Without string, or as some call it, cordage, we would be a lot colder today, and wouldn't be able to build many of the great structures and machines that make up modern life.

When Otzi the iceman was found in the Italian Alps, he had clothing and equipment which used lots of different types of cord from multiple different materials. One of the earliest cords was simple sinue taken from dead animals. This is an interesting material to sew with, but it's strong and quite durable.

3/n

The next big technological development in the world of string was to twist fibres together. The bow string on Otzi's bow was made of sinue fibres twisted together. This allows for a strong longer than the raw material, but also stronger. Much stronger. There more to twisting fibres than you might think tho. If you twist a set of fibres one way to make a cord, and do that a few times, then twist those cords together the opposite way. The twists work to keep the cord together.

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In the world of spinners depending on which direction you twist the fibres, it's called either z twist, or s twist. And using the two in combination makes for the world of cordage and fabric we have today.

The next big leap is rather than using cord to sew bits of animal together to make clothes, we tangle bits if thread together in highly specific arrangements to make bigger pieces we can use to make clothes from. The invention of weaving changed humanity.

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Weaving was essential to move away from a hunter gatherer lifestyle to a settled farming one. It was also necessary for population to grew. It's a lot simpler to farm a field of linen, or to collect fleece from live sheep, than to have to kill an animal each time you needed a new jacket. That's not to say the process of producing fibre from plants is easy. To find a gootube video in how to make linen from flax plants. It's many stages. Laborious and complicated.

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Like when Billy Connolly said "who discovered milk came from cows, and what were they doing at the time ?" You have to wonder how the first human came up with the method for getting fibre from the flax plant. It's a multiple step process that requires days to do. And then it all needs to be spun before it can be Woven.

For millennia spinning was done with a tool called a drop spindle. It was slow, and repetitive, and it took a lot of time to make the thread for a simple garment.

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Spinning was something typically (in western cultures at least) done by women & girls. Picture the Norse Goddess Frigg weaving clouds from her distaff. (Distaff is a tool used to hold the raw fleece while you spin it with a drop spindle). But using a drop spindle is something you can do while you stir the dinner, watch the kids, walk to the market. But it takes ages. It wouldn't be until as late as the 18th century that this technique would be replaced by the more familiar spinning wheel
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Because it was such a slow process it wasn't really something you could make a living from at least not a big one. So spinning remained women's work right up to the industrial revolution.

With the thread woven. Time to weave. The first looms are what we call warp weighted looms. In weaving you have two sets of thread. The warp going up and down. And the weft side to side. With a warp weighted loom tension was applied to the warp using weights. These usually ceramic donut shaped objects...

9/n

Are common finds in archeology. Being ceramic they don't really rot. But this design is slow, laborious, and doesn't make particularly wide cloth. It could take months to make enough cloth to make a dress. The technique stood up for centuries. It was the height of fabric technology. That is until the 12-13th century and the invention of the two bar loom.

This moves the weaving from vertical to horizontal, and from women to men.

Why? It's not like it's operated it with genitals?

10/n

Why then does weaving move from women's work to men's work? Because now with a two bar loom fabric can be made a lot faster, and it can be made wider. This allows for it to be made at a larger scale, & crucially, for it to be something one can do professionally. As soon as a technology can be used to provide an income to support a family, it moves from women's work, to men's work. We see this throughout history. See also computer programming. Once we valued it more, the white men took over

11/n

From the time the two bar loom took over, until the industrial revolution weaving was men's work. That is until technology advanced and made it so the pay was less, and it was harder to support a family on an industrial weavers salary. Then it became women and children's work.

But the construction of the fabric isn't the only part. We like our clothes coloured and vibrant. That means dying.

A complicated process involving mordants and chemicals and boiling stuff.

12/n

Dying cloth was laborious, messy, and slow. And in many regards was too similar to cooking. It also didn't change much until the development of synthetic dyes in the 19th century. At which point, oh look, the men took over...

Developing dyes that don't run, and last well, and in vibrant colours is incredibly complicated (and also really interesting) and all of that is technology. We don't think of it as such. But it really is.

13/n

And this is before we get onto the technological marvel that is synthetic fibres. They may be an environmental disaster. But the way the fibres work is an amazing feat of chemical engineering. It unlikely that the clothes you're wearing now are purely made from natural fibres. There's probably some polyester, or elastane in there. They make the fabric more durable. More comfortable. Require less ironing. The amount of research and technology that goes into easy iron clothing is incredible.

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But we don't think of it as technology. Not least because most men aren't the ones who no longer have to iron the shirts...

The train of technologies that have been connected together, one after another, over millennia, take us from sinues pulled from a carcase next to a fire right up to the no Iron shirt and the gore Tex jacket today. Each step is a new technology. Technology we all very much take for granted.

When spring comes round, put on some gloves, find some nettles. And ...

