Dehydrated Water

[Photon Guy]

I've seen in science fiction this special product called "dehydrated water." What it consists of is simply a can of hydrogen so that if you're in an environment that has an atmosphere with oxygen (such as what we have on Earth) when you let the hydrogen out it bonds with the oxygen in the air and makes water. The idea is that it's supposed to enable you to have access to water when you need it without having to lug around lots of water. Such a can would be smaller than a canteen and would certainly be smaller than a whole water tank, and yet it would contain enough hydrogen to be able to produce tubs full of water by bonding with oxygen. 

Anyway, Im wondering what the possibility of having something like that can be in real life. We have been able to duplicate some stuff from science fiction such as the communicators from Star Trek that we now have in the form of smart phones, so how about something like this? What are the possibilities?

[exchemist]

1 hour ago, Photon Guy said:

I've seen in science fiction this special product called "dehydrated water." What it consists of is simply a can of hydrogen so that if you're in an environment that has an atmosphere with oxygen (such as what we have on Earth) when you let the hydrogen out it bonds with the oxygen in the air and makes water. The idea is that it's supposed to enable you to have access to water when you need it without having to lug around lots of water. Such a can would be smaller than a canteen and would certainly be smaller than a whole water tank, and yet it would contain enough hydrogen to be able to produce tubs full of water by bonding with oxygen. 

Anyway, Im wondering what the possibility of having something like that can be in real life. We have been able to duplicate some stuff from science fiction such as the communicators from Star Trek that we now have in the form of smart phones, so how about something like this? What are the possibilities?

"Simply a can of hydrogen", eh? 

To get 18g of water would require 45l of hydrogen at atmospheric pressure and room temperature. So for a litre of drinking water you would need 2.4 m³ hydrogen at STP. You would compress it, of course, perhaps to 200bar, in which case the volume per litre of water would be 12l. But you would then have the weight of the pressure tank and the conversion catalyst, or burner + condenser, to react the hydrogen with atmospheric oxygen. I find it hard to imagine the weight of all this kit would be less than 1kg, which would be the weight of a litre of water.  So I don't see this working out in practice.   

Edited July 13, 2023 by exchemist

[swansont]

1 hour ago, Photon Guy said:

I've seen in science fiction this special product called "dehydrated water." What it consists of is simply a can of hydrogen so that if you're in an environment that has an atmosphere with oxygen (such as what we have on Earth) when you let the hydrogen out it bonds with the oxygen in the air and makes water. The idea is that it's supposed to enable you to have access to water when you need it without having to lug around lots of water. Such a can would be smaller than a canteen and would certainly be smaller than a whole water tank, and yet it would contain enough hydrogen to be able to produce tubs full of water by bonding with oxygen. 

A can of hydrogen wouldn’t contain all that much; it’s a gas

(and I see that exchemist has just responded along these lines, so I won’t duplicate the effort)

1 hour ago, Photon Guy said:

Anyway, Im wondering what the possibility of having something like that can be in real life. We have been able to duplicate some stuff from science fiction such as the communicators from Star Trek that we now have in the form of smart phones, so how about something like this? What are the possibilities?

We already had wireless voice communication, decades before Star Trek, so I reject the notion that this “came from science fiction”

[Photon Guy]

7 hours ago, exchemist said:

"Simply a can of hydrogen", eh? 

To get 18g of water would require 45l of hydrogen at atmospheric pressure and room temperature. So for a litre of drinking water you would need 2.4 m³ hydrogen at STP. You would compress it, of course, perhaps to 200bar, in which case the volume per litre of water would be 12l. But you would then have the weight of the pressure tank and the conversion catalyst, or burner + condenser, to react the hydrogen with atmospheric oxygen. I find it hard to imagine the weight of all this kit would be less than 1kg, which would be the weight of a litre of water.  So I don't see this working out in practice.   

Well it was science fiction so there you have it. Anyway, lets say you take a cup of drinking water and take out all the oxygen atoms. With the hydrogen that's left, how hard would it be to get it to bond with the oxygen that is readily available in the Earth's atmosphere so that you get back your one cup of drinking water? 

7 hours ago, swansont said:

We already had wireless voice communication, decades before Star Trek, so I reject the notion that this “came from science fiction”

But we didn't have any wireless communication devices that could work at the range at which the Star Trek communicators could work while being the same size or smaller than the communicators, not until we had small cell phones. 

