Looks like the when the heat hits the scale surface, expansion causes the middle to bend upwards slightly, as the sides are constrained and it can't expand that way. Would be interesting to see the same experiment with a heat barrier, like a block of wood or something, between the scale and the paper. Tared back to zero after the barrier is put on of course.
The weight is higher at the end, because the composition is different than the start. The chemical reaction with the air has left a different set of chemicals behind.
Lavoisier did such experiments in sealed containers, and was the first to demonstrate that mass does not "disappear", but transforms into other bodies (e.g. gaz like CO2)
I think most of this is the heat updraft. The weight probably is changing, but accuracy below .03 isn't usually very good, and the negative reading at the end doesn't help.
Not really negative, just "less than what we call normal." The scale isn't measuring absolute weight above it, otherwise it would always be measuring the 14lbs/squ.inch of the air column. In this case, the hot air that was just made by all that flame is displacing some of that, and thus lowering the background pressure on the plate by a little, just enough to throw off the reading.
The heat doesn't expand the metal anywhere near enough to cause buoyancy. It's just a cheap crappy scale that reports higher precision than it can actually measure.
No, but I know enough physics to know what’s reasonable. The expansion would be on the scale of a few microns.
I did, however, find that same model of scale on AliExpress for 99 cents with free shipping. Let’s just say that’s not really the price point for accurate high-precision scientific instruments.
I do… Unheated air in a balloon is pulled down by gravity, applying a force on the bottom of the envelope. That force exactly matches the ambient air pressure, because it's the same gas getting pulled down by the same gravity. As the balloon's gas heats, its density lowers, so there's less total downward force. The pressure outside the balloon is unchanged, so there's a net upward buoyant force that makes the balloon rise. That's the same as for a helium balloon.
Aww… @ARedSM deleted all their increasingly-outraged comments. They were entertaining.
What's actually happening in this video is that the scale is a cheap uncalibrated pocket scale meant for measuring food. Even though it shows 0.01g increments, it can't measure that precisely. It can tell that mass went away as the paper burned, but it kinda sucks at measuring exactly how much mass.
This is a lousy scale. But you see this on good scales as well: if you weigh something warm, you will create an updraft that will artificially deflate the weight of the object being measured. You need a decent amount of precision to see it though. Opposite can happen with cold stuff, but there you need to worry about condensation throwing off weights as well.
It takes some time for those things to adjust. The number isn't displayed immediately, there's some delay. They probably take N measures per second and display the average of those N measures, so what you see is the weight one second ago, more or less.
No lab scale is going to use a rolling average. Sometimes it doesn't give you your result right away, but it's a lab scale, however cheap. It gives as precise a result as it is capable of, or it gives no result, that's the only way you would intentionally design these.
There is no scenario where you would want a scale with two decimal places to give you an incorrect answer on purpose.
I imagine oversampling is a good way to get a more accurate measure. Those analog sensors probably have a lot of measuring noise so doing some filtering/average over a, few samples is not a stupid idea. But maybe not what's going on in here.
If you do, you freeze the display while you take the readings, because you know some of the readings will be wrong. This may very well be what happens in scales with a delay between readings, waiting to accumulate enough measures for a good sample.
Neat. Fire doesn't change how much mass there is, it just changes where it is.
I assume the decrease is weight is from an updraft from the hot hair.
If this were done in a totally sealed container there would be no change whatsoever. But being done in open air it's kind of surprising how close the numbers before and after are. There are loads of places where particles could move to.
As a few observed, the measure at the end is NOT 0.008 but -0.008. The progression is 0.007, 0.000, -0.008. The total mass lost in combustion is 0.015. This would be dominated by hydrocarbons oxidized into CO₂ and H₂0, the former a gas at room temp and the latter a gas at combustion temp. Any moisture in the paper also evaporates during combustion. If the scale was calibrated, we would know the ash ratio. If the scale was stable and we waited, the ash would partially rehydrate over time.
