Everything Everywhere Daily: History, Science, Geography & More - Copper

Starting point is 00:00:00 When humans first learned how to work with metal, the very first metal they probably used was copper. Copper was easy to shape, easy to find, and relatively abundant. Since those early humans began using copper, usage of the metal hasn't diminished. It's just that the modern uses of copper are for purposes that the ancients never could have imagined. Learn more about copper, and its many uses throughout history on this episode of Everything Everywhere Daily. What if your perceptions about the past were wrong? is a podcast that takes you back in time to uncover the parts of the story that may have gone unnoticed. It effectively turned day into night. And how it shaped the world now. Time travel with us

Starting point is 00:00:56 every week on the Thuline podcast from NPR. As I've mentioned before in previous episodes, there were seven medals known in the ancient world. Gold, silver, lead, tin, iron, mercury, and copper. And today is Copper's Turn in the Spotlight. Of the seven metals that ancient people were aware of, copper was probably the first. And if it wasn't copper, it was probably the much rarer gold or iron which came from meteorites. There are several reasons why copper was probably the first metal. First, unlike most metals, copper can be found in its native form similar to gold. While it can be found in oxides and other compounds, it's also possible to find pure copper.

Starting point is 00:01:44 Second is that copper is very malleable and has a low melting point. That meant that early humans could take a hug of copper ore and beat it into something even without the use of fire. If you remember back to my episode on the Three Ages system for the ancient world, many historians broadly categorized ancient history into the stone, bronze, and iron ages. However, there is an argument to be made that there should also be a copper age as well. The copper age is sometimes used and it's known as the Chalkalal. Ethnic era. The first evidence of copper working dates back around 11,000 years in the Middle East. The oldest known copper object dates back to 8,700 BC, and it was found in northern Iraq.

Starting point is 00:02:27 The first evidence of copper smelting dates back about 5,000 years. Copper smelting appears to have been independently developed in many places around the world, with copper smelting appearing in China, Mesoamerica, and West Africa. Atsy the Iceman, a 5,000-year-old man who was found on a glacier, had an axehead that was made out of almost pure copper. And North American Indians were mining copper in Wisconsin and Michigan at least 8,000 years ago. So suffice to say that copper working could be found pretty much all over the earth, at least as far back as the advent of agriculture. Copper tools were indeed a huge advancement, but they had drawbacks. Because copper was so soft

Starting point is 00:03:09 and malleable, copper tools were easily damaged when they were used. A copper axe, for example, would quickly lose its edge and develop nicks in its blade. A copper axe or saw was certainly better than nothing, but they were hardly ideal. The big advancement in copper came when it was used with tin to make an alloy called bronze. I've already discussed bronze in depth in my episode on tin, so I'm not going to spend a lot more time with it here, but suffice to say that bronze was a big advancement over just plain old copper. As bronze and later iron became dominant, the use of of copper changed from tools to jewelry, utensils, cookware, and most importantly, coinage. Gold and silver were preferred for use in coinage, but there was a problem. For really small

Starting point is 00:03:58 transactions, it wasn't possible to make a coin small enough to have the proper amount of value of gold or silver. And that is where copper came in. Copper was much more abundant and was used for small value coins. The oldest copper coins that we have discovered date back to the 3rd century BC. These coins were issued by Greek rulers in Bactria, what is today parts of Iran and Afghanistan, in the aftermath of Alexander the Great's conquests. These earliest coins were an alloy of copper and nickel. The Romans issued small denomination copper-based coins known as an ass. These coins are made out of bronze or copper at different points in history. Because it was primarily used for money, in addition to other uses such as plumbing, the Romans

Starting point is 00:04:43 had a huge appetite for copper, and their biggest copper mines were on the island of Cyprus. The metal in Latin was known as Ice-Ciprium, which simply meant metal from Cyprus, but it was later changed to just cupram. Coopram eventually became copper in English, and it's why the abbreviation for the element on the periodic table is CU. At its peak, the Romans were producing about 15,000 tons of copper per year throughout the empire. The Roman use of copper and copper-based alloys for its small coins is still practiced by most

Starting point is 00:05:17 countries around the world today. If you come across a copper-looking coin, it probably isn't worth very much. For the next several hundred years, the uses for copper remained pretty much the same. It was a metal used in art ornaments and coins. Nonetheless, it was still a very important metal. One of the most important sources of copper in the Middle Ages was the copper mine in Falloon, Sweden. The mine supplied two-thirds of all the copper in Europe for centuries, and it was the biggest source of revenue for the Swedish crown.

Starting point is 00:05:50 Many of the wars fought by Sweden in the 17th century were all funded by the copper mine in Falloon. On a personal note, I visited the Falloon mine, which is today a UNESCO World Heritage site, and it's a fascinating place to visit to see how mining was once conducted. It's located about 200 kilometers northwest of Stockholm, and I highly recommend visiting if you're ever in the area. Before I move on to how the human consumption of copper has changed, let me go over some of the basic facts about copper. Copper is the 29th element on the periodic table, situated between nickel and zinc. It's also in the 11th group or column on

Starting point is 00:06:28 the table, along with silver and gold. And copper is the only metal other than gold, which doesn't have a silvery, sort of grayish color. There are two properties of copper that were not well known to the ancients that you are probably very familiar with and are probably the first things you think of when you think of copper. Heat and electrical conductivity. Copper is not the best conductor of heat and electricity. Silver is much better than copper at both, but it's not that much better than copper. These properties of copper made it extremely valuable with the advent of the Industrial Revolution. Almost as soon as researchers began experimenting with electricity, they found that copper was an excellent conductor.