And Im talking Star Trek TOS of course. 

[John Cuthber]

3 hours ago, Photon Guy said:

With the hydrogen that's left, how hard would it be to get it to bond with the oxygen that is readily available in the Earth's atmosphere

     Very easy.

A can of compressed hydrogen with a catalyst would be a better weapon than a water supply.

[swansont]

10 hours ago, Photon Guy said:

But we didn't have any wireless communication devices that could work at the range at which the Star Trek communicators could work while being the same size or smaller than the communicators, not until we had small cell phones. 

And Im talking Star Trek TOS of course. 

But that’s just an extrapolation of the technology. It’s not like the idea required ST to move it forward.

[zapatos]

11 hours ago, Photon Guy said:

But we didn't have any wireless communication devices that could work at the range at which the Star Trek communicators could work while being the same size or smaller than the communicators, not until we had small cell phones. 

 

Cell phones might reach a tower 45 miles away. In 1901 Marconi received a radio message across the Atlantic.

[swansont]

1 hour ago, zapatos said:

Cell phones might reach a tower 45 miles away. In 1901 Marconi received a radio message across the Atlantic.

Marconi didn’t have to limit his transmission power owing to government regulation (and he wasn’t sending a voice signal). But all you have to do is look at the trajectory - the first US patent for a mobile phone was 1908. The first car phone was used in 1946. Cell phone development was probably ongoing when ST first aired.

[studiot]

22 hours ago, Photon Guy said:

I've seen in science fiction this special product called "dehydrated water." What it consists of is simply a can of hydrogen so that if you're in an environment that has an atmosphere with oxygen (such as what we have on Earth) when you let the hydrogen out it bonds with the oxygen in the air and makes water. The idea is that it's supposed to enable you to have access to water when you need it without having to lug around lots of water. Such a can would be smaller than a canteen and would certainly be smaller than a whole water tank, and yet it would contain enough hydrogen to be able to produce tubs full of water by bonding with oxygen. 

Anyway, Im wondering what the possibility of having something like that can be in real life. We have been able to duplicate some stuff from science fiction such as the communicators from Star Trek that we now have in the form of smart phones, so how about something like this? What are the possibilities?

Interesting idea, but exchemist has done and exhaustive job of demonstrating it's impracticability.  +1

However the idea of only carting 2g of hydrogen and not the extra 16g of oxygen with you, but finding it already there is one of these theoretically attractive but practically less useful, so should not be ridiculed.

Some similar was shown in that great film "The Martian", as was the danger og burning hydrogen to get water.

[exchemist]

14 minutes ago, studiot said:

Interesting idea, but exchemist has done and exhaustive job of demonstrating it's impracticability.  +1

However the idea of only carting 2g of hydrogen and not the extra 16g of oxygen with you, but finding it already there is one of these theoretically attractive but practically less useful, so should not be ridiculed.

Some similar was shown in that great film "The Martian", as was the danger og burning hydrogen to get water.

Yes the basic problem is that, while hydrogen is light, it is a gas that can't be liquefied under pressure (at normal temperatures), as it is above its critical temperature. So you have an intractable volume problem.

[Photon Guy]

4 hours ago, swansont said:

But that’s just an extrapolation of the technology. It’s not like the idea required ST to move it forward.

The point is we didn't have anything back then that could function just like the communicators in Star Trek where you could communicate with an orbiting spacecraft while at the same time being able to fit in your pocket. Today we do, they're called satellite phones.

Sure, we had walkie talkies back in the 60s but they were these big huge things that you couldn't fit in your pocket and that had nowhere near the range of the communicator. Now we do have real Star Trek communicators. 

3 hours ago, zapatos said:

Cell phones might reach a tower 45 miles away. In 1901 Marconi received a radio message across the Atlantic.

But the 1901 Marconi is way too big to fit in your pocket. And we do have phones today that can communicate with orbiting spacecraft (as the Star Trek communicators could) and that can fit in your pocket in the form of satellite phones. 

2 hours ago, swansont said:

Cell phone development was probably ongoing when ST first aired.

Be that as it may we didn't have the technology back then, we do now. 

