All About Iron

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Podcast Transcript

Located at the 26th place on the periodic table is the element iron. 

Iron is one of the most important elements in the universe. It has a vital role in almost everything, from the formation of stars, the creation of chlorophyll in plants, the Earth’s magnetic field, and even your own health. 

Iron has been responsible for the rise of civilization, and there is a good chance there is an object next to you right now that is made of iron. 

Learn more about iron, one of the most important elements in the universe, on this episode of Everything Everywhere Daily.

Everyone listening to this is familiar with iron, even if you don’t know it.

Iron is incredibly important in ways that you probably don’t realize. I’m not just talking about the use of iron in things like steel, but the importance Iron has in the very formation of the universe and in the establishment of life on Earth. 

With that, Iron is the 26th element on the periodic table, having 26 protons in its nucleus. 

There are four stable isotopes of iron, Iron 54, 56, 57, and 58. As we will see in a bit, they are not just stable; they are extremely stable. By far, the most common isotope is iron 56, which makes up almost 92% of all iron.

Iron is very reactive and oxidizes easily. Unlike other elements that bind with oxygen and form a single oxide, iron has multiple oxides with different numbers of iron and oxygen atoms in each one. The most common version is magnetite which is a common black magnetic substance.

If you ever visit a beach and see black specks in the sand, that is usually magnetite, and you can pick it up with a magnet.

Iron oxidation is more commonly known as rust. Unlike other elements such as aluminum or copper, where an oxide will form a protective layer, that is not the case with iron. Iron will continue to oxidize until everything is turned to rust.

The chemical symbol for iron is Fe, and it comes from the Latin word Ferrum.

In previous episodes, I talked about the formation of stars. The enormous gravity of stars fuses hydrogen together to form helium. Helium then is fused together to form heavier and heavier and heavier elements. 

This continues, but only to a point. That point is iron. 

When you split the nucleus of heavy elements such as uranium, it releases energy. When you fuse together light elements, you get energy. 

As you move down the heavy elements, you get less energy from splitting atoms, and when you move up from hydrogen, you get less energy from fusing atoms. 

There is a point in the middle when you can’t get energy in or out anymore, and that point is iron. 

For this reason, despite being the 26th element, iron is the 6th most common element in the universe. 

Iron is considered to be the stablest of any element. Yes, before I get any emails, nickel-62 technically does have higher binding energy, but because it has a higher mass, iron-56 is usually considered to be more stable.

Iron is the primary component of meteoroids. In the ancient world, the few iron meteorites that were discovered were considered to be extremely valuable because of their iron purity. There was a dagger made from an iron meteorite found in the tomb of King ??Tutankhamun.

Located in the corner of the Kabbah in Mecca, the holiest site in Islam, is the Black Stone. The Black Stone is believed to be a meteorite that fell to Earth to show Adam and Eve where to build an altar. Immams stress that the stone has no divine significance it is only a historical artifact.

As you probably know, iron is magnetic. The abundance of iron in the Earth, plus the magnetic properties of iron, creates the Earth’s magnetic field. The magnetic field is the first of many things which allow life on Earth to exist. 

The magnetic field protects the planet from the sun’s solar wind, preventing radiation from hitting the planet and potentially causing the seas to dissipate.

The molten outer core of the Earth, which is responsible for the magnetic field, consists of approximately 85% iron. The solid inner core is believed to be almost 95% iron.

The magnetic field isn’t the only thing that allows life on Earth to exist. 

Iron is an important part of chlorophyll synthesis. Without iron, plants wouldn’t be able to grow and reproduce. 

This can be seen in the places where phytoplankton grows in the ocean. The highest density of phytoplankton is off of continental coastal areas where iron is continuously being sent into the oceans by rivers. 

In the deep open ocean, there is very little phytoplankton growth, mostly because there is little dissolved iron in the water. 

This has led many people to suggest fertilizing the open ocean with iron to feed phytoplankton. This would cause massive blooms in phytoplankton, which would take CO2 out of the atmosphere and the water. 

Likewise, animals need iron as well for the transportation of oxygen. Iron is the essential element in hemoglobin. Hemoglobin is a protein in red blood cells that binds to oxygen in the lungs and carries it to tissues throughout the body, ensuring the delivery of oxygen necessary for cellular respiration and energy production.

The average adult human only has about 4 grams of iron in their body, but those 4 grams are vital. The Recommended Dietary Allowance of iron ranges from 8 to 18 milligrams per person per day.

Iron has also had a huge role to play in the development of the modern world. In fact, it isn’t a stretch to say that the modern world wouldn’t exist if it weren’t for iron.

