For Questions That Don't Merit Their Own Thread

[StrandedonEarth]

I probably mentioned  this before, years ago....

An old mystery story: a woman dies. She appears to have died from lack of water (organ failures), yet her tissues are well if not excessively hydrated. 

The solution was that she only drank from the bottled water in her fridge, and hubby worked at a lab with access to heavy water, which he replaced her drinking water with. But although it’s not poisonous, the body can’t use heavy water, so she died. 

Is this a valid scenario?

[Kerwood Floyd]

5 minutes ago, StrandedonEarth said:

I probably mentioned  this before, years ago....

An old mystery story: a woman dies. She appears to have died from lack of water (organ failures), yet her tissues are well if not excessively hydrated. 

The solution was that she only drank from the bottled water in her fridge, and hubby worked at a lab with access to heavy water, which he replaced her drinking water with. But although it’s not poisonous, the body can’t use heavy water, so she died. 

Is this a valid scenario?

This sounds fishy to me. Why can't the body use heavy water? I suppose that if every single hydrogen atom in every single water molecule was deuterium instead of protium, then that might be a problem. But as I understand it, "heavy water" is merely water with a higher than natural proportion of deuterium, but still in absolute terms a relatively low proportion. How high a proportion of deuterium would be necessary to render the water unusable?

[kerbiloid]

5 minutes ago, Kerwood Floyd said:

Why can't the body use heavy water?

Because deuterium ions are twice heavier, and reaction rates change.

P.S.
And here we rteturn to the theme of heavywatermelons...

Edited February 19, 2021 by kerbiloid

[TheSaint]

47 minutes ago, adsii1970 said:

@VoidSquid:

Yes, but I still love consuming it, especially when it is mixed with chlorogenic acids in their naturally occurring state as the Rubiaceae plant family, more specifically, the Coffea arabica plant. The berries release an awesome aroma when roasted and ground. Add them to hot boiling water through either a drip or peculated process to make make a great and natural energy beverage.

I am desecrating my mortal frame with said substance as we speak....

[Kerwood Floyd]

39 minutes ago, kerbiloid said:

Because deuterium ions are twice heavier, and reaction rates change.

Fair enough. But there is still the question whether heavy water is available, even in a lab, in sufficiently pure form for this to prove fatal.

[JoeSchmuckatelli]

1 hour ago, adsii1970 said:

@VoidSquid:

Yes, but I still love consuming it, especially when it is mixed with chlorogenic acids in their naturally occurring state as the Rubiaceae plant family, more specifically, the Coffea arabica plant. The berries release an awesome aroma when roasted and ground. Add them to hot boiling water through either a drip or peculated process to make make a great and natural energy beverage.

It's frozen state also acts to enhance a complex mixture of lactones, phenolic compounds, aldehides, esters, and other compounds. 

 

https://www.compoundchem.com/2015/03/31/whisky/

[kerbiloid]

8 minutes ago, JoeSchmuckatelli said:

It's frozen state also acts to enhance a complex mixture of lactones, phenolic compounds, aldehides, esters, and other compounds. 

Spoiler

 

 

[K^2]

5 hours ago, Kerwood Floyd said:

Fair enough. But there is still the question whether heavy water is available, even in a lab, in sufficiently pure form for this to prove fatal.

Yes. Because mass difference is so high, high purity heavy water is available and has laboratory uses. You need fairly high fraction of your body water replaced with heavy water, but it's definitely possible if you only drink heavy water and don't get a lot of water with foods you eat.

[JoeSchmuckatelli]

Is snow unique to water?  Can other vapors in different / extreme environments form the crystal structure of and fall like snow? 

[kerbiloid]

That's no snow.

(Look, a poetry!)

"Snow" is ice.
Just the ice is a compressed dense ice, while the "snow" is a freely frozen (being suspended in air) fuzzy ice.
New particles get added to existing hexagonal ray-like fractal structures, to its tips.
On ground they get added from top and immediately get crushed by new layers above, so they get compressed and form a dense material with same hexagonal structure.

So, everything that can make ice can make "snow".

On Titan you can see hydrocarbon snow, but this doesn't make that place better.

