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Storing weight (feruchemy) & Bouyant forces


Sirscott13

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So something that has been nagging the back of my mind for a long time is whether or not Bouyant forces come into play when someone stores weight.

The obvious thing being is if you can sink or float depending on your storage/tapping of weight.

The real question though is whether or not you could float like a balloon in normal air.

Let's say you are naked with a swallowed iornmind. You store as much weight as you can, would not this create a negative buoyancy space where you stand. If so, you become a lighter than air balloon and would thereby float.

So someone like Wax could get to the top of a building using nothing but a storage of weight.

But in the books this effect doesn't seem to take place. Thoughts?

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Short answer: No. It's impossible in the air.

Proof: IIRC the body goes up if it's less dense than surroundings, sinks when it's denser and floats when it's of the same density. So for it to take effect Skimmer would have to store...

let's see, shall we? Density of the air at sea level (the higher the less) in 20*C is 1,2 kg/m^3. Human body is about 1100kg/m^3. So Skimmer would need to decrease his weight over 900 times. 1/900 is about 0,11%. Skimmer would need to store about 99,8% of his weight to be of the same density as the air at the sea level and let's keep in mind that air density decreases as you go up.
We have it confirmed that Feruchemist can store up to 80%, at his best. So he wouldn't be even able to float in the air.

However, a Skimmer could definitely mess with floating and sinking in the water. That is, if storing weight changed your density...

 

We have it confirmed that storing weight doesn't affect your density. At all. Both in books and by WoB. It's something related to bosons.

Edited by Oversleep
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Feruchemical iron affects the interaction with the Higgs field IIRC, now that's a bit beyond my physics understanding so I can't say for sure how it would react but I believe it would still allow for buoyancy, the problem is the metalmind itself needs to weigh a certain amount which would drag you down and it needs to be large enough for you to continually store all of your weight.

 

 

Short answer: No. It's impossible in the air.

Proof: IIRC the body goes up if it's less dense than surroundings, sinks when it's denser and floats when it's of the same density. So for it to take effect Skimmer would have to store...

let's see, shall we? Density of the air at sea level (the higher the less) in 20*C is 1,2 kg/m^3. Human body is about 1100kg/m^3. So Skimmer would need to decrease his weight over 900 times. 1/900 is about 0,11%. Skimmer would need to store about 99,8% of his weight to be of the same density as the air at the sea level and let's keep in mind that air density decreases as you go up.
We have it confirmed that Feruchemist can store up to 80%, at his best. So he wouldn't be even able to float in the air.

However, a Skimmer could definitely mess with floating and sinking in the water.

 

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BTW, we have it also confirmed that storing weight doesn't affect your density. At all. Both in books and by WoB. It's something related to bosons.

Where did you get that 80% figure? To my knowledge there's no confirmation on the limits of feruchemy beyond that storing beyond a certain amount of certain attributes will kill you (I believe the mentioned figure was that storing your strength beyond 80% might kill you which is why I ask in case you got confused with this quote)
Iron has been stored to 100% I believe and there is at the least a very heavy indication that other attributes have been as well in BoM, spcifically:

BoM spoilers


Storing Identity to create universal metalminds, all of your identity must be stored.

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You can't make yourself 100,000 times slower and gain 100,000 times multiplication. You can give up all of your normal speed, and so when you tap that speed out you are at 200% for an equal period. (And that's a theoretical maximum; realistically, you can only go to down around 75% slower or the like.)

source (48, I don't know how to link it)

That's the quote, I think. Maybe some attributes can be stored 100% and some can't? I don't know. If somebody can store 100% in BoM, then of course it's canon that's possible. But I don't know if it applies to all attributes.

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That's the quote, I think. Maybe some attributes can be stored 100% and some can't? I don't know. If somebody can store 100% in BoM, then of course it's canon that's possible. But I don't know if it applies to all attributes.

