incredible

There's a book called How to Invent Everything: A Survival Guide for the Stranded Time Traveler that covers this stuff. Don't think it's comprehensive enough to actually invent everything from scratch, but still a fun read.
- By Ryan North, the author of Dinosaur Comics! He based the book on a time travel survival guide he published and made into a T-shirt.
- Just finished it. Thank you!

Skip electricity. That doesn't matter until you can make reliable turbines with copper and magnets. Go to steam power first. It can move things. Which will speed up delivery of copper and magnets. But also teach them to plant trees. Every tree removed to smelt and power a steam engine needs to have three more planted. You could start greening the Sahara before umit even starts collapsing. "he sure had this steam thing figured out. I guess we will forgive him for all these useless trees".
- A great master plan to prevent climate change, although the industrial revolution will start 2000 years earlier, so I'm not sure it matters
  
  The sooner it starts the sooner I can get back. :)
- I read they knew about steam power for a long time but couldn't make the engines / containers / doohickies strong enough to contain the pressure.
  
  That's true, it was cannon technology that allowed steam engines to be created
- Yes, electricity would be magic for medieval (and prior) people. Spells trouble for you.
  But no, Steam... the principle was known and seldom used by ancient greeces and egypts already, but they couldn't really utilize it, because metallurgy wasn't there yet.
  And Sahara was almost green 1000+ years ago, lots of oases.
- What is the 'Carnot cycle'? - I don't know
- Is there a guide for DIY steam engines?
  
  Boil water in a closed system that uses steam to move a paddle on the inside that is on the same shaft as a wheel on the outside. That's the basics. Everything else is just variations on the theme. The higher the pressure the faster it goes and more torque you get.
  
  Pop Pop boats are really simple steam engine systems.
- Go to steam power first. It can move things
  They had steam power over 2000 years ago, they used it in temples and as toys to amuse the rich.
  Slaves could move things, and were much cheaper.
  
  They might have had it, but they didn't use it right
- The problem with this is that you assume that wood is the best fuel source for steam. Very quickly you would realize that coal is far more energy dense than just about anything except nuclear fission. Planting trees is still a good idea though, but wood as fuel is utter shite on any large application.
  
  When starting out you don't need the most efficient. You need what's available. And I'd rather not reinvent coal mining and whaling.

Electricity is easy to make though... a couple magnets and some copper wire.
- Easy materials to get from your local 1st century hardware store
  
  they'd probably have non-shitty copper by then, but magnets? thems witchcraft
  
  Copper wire: yes. Magnets, get lodestones
  
  You can literally mine lodestone and copper. Ancient people have mined those two things since antiquity. Where do you think it comes from now? Fairies?
- You can induce voltage on more than just copper you know. Or maybe you don't know. You probably don't know.
- Magnets, how do they work?

I read a sci-fi short story about that once. A scientist brings back a guy from the future, but the guy either can't explain how things work or does so using a vocabulary the scientist doesn't understand.
It was like:
"How do you make a teleporter?"
"Well you take a zargnix and put it on top of a floon."
- Actually the floon goes inside the zargnix. Duh.
  
  Aren't you thinking of the floov compensation harpon? People typically get them confused.
- where did read it? do you have a link?
  
  Years and years ago in some anthology or other. Sci-fi short stories are my favorite literary medium, so I've read far more than I could count. I wish I could tell you the name or the author.

Pretty much everyone in this thread needs to go read Ryan North's book "How to Invent Everything: A Survival Guide for the Stranded Time Traveler".
https://www.amazon.com/How-Invent-Everything-Survival-Stranded/dp/0735220158/
Or, if you don't have time, just print this out and keep it with you at all times:
- "Wrap some copper wire around a core"
  Mr. Stegosaurus, please point out the nearest refinery so I can grab some copper wire.
- I don't know if this helps. It's enough to know you're fucked.
- I find this to be brilliant.
- I've been meaning to buy this! Does he have a section on how to handle no one speaking your language?
- My biggest issue with this is the flight part - it's a counterintuitive explanation that doesn't really explain how to make the flight work. It's not technically wrong, and if you trace that cross-section you will get a working aerofoil. However, you can't make the Wright Flyer on that explanation, or in fact any of the early aeroplanes that were constructed with simple fabric stretched between wooden frames.
  A far more useful and intuitive explanation is that planes fly by flow-turning, basically the interaction between the aerofoil and the air turns the air in one direction, which pushes the aerofoil in the other. This also means the air below will end up slower than the air on top, which will create a pressure differential. Either of these methods can completely describe how flight works.
  Also, a plane isn't just two aerofoils attached to a central body. Early planes were at least biplanes, and you need horizontal and vertical stabilisers to have full control. You need flaps that give you pitch, yaw and roll, and you need the centre-of-mass - the point where it balances - to be in front of the centre of pressure. That means you need the stabilisers to be at the back to keep the plane stable like a dart.
  This isn't just a "well akshually", although it sort of is. If you tried to follow the advice as-written and didn't know this, there's a good chance you'd end up on the long list of people killed by their own inventions. Actually, I suspect most of these explanations give you just enough information to kill yourself but not really enough to actually make any of them work from first principles.