I mean, it says negative 8 after it burned out because whoever calibrated that scale did a pisspoor job at it, it should have read 16 at the beginning. And yeah, the matter is just displaced into the air in the form of CO2 and ash particles that'll eventually settle again elsewhere.
Even if it was done in a sealed container, there would be a change in mass displayed as the solid was now a gas and is no longer affecting the pan with its force from gravity. It too would likely experience the convection currents and appear to lose mass when it is simply force from an updraft.
It doesn't release oxygen. It takes oxygen from the air to react with the carbon and hydrogen in the paper to produce carbon dioxide and water, which are gases, driven away by the heat that was produced by their production
The lost mass is the carbon that becomes carbon dioxide and the hydrogen that becomes water (steam)… which is most of the paper's mass, and it all disperses into the air, and doesn't weigh down on the scale*.
You can get the same effect by setting up a balance scale with two inflated balloons, then deflating one (pierce a hole near the stem). Once the gas isn't trapped in the balloon, its mass doesn't contribute to downward force.
* Kinda… It contributes to air pressure in all directions.
This only works if the gas is significantly pressurized. Otherwise, it doesn't matter if the air is inside or outside the balloon - if it's inside, it'll just provide buoyancy and it will "weight zero" effectivley.
If it was sealed, it would still need enough oxygen to burn. And that oxygen will bind to that carbon, to become heavier than what it started as. Might increase weight an extra 10% from no loss of particles.
C (12u) + O2 (32u) = CO2 (44u), so it gains quite a bit. Well, cellulose is more like C6H10O5 (162u) burning to 6 CO2 + 5 H2O (354u), but still, it more than doubles its weight.
Both "Fire doesn't change how much mass there is..." and "...it's kind of surprising how close the numbers before and after are." make it sound like you think the scale reads the same at the start as at the end, when in fact the 2 readings are nearly opposite. Positive .07 vs negative .08
That does seem to be the confusion, but I thought the rest of the comment would have prevented that confusion.
The mass doesn't change, as in matter is neither created or destroyed. But particles do move around. So the measured weight, the stuff on the scale, does change.
It's surprising the recorded weight is at all similar as this isn't a sealed container. The paper is free to go anywhere, including not on the scale.
Even still, the decrease in weight isn't because of an updraft, it's because the solid has been converted into a gas. In a sealed chamber it would still change, because the dense, solid piece of paper would be converted to less dense gas and expand to fill the chamber.
In this specific experiment yes. There's another experiment where they burn a metal wool, and it counterintuitively gains weight. In that case, fire does not displace the mass, the metal just heats up and cools back down. I have no scientific background to tell exactly what happens but I suspect some sort of oxidation on the metal caused by the heating, the metal literally gets covered in oxygen, hence gaining weight
I'd guess it oxidizes, so you end up with metal oxide, which is a solid, and the weight of the metal plus the oxygen is more than that of the metal alone, unlike when you burn carbon and get CO2, which is a gas that just goes away instead of staying as a solid.
The iron reacts with the oxygene, the oxygene bonds to the iron, so the weight of the oxygene molecules is added to the (now oxydized) metal wool. -> it gets heavier. The formula is 2Fe(s) + 3/2 O2(g) → Fe2O3(s). On the paper, the carbon of the paper is transformed to co², which is a gas and the heat can even propel it up. And no, I'm no chemist whiz.
Well, yes, matter is not created or destroyed. I think it's inaccurate to say that an object you burn doesn't gain it lose mass, but the process certainly doesn't create or destroy mass.
Agree; I think the heat expanded mechanisms in the scale and if it cools back to room temp then back to zero. Or the burning temporarily reduced air pressure above the scales. ,008 is miniscule so tiny changes are being registered.
Might not be mechanical, might be fucking with the electronics. It's pretty brief heat and a large plate as a heat sink, so my first guess would be that the sensor isn't accurate when hot. But given how little I know about the scale and how it reads force, I could buy any of these answers.
Yeah, maybe you're right. It stays at zero for quite some time and then suddenly drops to -0.08 so something's fucky there. Probably the heat messing with the sensor is a plausible explanation after all.
