I didn't get it. : (.
“Don't let yourself get attached to anything you are not willing to walk out on in 30 seconds flat if you feel the heat around the corner.”
Robert DeNiro as Neil McCauly, Heat (1995)
This quote has nothing to do with this blog post. I just like Heat.
Heat makes things expand. This occasionally gets used as a plot device in inflation stories. So today we’ll be taking a look at thermal expansion.
So the question is, how much bigger can heat make things? Short answer: not that much.
Dealing with gasses is simple thanks to the beauty of the Ideal Gas Law.
PV = nRT
V = nRT/P
P = pressure
V = volume
n = number of gas molecules, in moles
R = the universal gas constant
T = temperature, in Kelvin
It has a number of implications, but the important one for our purposes is this: all gasses respond to heating/cooling the same way. Assuming pressure remains constant, an absolute increase in temperature by 10% will cause an increase in volume by 10% whether you’re dealing with oxygen, hydrogen, helium, or methane.
To demonstrate, let’s use our hapless victim from the post Water. She’s currently filled with two thousand liters of hydrogen and oxygen, making her slightly over five feet in diameter (and dangerously explosive, but that’s an issue for a different post).
Let’s assume that water she consumed, and resulting converted gas, was at 60℉ and that gas is slowly heating up to body temperature, 98.6℉. When you convert to Kelvin and run the numbers, and assuming pressure stays constant, she goes from 2000 liters to 2,149 liters. Volume increases by 7.5%, resulting in an increase in diameter of about an inch and a half.
I’m sure that our test subject would find that to be quite significant, but the casual observer wouldn’t notice.
We can push this a bit farther, but there are limits. We have to keep the temperature within a range that will neither freeze nor cook a person. If we start at 32℉ and heat to 105℉, we get a 15% increase in volume and a three inch increase in diameter.
So heat doesn’t provide a significant amount of expansion over any reasonable temperature range. But you shouldn’t feel obligated to be reasonable. Exaggerations of various sorts are central to inflation fiction, so please carry on.
How about wish no. 2? Could you scientifically explain how to inflate a person using helium? If it were possible?
That is exactly what I meant and that's exactly how I saw it. I was talking about a fictional world where that sort of thing is possible.
So true in some imaginary worlds. I'll take mine, if that's all right.
Let's take an amateur leisure inflatist who doesn't stretch out too hard in the gym but already has some modest skills to show. She is average height (5'5"), average build, not too strong or resilient. She owns an amateur air pump that completely fills her in 40 minutes.
This lady will become full at 9'2" and slips if she stretches to 9'10". If she just finished filling comfortably full and wants to slip - she'll have to leave her pump purring for eight more minutes, very long.
Another way to slip is simply to roll into a sauna. The heat will make her slip much faster than a pump.
External observer won't notice a change in size, but observer won't miss how she becomes translucent, starts shaking and loses control. Heat matters in my imaginary world - it takes a lot to keep together if you became just a balloon ^_^
* cool office air - 65 F
* hot sauna air - 165 F
* a pump has a flux 0.1 l/s (or a score DAM 30 in Arena)
* uninflated inflatist - 5'5" high correspond to 500 pixels in VSG
* an inflatist when full - 9'2" correspond to 840 pixels in VSG and zero effort, in Arena it is ability score VOL 240
* the same inflatist when about to slip - 9'10" correspond to 900 pixels in VSG and effort 850 kcal ph, in Arena it is ability score VOL 288
Most liquefied gases would be cold enough to kill immediately. Even air at room temperature would be problematic. However, how about refrigerating capsules with their own power supply which warm up and slowly release their content? Sulphur trioxide and butane seem like possibilities to me, though toxicity would be a problem there I imagine. Alternatively, some kind of molecular cage for gases could be productive. Palladium can apparently hold fifty times its volume in hydrogen and I think it's non-toxic.
I believe there is a way to do this.
I've probably seen that movie like nine times. It completely rules.
I like school now.
Actually, this had got me thinking to a story concept I once had but never got around to finishing called The Detonatrix--about a supervillain that can gain weight and explode like a bomb almost at will. One idea I had was giving her the ability to convert some of her 'firm fat' into hydrogen so she could safely (kinda) ignite it to fly. If she converted a pound of fat into hydrogen, it would produce 192 cubic feet/5.047 cubic meters of gas. And yeah, it'd take more than just a couple pounds to make her airborne...
And blast an old story I wrote into oblivion. Heh.