A decanter of endless water pours out water at a constant flow rate. If I place this object in a demiplane, eventually the demiplane will be full of water and the water pouring out of the decanter is thus going to force the surrounding water to compress and increase its density.
Now, where I get fuzzy is in how water will respond to being compressed. I think it will go into a quasi solid until its dense enough for nuclear fusion to occur(water gets weird at high density), but am no expert. I am pretty sure this will be a very high energy system that I can use to annihilate my enemies though. The decanter should be fine as long as it is held by someone in a life bubble.
Just wanted to check with the forums and see if anyone knows how such a high energy system will interact with the pathfinder rules.
http://www.d20pfsrd.com/magic-items/wondrous-items/wondrous-items/c-d/decan ter-of-endless-water
http://www.d20pfsrd.com/magic/all-spells/l/life-bubble
http://www.d20pfsrd.com/magic-items#TOC-Damaging-Magic-Items
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water is for all intents and purposes considered incompressible in liquid phase. Seeing as how the decanter of endless water lists a flow rate it must have an applied pressure to reach this rate.
AKA the decanter of endless water will not have enough pressure to significantly compress the water and when the pressure of the flow and the pressure of the water equalize the flow will stabalize and nothing should happen.
Basically you can calculate pressure from the endless decanter based on flow rate, density of water, and the size of the nozzle and you'll know where the pressure in the liquid should equalize.
Also your plane can start off full of water if you want it to. I like Thomas Long's answer, but at least you can save yourself a little time by initially filling it with water.
Thomas Long 175 is correct.
Wiki (not that Wiki is a definitive source but it is a ready source) wrote: Compressibility
The compressibility of water is a function of pressure and temperature. At 0 °C, at the limit of zero pressure, the compressibility is 5.1×10−10 Pa−1.[27] At the zero-pressure limit, the compressibility reaches a minimum of 4.4×10−10 Pa−1 around 45 °C before increasing again with increasing temperature. As the pressure is increased, the compressibility decreases, being 3.9×10−10 Pa−1 at 0 °C and 100 MPa.
The bulk modulus of water is 2.2 GPa.[28] The low compressibility of non-gases, and of water in particular, leads to their often being assumed as incompressible. The low compressibility of water means that even in the deep oceans at 4 km depth, where pressures are 40 MPa, there is only a 1.8% decrease in volume.[28]
- Gauss
Lol sorry I'm a mech Eng that specializes in refrigerant and fluid systems. Thats just one of the basic rules. Liquids are considered to be basically incompressible.
Edit: Don't get me wrong the sheer pressure from being in a situation similar to being at the bottom of the ocean would probably crush them (I don't know how big the demiplane is) but you'll never achiever nuclear fusion like this.
No worries Thomas. My background is in electronics and semiconductor manufacturing but some of the training I got covered hydrodynamics. Nowhere near your level of course.
- Gauss
Thomas Long 175 wrote: water is for all intents and purposes considered incompressible in liquid phase. Seeing as how the decanter of endless water lists a flow rate it must have an applied pressure to reach this rate.
AKA the decanter of endless water will not have enough pressure to significantly compress the water and when the pressure of the flow and the pressure of the water equalize the flow will stabalize and nothing should happen.
Basically you can calculate pressure from the endless decanter based on flow rate, density of water, and the size of the nozzle and you'll know where the pressure in the liquid should equalize.
This is a pretty big assumption. Nowhere does it state that the flow rate of water is dependent on the environment. It simply lists a flow rate for the water out of the decanter. What you are suggesting is that I change the flow rate from the listed value. Ultimately it doesn't matter though. Even if I accept your houserules, the water could be shot out of an air bubble or life shell and obtain the same results.
Also, water is considered incompressible for most intents and purposes. Not all. There is research into how water compresses at high and low pressures.
Also keep in mind that gases are easily compressible but in order for hydrogen (for example) to achieve fusion you need an amount the size of a small star.
johnlocke90 wrote: Thomas Long 175 wrote: water is for all intents and purposes considered incompressible in liquid phase. Seeing as how the decanter of endless water lists a flow rate it must have an applied pressure to reach this rate.
AKA the decanter of endless water will not have enough pressure to significantly compress the water and when the pressure of the flow and the pressure of the water equalize the flow will stabalize and nothing should happen.