I don't buy that explanation here. Carbon combustion turns hydrocarbons plus oxygen into carbon dioxide and water — both of which are gaseous, and don't remain on the scale. ... In the version with burning steel wool, the reaction is iron to iron oxide, so the solid actually gains mass.
Paper, being made from wood, contains significant amounts of both potassium and calcium as well as smaller amounts of other minor metals. The increase in mass from oxygen in the solid oxides seems to nearly balance out the decrease in mass from the carbon and hydrogen turning to gaseous oxides and no longer being weighed on the plate.
The scale only measures significant units to 0.01? (I didn't catch the units). Which means the mass is between 0.0650 and 0.0749. There is a potential for 10% (up to 14%) mass loss, and the scale reading would not change.
That would be complete combustion of pure hydrocarbons (or carbohydrates etc). Often, you'll generate incompletely burnt soot, along with ashes of non-hydrocarbons in the fuel.
Doesn't have to pure. Just the right amount of oxygen and fuel mix. Too much fuel ( even if it was magically 100% pure) with insufficient oxygen, and you'll get VOCs an soot all over the place. One of the reasons smoking and raping are so bad for you. VOCs is bad.
yeah, but you'd still get complete combustion of the hydrocarbons. the impurities get oxidized too unless you supply insufficient oxygen, or quench the reaction too quickly
It can absolutely change how much weight you measure. Turning solids into gasses, or absorbing gasses from the air.
I'm surprised how close this one is to the ideal of not changing mass. Considering the mass that's being measured here is the paper, not the paper plus gas.
Snoman314
Looks like the when the heat hits the scale surface, expansion causes the middle to bend upwards slightly, as the sides are constrained and it can't expand that way. Would be interesting to see the same experiment with a heat barrier, like a block of wood or something, between the scale and the paper. Tared back to zero after the barrier is put on of course.
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BishlamekGurpgork
He found out what heat does to his scale's sensor, I think, with that negative reading.
LeCoq1963
There was a momentary tug-of-war between what I see, and what I know.
tombeithemist
Now do the 21 grams Experiment, atheist.
editheraven
Or 50mg.
pupquine
AdrianDunne
Do it with black powder and smokeless powder and compare how much mass is converted to a gaseous state.
cousteau
All of it?
mmontour
Hmm, I wonder what that "tare" button is for. And as others have mentioned, air currents from the heat would affect the reading.
cousteau
If those are ounces, one sheet of paper weighting 0.16 oz (5 g) sounds about right.
SheriffJackCarter
This post is why I made the favorites folder, “Shit I Find Interesting”
BeefiusMaximus1
I think I could have told you how this experiment would end, not really mind boggling.
cousteau
Well I wasn't expecting the final weight to be negative, but I guess not everyone can be perfect when it goes to calibrating scales.
ReallyFastSloth
Oh hey i have these for um, baking
secularink
Whoa! What a long rolling paper!
Gestalted
That's fun!
Allfather262
The weight is higher at the end, because the composition is different than the start. The chemical reaction with the air has left a different set of chemicals behind.
cousteau
The weight is negative at the end, not higher. The scale was just not calibrated at 0.
januarylover
Scientists of imgur, can you please cuddle me?
noReallyIamPrincessBob
Up in smoke, you say?
duktayp
Cool, now do magnets
championboilie
Magnets burn?
spliffen
apply enough heat, anything burns... yes, even that
NorthmanoftheNorth
And apply lube in form of 100% oxygen
nobodyspecial995
How do they work?
sigmatis
Magnets don't work, they just are.
cepacolusmaximus
cool, now do magats
plinkey
nice drugs scale, very accurate.
djarcas
Phlogiston!
cousteau
This is the only plausible explanation.
DavidNightingale
The scale doesn't measure mass, it measures force. We calibrate the force then display it as a mass. F=ma. F=mg.
Emrys12
Scientifically this is known as having a shitty scale
DrKonrad
Lavoisier did such experiments in sealed containers, and was the first to demonstrate that mass does not "disappear", but transforms into other bodies (e.g. gaz like CO2)
BishlamekGurpgork
I think most of this is the heat updraft. The weight probably is changing, but accuracy below .03 isn't usually very good, and the negative reading at the end doesn't help.
cousteau
Yeah that scale is probably not well calibrated.