Me: The opposite of B, the opposite of B, plus or minus a square root...
Them: What does that mean?
Me: I have no idea.
- X equals negative b, plus or minus the square root, of b squared minus 4 a c, all over 2 a
  Thanks a lot. Now that song is stuck in my head.

I feel like you could still give science a head start by giving them rough ideas of how things work, like penicillin and steam power and whatnot
Even if you don't know all the ins and puts you can give them something to go off of to develop the technology faster
- If you couldn't prove it, things probably wouldn't go well for you.
  
  Even if you could prove it, it would still go badly in a lot of places in a lot of times.
- "Science" ≠ Technology!
  If you give them the technology without giving them stuff like empiricism and cultural acceptance of critical thinking, they'll just worship it like any other faith, and stagnate for the next thousand years.
  Inversely, you don't even need to give them too much technology, because if you just give them stuff like evidence-based medicine, the printing press, rigorous experimentation and reproducibility, and a couple institutes dedicated to the craft, plus a couple starting points, then they'll figure it on their own soon enough (assuming an overall stable civilization).
  
  Most likely, people would consider you to be another wacko shouting at passersby.
  Or even more likely, you drink some stanky water that your body doesn't know how to deal with and die within the first week.
- Ayyyyy gotta love some quick typing typos lol

This reminds me of Dara O'Briain's bit about going back in time and thinking you'll impress the greatest minds in history with your future knowledge but it falls apart quickly.
https://www.youtube.com/watch?v=BVxOb8-d7Ic

I think it would actually be easier to wow people than people think. You'd just have to focus on older technology rather than completely modern stuff. If you know that steam engines are a thing, and even vaguely how they work, you can build the king a pump to get running water without having to run massive aqueducts, or a crane to build his massive projects, or any number of directly useful things. An understanding of basic germ theory could set you up to be the best doctor in the world. Or even just a bicycle would probably be quite useful to get around without a horse, and I'm sure anyone could make a rough mockup of a bike.
- I think you underestimate what it takes to get modern plumbing water tight and easy to manage. Threading, clean threading, teflon, and easy to manage plastic pipes, have all been invented within the last 200 years. Mostly, the last 80.
  and that's just the literal direct infrastructure within a house. Water towers are not simple. Underground pipes are not simple. Civil plumbing and waste management is not simple.
  
  Yeah, even electricity is easy to explain. You just rotate a high quality magnet within a coil of thin high quality copper wire. Easy.
  Problems are:
  How do you make a high quality magnet?
  How do you purify copper fine enough?
  How do you make a spool of the copper wire?
  How do you make the bearings for the shaft?
  
  and that’s just the literal direct infrastructure within a house. Water towers are not simple. Underground pipes are not simple. Civil plumbing and waste management is not simple.
  The romans did manage to build a nice system, tho. I hear the persians also managed one.
  
  But it doesn't have to be up to modern standards, and certainly doesn't have to be with modern materials. Get the local cooper to make your pipes and reservoir with pitch-sealed wood. Or make it out of stone, or cast copper, or whatever they use to store water anyway. If it's Roman or post-Roman, they've already had some experience with running water anyway, that wouldn't be the impressive bit.
  Threading and such is mostly useful for mass-manufacturing standard pipes and using it everywhere, but at least at first you'd just be doing it for a rich/powerful person or two, where you could do something labour-intensive and unscalable.
  I'm not saying that you would get a perfect, modern system straight away, but if you can convince the people to give you the benefit of the doubt through a prototype or two, you could make something that works well enough. That would be what I'd be concerned about, even if you can magic away the language barrier, they'd likely just think you're mad.
- I can't even draw a bike.
- Can you build a metal laythe? Can you build one precise enough for a pump?
  Can you get rubber or silicone for gaskets?
  There are a lot of problems
  
  You don't need to be super accurate for a basic pump. If you know the design you can get medieval blacksmiths to make the parts for you with close enough accuracy.
  