Basically you can calculate pressure from the endless decanter based on flow rate, density of water, and the size of the nozzle and you'll know where the pressure in the liquid should equalize.
This is a pretty big assumption. Nowhere does it state that the flow rate of water is dependent on the environment. It simply lists a flow rate for the water out of the decanter. What you are suggesting is that I change the flow rate from the listed value. Ultimately it doesn't matter though. Even if I accept your houserules, the water could be shot out of an air bubble or life shell and obtain the same results.
Also, water is considered incompressible for most intents and purposes. Not all. There is research into how water compresses at high and low pressures. No its not. Its physics. Flowrate is dependent on force behind it, which is pressure. And yes it is. Its considered incompressible. It takes huge amounts of pressure to reach any amount of compression. Would you like me to type up the equations for you?
The Terrible Zodin wrote: Also keep in mind that gases are easily compressible but in order for hydrogen (for example) to achieve fusion you need an amount the size of a small star. No you don't. Nuclear fusion is achieved with very small amounts of matter all the time in a laboratory. All you need is a lot of energy(stars obtain this through large amounts of matter creating gravity).
Thomas Long 175 wrote: johnlocke90 wrote: Thomas Long 175 wrote: water is for all intents and purposes considered incompressible in liquid phase. Seeing as how the decanter of endless water lists a flow rate it must have an applied pressure to reach this rate.
AKA the decanter of endless water will not have enough pressure to significantly compress the water and when the pressure of the flow and the pressure of the water equalize the flow will stabalize and nothing should happen.
Basically you can calculate pressure from the endless decanter based on flow rate, density of water, and the size of the nozzle and you'll know where the pressure in the liquid should equalize.
This is a pretty big assumption. Nowhere does it state that the flow rate of water is dependent on the environment. It simply lists a flow rate for the water out of the decanter. What you are suggesting is that I change the flow rate from the listed value. Ultimately it doesn't matter though. Even if I accept your houserules, the water could be shot out of an air bubble or life shell and obtain the same results.
Also, water is considered incompressible for most intents and purposes. Not all. There is research into how water compresses at high and low pressures. No its not. Its physics. Flowrate is dependent on force behind it, which is pressure. And yes it is. Its considered incompressible. It takes huge amounts of pressure to reach any amount of compression. Would you like me to type up the equations for you? You are forgetting that the water is created by magic. There actually isn't any water in the physical decanter so there is no evidence of a force expelling the water. All we know is that the decanter pours water out at a set flowrate. Thats how the magic works. It says nothing about altering the flow rate based on the external conditions.
Also, you just admitted that water is compressible. Sure, its not compressible with our technologies, which is why I am using magic to increase density.
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johnlocke90 wrote:
You are forgetting that the water is created by magic. The decanter pours water out at a set flowrate. Thats how the magic works.
Also, you just admitted that water is compressible. Sure, its not compressible with our technologies, which is why I am using magic to increase density.
1. Read: I said basically incompressible in the beginning.
2. Magic has limits in pathfinder. Those limits are the power of the caster. Its why not every caster can create a fireball as strong as the sun.
3. We can compress water. Just not a lot. It takes huge amounts of pressure to make even a dent. To put it bluntly compressibility of any material is measured by the bulk modulus. Steel is 20.2 x 10^6 psi. Water is 2.2 x 10^9 psi aka it requires over 100 times more force to compress water an equivalent amount to solid steel.
Edit lol sorry forgot the conversion its slightly less.
Thomas Long 175 wrote: johnlocke90 wrote:
You are forgetting that the water is created by magic. The decanter pours water out at a set flowrate. Thats how the magic works.
Also, you just admitted that water is compressible. Sure, its not compressible with our technologies, which is why I am using magic to increase density.
1. Read: I said basically incompressible in the beginning.
2. Magic has limits in pathfinder. Those limits are the power of the caster. Its why not every caster can create a fireball as strong as the sun.
3. We can compress water. Just not a lot. It takes huge amounts of pressure to make even a dent. To put it bluntly compressibility of any material is measured by the bulk modulus. Steel is 20.2 x 10^6 psi. Water is 2.2 x 10^9 psi aka it requires over 100 times more force to compress water an equivalent amount to solid steel. 2. The "power" of spells varies widely. I don't think this is any more powerful than creating matter(which you can do with very low level spells). Considering that matter takes a ton of energy to create.