Walfas
Now do this with a ball of steel wool. The weight actually goes up because you're converting iron into iron oxide.
017renegade
Negative weight? Maybe if we find out how this works, we can fly into space?
NightOwlRally
Double jump fucking unlocked, boys
DrKonrad
The negative values probably depend on how the tare was set at the beginning, so not really "negative weight"
Humputse
Maybe we could ignite some sort of fire under the rockets?
Navrodel
Not really negative, just "less than what we call normal."
The scale isn't measuring absolute weight above it, otherwise it would always be measuring the 14lbs/squ.inch of the air column.
In this case, the hot air that was just made by all that flame is displacing some of that, and thus lowering the background pressure on the plate by a little, just enough to throw off the reading.
CeruleanSky1988
something something the soul left the piece of paper.
cousteau
It's not "the soul", the technical term is "phlogiston".
dirtmarker
I wonder where the weight sensor is and if the heat expanding the metal plate changes the way it reads the weight.
Tarmaccian
The heat doesn't expand the metal anywhere near enough to cause buoyancy. It's just a cheap crappy scale that reports higher precision than it can actually measure.
dirtmarker
Excellent. I take it you designed that scale?
Tarmaccian
No, but I know enough physics to know what’s reasonable. The expansion would be on the scale of a few microns.
I did, however, find that same model of scale on AliExpress for 99 cents with free shipping. Let’s just say that’s not really the price point for accurate high-precision scientific instruments.
dirtmarker
So you're just guessing. Not that I wasn't but you don't know any more about this than the backside of the moon.
htapoicoS
That was my thought as well. 1. The scale isn't very exaxt below 0.03 and 2. The heat is messing with the sensor.
So much bullshit on the internet and people think it's magic lol
BishlamekGurpgork
I mean, it's reading negative numbers, so . . .
knexusatx
This piece of shit must be my coke guy's scale. Fuck you Chris
DaveSamsonite
The heat creates an updraft which tugs the paper upwards
FuzzyX
Such commercial scales are normally quite bad on the low end of the scale making it more of a best fit guess.
DongleDingler
This is definitely a consumer-grade scale, not commercial. I've bought the same one on Amazon for about $10
Tarmaccian
$0.99 on AliExpress with free shipping, as one of the first search results for "pocket scale". Don't expect great results.
chrisckelly
Quick shout-out to my FBI guy down the street in the flower delivery truck: Gary, I’ve never seen this person in my life!
honeybadgersRus
You smell like a snitch
Alurkerforcedtologin
We're not falling for that, again.
RickRollEditor
Nothing wrong with the scale. The heat pulls it up. Unless you put your coke on fire, it weighs in fine.
trump81
Also don’t do that, it Will destroy the coke
RickRollEditor
You can breathe it in fine, just like horse. Just terrible for weighing.
Tarmaccian
Can you explain a bit more how that works? That’s not any physics I’m aware of…
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Tarmaccian
I do… Unheated air in a balloon is pulled down by gravity, applying a force on the bottom of the envelope. That force exactly matches the ambient air pressure, because it's the same gas getting pulled down by the same gravity. As the balloon's gas heats, its density lowers, so there's less total downward force. The pressure outside the balloon is unchanged, so there's a net upward buoyant force that makes the balloon rise. That's the same as for a helium balloon.
That's not what happens here.
Tarmaccian
Aww… @ARedSM deleted all their increasingly-outraged comments. They were entertaining.
What's actually happening in this video is that the scale is a cheap uncalibrated pocket scale meant for measuring food. Even though it shows 0.01g increments, it can't measure that precisely. It can tell that mass went away as the paper burned, but it kinda sucks at measuring exactly how much mass.
Metrology is important, kids!