15/n

Try to make some string from it. There's loads of videos online of how to do it. Give it a couple of hours. Make a couple of meters if string. Then imagine if you wanted to produce enough to make a t-shirt. (Nettle has been used as a source of fibre for clothing, and it's part if the hemp family). You'll gain a whole new appreciation for the technology (and underpaid labour) that goes into allowing you to buy a t-shirt for a fiver...

So that's string. IMHO One of the fundamental machines.

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The principles from spun flax fibres have also gone into the making of steel cables that support megastructures like bridges. Or the giant cranes that built them. Woven fibres give us the fibre in carbon fibre. The composites that our aircraft are made from. All of these stem from the basic piece of string. Without it. Modern society would be very very different.

On to the second everyday item. The knife. Goto the kitchen and grab a knife from the draw.

17/n

Hold that knife up to the light. Look at it. You'll likely be able to spot two things. 1) it's not rusty. And 2) it probably says something like 18/8, or stainless, or RVS.

That knife you're holding probably cost you maybe a euro or two, most likely at IKEA. Now put that knife back and grab your sharpest knife. Again. Notice. It's not rusty. And you probably haven't needed to sharpen it for a while. But it still cuts just about ok.

Let's look at the technologies that got us to here.

18/n

First off put the knife back in the drawer so you don't cut yourself.

I'm gonna skip past the stage of cutting implements made of unboiled rocks. The technologies of the stone ages are fascinating, spanning multiple tens of millennia, and show massive variety in styles, methods, and materials. But if I include all of those I'll still be writing next year.

19/n

Somewhere around 5000BC, someone worked out if you boil some rocks just right, at the right temp, and the right conditions. You get copper. That day. The world changed.

First it was just copper, then someone worked out how to add a second type of rock (tin) and it made the copper stronger, hold an edge better, and be easier to use. The bronze age began.

Eventually someone worked out that if you got it hot enough, and used the right kinda of rocks. You could get iron.

20/n

Iron. It sounds so simple. But it's one of the most amazingly complex technologies we had for millennia. It's developed changed whole civilisations. If you've ever held a piece of iron, or a non stainless steel, you've probably seen it has rust. Iron really doesn't like being on its own as iron, and really likes oxygen. In the right conditions it can rust in minutes (ask any tool user about flash rust).

In it's natural state iron is usually found as some form of rust.

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Of course chemists don't like us calling it rust. It's iron oxide. But basically the raw form of iron, also called iron ore, is iron molecules bonded to oxygen. Smelting is a process of persuading the iron to let go of the oxygen, mostly by providing a lot of energy and by giving the oxygen some much more appealing carbon to grab on to. This was done fro centuries in something called a bloomery. Feed charcoal (source of carbon), and iron ore in the top, blow in lots of air. Out comes iron.

22/n

That feeding in charcoal, carbon, to get the iron to give up it's oxygen to the carbon, is why steel production accounts for about 8% of world wide emissions of CO2. Over twice aviation and shipping combined. But we digress.

Out the bottom of the bloomery comes iron. Except it doesn't look like the iron we know and love. It's spongy. Unconsolidated. And not all of it is iron.

Some of it is steel...

23/n

Steel is an alloy of iron and a small amount of carbon. It's not chemically bonded, like iron oxide was, but rather mixed in. A bit like the way a cocktail is mixed. Yes I am suggesting a martini is an alloy of vodka and vermouth... Yes that's wrong. But you get the idea of mixed. But not chemically bonded... Hmm maybe the chocolate chips in a cookie would be a better example ...

Anyway, step away from the drinks cabinet, and put that cookie down. Back to steel.

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Steel is a mix of iron, and about 0.1-1% carbon. When you hear someone talk about high carbon steels that's typically 0.8-1% carbon. Wrought iron is typically next to zero carbon. Mild steel is typically 0.05-0.3% carbon. The carbon mixed in with the iron changes the crystal structure of the metal. Yes iron and steel are crystalline. You generally don't see it with the naked eye. But it's there. Having carbon contents above about 0.4% allow for hardening. But we'll come back to that later.

25/n

So you got your spongy iron blob with a little steel mixed in. Time to consolidate it.

How?

Hit it.

Hit it a lot. Heat it up to a high temperature and smack the hell out of it. This takes a lot of effort but eventually. You get a solid lump. By hitting it with the right stone. Sparks come off and by identifying the colour and amounts, you can work out what is steel and what is iron.

This is how iron and steel was made for a couple of millennia.

26/n

I'm gonna gloss over all the technologies that went into producing steel, and how the evolved, again for brevity. But I wanna look at the iron and steel we have.

Cos only a small portion of the metal produced is steel and not iron. The steel is a lot more valuable. the labour involved meant until the industrial revolution steel was incredibly expensive.

It's also why a lot of tools would be laminated.

Make the bulk of an axe head from iron. Then weld on a steel cutting edge.

27/n

It's important to remember all of this so far is done before the invention of the thermometer. We might think of the melting point of iron as a number, or the temp of a bit of metal as so many degrees. But that's a really modern idea in the grand scheme of things.