3. Which is exactly why a highly compressed amount of water would make a very potent bomb. I am simply trying to determine how exactly it would work if I created a gate between this extremely high pressure water(or possible plasma after I can get the pressure high enough for fusion to begin) and an enemy base.
Even if the decanter can keep generating water, the water pressure in the demiplane will most likely break the decanter, which makes it stop generating water, long before the water starts seriously compressing.
Also, I would say that based on the description of the item, the water must be poured from the decanter, which implies that it must have open air around it. If the decanter is completely submerged in water, nothing can be poured out and no more water is generated.
johnlocke90 wrote: 2. The "power" of spells varies widely. I don't think this is any more powerful than creating matter(which you can do with very low level spells). Considering that matter takes a ton of energy to create.
3. Which is exactly why a highly compressed amount of water would make a very potent bomb. I am simply trying to determine how exactly it would work if I created a gate between this extremely high pressure water(or possible plasma after I can get the pressure high enough for fusion to begin) and an enemy base.
1. The power of a decanter is already set. They already give a maximum flow rate given basically no resistance (air resistance and thats it)
Lets put it this way: compression is so hard for you to achieve that any school that teaches engineering anywhere in the nation, first thing they will teach you is ignore compression of liquids. You will never get enough pressure to create compression that will affect your system to any significant effect.
johnlocke90 wrote: The Terrible Zodin wrote: Also keep in mind that gases are easily compressible but in order for hydrogen (for example) to achieve fusion you need an amount the size of a small star. No you don't. Nuclear fusion is achieved with very small amounts of matter all the time in a laboratory. All you need is a lot of energy(stars obtain this through large amounts of matter creating gravity). I am aware of those experiments. They made up for the lack of gravity by A) increasing the temperature to 100 million degrees (stars are only at 10 million degrees B) using a tiny amount of matter (certainly less than the amount of water needed to weaponize a demi-plane and C) for a very, very short amount of time.
OK, you don't need more an "instantaneous" duration. But A and B do not match the orignal poster's needs.
Dominigo wrote: Even if the decanter can keep generating water, the water pressure in the demiplane will most likely break the decanter, which makes it stop generating water, long before the water starts seriously compressing.
Also, I would say that based on the description of the item, the water must be poured from the decanter, which implies that it must have open air around it. If the decanter is completely submerged in water, nothing can be poured out and no more water is generated.
Actually an attended magic object doesn't take any damage from the environment. I even linked to the relevant rules in the OP. As long as the holder is surrounded by a life bubble the object is safe.
As to the second paragraph, nothing in the definition of pour implies open air and in fact it supports my statement that water flows out of the decanter.
https://www.google.com/search?q=pours&oq=pours&aqs=chrome.0.57& sugexp=chrome,mod=12&sourceid=chrome&ie=UTF-8
Thomas Long 175 wrote: johnlocke90 wrote: 2. The "power" of spells varies widely. I don't think this is any more powerful than creating matter(which you can do with very low level spells). Considering that matter takes a ton of energy to create.
3. Which is exactly why a highly compressed amount of water would make a very potent bomb. I am simply trying to determine how exactly it would work if I created a gate between this extremely high pressure water(or possible plasma after I can get the pressure high enough for fusion to begin) and an enemy base.
1. They already give a maximum flow rate given basically no resistance (air resistance and thats it)
Where do they do this? I see a flow rate, but I don't see any mention of air resistance.
I really don't see how compressing water is more difficult than creating water, which also requires a massive amount of energy.
johnlocke90 wrote: Thomas Long 175 wrote: johnlocke90 wrote: 2. The "power" of spells varies widely. I don't think this is any more powerful than creating matter(which you can do with very low level spells). Considering that matter takes a ton of energy to create.
3. Which is exactly why a highly compressed amount of water would make a very potent bomb. I am simply trying to determine how exactly it would work if I created a gate between this extremely high pressure water(or possible plasma after I can get the pressure high enough for fusion to begin) and an enemy base.
1. They already give a maximum flow rate given basically no resistance (air resistance and thats it)
Where do they do this? I see a flow rate, but I don't see any mention of air resistance. If it discards air resistance then the maximum flow rate is beneath the 30 gallons/round.