I imagine that's an issue with safely storing to that amount, as he mentioned that 100% is the theoretical maximum, you technically can but with some attributes doing so will kill you (Notably strength, speed and health)

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That's the quote, I think. Maybe some attributes can be stored 100% and some can't? I don't know. If somebody can store 100% in BoM, then of course it's canon that's possible. But I don't know if it applies to all attributes.

You know... I don't think there's a cap on how unlucky you can be. But then again... having a heart attack, the moon falling, getting struck by lightning and all the volcanoes going off simultaneously would probably kill you. Probably.

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I imagine that's an issue with safely storing to that amount, as he mentioned that 100% is the theoretical maximum, you technically can but with some attributes doing so will kill you (Notably strength, speed and health)

I imagine you could store 100% of weight then (being weightless isn't particularly unhealthy, right?). But since Wax never did that, let's assume it's impossible.

Storing 80% means he weights about 20 kilograms (assuming he weights about 80 kg). That doesn't affect the gravity, but since his strength is unchanged, he can definitely jump higher on his own. I'd say 5 times higher, but I need to do the physics, so I'll later post it.

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I imagine you could store 100% of weight then (being weightless isn't particularly unhealthy, right?). But since Wax never did that, let's assume it's impossible.

Storing 80% means he weights about 20 kilograms (assuming he weights about 80 kg). That doesn't affect the gravity, but since his strength is unchanged, he can definitely jump higher on his own. I'd say 5 times higher, but I need to do the physics, so I'll later post it.

I'm not entirely certain that he never does actually, I believe Sazed does in WoA but even if not that's no reason to assume it's impossible, Wax might just not have much reason to be completely weightless, having a little weight is actually beneficial since if he weighed nothing the air resistance would actually make it harder to move.

Physics with iron feruchemy is weird, it's not weight it stores, it's not mass either it's something more complicated, I'm not sure we even have the equations necessary to describe it, let alone the understanding of it necessary to apply those. There's also actually some debate as to whether or not strength is altered, you can't crush yourself under your weight so the strength needed to support your body increases proportionately (And the obvious corollary to this is that your strength decreases proportionately to how much you store) however Wax has said that storing allows you to be lighter on your feet so there's some contradiction.

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I'm not entirely certain that he never does actually, I believe Sazed does in WoA but even if not that's no reason to assume it's impossible, Wax might just not have much reason to be completely weightless, having a little weight is actually beneficial since if he weighed nothing the air resistance would actually make it harder to move.

Physics with iron feruchemy is weird, it's not weight it stores, it's not mass either it's something more complicated, I'm not sure we even have the equations necessary to describe it, let alone the understanding of it necessary to apply those. There's also actually some debate as to whether or not strength is altered, you can't crush yourself under your weight so the strength needed to support your body increases proportionately (And the obvious corollary to this is that your strength decreases proportionately to how much you store) however Wax has said that storing allows you to be lighter on your feet so there's some contradiction.

Internal strenght is increased, but from Sazed vs. Marsh I remember Sazed tapping strength to be able to move while tapping weight. And without that he had problems with moving, he felt his fists as if they were made of iron. His weight crushed him into the floor.

If weight can be stored 100%... I remember passage about Wax storing it while riding a horse "to the point of almost floating". The question is, why not store all of it and strap yourself to the horse?

I understand problems with moving, but certainly he had a lot of occasions to store all of it.

 

The way I see it it's that density doesn't change (confirmed) but everything which interacts with weight is affected. Similar how in near light speeds objects interact as if they weighted a lot more but there is no increase in mass.

So I just use normal equations but with decreased mass.

Edited by Oversleep
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Internal strenght is increased, but from Sazed vs. Marsh I remember Sazed tapping strength to be able to move while tapping weight. And without that he had problems with moving, he felt his fists as if they were made of iron. His weight crushed him into the floor.

If weight can be stored 100%... I remember passage about Wax storing it while riding a horse "to the point of almost floating". The question is, why not store all of it and strap yourself to the horse?