Iron is one of the seven metals of antiquity, the metals that were known to the earliest humans. These also included copper, tin, gold, silver, mercury, and lead. 

While iron was known, it was the last of the seven to be exploited because it has the highest melting point. 

If you remember back to my episode on the three-ages system, there was an entire age of human history known as the iron age. The iron age followed the bronze age, and if you used bronze tools, you could understand why people shifted to iron. 

There are some YouTube videos out there that show what happens when bronze sword clashes with an iron sword. The bronze sword will quickly become deformed with large nicks in the blade, whereas the iron sword will remain almost entirely intact. 

In addition to being stronger and able to keep a sharper edge, iron was simply more abundant. Bronze required the importation of tin from faraway places. If someone disrupted your trade routes, they disrupted your ability to make bronze. 

Iron required special forges operating at higher temperatures to work the metal. This technology in the Mediterranean was believed to have been first discovered by the Hittites and then slowly spread. 

Some of the first people to regularly work iron were in India. There is evidence of early ironworking as far back as 1800 BC in the Ganges Valley. 

It appears that ironworking was independently developed several times around the world. In addition to the civilizations I just mentioned, it may have been independently developed in China, West Africa, and Egypt.

One of the best examples of ancient ironworking is actually still standing. Known as the Iron Pillar of Delhi, it is a solid iron column that is 7.21 meters or 23 feet 8 inches high with a 41-centimeter or 16-inch diameter.

The Emperor Chandragupta II built it in the early 5th century. 

To our modern sensibilities, it doesn’t look like much. It is just a big iron pole. However, at the time, it was a massive demonstration of the skill of the ironworkers and the technical ability of the Gupta Empire. 

Also, in almost 1600 years, it hasn’t rusted. 

Today you can see it at the Qutb Minar complex in Delhi, a UNESCO World Heritage site and a place I highly recommend visiting if you are in Delhi.

Hand in hand with the development of ironworking was the creation of steel. Steel is just an alloy of iron and carbon. Carbon would often be accidentally added to iron during the ironworking process, which led to the discovery of steel.

High carbon content iron has a lower melting point than regular iron. This allowed for it to be melted in a crucible, whereas regular iron couldn’t be melted as ancient people couldn’t create temperatures that high.

Crucible steel, initially developed in India, became highly prized in the creation of weapons. These steels are known as Wootz steel and Damascus steel. 

Save for things like crucible steel, almost all ancient ironworking was wrought iron. Wrought iron is when the iron is heated and softened and then hammered into shape.

One of the things which allowed the industrial revolution to take place was the creation of blast furnaces that could completely melt iron. Blast furnaces were first developed in China in the 5th century BC, but they were on a relatively small scale. 

In the 14th century, they were introduced to Europe, where they used charcoal as their fuel source. 

Refinements in blast furnaces, and the move to coke as a fuel source, a derivative of coal, allowed large-scale furnaces to melt large amounts of iron that could be poured into molds. This was known as cast iron. 

Cast iron allowed for the creation of more complex shapes than could be created with wrought iron. This included parts for machines and locomotives. 

By the 19th century, steel had replaced iron for most industrial uses, given its improved strength and resistance to fracturing. Improvements in technology, such as the Bessemer process and open hearth furnaces, made the production of steel more affordable at a higher quality. 

One of the biggest developments in steel production was the discovery of stainless steel. 

Stainless steel wasn’t developed all at once. It began in 1798 in France when the element chromium was added to steel, and it was observed that these chromium steels were resistant to corrosion. 

Chromium steels were used in the 19th century for very niche applications, and even into the early 20th century, it was still a very niche market. It was hard to make and expensive.

It wasn’t until the 1960s that the technology existed to produce stainless at quantity and a lower price.

Today stainless steel is commonly used in hospitals, kitchens, and bathroom fixtures. 

While steel is now by far the biggest use of iron, there are still uses for cast iron. The one that most people are familiar with is cast iron cookware. 

I’ve recently become a convert to using cast iron cookware. Its ability to distribute heat makes it much better than lighter metals such as aluminum or stainless steel. Moreover, the more you use it, the better it gets, and it can last for decades. 

Despite the use of other metals, such as aluminum and titanium, iron is still overwhelmingly the most popular metal used by humans today. Over 90% of all the metal used globally is still iron, mainly in the form of steel. 

I think you can see just how important the element iron is. Iron plays a role in almost everything. It is in the stars, it is in meteoroids, it is in the Earth, it is in our bodies, and it is in the tools and machines we use.

You could say, without any exaggeration, that we are still in the iron age.