But lets do this by raw rules. Press the decanter against a perfectly flat wall. Order it to produce a geyser. No matter how long you sit there like that it takes a 12 strength check to keep from being knocked over or back by that. aka well within human strength can keep this thing stopped up.
Thomas Long 175 wrote: johnlocke90 wrote: Thomas Long 175 wrote: johnlocke90 wrote: 2. The "power" of spells varies widely. I don't think this is any more powerful than creating matter(which you can do with very low level spells). Considering that matter takes a ton of energy to create.
3. Which is exactly why a highly compressed amount of water would make a very potent bomb. I am simply trying to determine how exactly it would work if I created a gate between this extremely high pressure water(or possible plasma after I can get the pressure high enough for fusion to begin) and an enemy base.
1. They already give a maximum flow rate given basically no resistance (air resistance and thats it)
Where do they do this? I see a flow rate, but I don't see any mention of air resistance. If it discards air resistance then the maximum flow rate is beneath the 30 gallons/round.
But lets do this by raw rules. Press the decanter against a perfectly flat wall. Order it to produce a geyser. No matter how long you sit there like that it takes a 12 strength check to keep from being knocked over or back by that. aka well within human strength can keep this thing stopped up. The wall would form small fissures from the water pressure which would allow the water to vent out. There is nothing to suggest that water would stop flowing(that would contradict raw).
johnlocke90 wrote: The wall would form small fissures from the water pressure which would allow the water to vent out. There is nothing to suggest that water would stop flowing(that would contradict raw). There is nothing to suggest it has the power to overcome hardness. It deals 1d4 damage. That will not overcome stome's hardness or even that of wood.
Thomas Long 175 wrote: johnlocke90 wrote: The wall would form small fissures from the water pressure which would allow the water to vent out. There is nothing to suggest that water would stop flowing(that would contradict raw). There is nothing to suggest it has the power to overcome hardness. It deals 1d4 damage. That will not overcome stome's hardness or even that of wood. Actually the 1d4 points of damage is from the kinetic energy of the geyser hitting someone("the powerful force of the geyser", which is closer to hitting someone with a blunt object). Not from the water filling up the area and trying to force its way out(due to waters low compressibility). Those are two different sources of damage.
johnlocke90 wrote: Thomas Long 175 wrote: johnlocke90 wrote: The wall would form small fissures from the water pressure which would allow the water to vent out. There is nothing to suggest that water would stop flowing(that would contradict raw). There is nothing to suggest it has the power to overcome hardness. It deals 1d4 damage. That will not overcome stome's hardness or even that of wood. Actually the 1d4 points of damage is from the kinetic energy of the geyser hitting someone("the powerful force of the geyser", which is closer to hitting someone with a blunt object). Not from the water filling up the area and trying to force its way out(due to waters low compressibility). Those are two different sources of damage. Thats because there is no damage given for that. Per raw though the water geyser will never do damage more than 1d4. given that, a moderate strength human can take 10 and will never be knocked over and the wall will never give. There's raw for you. They do not account anywhere for any force from the water being blocked.
Thomas Long 175 wrote: johnlocke90 wrote: Thomas Long 175 wrote: johnlocke90 wrote: The wall would form small fissures from the water pressure which would allow the water to vent out. There is nothing to suggest that water would stop flowing(that would contradict raw). There is nothing to suggest it has the power to overcome hardness. It deals 1d4 damage. That will not overcome stome's hardness or even that of wood. Actually the 1d4 points of damage is from the kinetic energy of the geyser hitting someone("the powerful force of the geyser", which is closer to hitting someone with a blunt object). Not from the water filling up the area and trying to force its way out(due to waters low compressibility). Those are two different sources of damage. Thats because there is no damage given for that. Per raw though the water geyser will never do damage more than 1d4. given that, a moderate strength human can take 10 and will never be knocked over and the wall will never give. There's raw for you. They do not account anywhere for any force from the water being blocked. Per raw, the water will stream out at a set amount of gallons each round.
I don't see how you have concluded that the wall will never give. Raw makes no statement one way or the other.
johnlocke90 wrote: Per raw, the water will stream out at a set amount of gallons each round.
I don't see how you have concluded that the wall will never give. Raw makes no statement one way or the other.
Because the item gives a damage for things hit by the stream. This damage is barely half enough to even do a point of damage to the wall. The statement is you will never have enough damage to damage the wall.
