OOTS #1049 - The Discussion Thread

[Yendor]

You can't just go summoning helium elementals, no matter how jolly it would make the airship.

[8BitNinja]

You can't just go summoning helium elementals, no matter how jolly it would make the airship.

What if they were able to summon dead elementals?

But then again, I'm not the sharpest tool in the shed.

[Kantaki]

You can't just go summoning helium elementals, no matter how jolly it would make the airship.

I'm not sure what the EoB being a horrible place has to do with this.

[Grey_Wolf_c]

I'm not sure what the EoB being a horrible place has to do with this.

You may want to read the description of how Bluddy, the Empire's mascot, is held aloft.

GW

[brian 333]

Helium.

Also, the summon duration for wizards would be a bit taxing

Nope, I want hydrogen. Not only is it twice as buoyant as helium, it's flammable when mixed with oxygen and heat. Hoo-boy is it flammable when mixed with oxygen and heat.

On that note, does setting a hydrogen elemental afire kill it or does it convert it into a weird para-fire elemental?

[Kantaki]

You may want to read the description of how Bluddy, the Empire's mascot, is held aloft.

GW

I got what Yendor was referring to, but specifying that I meant that the Empire is a horrible place specifically for elementals seemed unnecessary because it is a horrible place for (almost) everyone.

But it seems kinda unlikely that Julio would accept those methods being used on the Mechane. If they employ elementals at all (seems unlikely judging by Roy’s explanation) a voluntary* (or at least torture-free) arrangement seems more likely.

*As much as that's possible. Depends on the used magic I guess.

[Kish]

Who brought up the Empire of Blood being a horrible place? Unless I missed something someone posted before this page, it looks like you just said, "I am bringing up something and simultaneously declaring it irrelevant."

[Rogar Demonblud]

Yendor. The linked comic is about how the EoB fills parade balloons by torturing air elementals to harvest their screams. Kantaki's point is that the EoB is a horrible place that does horrible things to pretty much everyone, elementals included, but that has no bearing on how a Chaotic Neutral type like Julio will fill his balloons.

[Kish]

Really? That's your description of what happened? Because mine goes "Yendor made a throwaway joke about bound elementals making a jolly balloon, Kantaki chose to treat it as a serious assertion of...I'm not even sure what, and you're jumping on the bandwagon with Kantaki."

[Kantaki]

Really? That's your description of what happened? Because mine goes "Yendor made a throwaway joke about bound elementals making a jolly balloon, Kantaki chose to treat it as a serious assertion of...I'm not even sure what, and you're jumping on the bandwagon with Kantaki."

From my perspective it went more like this:
-Yendor made the jolly ballons-joke
-I (half)jokingly wanted to know what the situation in the EoB has to do with the current situation
-Grey_Wolf_c assumed I missed the part with Bluddy
- I elaborated what I meant with my previous comment.

[Peelee]

Nope, I want hydrogen. Not only is it twice as buoyant as helium, it's flammable when mixed with oxygen and heat. Hoo-boy is it flammable when mixed with oxygen and heat.

On that note, does setting a hydrogen elemental afire kill it or does it convert it into a weird para-fire elemental?

Well, the chemical reaction for burning hydrogen is 2H₂ + O₂ => 2H₂O. So, in theory, the hydrogen elemental would turn into a water elemental.

[Kantaki]

Well, the chemical reaction for burning hydrogen is 2H₂ + O₂ => 2H₂O. So, in theory, the hydrogen elemental would turn into a water elemental.

Wouldn't that be a water-molecular?
I remember that some unnamed character ranted about this at some point.
Something about the classical elements not being elements.

[Peelee]

Wouldn't that be a water-molecular?
I remember that some unnamed character ranted about this at some point.
Something about the classical elements not being elements.

Yeah, he can talk all he wants to about that, but that handy dandy link up there confirms that, at least, air elementals are still in play

[Quibblicious]

Just a question about this; is the safety procedures different for the two gases? I'm wondering because helium is light while nitrogen is much heavier. Without understanding the exact physics, helium would fill an enclosed space from the ceiling down (like smoke) while nitrogen would fill from the floor up (like dry ice). I'll freely admit I'm not a chemist and shouldn't be allowed unsupervised access to liquid anything.

*Warning: It's been a while since I've done the volume conversions so I may have an error in there. I went metric to simplify the comparisons. I've checked the numbers a couple times and they seem right.*

Technically, this is physics

You are correct that the gases fill the room differently. Cold nitrogen sinks and fills bottom to top while helium in gaseous form rises and fills top to bottom.