  If you're asking if I know how to rub 3 plates together the answer is yes!
- Steam engines are more complicated than people seem to think. There’s more to it than just boiling some water and voila! They’re pretty much useless without a governor. How many people know how to make this crucial component?
  https://en.m.wikipedia.org/wiki/Centrifugal_governor

Go back in time with a 4th grade science book from 1997 and be a fucking wizard.
- This was the (side) plot of Army of Darkness
  
  He basically was a wizard in Army of Darkness. He made a robot hand in a blacksmith's shop.

You could probably make explosives from manure. Use that to conquer a small community and make yourself the leader. And start a rebellion against the local lord and become the king. Then you have the resources and slaves to find copper and magnets and shit. Problem is the massive language barrier. Their language is just gibberish to us and vice versa.
- Then you have the resources and slaves to find... magnets and shit.
  They already had magic in the old days though. They used to have to fight dragons and witches and shit back then.
  
  You'd kill them off before they'd get a chance, though
- And all the germs we carry to which we're already immune.
  
  They'd actually kill off any would be time traveling conqueror pretty quickly with smallpox.
- I don't want to type out that thing you said, because I don't want to end up on a list, but idk how to do that.
  
  The Anarchist Cookbook can show you the way.
- Man Makes Dynamite Out of His Own Pee (It's Cody)

If you paid attention in high school you could bring mathematics up to about the 17th century, if you really paid attention you could even grab some stuff from the 20th (wtf vectors why did you take so long to figure out?) and the 19th.
Plus there is just so much basic stuff you know. Used boiled and sealed water to clean a wound. Bleeding a person only makes them feel good for a bit and does nothing else. Steel in cement makes cement better. Or in the case of this picture zinc and copper and lemon.
- anything about sanitary practices faces a massive barrier of getting people to accept and implement it. I could tell ancient doctors to wash their hands, but the first time someone tried that in actual history they laughed in his face.
  
  Monarchs cares about power. Give the ruler some more metallurgy or siege engines first, so you have their favour. Then split the Royal Court's physicians into two groups, one that washes their hands, and one that doesn't. Do the same for leeches, bloodletting, hydration, etc. It'll be hard to argue with the resulting death rates. And in the long run, you'll have a much bigger impact by introducing empricism/A-B testing/evidence-based medicine than any one thing specific thing you could have done.
  
  But on the other hand, there's a decent chance of you worked hard enough, they could probably get there at least a century or two after your death.
- That's assuming you don't either kill them all off with your 21st century germs and/or be killed because the church doesn't like you.
  
  Yes, most of my plans for myself run on the unspoken assumption that I am not dead.
  
  Or drown because the Pythagoreans hate your guts
- People were so moronic back then, even more than today, saying any one of those things would have you burned like a witch 😂
  
  Non-historian detected
  
  You should research how people actually were. It will do a lot for your opinion of human nature.
  It makes me happy realizing that im not better than people in ancient Egypt.
- Steel, like the strong metal for weapons? You want how much of it, and throw it where? And what's a "lemon"?
  
  They had citrus fruits. It wasn't a mind bending concept.
- Steel reenforcement of old European concrete would have been disastrous. They used limestone in the aggregate and cement and it would have eaten the steel in a decade or two.
  
  Ok fine but the smallpox would have killed me before that happens

You know, a fun project would be compiling an instruction book for elevating/fast forwarding technology just in case someone does get sent back in time.
- We could send them to the end of the galaxy to compile an encyclopedia of all human knowledge but they'd secretly be there to start the next iteration of civilization through the foolproof strategy of not doing much and just letting the pre-calculated history take its course.
  
  Or we could just fly around in space on a religious drug trip until we find a planet with some worms that make some freaken killer drugs.
  
  Hail Seldon
  
  You just gave Hari an idea...
- I want this for when climate collapse destroys modern civilization and the survivors are left to rebuild society without the benefit of global supply chains or information infrastructure.
  
  Download wikipedia. Its not only possible, but its actually easy. There are some apps for it, see Kiwix and https://en.wikipedia.org/wiki/Wikipedia:Database_download. Just bring a couple phones and some solar panels for when they run out of charge.
- There's a couple of books that do this: How to Invent Everything, and How Rebuild Civilization.
- Clock of the long now
  
  I don't know why they put just one zero in front of years. That just makes the clock slightly longer, and it's still insignificant in the grand scheme of things.
  02023 in years only is good until 99999, then you'd need to prepend another zero.

