Crafting Olympic Medals with Chemistry (Basic)

The Olympic Medal is one of the most recognizable symbols in all of sports. Thousands of athletes strive to earn one of these medals every 2 years at either the winter games or the summer games.

An Olympic medal must be made to some very exact specifications. Contrary to popular belief, an Olympic Gold Medal is mostly silver. Both the silver and gold medals are 92.5% pure silver while the gold medals are plated with 6 grams of gold. All medals must be at least 3 millimeters thick and 60 millimeters in diameter.

In order to produce Olympic Medals of the highest quality, extremely pure base metals must be used. When metal is mined, the rock, called ore, that contains the metal must be removed. This can be done in huge furnaces. Most of the ore used to produce Olympic Medals comes from ore mined at Kennecott Utah copper mine! When the ore melts, the desired metal detaches from the ore and sinks. The undesirable materials such as rock and other minerals, called slag, floats to the top and is removed. What is left is a purer form of the metal. This process is repeated multiple times depending on the desired metal purity.

For the London 2012 Games, 4700 medals were created. To do this, a die must be created that will imprint the desired design onto the medal. To create a die, an artist must first sketch out the design. Next, an oversized plaster design is created. A computer instrument is able to read this plaster design and this information can be sent to a computer controlled engraver that will produce the correctly sized die.

After the designs have been imprinted, the future gold medals will undergo an electroplating process to gain their 6 grams of gold. To plate the medals, they are placed in a bath of sulfuric acid with a plate of pure gold. The medals and the gold are connected to a battery or other power source to create an electric current. When the current is activated, the medals act as the cathode (negative) while the gold acts as the anode (positive). When this occurs, electrons from the pure gold are attracted to the medals and move through the acid solution and plate onto the medals. Each medal, from oven to the end of electroplating, takes approximately ten hours to produce.Once the die is created, the purified metal must be sent through a 750 degree oven to be softened. Without this softening process, the design would not transfer from the die to the metal. When the metal reaches its desired temperature, it is cut to the correct size and sent to the die press. This press imprints the design onto the metal at a tremendous pressure.

By: Kenny Morley, Ohio State University 

References:

Electrochemistry Encyclopedia. (2012, June 25). Electroplating. Retrieved from http://electrochem.cwru.edu/encycl/art-e01-electroplat.htm.

What Are Olympic Medals Made Of? July 13, 2012. Retrieved from http://chemistry.about.com/od/metalsalloys/f/what_are_olympic_medals_made_of.htm.

Articles by Kenny Morley.

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