Edited February 20, 2021 by kerbiloid

[StrandedonEarth]

I guess the better question if there is another element or compound besides water that self-organizes into a crystal as it freezes so that the frozen state is less dense than the liquid state? As in, has that rare property of ice  where frozen bits float instead of sink as a pool of liquid freezes... 

[JoeSchmuckatelli]

1 hour ago, StrandedonEarth said:

I guess the better question if there is another element or compound besides water that self-organizes into a crystal as it freezes so that the frozen state is less dense than the liquid state? As in, has that rare property of ice  where frozen bits float instead of sink as a pool of liquid freezes... 

That is kind of what I asked. 

[Terwin]

Snow is basically ice with air in/around it, sort of like a pumice stone is stone with air in/around it.

We do not have a lot of materials that both evaporate and freeze in large quantities within our atmosphere. 

While the hexagonal structure would be due to the chemical structure of the water molecule, other materials could also form loosely packed crystal structures if they were to condense out of an atmosphere and freeze, but most would probably not form a hexagonal structure like water does.

 

[kerbiloid]

7 hours ago, StrandedonEarth said:

I guess the better question if there is another element or compound besides water that self-organizes into a crystal as it freezes so that the frozen state is less dense than the liquid state? As in, has that rare property of ice  where frozen bits float instead of sink as a pool of liquid freezes... 

Yes. Any.

That's why lunar regolith is abrasive and sticky. It consists of naturally grown crystals, with fractal structure and pointed tips.
So, the lunar dusticles are micro hedgehogs or rocky snowstoneflakes.

On the Earth they are polished by air, water, and friction, but the Moon is covered with the stonesnow.

Edited February 21, 2021 by kerbiloid

[JoeSchmuckatelli]

29 minutes ago, kerbiloid said:

Yes. Any.

That's why lunar regolith is abrasive and sticky. It consists of naturally grown crystals, with fractal structure and pointed tips.
So, the lunar dusticles are micro hedgehogs or rocky snowstoneflakes.

On the Earth they are polished by air, water, and friction, but the Moon is covered with the stonesnow.

Quite poetic - but alas, I must trouble;

Regolith is shattered space-borne rubble.

[kerbiloid]

22 minutes ago, JoeSchmuckatelli said:

Regolith is shattered space-borne rubble.

And naturally grown crystals being never polished since they were condensed from melted stuff.

Btw, the snowflakes.

Spoiler

 

So, any material with appropriate crystal structure at those exact conditions (many materials have different structures under different pressure and temperature).

[K^2]

7 hours ago, JoeSchmuckatelli said:

That is kind of what I asked. 

Not really, though. You don't strictly speaking need the less-dense-than-liquid property to form snow. But it's true that the reason water ice makes flakes in the atmosphere is partially due to odd crystal structure of ice.

You know how sometimes you get this frozen dusting of almost micro-hail instead of flakey snow? The kind that bites your skin as it strikes, because it's actually falling quite fast? I imagine, most compounds with simple molecular structure would have frozen precipitation be more like that than the flakey snow.

But then, there are a lot of crystals that can form flakes despite the fact that the crystal form is still heavier than the liquid.

So there are really three things going on.

1) Can other materials go from gaseous to solid state in the atmosphere and precipitate? - Yes. You can get some sort of solid precipitation from pretty much anything that has a solid state under given conditions. You can have iron "snow" technically. Probably wouldn't be pleasant.

2) Will that solid precipitation form flakes? - That one depends on conditions. Even water ice doesn't always do that. We get hail and other phenomena. But some materials will form flakes more readily than others, and some might not make it at all. Crystal structure of water is particularly good for making flakes, so that's why snow is common. With other substances, something that resembles might be rare or impossible.

3) Will the solid form float? - That one's super rare. I'm not actually aware of another example besides water. I'm absolutely sure that there are complex organic compounds that behave the same way, but as for simple inorganic compounds? Water might actually be unique. What makes it even more interesting is that water starts forming domains at temperatures above freezing, which leads to negative thermal expansion coefficients. And while I know that there are substances that give you negative thermal expansion coefficients in solid form, having a liquid do this is quite bizarre. Yet, that's what protects a lot of aquatic life in the winter, so it's a very useful property, and I'm not aware of another substance that does all of that.