John, your idea is genius, you can weaponise a demiplane and create a universe killer from a decanter with the pressure of a garden hose. Congrats on your plan.
Thomas Long 175 wrote: johnlocke90 wrote: Per raw, the water will stream out at a set amount of gallons each round.
I don't see how you have concluded that the wall will never give. Raw makes no statement one way or the other.
Because the item gives a damage for things hit by the stream. This damage is barely half enough to even do a point of damage to the wall. The statement is you will never have enough damage to damage the wall. Which is why I agree with you that being hit with the stream won't damage the wall.
I was referring to damage from the water being created in an area too small for it to fit in.
If I was your GM I would say the following thing happens.
First, the water builds up enough pressure to crush you while in the demiplane.
Second, The Decanter falls in the water and stops pouring.
Third you make a new character or find someone to cast true res, cause good luck getting that body back.
Thomas: You cannot take 10 on an ability check. Only on skill checks.
johnlocke: the damage of the geyser will not harm a wood or stone wall in your lifetime. The hardness is 5 for wood, 8 for stone. Thus, in the case of solid stone, it will never create any cracks to penetrate.
Regarding the 'RAW' of all of this, johnlocke, there are corner cases all over the place. Heck, there is no RAW covering the actions of dead people and yet dead people cannot act because it is common sense. This is another corner case.
Something that requires a strength check with a DC of 12 to hold it back simply does not have the force to equal 40 Megapascals of pressure. 40 Megapacals of pressure (4km depth on earth) is what is required to compress the water by 1.8%.
Note: I am not saying it will not kill someone. I am saying it is not going to create compressed water. I do not know at what depth humans cannot dive down to without some kind of pressure suit.
- Gauss
Timothy Hanson wrote: If I was your GM I would say the following thing happens.
First, the water builds up enough pressure to crush you while in the demiplane.
Second, The Decanter falls in the water and stops pouring.
Third you make a new character or find someone to cast true res, cause good luck getting that body back.
Which is why I surrounded myself with life bubble which prevents all pressure damage.
johnlocke90 wrote: Which is why I agree with you that being hit with the stream won't damage the wall.
I was referring to damage from the water being created in an area too small for it to fit in.
Yes, I get that. But pathfinder doesn't cover that. There is no damage for that. The game "covers" pressures, but it doesn't. As a mechanical engineer I can tell you the pressure behind a pump that would produce the maximum flow rate from the endless decanter and the required strength of a material to stop it.
Thats all I can give you per raw physics. They give you a maximum flow rate. Given a size of the decanter and a density I can give you pressure and it will be nowhere near what is necessary. The pressure produced by the decanter, the maximum pressure, can be found via maximum flow rate. If the force behind it were any stronger it would flow faster. But it doesn't so we know the maximum force it can produce. We can therefore counteract it with a force that is equal even if it is non magical. AKA a full environment.
johnlocke90 wrote: A decanter of endless water pours out water at a constant flow rate. If I place this object in a demiplane, eventually the demiplane will be full of water and the water pouring out of the decanter is thus going to force the surrounding water to compress and increase its density.
Now, where I get fuzzy is in how water will respond to being compressed. I think it will go into a quasi solid until its dense enough for nuclear fusion to occur(water gets weird at high density), but am no expert. I am pretty sure this will be a very high energy system that I can use to annihilate my enemies though. The decanter should be fine as long as it is held by someone in a life bubble.
Just wanted to check with the forums and see if anyone knows how such a high energy system will interact with the pathfinder rules.
http://www.d20pfsrd.com/magic-items/wondrous-items/wondrous-items/c-d/decan ter-of-endless-water
http://www.d20pfsrd.com/magic/all-spells/l/life-bubble
http://www.d20pfsrd.com/magic-items#TOC-Damaging-Magic-Items
Also sort of confused, how are you annihilating people with your demi-plane?
Timothy Hanson wrote: Also sort of confused, how are you annihilating people with your demi-plane? He's trying to initiate nuclear fusion by the sounds of it.
Timothy Hanson wrote: johnlocke90 wrote: A decanter of endless water pours out water at a constant flow rate. If I place this object in a demiplane, eventually the demiplane will be full of water and the water pouring out of the decanter is thus going to force the surrounding water to compress and increase its density.