[zapatos]

42 minutes ago, Photon Guy said:

But the 1901 Marconi is way too big to fit in your pocket. And we do have phones today that can communicate with orbiting spacecraft (as the Star Trek communicators could) and that can fit in your pocket in the form of satellite phones. 

I was responding to you comment that said cell phones, not satellite phones.

[swansont]

52 minutes ago, Photon Guy said:

The point is we didn't have anything back then that could function just like the communicators in Star Trek where you could communicate with an orbiting spacecraft while at the same time being able to fit in your pocket. Today we do, they're called satellite phones.

Sure, we had walkie talkies back in the 60s but they were these big huge things that you couldn't fit in your pocket and that had nowhere near the range of the communicator. Now we do have real Star Trek communicators. 

Which we would have regardless of the show. It was set in the future, so naturally they extrapolated from existing technology. What’s interesting is what they got right and what they didn’t. They use data tapes - smaller than the contemporary technology, just like the communicators - but still bound by it. No digital media. No hand-carried high-res displays (no surprise, since that would have been hard to simulate). Almost like the writers just took miniaturization, that was ongoing with transistor technology, to the next step.

 

[Photon Guy]

6 hours ago, studiot said:

Interesting idea, but exchemist has done and exhaustive job of demonstrating it's impracticability.  +1

However the idea of only carting 2g of hydrogen and not the extra 16g of oxygen with you, but finding it already there is one of these theoretically attractive but practically less useful, so should not be ridiculed.

Some similar was shown in that great film "The Martian", as was the danger og burning hydrogen to get water.

 

6 hours ago, exchemist said:

Yes the basic problem is that, while hydrogen is light, it is a gas that can't be liquefied under pressure (at normal temperatures), as it is above its critical temperature. So you have an intractable volume problem.

Well here is the science fiction media where I got the idea of dehydrated water. As I said, it's science fiction. 
https://spacequest.fandom.com/wiki/Dehydrated_Water_(original_version)

4 hours ago, zapatos said:

I was responding to you comment that said cell phones, not satellite phones.

The point is that we have technology today that functions just like the communicators in Star Trek, whether its cell phones or satellite phones the point is we have the technology that at one time only existed in science fiction. 

4 hours ago, swansont said:

Which we would have regardless of the show. It was set in the future, so naturally they extrapolated from existing technology. What’s interesting is what they got right and what they didn’t. They use data tapes - smaller than the contemporary technology, just like the communicators - but still bound by it. No digital media. No hand-carried high-res displays (no surprise, since that would have been hard to simulate). Almost like the writers just took miniaturization, that was ongoing with transistor technology, to the next step.

 

Yes you're probably right that we would have mobile phones that function just like the communicators from Star Trek whether we had Star Trek or not. And yes they do get some stuff right but lots of stuff they don't. Im still waiting for phasers that can be set on stun or kill and which can completely disintegrate an object, transporters where you can almost instantly teleport down to a planet's surface and back or over other vast distances, and warp drive that can break the lightspeed barrier. 

[exchemist]

5 hours ago, Photon Guy said:

 

Well here is the science fiction media where I got the idea of dehydrated water. As I said, it's science fiction. 
https://spacequest.fandom.com/wiki/Dehydrated_Water_(original_version)

OK. So someone had not thought it through, evidently. That happens a lot in some sci-fi, which is why people like me can find some of it rather irritating.

[Moontanman]

"I bought a box of powdered water... I didn't know what to add."

                                                                                        Steven Wright

[pzkpfw]

Has anyone mentioned the water byproduct of hydrogen fuel cells? (not quite what the OP is after, but slightly related.)

https://airandspace.si.edu/collection-objects/fuel-cell-gemini/nasm_A19660646000

https://en.wikipedia.org/wiki/Hydrogen_vehicle

[Photon Guy]

On 7/15/2023 at 2:18 AM, exchemist said:

OK. So someone had not thought it through, evidently. That happens a lot in some sci-fi, which is why people like me can find some of it rather irritating.

There is also the fact that science can "ruin" science fiction. For instance, back when Spiderman first came out the story was that he was bitten by a radioactive spider and that's how he got superpowers. Today, with all the scientific discoveries we made since, we know that if you're bitten by a radioactive spider you will die when the radiation goes through your bloodstream and all. Back then, though, they didn't understand all the stuff about radiation that they do now. 