[magnemoe]

3 hours ago, K^2 said:

Not really, though. You don't strictly speaking need the less-dense-than-liquid property to form snow. But it's true that the reason water ice makes flakes in the atmosphere is partially due to odd crystal structure of ice.

You know how sometimes you get this frozen dusting of almost micro-hail instead of flakey snow? The kind that bites your skin as it strikes, because it's actually falling quite fast? I imagine, most compounds with simple molecular structure would have frozen precipitation be more like that than the flakey snow.

But then, there are a lot of crystals that can form flakes despite the fact that the crystal form is still heavier than the liquid.

So there are really three things going on.

1) Can other materials go from gaseous to solid state in the atmosphere and precipitate? - Yes. You can get some sort of solid precipitation from pretty much anything that has a solid state under given conditions. You can have iron "snow" technically. Probably wouldn't be pleasant.

2) Will that solid precipitation form flakes? - That one depends on conditions. Even water ice doesn't always do that. We get hail and other phenomena. But some materials will form flakes more readily than others, and some might not make it at all. Crystal structure of water is particularly good for making flakes, so that's why snow is common. With other substances, something that resembles might be rare or impossible.

3) Will the solid form float? - That one's super rare. I'm not actually aware of another example besides water. I'm absolutely sure that there are complex organic compounds that behave the same way, but as for simple inorganic compounds? Water might actually be unique. What makes it even more interesting is that water starts forming domains at temperatures above freezing, which leads to negative thermal expansion coefficients. And while I know that there are substances that give you negative thermal expansion coefficients in solid form, having a liquid do this is quite bizarre. Yet, that's what protects a lot of aquatic life in the winter, so it's a very useful property, and I'm not aware of another substance that does all of that.

Lots of solid thing floats for some time, its how you get sand from Sahara ending up in the alps and volcanic clouds after all. 
I guess the air has to be well colder than the freezing temperature. Snow making machines don't work at -1 centigrade but prefer cold dry air. 
As you say it need to form crystals then condensing. 
Only water do this on earth, however I can imagine you might get co2 snow on Mars or at least could if the atmosphere was thicker. 
 

[JoeSchmuckatelli]

7 hours ago, K^2 said:

Will the solid form float? - That one's super rare. I'm not actually aware of another example besides water.

Yeah - that's a very interesting question - whether any other substances' solid form would float in its own liquid form. 

I know Iron does not.  I don't believe glass does either. 

Kind of intriguing - we have bountiful liquid water and ice - but not much else that can be in both liquid and solid states at the surface.  In fact I can't think of anything where I'm familiar with the liquid and solid forms occurring naturally on the planet. 

 

Well, lava. 

But I don't think you can count oil seeps and plastic. 

 

[magnemoe]

4 hours ago, JoeSchmuckatelli said:

Yeah - that's a very interesting question - whether any other substances' solid form would float in its own liquid form. 

I know Iron does not.  I don't believe glass does either. 

Kind of intriguing - we have bountiful liquid water and ice - but not much else that can be in both liquid and solid states at the surface.  In fact I can't think of anything where I'm familiar with the liquid and solid forms occurring naturally on the planet. 

 

Well, lava. 

But I don't think you can count oil seeps and plastic. 

 

Lava is both solid and liquid yes but at this temperatures more materials will also melt  
You have produces like butter and some metals who will melt and freeze in everyday temperatures as in -30 to +50 C, none who is common in nature. 

But the special thing about water is that ice floats.  Googled this and found that heavy water ice sink in heavy water, guess water with one hydrogen and one deuterium atoms floats else it would be easy to separate them and this might even happen naturally in very calm water like an iced over pond. 

Is it other materials who float in their own liquid? 

Edited February 21, 2021 by magnemoe

[sevenperforce]

I was today years old when I realized that the pressure on the surface of Venus is 50% higher than the pressure inside a Shuttle SRB.

Correct me if I'm wrong, but doesn't that mean that if you were to drag an SRB all the way to Venus and then attempt to light it, the pressure inside would not be great enough to escape and so it would not produce thrust?

[SOXBLOX]

16 minutes ago, sevenperforce said:

the pressure inside would not be great enough to escape and so it would not produce thrust?

That doesn't sound right...

