How exactly does F-Iron work

[Rhythm of Discord]

When you store or tap an ironmind does your mass actually change or are you actually storing the affect of gravity on your body to reduce weight? 

[alder24]

1 hour ago, Rhythm of Discord said:

When you store or tap an ironmind does your mass actually change or are you actually storing the affect of gravity on your body to reduce weight? 

You store your mass. This does affect the force of gravity but not gravitational acceleration, so if you fall on someone when you're heavier then they can't push you off themself, but when you fall on them your falling speed is the same because you don't change g=9.81 m/s2. However if you store most of your mass, your surface area to mass ratio increases greatly which means your terminal velocity drops, so you can fall safely from any distance and behave like a feather. Storing mass also affects your momentum and follows conservation of momentum. But F-iron stores just mass, not gravity.

Spoiler

Questioner

Does Iron store mass or weight?

Brandon Sanderson

Excellent question. The thing is it really does involve mass, but I’m breaking some physics rules, basically. I have to break a number of physics rules in order to make Magic work in the first place. Those whole laws of Thermodynamics, I’m like “You are my bane!” (laughter) But I try to work within the framework, and I have reasonings built up for myself, and some of them have to be kind of arbitrary. But the thing is, it does store mass if you look at how it interacts, but when a Feruchemist punches someone, you’re not having a mass transference of a 1000 pounds transferring the mass into someone else.

So there are a few little tweaks. You can go talk to Peter, because Peter has the actual math. Oh Peter’s back there. Peter is dressed up as Allomancer Jak from the broadsheet. In fact we’re giving some out broadsheets, aren’t we Peter. So when you come through the line, we’re giving out Broadsheets. Please don’t take fifty—I think we might have enough for everybody. The broadsheets are the newspaper from the Alloy of Law time. It’s an inworld newspaper. It’s actually reproduced in the book in four different pages, and we put it together in one big broadsheet.

So anyway, you can talk with him, he’s got more of the math of it. I explained the concept to Peter and he’s better with the actual math, so he said “We’ll figure it out.”

Alloy of Law release party (Nov. 7, 2011)

 

[Quantus]

Short answer it that it hand-wavy breaks physics, much like classic comic book speedsters, and there has a been a ton of debate and discussion trying to reconcile it.  The latest Ive seen kind of dwindled off from a general "Higgs Field Shenanigans" statement that was really just a different sort of hand-wave. It's not gravity manipulation because the effects and math dont line up, and there's not physiological and/or bulk change the way there is with feruchemcial Strength.  

For practical purposes (and this is my sense of it) they are able to increase what mass the outside universe Thinks they have, sort of like a heavy, skin-level force field.  They cant get crushed under their own weight, but they also cant move an equivalent weight that isnt themselves.  

[Underwater_Worldhopper]

On 6/8/2023 at 5:58 PM, Quantus said:

Short answer it that it hand-wavy breaks physics, much like classic comic book speedsters, and there has a been a ton of debate and discussion trying to reconcile it.  The latest Ive seen kind of dwindled off from a general "Higgs Field Shenanigans" statement that was really just a different sort of hand-wave. It's not gravity manipulation because the effects and math dont line up, and there's not physiological and/or bulk change the way there is with feruchemcial Strength.  

For practical purposes (and this is my sense of it) they are able to increase what mass the outside universe Thinks they have, sort of like a heavy, skin-level force field.  They cant get crushed under their own weight, but they also cant move an equivalent weight that isnt themselves.  

I'm sure that has some fallacies in it too, but I don't see any, that's actually a very nice way of putting it!