I'm impressed at the strength of the guy's upper arm that he's sitting on.

I'd actually be able to teach them how to make it if they have copper and magnets, since I know how to make a simple generator. They'd be SOL on how to use it though, because I don't know how to make something entirely from raw materials that would require electricity. Which means they also wouldn't know I am creating it with the generator... 🤔 Uh... Shit.
This is actually kinda wild to think about and I hadn't considered it before. Making electricity is easy! Using it is actually more complicated.
- You could give people a mild shock. "Here. Hold these while I crank this thingy." Could be good for some lulz. Or get you burned as a witch.
  
  I mean, the Baghdad Battery's pretty old. We've had electricity for a while, just nobody knew what it was or how to use it. Just like us now.
- Making an "ouch" device or basic heater is something I could do.
  Even a battery I could make a simple alumium air battery cell. Or lemon battery. But I'd be viewed like a sorcerer asking for foreign ingredients like salt, aluminum, copper and zinc.
  
  I swear the Americans remove another letter from the word aluminium every time I look away
  
  Aluminum would be nearly impossible to obtain, it's actually my preferred grab in a hypothetical "You're going back in time and can take one thing" situation
  
  Depends on how far back and where you went. Whoever made the Baghdad Battery probably wouldn't even be impressed.
- Joe Rogan had a good line back before he became... whatever he is now. Anyways, the line is "if I dropped you off on a deserted island, how long before you could send me an email?"
  
  Why is email the metric?
- You can make a generator.. so then stretch wires to a distance and put a motor on the end of it (similar to the generator). Basically blow their minds in that you could transfer power over distance without a mechanical coupling.

Just spin a magnet in a copper coil.
BOOM! Electricity.
- How do you make a magnet?
  
  Expose molten ferrous metal to ... a magnet.
  Welp...
  Magnets are created by running an electrical current through a material, so there is no need to have a 'first magnet'. This is happening 'naturally' in the earth core, in the sun, and in other stars. (https://physics.stackexchange.com/questions/565245/how-was-the-first-magnet-made)
  So you need to look around and find some magic rocks.
  Natural magnets, called "lodestones", were found in iron ores (magnetite) from the ancient region of Magnesia, hence the name "Magnet". (https://physics.stackexchange.com/questions/615500/how-did-magnets-first-come-about)
  Maybe the sword with the stone was just a big lodestone with a sword sized hole in it. Just throwing that out there.
  And one more cool fact...
  Based on his discovery of an Olmec artifact (a shaped and grooved magnetic bar) in North America, astronomer John Carlson suggests that lodestone may have been used by the Olmec more than a thousand years prior to the Chinese discovery.[23] Carlson speculates that the Olmecs, for astrological or geomantic purposes, used similar artifacts as a directional device, or to orient their temples, the dwellings of the living, or the interments of the dead.[23] Detailed analysis of the Olmec artifact revealed that the "bar" was composed of hematite with titanium lamellae of Fe2–xTixO3 that accounted for the anomalous remanent magnetism of the artifact.[24] (https://en.wikipedia.org/wiki/Lodestone)
  
  Coil a lead wire around a big full metal cylinder (must be magnetizable) and attach one end to a big ass antenna and the other in the ground, then wait for lightning to strike the antenna. Although the amount of power will probably melt everything.
  Or you can just read this: https://sciencing.com/make-super-strong-permanent-magnets-6520830.html
  
  With electricity, duh
  
  Fucking magnets

Forget mathematics, logic and philosophy. Teach them about Jeebus and establish a solid patriarchy. After that make a shitload of McDonald's and Facebook.
- How dare you not Starbucks their Walmarts! Google is going to Microsoft you!

We learn how to generate electricity in Secondary School, it's pretty simple and fundamental to understanding electromagnetism, and it underpins our whole civilisation's existence. Surely you'd remember that?
- Yeh just gimme a cat fur and a plastic rod. I'll demonstrate electrostatic on a balloon.
  
  Or just almost touch a TV and your hairs will go there.

- One of the newest Brandon Sanderson books "The Frugal Wizard's Guide to Surviving Medieval England" has a similar premise. It's a novel so not a how-to guide so to speak, but parts of it are an in-world manual on how to survive in a medieval alternate dimension.

You'd still probably manage to get by offering services as an accountant. Illiteracy was the norm the world over for most of history, good math understanding was even rarer.
- Yeah, but no one gave a shit unless you read Latin. Nobody cared if you could read and write in those weird grunts the Angles and Saxons made.
  