RickRollEditor
Reported :)
Estitabarnak
This is a lousy scale. But you see this on good scales as well: if you weigh something warm, you will create an updraft that will artificially deflate the weight of the object being measured. You need a decent amount of precision to see it though. Opposite can happen with cold stuff, but there you need to worry about condensation throwing off weights as well.
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Tarmaccian
That's why lava falls from the sky, and ice is mined underground, right?
Hot stuff doesn't actually "go upward". Hot fluids are less dense, and less-dense fluids have an upward buoyant force.
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Phawtin
Scale was possibly calibrated to 0 when it had .08 grams on it so when nothing on it, it’s gone -.08.
Grimmrog
but then shouln't it start with 0? Someone would have had t set to 0 with a 0.04 weight first
Higure
The paper weighs 0.15 and someone tared the scale at 0.08.
macgerdo
No one rips you off.
BishlamekGurpgork
Then it wouldn't be zero while the ash was floating.
cousteau
It takes some time for those things to adjust. The number isn't displayed immediately, there's some delay. They probably take N measures per second and display the average of those N measures, so what you see is the weight one second ago, more or less.
BishlamekGurpgork
No lab scale is going to use a rolling average. Sometimes it doesn't give you your result right away, but it's a lab scale, however cheap. It gives as precise a result as it is capable of, or it gives no result, that's the only way you would intentionally design these.
There is no scenario where you would want a scale with two decimal places to give you an incorrect answer on purpose.
cousteau
I imagine oversampling is a good way to get a more accurate measure. Those analog sensors probably have a lot of measuring noise so doing some filtering/average over a, few samples is not a stupid idea. But maybe not what's going on in here.
BishlamekGurpgork
If you do, you freeze the display while you take the readings, because you know some of the readings will be wrong. This may very well be what happens in scales with a delay between readings, waiting to accumulate enough measures for a good sample.
HeresYourSauce
Neat. Fire doesn't change how much mass there is, it just changes where it is.
I assume the decrease is weight is from an updraft from the hot hair.
If this were done in a totally sealed container there would be no change whatsoever. But being done in open air it's kind of surprising how close the numbers before and after are. There are loads of places where particles could move to.
gesel
As a few observed, the measure at the end is NOT 0.008 but -0.008. The progression is 0.007, 0.000, -0.008. The total mass lost in combustion is 0.015. This would be dominated by hydrocarbons oxidized into CO₂ and H₂0, the former a gas at room temp and the latter a gas at combustion temp. Any moisture in the paper also evaporates during combustion. If the scale was calibrated, we would know the ash ratio. If the scale was stable and we waited, the ash would partially rehydrate over time.
cousteau
That is correct but like one order of magnitude off.
gesel
Can you explain the error?
cousteau
It says 0.07, not 0.007
gesel
So it does!
Huntergirl727
Flash paper or tissue paper also floats away in embers, which is part of the mass.
HeresYourSauce
Yeah. You can see at least one piece float off like that here. I assume the remainder is taking some amount of mass from the air to account for that.
neithermenoryou
I mean, it says negative 8 after it burned out because whoever calibrated that scale did a pisspoor job at it, it should have read 16 at the beginning.
And yeah, the matter is just displaced into the air in the form of CO2 and ash particles that'll eventually settle again elsewhere.
cousteau
What's this, ounces? An A4 sheet of paper at 80 g/m² weights exactly 80/16 = 5 grams, which is about 0.16–0.17 ounces. It checks out.
cousteau
Yeah, it stops being on the scale, hence why it goes down to zero. No idea how it ends up in the negatives though.
spookyactionatadistance
I mean, no. The release of carbon dioxide wouldn't be weighed by your scale
BlueSnowfox
This kills the fire
Pseudobatrachotoxin
Even if it was done in a sealed container, there would be a change in mass displayed as the solid was now a gas and is no longer affecting the pan with its force from gravity. It too would likely experience the convection currents and appear to lose mass when it is simply force from an updraft.
plinkey
it's just releasing oxygen atoms, there's still enough carbon or other shit that doesn't burn during the chemical reaction.
