, copper will turn to a reddish-brown, but it will never rust. This is due to the fact that the metal is able to react with the environment and reach weathering equilibrium. Copper can, however, be coated with a green film called patina. Patina develops when copper has been exposed to damp air for an extended period of time. Patina is not bad, though, because it helps protect against further corrosion. Patina is formed by a chemical reaction. As Ken Vlach, a Ph.D. in Materials Science and Engineering, explains, "Initially, bare Cu metal atoms react with air to form the pink oxide, cuprite, Cu2O, which has Cu+1 cations. This gradually oxidizes further to the black oxide, tenorite, CuO, with Cu+2 ions. The black sulfide CuS also sometimes forms. In the presence of moisture, the blackish layer slowly reacts with sulfur dioxide and carbon dioxide from the air to eventually form the patina, which is a mixture of three minerals." (Vlach) Patina is necessary when creating a dome; since most domes are part of an outside structure, it is important that they are able to withstand many different types of weather conditions. The dome must also

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