 I think that when the solid fuel expands into hot gases, it will still flow outwards into the atmosphere. It should still produce thrust, just less than on Earth.......I think.

@K^2, Mayday! 

 

Edited February 22, 2021 by SOXBLOX

[sevenperforce]

12 minutes ago, SOXBLOX said:

That doesn't sound right...

 I think that when the solid fuel expands into hot gases, it will still flow outwards into the atmosphere. It should still produce thrust, just less than on Earth.......I think.

In order to produce thrust, there has to be a flow from inside to outside.

If the pressure outside is greater than the pressure inside, then by basic physics there is flow from outside to inside.

So the pressure inside the SRB would have to increase above the pressure outside the SRB. Would this happen? Is the pressure environment inside an SRB dependent on the external atmospheric pressure?

If the pressure inside an SRB is dependent on external pressure, then does that mean the chamber pressure inside an SRB decreases with altitude as it climbs out of Earth's atmosphere?

Edited February 22, 2021 by sevenperforce

[paul_c]

1 hour ago, sevenperforce said:

I was today years old when I realized that the pressure on the surface of Venus is 50% higher than the pressure inside a Shuttle SRB.

Correct me if I'm wrong, but doesn't that mean that if you were to drag an SRB all the way to Venus and then attempt to light it, the pressure inside would not be great enough to escape and so it would not produce thrust?

The problem is, you can't just take a single value for the "pressure inside a Shuttle SRB" - because its an open, dynamic thing where combustion products are flowing out of the nozzle in the direction to give thrust. Venus' atmosphere is ~95 bar at the surface, so obviously there's going to be a number of physics effects on other components from the high pressure. But let's assume for a minute that the SRB doesn't implode or structurally fail etc. Effectively the burn rate of the fuel is a controlled explosion. With the extra 'push' of the Venus atmosphere trying to get into the SRB vs the burning of the fuel inside it, there will occur an equilibrium of sorts where the pressure inside rises and rises until it exceeds the outside pressure, then the hot gases will flow out of it at something >95 bar. They'll flow much slower than on Earth (1 bar), so for a given burn rate the energy*, thus temperature, thus pressure, will be (much) more inside the SRB than it would on Earth or in a vacuum. 

I suspect what would actually happen is the associated temperature would be too great for the materials to handle; and if you really wanted to launch off the surface of Venus, you would need a very differently specified and constructed SRB to do it in its 95 bar atmosphere, although the principle of rockets is the same.

* ETA, the burning of the fuel converts chemical energy to potential energy (of a hot gas) at a certain rate. That potential energy would not convert to kinetic energy so much, because of the lesser flowrate of that gas. So there would be more gas, more potential energy inside the rocket's interior before it left the nozzle - it would all eventually come out, over a longer period of time. Less thrust, but not zero thrust.

Edited February 22, 2021 by paul_c

[K^2]

1 hour ago, sevenperforce said:

I was today years old when I realized that the pressure on the surface of Venus is 50% higher than the pressure inside a Shuttle SRB.

Correct me if I'm wrong, but doesn't that mean that if you were to drag an SRB all the way to Venus and then attempt to light it, the pressure inside would not be great enough to escape and so it would not produce thrust?

The reason pressure inside SRB doesn't go higher is because there's an exhaust opening and pressure outside is close enough to zero.

If you are to try that in the Venusian atmosphere, the pressure inside is still going to increase above ambient once the fuel starts to burn. That does, however, present a new problem. Rate of burn of the fuel in SRB depends on the pressure. As pressure increases, the fuel burns faster. High ambient temperature is going to accelerate the burn as well. Since you are already at exceptionally high pressure, and it's only growing higher as combustion products struggle to get out, the burn rate is going to end up much, much higher than on Earth, and so the pressure inside SRB is going to get many times higher than nominal.

In short, my fear is that if you try to use a terrestrial SRB on Venus it'll just blow the bleep up.

That said, I'm pretty sure that you can adjust the mixture and grain size for a burn rate that will work in Venusian atmosphere. The I_SP won't be great, since you wouldn't really have a nozzle, but it should still be decent. Not that you'll end up going very fast or very far, given the density of the atmosphere.

Edit: Ninja'd by paul_c.

Edited February 22, 2021 by K^2