Grimmrog
what? it's paper it burns the carbon to carbondioxide. so mos of it will be gone. the scale is just pretty fucked up.
quadraspaz1
It doesn't release oxygen. It takes oxygen from the air to react with the carbon and hydrogen in the paper to produce carbon dioxide and water, which are gases, driven away by the heat that was produced by their production
HeresYourSauce
I go to bed for the night and come back to people saying I'm wrong, but for things I never said.
I seem to have explained myself baddly, but I'm even sure where the miscommunication happened. What do people disagree about?
Tarmaccian
The lost mass is the carbon that becomes carbon dioxide and the hydrogen that becomes water (steam)… which is most of the paper's mass, and it all disperses into the air, and doesn't weigh down on the scale*.
You can get the same effect by setting up a balance scale with two inflated balloons, then deflating one (pierce a hole near the stem). Once the gas isn't trapped in the balloon, its mass doesn't contribute to downward force.
* Kinda… It contributes to air pressure in all directions.
cousteau
This only works if the gas is significantly pressurized. Otherwise, it doesn't matter if the air is inside or outside the balloon - if it's inside, it'll just provide buoyancy and it will "weight zero" effectivley.
martineb72
If it was sealed, it would still need enough oxygen to burn. And that oxygen will bind to that carbon, to become heavier than what it started as. Might increase weight an extra 10% from no loss of particles.
cousteau
C (12u) + O2 (32u) = CO2 (44u), so it gains quite a bit.
Well, cellulose is more like C6H10O5 (162u) burning to 6 CO2 + 5 H2O (354u), but still, it more than doubles its weight.
badgesweedontneednostinkingbadges
But carbon dioxide is a gas, so it doesn't stay on the scale but disperses into the air, along with the smoke and some ash.
Walfas
My guy, you missed the negative sign at the end of the video. #ConfidentlyIncorrect
HeresYourSauce
What do you think I'm saying? Because I think my mistake is poorly wording my point.
Snaitf
Both "Fire doesn't change how much mass there is..." and "...it's kind of surprising how close the numbers before and after are." make it sound like you think the scale reads the same at the start as at the end, when in fact the 2 readings are nearly opposite. Positive .07 vs negative .08
HeresYourSauce
That does seem to be the confusion, but I thought the rest of the comment would have prevented that confusion.
The mass doesn't change, as in matter is neither created or destroyed. But particles do move around. So the measured weight, the stuff on the scale, does change.
It's surprising the recorded weight is at all similar as this isn't a sealed container. The paper is free to go anywhere, including not on the scale.
Walfas
Even still, the decrease in weight isn't because of an updraft, it's because the solid has been converted into a gas. In a sealed chamber it would still change, because the dense, solid piece of paper would be converted to less dense gas and expand to fill the chamber.
AdoraApplesauceMeowmeow
In this specific experiment yes.
There's another experiment where they burn a metal wool, and it counterintuitively gains weight.
In that case, fire does not displace the mass, the metal just heats up and cools back down. I have no scientific background to tell exactly what happens but I suspect some sort of oxidation on the metal caused by the heating, the metal literally gets covered in oxygen, hence gaining weight
cousteau
I'd guess it oxidizes, so you end up with metal oxide, which is a solid, and the weight of the metal plus the oxygen is more than that of the metal alone, unlike when you burn carbon and get CO2, which is a gas that just goes away instead of staying as a solid.
AdventurousDonut480
The iron reacts with the oxygene, the oxygene bonds to the iron, so the weight of the oxygene molecules is added to the (now oxydized) metal wool. -> it gets heavier. The formula is 2Fe(s) + 3/2 O2(g) → Fe2O3(s). On the paper, the carbon of the paper is transformed to co², which is a gas and the heat can even propel it up. And no, I'm no chemist whiz.
cousteau
Even if it fell down, it'd spread all over the table rather than staying on the scale.
BishlamekGurpgork
Fire is almost always a process of oxidation. Burning steel wool is the process of oxidizing it.
Tengenstein
Exactly, mass is gained or lost depending on if you can capture products for assessment. Real easy when they're solids, gases not so much.