I understand problems with moving, but certainly he had a lot of occasions to store all of it.

 

The way I see it it's that density doesn't change (confirmed) but everything which interacts with weight is affected. Similar how in near light speeds objects interact as if they weighted a lot more but there is no increase in mass.

So I just use normal equations but with decreased mass.

Doesn't seem to be a problem for Wax who has arguably used a heck of a lot more weight at a time.

Because strapping himself would gain him almost nothing but cost him a lot since he'd have to stop, strap himself on then unstrap himself at the destination. But arguably that was 100%, almost floating is a lot more than 80% in any case, with clothes, metalminds and such added in I'd say it was almost certainly 100%.

Sort of? I mean feel free but without knowing exactly how iron works there's not much value to it, biomechanics in particular are hard enough to judge even if we did know how iron worked, without it judging things like jumping height is nigh-impossible.

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Doesn't seem to be a problem for Wax who has arguably used a heck of a lot more weight at a time.

Because strapping himself would gain him almost nothing but cost him a lot since he'd have to stop, strap himself on then unstrap himself at the destination. But arguably that was 100%, almost floating is a lot more than 80% in any case, with clothes, metalminds and such added in I'd say it was almost certainly 100%.

Sort of? I mean feel free but without knowing exactly how iron works there's not much value to it, biomechanics in particular are hard enough to judge even if we did know how iron worked, without it judging things like jumping height is nigh-impossible.

Did Wax ever move while overtapping iron? I don't remember that. He always Pushes something, sure, but I don't remember him actually walking while tapping lots of weight.

There's not much value to it? The equations are the same, no matter jumping with your own legs or Pushing on metals. Those equations can tell us how Pushing (or jumping) is changed.  Maybe we could finally calculate Pushing force.

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But see, if you could store even eighty percent of your weight, a 200lb guy would weigh 40lb. But what I'm wondering is if he'd actually weigh less than 40lbs because now you have a greater Bouyant force acting upon him making him say 35-39lbs or so. If you could store 100% of your weight, you'd basically be a vacuum balloon. Even storing 99% of your weight would put you on par with a helium weather balloon right?

The fact of the matter is that the weight of the air vs the weight of the object creates the Bouyant force. A balloon rises because it weighs less than the surrounding air.

The formula for bouyancy force is Fb= PA where Fb is Bouyant force, P is pressure, and A is area

The standard atmospheric pressure of air is 14.696 psi

So would not then someone just have to achieve a similar weight per square inch ratio to float?

Edited by Sirscott13
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But see, if you could store even eighty percent of your weight, a 200lb guy would weigh 40lb. But what I'm wondering is if he'd actually weigh less than 40lbs because now you have a greater Bouyant force acting upon him making him say 35-39lbs or so. If you could store 100% of your weight, you'd basically be a vacuum balloon. Even storing 99% of your weight would put you on par with a helium weather balloon right?

The fact of the matter is that the weight of the air vs the weight of the object creates the Bouyant force. A balloon rises because it weighs less than the surrounding air.

The formula for bouyancy force is Fb= PA where Fb is Bouyant force, P is pressure, and A is area

The standard atmospheric pressure of air is 14.696 psi

So would not then someone just have to achieve a similar weight per square inch ratio to float?

Okay. Important distinction here. His weight would decrease only in relation to how much he stores/taps it, alright?

BUT if he were to stand on a scale, it would show less than he really weights. If we were to do some calculations with weight involved (like kinetic energy), we would still use Feruchemy-related weight, but if we were to do some math on jumping, we would use the one from the scale.

It's all related to density, not weight per se. Ballon rises because it weighs less than the air which would take the balloon-shaped-space. Which means that air is denser than balloon.

 

Bouyant force has nothing to do with weight! Changing his weight doesn't affect them at all! The buoyant force is related to do depth (of the air in this example) and the difference between top area and down area of the object (it's very hard with something such oddly shaped as human body. It would be easier if Wax was just a cube).

