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Background: I'm toying with the idea of an alternate Earth that never developed wireless technologies. Radio transmitters, Wi-Fi, etc... were never invented, meaning that light-speed communication is practically nonexistent. One nation progressed into the modern world with an extreme grasp on chemistry, synthesizing artifical hydrocarbons and hyper-efficient batteries. Without understanding of the electromagnetic spectrum, however, they have no means of instant digital communication.

Question: In a city with no need for underground power lines, the only utility that reaches homes is the tap water line. What are some viable ways that chemists can encode data into tap water itself, replicating widespread communication like radio or television without the need for wireless signals?

Note: I'm looking for answers that fit a "chemistry" theme, because my world is divided up into factions who have monopolies on different areas of science. One faction does know how to utilize the electromagnetic spectrum, and another does know how to encode data into DNA strands. This nation has exclusively chemistry going for it, and nothing else in particular.

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  • $\begingroup$ Do you mean by using the water as an electrical conductor or a more mechanical means? $\endgroup$ – Samuel Mar 21 '18 at 3:21
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    $\begingroup$ Handwavium, just like the batteries, nutrition, powerful neutralzers and artificial hydrocarbons. $\endgroup$ – RonJohn Mar 21 '18 at 3:21
  • $\begingroup$ @Samuel I'm looking for kind of a theme that links all the technology of this country together. If every development is based on a romanticized version of chemistry, how can I apply that to data transfer? $\endgroup$ – user10933 Mar 21 '18 at 3:28
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    $\begingroup$ Why? You already have electricity Trying to convert electricity into chemicals for transmission and then back into electricity for said speaker or TV screen would be incredibly slow and inefficient. The transmission speed would be dictated by the speed of the water flow. $\endgroup$ – Thorne Mar 21 '18 at 4:03
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    $\begingroup$ Steampunk cogs would be faster and more efficient. $\endgroup$ – Thorne Mar 21 '18 at 4:04
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There are projects looking at ways to use the water column within a pipe to acoustically transmit data.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/ett.3219

The working principle of the node is that it magnetically clips onto a pipe or valve, and either generates an acoustic vibration (transmitter mode) or analyzes the vibration of the pipe (receiver mode). In transmitter mode, the microcontroller generates a waveform (analog voltage), which is amplified by the haptic driver and applied to the macrofiber composite (MFC) piezo. Acoustic vibrations induced by the piezo are then transferred via the magnetic resonator into the pipe or valve, and relayed through the water column to a receiving node. Every node in the system can be constructed identically. Nodes can switch between the transmitter and receiver modes. Each node costs under US $100 at unit price, addressing the requirement to keep costs low.

Vibrations will travel a long way through a contiguous water column - this is why you can hear things at great distances underwater. You could send vibrations down the pipe to carry your digital data. It could be like a fax message, or morse code depending on what kind of resolution your receiver has.

Also note that these nodes can switch between receiver and transmitter. They can act as relay stations, receiving a message and then retransmitting it along. This can compensate for signal loss with distance.

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    $\begingroup$ Awesome. Also, sound travels faster in water than in air, so that's another reason to use water rathen than empty pipes to transmit data. $\endgroup$ – Renan Mar 21 '18 at 14:13
  • $\begingroup$ Some numbers: the speed of sound on air at sea level is in the order of 330 meters per second. In fresh water, it is around 1480 meters per second, and around +20 m/s faster in seawater. en.wikipedia.org/wiki/Speed_of_sound#Speed_of_sound_in_liquids $\endgroup$ – Renan Mar 21 '18 at 14:15
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The problem with using chemicals in water for digital information is that the chemicals would need to arrive at the tap in the same order they were sent. While this will sort of occur during conventional fluid dynamics, the loss of precision would mean that you'd not be working with a very high bandwidth on this at all.

That said, there is a solution; Laminar Flow. In fluid dynamics, laminar flow is the liquid equivalent of lasers. It affords coherent flow of fluids through things like water pipes and the like, and as I understand it many of the fire fighting nozzles for hoses are designed to generate laminar flow to make the water go further as a coherent stream from the nozzle than would normally be possible before it turns into a spray or mist.