BishlamekGurpgork
Well, yes, matter is not created or destroyed. I think it's inaccurate to say that an object you burn doesn't gain it lose mass, but the process certainly doesn't create or destroy mass.
Tarmaccian
It’s important to remember that you’re not just burning paper or steel wool… you’re also burning oxygen. That mass must be accounted for.
Burning 5g of iron and 2g of oxygen, leaving 7g of iron oxide? That makes perfect sense.
Burning 5g of paper and 5g of oxygen, leaving 0.2g of ash and some uncaptured mass of gas products? That also seems fine.
Walfas
Matter most certainly can be created or destroyed. It's energy that cannot.
Phawtin
Possibly calibrated to negative. So when scale is empty it’s gone back to negative.
BishlamekGurpgork
No, it's zero while the ash is floating. My guess is the heat is fucking with the sensor.
PastureofMuppets
Agree; I think the heat expanded mechanisms in the scale and if it cools back to room temp then back to zero. Or the burning temporarily reduced air pressure above the scales. ,008 is miniscule so tiny changes are being registered.
BishlamekGurpgork
Might not be mechanical, might be fucking with the electronics. It's pretty brief heat and a large plate as a heat sink, so my first guess would be that the sensor isn't accurate when hot. But given how little I know about the scale and how it reads force, I could buy any of these answers.
cousteau
Or maybe the thing is just not fast enough.
BishlamekGurpgork
I mean, you can see its response time when the paper begins to take off and it goes to zero.
Normally you'd see time between readings, not a delay before displaying a reading, but that's clearly not the case here.
cousteau
Yeah, maybe you're right. It stays at zero for quite some time and then suddenly drops to -0.08 so something's fucky there. Probably the heat messing with the sensor is a plausible explanation after all.
fantabuloustimewaster
I don't buy that explanation here. Carbon combustion turns hydrocarbons plus oxygen into carbon dioxide and water — both of which are gaseous, and don't remain on the scale. ... In the version with burning steel wool, the reaction is iron to iron oxide, so the solid actually gains mass.
InkGoat
Paper, being made from wood, contains significant amounts of both potassium and calcium as well as smaller amounts of other minor metals. The increase in mass from oxygen in the solid oxides seems to nearly balance out the decrease in mass from the carbon and hydrogen turning to gaseous oxides and no longer being weighed on the plate.
RawSugarPackage
The scale only measures significant units to 0.01? (I didn't catch the units). Which means the mass is between 0.0650 and 0.0749. There is a potential for 10% (up to 14%) mass loss, and the scale reading would not change.
Sakkura
That would be complete combustion of pure hydrocarbons (or carbohydrates etc). Often, you'll generate incompletely burnt soot, along with ashes of non-hydrocarbons in the fuel.
Tengenstein
Doesn't have to pure. Just the right amount of oxygen and fuel mix. Too much fuel ( even if it was magically 100% pure) with insufficient oxygen, and you'll get VOCs an soot all over the place. One of the reasons smoking and raping are so bad for you. VOCs is bad.
Sakkura
If there are impurities in there, like calcium or potassium, they get left behind as ashes. So purity definitely matters.
Tengenstein
yeah, but you'd still get complete combustion of the hydrocarbons. the impurities get oxidized too unless you supply insufficient oxygen, or quench the reaction too quickly
StopTheWorldIWannaGetOff
Smoking and whatnow?
Tengenstein
wow, my phone really doens't like vapists.
HeresYourSauce
It can absolutely change how much weight you measure. Turning solids into gasses, or absorbing gasses from the air.
I'm surprised how close this one is to the ideal of not changing mass. Considering the mass that's being measured here is the paper, not the paper plus gas.
Z0op
Im guessing you gotta take the accuracy of that scale into account when its such low weights
Tengenstein
Dude the scale goes negative. From +7 to -7, so 14 units difference, assuming the scale was accurate.
fantabuloustimewaster
ARGH WHY WOULD SOMEONE TARE IT THAT WAY
Tengenstein
For Internet points. Also might just be a crap scale, or obe that's not been maintained or calibrated properly