Now, where I get fuzzy is in how water will respond to being compressed. I think it will go into a quasi solid until its dense enough for nuclear fusion to occur(water gets weird at high density), but am no expert. I am pretty sure this will be a very high energy system that I can use to annihilate my enemies though. The decanter should be fine as long as it is held by someone in a life bubble.
Just wanted to check with the forums and see if anyone knows how such a high energy system will interact with the pathfinder rules.
http://www.d20pfsrd.com/magic-items/wondrous-items/wondrous-items/c-d/decan ter-of-endless-water
http://www.d20pfsrd.com/magic/all-spells/l/life-bubble
http://www.d20pfsrd.com/magic-items#TOC-Damaging-Magic-Items
Also sort of confused, how are you annihilating people with your demi-plane? Once enough water is put into the demiplane, the demiplane will basically turn into a bomb(very high pressure, lots of heat). I would then open a gate between my demiplane and the enemy base and all that energy would rush into the enemy base.
Imagine if you opened a gate between the sun and your enemy base(which is an interesting alternative).
hang on, if life bubble creates a shell around you, and you are holding the decanter, then how does the water exit the shell?
You are relying on RAI not RAW when you have the water leaving the shell.
Gate just allows the passage of creatures, there is nothing that would indicate that energy, water, fire, radiation, sound ect goes through the gate.
Shifty wrote: hang on, if life bubble creates a shell around you, and you are holding the decanter, then how does the water exit the shell?
You are relying on RAI not RAW when you have the water leaving the shell.
Life bubble only exists 1 inch around the wielder. The decanter probably won't be in the bubble, but even if it is, on the higher settings, the decanter produces a stream much wider than that. So the water would be created outside the bubble.
So whats stopping the decanter being crushed by the water over time?
regardless guys you know my stance and the physics. best of luck john. good luck with that philosophy thing. Hope your campaign goes well.
Happy thanksgiving all and see you after black friday :P
If there is no air I would say the decanter stops poring. You fill up a bathtub put a bucket in it and turn it upside down then you are not really poring at this point.
Timothy Hanson wrote: Gate just allows the passage of creatures, there is nothing that would indicate that energy, water, fire, radiation, sound ect goes through the gate. Good point. Gate does allow objects through. I would have to find a way to either transfer or contain the water. Alternately I would have to lure my enemies into it.
I could also cast the Word of Power Dimensional Gate if those are in use.
http://www.d20pfsrd.com/magic/words-of-power/effect-words/dimensional-gate
Shifty wrote: So whats stopping the decanter being crushed by the water over time? Read the rules on destroying magic items. The decanter is attended and thus won't take crushing damage. Its the same reason you don't roll for all of your items every time you take environmental damage.
Summary: johnlocke is trying to use physics to create a fusion bomb. johnlocke is also ignoring hydrodynamics in order to set up the conditions for that fusion by stating that he can create magically induced high pressures and temperatures. He is firmly out of RAW and into GM fiat territory regardless.
Either this is not really a question for the Rules forum or you got your answer a long time ago. This is not really possible unless the GM allows it.
- Gauss
johnlocke90 wrote:
Life bubble only exists 1 inch around the wielder. The decanter probably won't be in the bubble, but even if it is, on the higher settings, the decanter produces a stream much wider than that. So the water would be created outside the bubble.
Yet...
johnlocke90 wrote: Read the rules on destroying magic items. The decanter is attended and thus won't take crushing damage. Its the same reason you don't roll for all of your items every time you take environmental damage. Is it in the bubble or out of it? because if it is being 'attended' then its inside... hence my first question. If its outside then it isn't attended, hence the second.
Shifty wrote: johnlocke90 wrote:
Life bubble only exists 1 inch around the wielder. The decanter probably won't be in the bubble, but even if it is, on the higher settings, the decanter produces a stream much wider than that. So the water would be created outside the bubble.
Yet...
johnlocke90 wrote: Read the rules on destroying magic items. The decanter is attended and thus won't take crushing damage. Its the same reason you don't roll for all of your items every time you take environmental damage. Is it in the bubble or out of it? because if it is being 'attended' then its inside... hence my first question. If its outside then it isn't attended, hence the second.
How did you jump from "the object is attended" to the object is inside the bubble? The bubble only extends out 1 inch past the casters skin. Its attended because I am holding it.
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Okay, this is fun.