  Also, are you wearing pants? Damn unwashed barbarian!

trebuchets now exist in 3500 BC
- gun powder enters the chat
  Fossil Fuels is typing...

Not my idea, but sometimes it's just enough to listen to "crazy" people. They might not know what to do with wire seemingly spinning itself, but you will have much better idea what can be created with it. RIP Terry Pratchett

In the vast and intricate web of human understanding, where knowledge weaves its delicate dance with experience, I find myself positioned, albeit humbly, at a nexus of comprehension. This vantage point, carved out through relentless introspection and a profound engagement with the world, allows me to unravel, elucidate, and perhaps even, in some modest measure, illuminate the topic at hand with a level of profundity that few might grasp.
Turning our gaze to the curious and somewhat perplexing phenomena of temporal voyages, or what is colloquially understood as 'time travel', we encounter a host of philosophical and practical quandaries. Within this entangled morass, there arises a lamentable observation: the entities, or perhaps the emissaries, dispatched from the annals of future chronology to our present juncture, don’t always seem to represent the pinnacle of their epoch’s capabilities. The Jungian shadows of the future, one might muse, often obscure the brightest luminaries, leading to a situation where we are not always graced with the presence of the 'best' or most optimal representatives of these temporal sojourners. In simpler terms, they aren’t always sending their paragons back in time, but rather, we find ourselves navigating the intricate dance with a mosaic of characters, each embodying a unique facet of their origin's potentialities.

No problem, just tell them to ask from Baghdad, they should know where it is. :) A jug of wine or vinegar, one electrode of iron, another made of copper, voila... the Baghdad battery.
- I have nothing to add to this comment. I just want to make sure everyone knows that "the Baghdad battery" name goes fucking hard.
- Any conclusive proof that this was used to produce electricity? Consensus seems to be that it wasn't.
  
  No conclusive proof. It didn't have a passthrough for one electrode of the two. It did have remains of acid inside and corrosion on the electrodes. One can speculate whether it was an experimental device, a faulty device or what exactly happened (one alchemist trying to replicate another's secrets?).
  To add insult to the injury, it was lost or stolen during the war in 2003, so more analysis can't be done until it gets re-discovered. :o

If this concept intrigues you, I recommend watching Dr. Stone.
- Master of never used science.

But first, you need all the guns (and other modern weaponry) to gun down anyone trying to kill you. Might be useful to make them listen to you as well.
- Hopefully they will understand modern day English
- found the redneck.
  
  apparently common sense survival in an unfamiliar hostile place is a sign of being a redneck

I take these two completely different looking rocks, dig a small hole between them, and pee in the gap.
Electrolytes! It's what every caveman craves!

- Before or after you cause a pandemic with our modern germs and illness?
  
  I think you'd be more likely to be the one infected
- Unlikely. It looks like this would be around the time when magi were about.

Couldn't you just rub something with wool and demonstrate static electricity that way?
- And then what?
  
  Profit?
  
  The prompt is fulfilled, cut to credits
- I think they knew about that already.

The deconstruction I didn't know I needed

This is kinda the premise of Brandon Sanderson's new book The Frugal Wizard's Handbook to Surviving Medieval England lol, I recommend it! It's one of the secret project Kickstarter books so it might not be on regular shelves yet but it should be soon, and the audiobook is out for sure

won't going back in time spread coronavirus and other diseases?
- More likely you'd catch the bubonic plague and die within a few months
  
  We're the descendants of bubonic plague survivors. They haven't even gone through last year's flu.
- Only if you are sick at the time you go back. The occasional 1 1/2 viruses aren't going to survive long enough to infect anyone.

Relevant
- Same tbh. Christian homeschooling is very common where I live. It's borderline abuse imo

The best a human can do without the knowledge of how it fully works is be able to push them in the right direction. Depending how far back you go you'd either be considered a god or a witch 🤣. Humans man we are strange.

Eh, grab a big fur and a metal rod of some sort...you get static electricity that way.
- Tell your mom I said Hi btw.

If you want to get stuff going, what you have to do is help past people produce precision tools. Then you can build interesting machines and make use of electricity.

@neutralbipolar2
That's what youtube is for ...
scientific curiosity is very healthy

I thought everyone learned how to make electricity at home with a potato at school...

https://www.youtube.com/watch?v=QXy3uII-xn0

Just bring a Machinery's Handbook with you and you will be a god.

Oh you mean the stuff that comes from electrum? We got that…

When was the water wheel invented? pretty much everyone know how they work.