You could use chemicals in this flow, but if you want to preserve the ability to drink the water at the same time, you could experiment with some form of pulsed laminar flow from the tap. Water glasses would fill but the water would be coming out in very fast pulses, which if you get the system working well may look similar to a conventional flow of water in any event. BUT, a sensitive pressure valve may be able to read the intermittent slight drops in pressure as 0s and 1s, allowing you to transmit data over the (tap) line.

To be sure, this would require a very sophisticated plumbing system to be in place, but the reality is that without laminar flow, your chances of putting the chemical sequence together at the other end would be practically non-existent. Additionally, pulsed laminar flow could be detected via a pressure valve on a constant basis, meaning that so long as you have water flowing from a single tap (designed for this purpose) you can record the data being transmitted. That water could then be stored for sending back to a central location, allowing for a user to transmit data back via a 'return' pipe. It would also mean that you should (in theory at least) still be able to use your plumbing system for its original intent as well, which is dispensing water for household use.

I want to stress that I know there are some BIG holes in this model. Drawing a bath may well alter the pressure on the valve (although it should be able to detect relative pressure pulses), water pressure on the return trip may not be very high (unless you pump it into a gravity feed tank, kind of like a water antenna) and unless you have a separate supply pipe for every home, you're going to have a massively difficult time doing the equivalent of IP routing. Still, if it's all you've got, these problems are really engineering matters that would get solved with sufficient application of ingenuity.

All in all, water transmission would be difficult, but not impossible.

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  • $\begingroup$ Even in laminar flow, the velocity of the water in the pipe is not uniform, the layer closest to the pipe wall will be much slower than that of the central channel. $\endgroup$ – Gary Walker Mar 21 '18 at 17:18
  • $\begingroup$ Hi @GaryWalker you're right; that is one of those BIG holes in the model. It's not a perfect system I'm proposing here, or even completely science based. This answer should be read as being speculative. $\endgroup$ – Tim B II Mar 21 '18 at 22:28
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If you're transferring information on a medium that doesn't effectively limit packet loss, your message has to be repeated many, many times. This would either take forever, or require encoding individual parts of the liquid itself.

The lowest-hanging fruit would be genetic encoding like DNA/RNA being placed in the medium to be 'drawn out', but this only slightly meshes with your theme.

My favorite (but a bit more difficult) means of communication could come in the form of complex covalent bonds acting like kanji (characters standing for words) along with one or more cipher molecules used to arrange/structure the other molecules to make a cogent thought.

So you might have a page molecule saying to look at paragraph molecule A, then paragraph molecule B, etc. And paragraph module A has reference to the order of kanji in the paragraph. Then you'd include every kanji in the document to be assembled.

This would much better fit with the alchemy theme, but wouldn't allow for different messages in a short period of time or back-and-forth messages. It'd work best as a passive news system: Flood today's news in the pipes from 9-5, and then flush the pipes for a few hours so you can start again tomorrow.

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As my first proposal stepped on faction toes- for which I apologize-I offer another solution. https://news.wisc.edu/chemical-dial-controls-attraction-between-water-repelling-molecules/ see link for full details. you said digital and i thought on or off. a chemical coating around a small sphere that makes it on or off according to your whim and a flow bypass triggered by a membrane allowing the spheres to interact with another receptor membrane at their destination. simple compounds could be deposited on the receptor or on the spheres before making a round trip back to the sender. Slow but definitely digital information transfer and more with some imagination. A chemical solution presented.

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  • $\begingroup$ Not the way blood cells carry oxygen. - Data should be encoded in "junk" segments of DNA that the living plankton cells never naturally express, but that can be decoded from the pureed cells via a very fast DNA analysis process. $\endgroup$ – A. I. Breveleri Mar 21 '18 at 5:23
  • $\begingroup$ @A. I. Breveleri But, does that DNA analysis process use a computer with electronic components? You start to run into a "turtles all the way down" problem. $\endgroup$ – Muuski Mar 21 '18 at 14:33
  • $\begingroup$ It is possible to build a very powerful computer without any understanding of electromagnetism whatsoever. If they understand chemistry then they understand materials enough to create transistors. Electronic components do not require wireless technologies. $\endgroup$ – A. I. Breveleri Mar 21 '18 at 15:37
  • $\begingroup$ Yeah, they have computers. I'm assuming computation is a universally-understood concept in my world; this is specifically a question about broadcasting. And I'd love to use bioengineering, but there's a different faction who already has a monopoly on biotech. $\endgroup$ – user10933 Mar 21 '18 at 20:43

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