Tag: iron

Posted in History & Literature

Sweat Like A Pig

Posted on by Jinavie

The English idiom to describe profuse sweating is sweating like a pig. However, pigs lack the ability to sweat properly due to ineffective sweat glands, which is why they roll in mud to cool their bodies. The idiom is not wrong though, as it is not referring to the animal, but pig iron.

When refining iron, the iron ore is smelted in a furnace until it is liquid. As the liquid metal is extremely hot, it is poured into a mould where it can cool. The iron was set in a branching mould that apparently resemble many piglets suckling from a mother sow – hence the name: pig iron.

Back in the old days when technology was not as advanced, it was difficult to tell when the pig iron was cool enough to transport safely. This is where science came in handy. As the metal cools, the surrounding air reaches a dew point, causing droplets of water to form on the pig iron as condensation. The condensation made it look like the pig iron was “sweating”, hence the idiom. When the pig iron sweats, it is a sign that is cool enough to be moved safely without spilling and burning everything around it.

Posted in Science & Nature

Metal

Posted on by Jinavie

Next to the discovery of fire and the wheel, the discovery of metals and the mastery of metalworking was arguably one of the most important advances for prehistoric humanity. Metal was far superior to rock, clay, wood or any other natural resource known to man in terms of strength and sharpness. Because of these properties, metal soon became a valuable commodity. It can be seen how much impact metal had on humanity’s history, considering that the stages of human prehistory were named after the type of metal (or lack thereof) that was mastered then: Stone Age, Bronze Age and Iron Age.

The discovery of metal came in two ways.

One was through mining, where prehistoric people discovered that shiny, hard objects were buried in the ground. They later discovered that with enough heat, they could melt the metal out of ores (copper and tin were the first metals to be gathered this way) and mould them into any shape. After smelting technologies developed, our ancestors found that mixing copper and tin produced bronze – a much stiffer and more durable metal than either of its components. A mixture of metals is called an alloy. This was the start of the Bronze Age. Bronze was extremely useful and people quickly came up with innovative ways of using it, such as farming equipment and weapons.

Some other metals used during this age were: gold, silver, lead and mercury. It is likely that gold was one of the earliest metals used as it comes in pure nuggets and is easily workable thanks to its chemistry. However, given that gold is rather soft and was treated more as jewellery than a practical metal, it was not used as much to advance technology.

The second way mankind came upon metals was in the form of “gifts from the gods”. A prime example is iron. Although the Iron Age began around 1200BC at the earliest, there are iron objects (mainly jewelleries) that have been dated back to 5000BC. How could this be? This was before mankind had the technology to smelt iron ores (which is more difficult and needs much higher temperatures than copper or tin ores), so the iron could not have been gathered through mining. The answer to this conundrum lies in meteorites. About 6% of meteorites contain iron and nickel, which prehistoric civilisations may have stumbled onto and taken the shiny pieces back to their tribe. The people would have considered the gathered iron a “gift from the gods”, as it had crashed down from the “heavens”. Because of this reason, iron was considered more valuable than gold or silver and was frequently used for jewellery. This is reflected in Arthur C. Clarke’s science fiction short story, The Songs of Distant Earth, where sentient sea scorpions hoard metal objects stolen from the humans and wear it proudly as a badge of honour.

The history of iron and how it was believed to be a gift from the heavens relates to a common superstition of how finding a penny (or any coin) represents good luck. As “metal” (mainly iron) was considered a holy gift bestowed unto mankind, finding a piece of metal was believed to be a blessing and some form of protection against evil. This is also represented in various traditions such as hanging horseshoes over doorways and wearing charm bracelets with metal on it.

Although it sounds like a silly superstition, it clearly shows how metals have been an integral part of the development of civilisation.

Posted in Psychology & Medicine

Spinach

Posted on by Jinavie

Spinach is a vegetable that is excellent for your health as it is rich in nutrients such as vitamins and minerals. If you ask someone the first two things that come to mind regarding spinach, they will most likely reply Popeye and iron. Popeye is a cartoon that began airing in the 1930’s and every child knows that the man gains superhuman powers from eating a can of spinach. In fact, after Popeye began airing, US consumption of spinach grew 33%. Most people believe that Popeye gains powers due to spinach having a high iron content. Thus, adults always tell children that if they want to be as strong as Popeye, they must eat their spinach.

Unfortunately, eating spinach does not make you as strong as Popeye. In fact, it is not even related to iron either. Firstly, the reason why Popeye eats spinach was because the producers wanted to advertise the high vitamin A content in spinach. Furthermore, spinach does not have a high iron content. The spinach iron myth originated from a German scientist named Emil von Wolff. In 1870, von Wolff was analysing the nutrition contents of different foods when he, from severe fatigue, accidentally misplaced a decimal point while recording the iron content of spinach. This led to spinach being known to have ten times the amount iron it actually has (to the level of red meat).

One problem with this is that this story is not true either. There are no detailed records of von Wolff’s experiments and no one knows if he misplaced a decimal point or not. The myth most likely originates from a 1980 article in The British Medical Journal that first brought up the story. Does that mean spinach is actually is a good source of iron? Wrong. Vegetarians often claim that spinach has iron levels close to red meat, but there is something about iron that they do not know. Many plants have a high iron content (it is found in chlorophyll which is used for photosynthesis), but this is mostly non-heme iron. There are two types of iron the human body can absorb: heme and non-heme. Heme iron can be used directly after absorption whereas non-heme iron needs to be metabolised by the liver to be usable. This takes a long time and is inefficient meaning it is far more effective to eat foods rich in heme iron. Plant iron is all non-heme iron while 40% of iron in red meat is heme iron, meaning it is a much better source of iron. Furthermore, spinach has a high oxalate content, which is an iron absorption inhibiting agent, making what little usable iron it has unabsorbable. 

In short, it is true that spinach has “iron” but as we cannot absorb it or use it, it practically has no iron content. But if you tell this to your parents and refuse to eat spinach, you may get into a lot of trouble.