Safety procedures overlapped because either gas could drive out the oxygen in a room; the differences lie primarily in the sensors used and the location of the sensors. Sensors for He go high in the room, N goes at floor level and at about 6 feet up, IIRC.

It can happen fast -- 1 kilo of liquid He is about 8 liters in volume, and about 6 cubic meters as a gas. 1 liter is 1000cc, 1 cubic meter is 1,000,000cc, so we have 8000cc of liquid turning into about 6 million cc of gas. That's about a 750:1 volume increase. Nitrogen is similar. (Most liquid to gas conversions are, which is why steam is a great power source, but I digress).

The idea is to put the sensors for early detection, have linked ventilation systems, and when a sensor fires off, rapidly evacuate the lab and have the auto ventilators kick in.

He and N generally won't hurt most equipment unless you immerse the equipment in the liquid form of the gas (Um, not that we ever did that with obsolete equipment. Nope, never did that...).

Once the people were out of the lab, the building would be vented and everyone would wait for the detectors to indicate the air was back to normal.

Our lab had a big roll-up door we'd leave open when handing the dewars or transferring cryo liquids, so we'd have a quick exit as well as a large vent area in case of a spill or accidental venting. We left that door open when testing as well.

This was for superconductor magnet testing. i worked with the entire instrument package for the lab, writing the software to manage the gas flow control units and to pull data for them and a bunch of temperature sensors, as well as control the four quadrant power supply we had for the testing we were doing (+/-5v, +/-10Kamps), and for the massive capacitor banks we had to control power bleed off when a magnet quenched. If you know the basic math for electrical power supplies, you'll understand how much power we were dealing with for these magnets.

One cool thing we could do is manage the gas space above the liquid He to control the evaporation of the He in the dewar to drop the magnet to a temp that's up to a degree lower than the actual temp of the liquid He. It's the similar to the way that you can use isopropyl alcohol to cool the skin to a point cooler than the temperature of the alcohol when applied.

Q

[Quibblicious]

Air is almost 80% nitrogen. I think it's something like 79% nitrogen, 20% oxygen, and 1% other. The N₂ would likely disseminate more or less evenly throughout the room, I'd imagine.

Close, but it's usually colder than the surrounding air so tends to settle to the low points.

Q

[Quibblicious]

Nope, I want hydrogen. Not only is it twice as buoyant as helium, it's flammable when mixed with oxygen and heat. Hoo-boy is it flammable when mixed with oxygen and heat.

On that note, does setting a hydrogen elemental afire kill it or does it convert it into a weird para-fire elemental?

That would be the undead form of a hydrogen elemental

[8BitNinja]

Nope, I want hydrogen. Not only is it twice as buoyant as helium, it's flammable when mixed with oxygen and heat. Hoo-boy is it flammable when mixed with oxygen and heat.

On that note, does setting a hydrogen elemental afire kill it or does it convert it into a weird para-fire elemental?

You want another Hindenburg?

Very well then.

[Peelee]

Nope, I want hydrogen. Not only is it twice as buoyant as helium

Huh. Apparently, helium has 92.7% of the buoyancy of hydrogen.

Spoiler

Show

Hydrogen and helium are the most commonly used lift gases. Although helium is twice as heavy as (diatomic) hydrogen, they are both significantly lighter than air, making this difference negligible.

The lifting power in air of hydrogen and helium can be calculated using the theory of buoyancy as follows:

The density at sea-level and 0 °C for air and each of the gases is:

Air (ρair) = 1.292 kg/m3 = 0.0807 lb/ft³.
Hydrogen (ρH2) = 0.090 kg/m³
Helium (ρHe) = 0.178 kg/m³

Thus helium is almost twice as dense as hydrogen. However, buoyancy depends upon the difference of the densities (ρgas) − (ρair) rather than upon their ratios. Thus the difference in buoyancies is about 8%, as seen from the buoyancy equation:

FB=(ρair - ρgas) * g * V,
Where FB = Buoyant force (in Newton); g = gravitational acceleration = 9.8066 m/s² = 9.8066 N/kg; V = volume (in m³).

Therefore the amount of mass that can be lifted by hydrogen in air at sea level, equal to the density difference between hydrogen and air, is:

(1.292 - 0.090) kg/m3 = 1.202 kg/m³

and the buoyant force for one m³ of hydrogen in air at sea level is:

1 m3 * 1.202 kg * 9.8 N/kg= 11.8 N

Therefore the amount of mass that can be lifted by helium in air at sea level is:

(1.292 - 0.178) kg/m3 = 1.114 kg/m³

and the buoyant force for one m³ of helium in air at sea level is:

1 m3 * 1.114 kg * 9.8 N/kg= 10.9 N
Thus hydrogen's additional buoyancy compared to helium is:

11.8 / 10.9 ≈ 1.08, or approximately 8.0%

This calculation is at sea level at 0°C. For higher altitudes, or higher temperatures, the amount of lift will decrease proportionally to the air density, but the ratio of the lifting capability of hydrogen to that of helium will remain the same. This calculation does not include the mass of the envelope need to hold the lifting gas.