[swansont]

29 minutes ago, Photon Guy said:

There is also the fact that science can "ruin" science fiction. For instance, back when Spiderman first came out the story was that he was bitten by a radioactive spider and that's how he got superpowers. Today, with all the scientific discoveries we made since, we know that if you're bitten by a radioactive spider you will die when the radiation goes through your bloodstream and all. Back then, though, they didn't understand all the stuff about radiation that they do now. 

Pretty sure we knew that getting bitten by a radioactive spider wouldn’t give you superpowers 60 years ago, and that the spider would die if it was inside a reactor. What is a “radioactive spider” anyway? Merely irradiated? What about it is radioactive, and how, specifically, did that happen? The comic says it “absorbed a fantastic amount of radioactivity” which is good copy but is nonsensical, technically speaking 

[mistermack]

On 7/13/2023 at 8:15 PM, Photon Guy said:

The idea is that it's supposed to enable you to have access to water when you need it without having to lug around lots of water.

I have access to water when I need it, without having to lug around lots of water. And I don't have to lug lots of hydrogen around either. Having water available in water mains is pretty good. No lugging involved. Just turn on the tap.

If an alien world had an oxygen-rich atmosphere, that means it would be sure to have plants that photosynthesise, and that would mean rain on land and oceans of water. So making water available would be a similar process to what we do on Earth. 

[exchemist]

8 hours ago, Photon Guy said:

There is also the fact that science can "ruin" science fiction. For instance, back when Spiderman first came out the story was that he was bitten by a radioactive spider and that's how he got superpowers. Today, with all the scientific discoveries we made since, we know that if you're bitten by a radioactive spider you will die when the radiation goes through your bloodstream and all. Back then, though, they didn't understand all the stuff about radiation that they do now. 

That was a story for kids. Anyone back in the 60s who knew any science realised the concept of a “radioactive spider” made no sense. In sci fi there is often a macguffin to enable the plot that is scientifically dodgy, (faster than light travel being perhaps the most obvious).
 

But writers, even today, have a blind spot about radiation. I was appalled, in the 2019 TV dramatisation of the Chernobyl disaster, to see them claim the bodies of workers who died of radiation sickness had to be buried in sealed coffins, as if they had become radioactive as a result of exposure to radiation. That’s  utter bullshit - but makes for suitably harrowing TV, with distraught relatives unable to say goodbye to loved ones etc etc.
 

So they put it in, regardless. It appalled me as I think it irresponsible to perpetuate superstitious myths about the effects of radiation, among the general public. And especially in a drama documentary with pretensions to accuracy. It made me suspect there were other fictions in the series - as indeed there were.

Edited July 18, 2023 by exchemist

[swansont]

7 hours ago, exchemist said:

I was appalled, in the 2019 TV dramatisation of the Chernobyl disaster, to see them claim the bodies of workers who died of radiation sickness had to be buried in sealed coffins, as if they had become radioactive as a result of exposure to radiation. That’s  utter bullshit - but makes for suitably harrowing TV, with distraught relatives unable to say goodbye to loved ones etc etc.

They could have become contaminated, though. Breathing in radioactive particulates that stay in the lungs, for example, or breathing/ingesting anything that the body takes up (or just transits through the body)

The reporting about the lead coffins is not just from the TV show.

https://programs.fas.org/ssp/nukes/fuelcycle/chernobyllessons.html

[exchemist]

43 minutes ago, swansont said:

They could have become contaminated, though. Breathing in radioactive particulates that stay in the lungs, for example, or breathing/ingesting anything that the body takes up (or just transits through the body)

The reporting about the lead coffins is not just from the TV show.

https://programs.fas.org/ssp/nukes/fuelcycle/chernobyllessons.html

I couldn’t see anything about sealed coffins in that description. Does it say that?

[John Cuthber]

18 hours ago, Photon Guy said:

. Today, with all the scientific discoveries we made since, we know that if you're bitten by a radioactive spider...

Actually, we now know that all spiders are radioactive.

[swansont]

3 hours ago, exchemist said:

I couldn’t see anything about sealed coffins in that description. Does it say that?

“They are buried in zinc-lined, lead coffins set in deep graves near Moscow.”

1 hour ago, John Cuthber said:

Actually, we now know that all spiders are radioactive.

People, too. But those bites turns you into a zombie.