What changing weight affects is the force of the gravity. And what matters here is if the gravity force is greater than, equal, or less than buoyant force.

I don't mind someone with knowledge in the subject going through my post since I haven't done this particular field for few years :)

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I think I'm confused here...

I don't think buoyant force changes when storing weight, I'm wondering if you could store your weight enough for Bouyant force to counteract your weight making you float in air. Maybe not rise in the air like a balloon, but surely given enough weight storage you could weigh as much as the air around you for simulated weightlessness even if you can't store 100% of your weight.

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Given the demonstrated effects of air resistance on weight stroring individuals I believe that buoyancy is possible, though again the metalmind itself has weight and will drag you down.

 

Did Wax ever move while overtapping iron? I don't remember that. He always Pushes something, sure, but I don't remember him actually walking while tapping lots of weight.

There's not much value to it? The equations are the same, no matter jumping with your own legs or Pushing on metals. Those equations can tell us how Pushing (or jumping) is changed.  Maybe we could finally calculate Pushing force.

The equations aren't the same at all, the biomechanics of jumping are pretty insane if you want to calculate precise forces and since we have almost no information on the actual workings or any actual numbers it would be a glorified guess at a dozen different variables, all of which would compound the inaccuracy of the result into meaninglessness.

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Does the metal weigh you down if ingested? What attributes of your weight do you store? Is it everything inside you, or every living part of you? What if you tapped feruchemy and made yourself huge and stored weight?

Probably, I imagine it'd depend on certain cognitive factors, whether the metal was perceived to be a part of you or not but I'm inclined to say that it'd probably still weigh you down for most people in most situations.

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The equations aren't the same at all, the biomechanics of jumping are pretty insane if you want to calculate precise forces and since we have almost no information on the actual workings or any actual numbers it would be a glorified guess at a dozen different variables, all of which would compound the inaccuracy of the result into meaninglessness.

Is jumping really that complicated? I assumed that if with normal weight you can exercise X Newtons of force, then with added weight the force doesn't change, as there is no difference in muscles and such; anyway, I can skip jumping and steer into Steelpushing right away.

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So I have no where near the knowledge to take part in this discussion on a mathmatical/scientific level. However, I did recall/think of two things that may help. First, in the original trilogy, Sazed was never weightless enough to float up. He just reduced it so much that when he leapt off the tree, his fall was significantly slowed/gentler. Second, if I was testing to see if this was possible, I would stand naked, having fasted for a day or so and recently have voided my bladder. I would have a compatriot standing by on a lift, ladder, or some contraption that can raise him up from ground level up into the air. I would then have said compatriot hold my metal mind so my only contact with it is my finger. I would them store into this metal mind. That would enable me to have a large metal mind to store a significant portion of my weight, without the metal mind itself weighing me down. If by storing I do actually rise into the air, my compatriot could climb the ladder, or use the lift to rise into the air with me to observe how much hang time I gain. The reason why i go into detail with that, is it has been mentioned the metal mind being a limiting factor. I was merely offering an alternative. 

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Is jumping really that complicated? I assumed that if with normal weight you can exercise X Newtons of force, then with added weight the force doesn't change, as there is no difference in muscles and such; anyway, I can skip jumping and steer into Steelpushing right away.

Depends how the weight is changed, joints, muscles and cell chemistry could all change drastically depending on how exactly it changes. 

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Well has anyone considered then that if you take all aspects of internal weight and the metalmind out of the question as pathfinder mentioned, that you could potentially float if not rise in the atmosphere.

Would there be side effects though? Considering that you weigh nothing, but the air is treating you like vacuum density? Wouldn't that crush you?

The fact remains that weight change without a change in density is so complex! The only thing I can begin to imagine is that maybe you wouldn't float because the weight of the atmosphere pressing against you would hold you down? Idk anymore

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