[GreatWyrmGold]

You may be correct, but it is hard to say for certain. If you are correct, then if the Mechane were to lose all power to the propellers, the ship would tilt dangerously, possibly throwing crew over the side to their deaths. That makes it nearly impossible to do any kind of repairs to the engines or propeller gearing without landing first. Seems like a design flaw in a vessel that can expect to see combat.

All things considered, I doubt the propellers provide a substantial proportion of the Mechane's lift. They're just too small. I'm in the same camp as whoever said that they were probably for controlling pitch and possibly roll, rather than lift. The Mechane might well tip if the propellers got damaged, but not that much.

On that note, does setting a hydrogen elemental afire kill it or does it convert it into a weird para-fire elemental?

Technically, it would have a claim on being turned into a very, very hot water elemental. Sorry, Redcloak, some people still care about the classics.

[Centaur]

Technically, it would have a claim on being turned into a very, very hot water elemental. Sorry, Redcloak, some people still care about the classics.

A sufficiently hot Water Elemental is indistinguishable from a particularly moist Air Elemental.

[King of Nowhere]

I'm wondering if this discussion serves a particular role in the book.
I now theorize that the mechane be subjected to an anti-magic field, so that it needs explaining beforehand why it would not fall down. Though it would still need explaining why the hull does not breach, since it was reinforced magically to make it lighter and harder.

[Kantaki]

A sufficiently hot Water Elemental is indistinguishable from a particularly moist Air Elemental.

A steam-elemental*! With properties of water-, air-, and fire-elementals.
Well, mostly the former two.

*para-elemetal? paramental?

[Quibblicious]

A steam-elemental*! With properties of water-, air-, and fire-elementals.
Well, mostly the former two.

*para-elemetal? paramental?

Pair o' elementals.

It's a dwarven term.

Q

[8BitNinja]

A steam-elemental*! With properties of water-, air-, and fire-elementals.

The water one is actually a substancal

The fire one is a reactional

The earth one is actually a carbon elemental

[King of Nowhere]

The earth one is actually a carbon elemental

A carbon elemental would come in the graphite and diamond variety. With some rarer exotic kinds like fullerene and nanotubes. earth is actually a mixture of lots of different stuff. So an earth elemental would be a swarm of really tiny elementals

[Goblin_Priest]

According to the SRD, water elementals aren't immune to fire. Nor do they react to it in any special way, save for their drench ability to put out fires up to a certain size. Thus, fire spells can damage them, and thus, they can die from them. Therefore, per RAW, elementals are one with the matter that composes them, including its state. A water elemental turned to steam dies. Therefore, a hydrogen elemental that was ignited would also die. No new elemental would take its place.

[Peelee]

The water one is actually a substancal

The fire one is a reactional

The earth one is actually a carbon elemental

More to the point, water would be a compoundal, while earth would be a mixtural.

[hamishspence]

MM3 did have Storm Elementals - which could be said to be Water Vapour based - so, like steam.

[Straybow]

Ah, at last a discussion were physics is not told to stand in the corner.

No, the physics is being shoved into a corner with ducktape over the mouth. Just because someone mentions mundane sources of lift doesn't mean the physics would actually work.

I was going to say those balloons are not big enough, but enchanting the hull to be lighter answers that.

No, not really. When you look at a real airship, the gasbag is typically ~100 times the size of the gondola and mechanical equipment. It has to be, because lighter-than-air can only provide lift on the order of 1 gram per liter. Water is 1000 times as dense, and so to lift 1 liter of water (or human body, only a few % difference in density) requires 1 m³ of He (ignoring the weight of the gasbag).

Yes, most of the passenger compartment is empty space. That's why the gasbag is only ~100 times as big instead of 1000 times as big. The Mechane has a gasbag that is may double the volume of the ship hull, which would provide about 2% of the lift needed.

All things considered, I doubt the propellers provide a substantial proportion of the Mechane's lift. They're just too small. I'm in the same camp as whoever said that they were probably for controlling pitch and possibly roll, rather than lift. The Mechane might well tip if the propellers got damaged, but not that much.

Since the He gasbag can only provide a tiny fraction of the lift needed for the Mechane's hull, crew, and cargo, those propellers could easily provide more lift than the tiny balloon.