Starting point is 00:07:12 Electricity could flow through copper with very little resistance. In the late 19th century, as the world began becoming electrified, the demand for copper skyrocketed. It wasn't just ornamental anymore. Copper became a vital strategic resource. Copper wires were stretched across thousands of miles to create a network of telegraph terminals. Vast quantities of copper were needed for the electrical wires that were stretched from power stations to cities. And within those cities, copper wiring could be seen connecting buildings that

Starting point is 00:07:43 were strung together on poles above the street. And it wasn't just wiring to transmit electricity that was needed. Almost every electrical device required copper. Electrical motors required copper for their electromagnets and brushes. Switches would have copper, as did most light bulbs. When telephones were invented, it required even more copper wiring. Automaviles eventually required copper wiring as well. They were a vital part of the generator and electrical system of cars. With the advent of cable television, copper-based coaxial cable required more copper, and of course computers in the internet created the need for computer cables like Category 5 and USB cables, as well as a host of others. Today, electrical wiring is responsible for 60% of the total world demand for copper.

Starting point is 00:08:31 Most of you are at least familiar with the electrical properties of copper, so I won't spend too much more time on it, but copper does have some other amazing properties as well. As I previously mentioned, copper is a great conductor of heat. Copper is the preferred material for heat sinks on computer processors. Copper heat sinks are placed on top of a hot processor. Then the heat sink can transfer the heat away from the processor where it can then be dissipated. Copper's heat conducting abilities also makes it commonplace in car radiators as well as in refrigerators. The heat-conducting properties of copper also make it a good choice for cookware for some cooks. Because it distributes heat so well, heat is evenly distributed throughout a pot,

Starting point is 00:09:14 avoiding spots that are hotter than others. Connecting electricity and heat aren't the only properties of copper that have been taken advantage of in the modern world. Copper is also highly resistant to corrosion. If you've ever seen a building that was built in the 19th or early 20th centuries, you might have noticed a green roof. Odds are, the roof was made out of copper. When copper is exposed to air, it will oxidize and form a thin layer of copper oxide known as pantina. This pantina, which is usually only about a tenth of a millimeter thick, serves as a protective layer on the copper. The skin of the Statue of Liberty is made out of copper, and its light green hue is due to its pantina.

Starting point is 00:09:58 This corrosion resistance is what makes copper a good choice for spires, rain gutters, and some old doors. The benefits of copper get even better. Copper is considered to be a biostatic substance, and that means it's very difficult for anything living to grow on it. 18th century sailing ships would use copper to line their halls as it would prevent the growth of barnacles, which would slow down ships. Likewise, the interior water tanks and ships were often lined with copper to prevent the growth of harmful agents. And this brings me to what is perhaps the feature of copper that might prove to be the most important going forward. Copper is antibacterial. Surfaces that are coated in copper have been shown to kill 99.9% of disease-carrying microbes. Because hospitals are

Starting point is 00:10:49 major vectors for the transmission of diseases, there have been calls to replace many of the fixtures in hospitals, such as doorknobs, sinks, faucets, handrails, and other things that people touch, with copper. Hospitals in many countries around the world are starting to install copper or copper alloys like brass to prevent the spread of disease. The reason why copper is antimicrobial is due to something called the oligodynamic effect. The oligodynamic effect is when ions of heavy metals like copper disrupts cellular processes. While copper prevents growth, on its surface, that doesn't mean it's inimicable to life. Copper is actually an essential trace element for almost all plants and animals. The recommended daily allowance of copper for an

Starting point is 00:11:34 adult human is around 1,400 micrograms. Foods that are good in dietary sources of copper include oysters, liver, and some mushrooms. Symptoms of copper deficiency include tiredness and weakness, anemia, vision loss, memory issues, and sensitivity to cold. But before you start eating pennies to get your copper, realize that you can also get copper toxicity. Copper toxicity is pretty rare, but it can happen. In a very real way, copper is the backbone of our modern civilization. The internet and everything electrical involves copper. The device that you are listening to these words right now probably has some copper in it. Copper is a pretty amazing substance, despite being one of the oldest metals that humans have ever worked with,

Starting point is 00:12:24 we are still using more copper than ever today. The executive producer of Everything Everywhere Daily is Charles Daniel. The associate producers are Peter Bennett and Cameron Kiefer. I wanted to give a big thanks to everyone who supports the show on Patreon. Your support helps me put out a new show every day. And if you're interested in Everything Everywhere Daily merchandise, Patreon is currently the only place where it's available. And if you'd like to talk to other listeners of the show

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Everything Everywhere Daily: History, Science, Geography & More - Copper

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