Yes, your scheme would work.
First, I’m defining a “demiplane” as an thermodynamically fully isolated system which is isochoric (volume can’t change)… just so we’re on the same page. If someone thinks “planes” wouldn't be thermodynamically isolated (maybe there’s energy transfer with the astral or ethereal plane) then my argument won’t be valid.
Assuming a minimum-sized demiplace (one 10-foot cube, or 1000 cubic feet), at the moment the plane is filled at density 1 we’ll have 2.8317e+7 grams of water, or 1.573e+6 moles of water (assuming the decanter itself has negligible relative displacement).
Now, assuming this is an indestructible decanter that somehow lacks a “limiter” which responds to environmental pressure, so we keep adding water to this isochoric system. One interesting feature about water is that its phase diagram’s liquid-solid boundary has negative slope, so you essentially can’t press water “solid” (indeed, its solid phase is less dense that liquid, because strong hydrogen bonding forces the solid into a tetrahedral geometry, increasing “spacing” over its liquid form). Now, we’re adding pressure VERY slowly (30 gallons per round to an essentially 7480 gallon “tank” – our demiplane), but we also have an isolated system, so we’re slowly, inexorably adding heat – it can’t dissipate – so our water is getting hotter. Slowly, but hotter.
Folks have mentioned that water is pretty impervious to pressurization – this is a feature of liquids – but we’re dealing with a pretty unusual system (an ideally isolated thermodynamic system) – so we actually can explore some exotic states of water. For example, at some point, our phase diagram get a bit wonky, and we might move in and out of some different-geometry solid states (as systemic heating begins overpowering hydrogen bonding, for example). If you’re curious about these metastable forms of water, this paper has an extended phase diagram.
So, after a lot of interesting chemistry happens, and we start sort of moving away from a pressurized system of water to more things like hydronium. At 10,000 atmospheres (equal to a terrestrially-impossible 64 mile depth), for example, we’ll see Ice IV… so we still haven’t fused, but we’re at another exotic solid state, and we’re still adding water to the system. What we DO have, at this point, is something like the atmosphere of a water world… kind of interesting.
By the way, it’s probably important to point at t at this stage: it will take the decanter 2,055,000 years to achieve this level of pressure, adding its 30 gallons per round (the first problem evident in the scheme).
But we continue adding water, and our demiplane gets hotter, and goes through yet more exotic phase changes (there are fourteen forms of ice to go through!) The pressure needed to fuse water doesn’t really matter, because our water will have long ceased to be water by the time we get there – it’s elemental oxygen and hydrogen, and some other kinds of ions of the two in certain forms.
So what about fusion? This is a matter of sheer guesstimate outside of some very complex calculation of the Lawson criterion triple product (which I don't intend to do at 1:41am), and it’s hard to say what the pre-fusion conditions are like insofar as temperature, pressure, and so on. I guess we’re just looking for an explosion rather than sustainable fusion (building a star inside our demiplane)? It’s largely a matter of temperature, and relation of pressure to temperature for liquids involves evaluating a partial differential equation (again, meh), but it’s on the order of a billion atmospheres (the sun is 340 billion, but it's a fully sustained star, and there are non-nuclear explosive which achieve pressures of 100 million atmospheres, so… 1 billion seems like a good estimate).
Using a decanter of endless water, it would take 6.49e+14 years – that’s 649,000 one-billion year intervals of time – to achieve fusion in a 10x10x10 demiplane.
For scale, our (real) universe is estimated to be 13.75 billion years old – your project will take 47212 times longer than that (not to mention that it might well drain the elemental plane of water!)
The verdict: the plan works, but perhaps on a different time horizon than one might want.
Of course, we can mess with the flow of time when we create our demiplane, but that’s another discussion.
I am loving this discussion. I just wish I knew more about liquid physics because fact-checking all this is a total pain.
johnlocke90 wrote: The bubble only extends out 1 inch past the casters skin. Actually... "You surround the touched creatures with a constant and moveable 1-inch shell of tolerable living conditions". Doesn't specify 'from the skin', therefore, like invisibility, it obviously covers the held objects too.
David Haller wrote: ... Thanks for the information. I still have to wonder what kind of effect charging this up for a year then unleashing it on an enemy base would have. It seems like the water would have a ton of energy in it simply because water takes a ton of energy to compress.
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