So how did we measure temperature without being able to measure temperature?

Colour.

If I have an object that's 1200°C. It will glow orange. Doesn't matter if it's steel, or glass or anything else.

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Colour and temperature are intrinsically linked. So if I heat up a bit of metal to orange. And you do the same. They will be about the same temperature.

That's important.

Now remember I mentioned hardening? If you take unhardened steel, or raw iron, and you shape it into a cutting edge. Then use it. The edge goes blunt fast. This was also the problem with copper and bronze.

But if you treat the steel properly. You can make a durable edge.

And this, the technology of heat treatment

29/n

This is utterly amazing. Verging on magic.

If I take a piece of high carbon steel, shape it into a blade, and sharpen it. Then rather than using it straight away, I heat it up again. This time to a dull red. Or about 800°. You can also check if it's no longer magnetic. But magnets are a relatively recent discovery (at least easy availability of them anyway). Then take your dull red hot steel. And plunge it into water.

This is called quenching.

Now remember I said about crystal?

30/n

By plunging the hot metal into water (or oil), you cool it rapidly. This stops large crystals forming. Specifically we're talking about forming a crystal structure called Martensite. But that's diving off into way too detailed for a fedi thread. The quench, as this is called. Alters the crystal structure of the steel. And makes it incredibly hard. Really hard. If you try to shape it with a file, it just skates off. Smiths call this glass hard.

31/n

Great. Hard steel. Win.

Well not so fast. There's a trade off. If you smack that hard steel against the anvil or floor, it'll break. It's brittle. Which isn't much good. We don't want a sword that breaks on impact.
So we do something called tempering. This is heating it up again. But not as hot.

In the modern age, this is best done by putting it in the oven at 200°. But in an age before the electric oven, and the thermometer, we need another method. Once again we look to colour.

32/n

Hold the steel next to the heat, and it will slowly change colour. Different temp, different colour. This isn't a glowing incandescence like when we heated it up to cherry red. This is a chemical change on the surface. The hotter it gets the more the colour changes. At 200° we get pale straw colour. Which is what we want for a knife blade. But if you just want fancy colours. Keep going. About 280° you can get a beautiful purply blue. It's still steel. But the crystal structure has change.

33/n

We now have a relatively hard edge, but it isn't too brittle. Much more useful.

The discovery of heat treating, and it's mastery in the absence of thermometers, is a true wonder. Without it our society would have really struggled. All our cutting tools rely on the technology of heat treatment to be useful. I find it fascinating how we arrived at this state. Before anyone could look under a microscope and see the crystal structure. Or understand the chemistry of what was going on.

34/n

Alas this didn't solve the issue of the blade rusting if you looked at it wrong. Or didn't look after the steel and iron carefully.

We needed another technology to be developed.

Advanced alloys. In the grand scheme of things. Relatively recently (well 1840's), someone had the bright idea of adding chromium to steel. And thus stainless steel was born.

By mixing in at least 10.5% chromium into steel, you get a metal that is very resistant to rusting. These days nickel is also added.

35/n

Stainless steels are more complicated than normal carbon steels. Even more so when you want to use it as a cutting edge. The Chromium and the nickel mess with the carbon and the heat treatment making it a lot more complicated to forge. But we have the technology now. And the ability to weld it reliably is a major breakthrough. Thanks to some engineers in Texas...

We don't really think about the knife we use to spread the jam on our toast. Or slice the tomatoes at lunch.

36/n

We take for granted that we can get a good quality knife for about the same money as an the min wage hourly rate. Which will hold a reasonable edge. Doesn't break when we drop it. And if you leave it to soak in the sink overnight doesn't revert to iron ore. The technologies that have gone into producing that knife are as important, if not more so, than any computer you have.

But we don't think if them as technology. It's everyday. It's hidden in plain sight.

37/n

But our lives would be very different with out it.
Think of all the things around you made of steel. Your bike. Your car. Your home. The tools with which you make breakfast. The handle for your door. The springs in your mattress. Each of these requires a slightly different steel.

Someone found adding a little chromium, and some molybdenum to steel makes for great bike frames.

Someone else worked out that if you add silicon, vanadium, manganese, & a few others in the right proportions

38/n

You get a steel which develops a layer of rust in the surface, which then provides a protective coating to stop further rust from happening. Weathering steel, as it's called, allows for steel structures that don't need as much maintenance.

Someone else realised that steel and concrete have the same coefficient of expansion with heat. And that if you combine steel and concrete you get the best of both. Without steel reinforced concrete. The built environment would be very different.

39/n

It's all technology. It surrounds us all. From the clothes we wear, the tools we used, or the very buildings in which we live. Without these technologies, we would not have our modern world (feature or bug, you decide).

So please, stop thinking of technology as only stuff with electronics. There's technology all around us. We just don't generally notice most of it.

Thank you for reading all this way (if you have). Hopefully you've learned something & look at the works a little different

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