carbon dioxide filled latex balloons
sydscience
of latex balloons filled with helium, carbon dioxide and compressed
air. The carbon dioxide balloons deflated fastest but we have no idea
why. Does anyone know the reason that carbon dioxide filled balloons
deflate faster than helium or compressed air? Many thanks.
N:dlzc D:aol T:com (dlzc)
"sydscience" <nkco...@mydurango.net> wrote in message
news:6752b069-d86e-4ea4...@y23g2000pre.googlegroups.com...
> My daughter did her science experiment measuring the
> deflation rates of latex balloons filled with helium, carbon
> dioxide and compressed air. The carbon dioxide balloons
> deflated fastest but we have no idea why.
These folks don't either:
http://www.answerbag.com/q_view/734234
> Does anyone know the reason that carbon dioxide filled
> balloons deflate faster than helium or compressed air?
> Many thanks.
No reason for this to happen that I know of. How did you decide
rates of deflaton?
David A. Smith
sydscience
wrote:
> Dear sydscience:
>
> "sydscience" <nkconr...@mydurango.net> wrote in message
We measured the circumference of the balloons every 30 minutes.
N:dlzc D:aol T:com (dlzc)
"sydscience" <nkco...@mydurango.net> wrote in message
news:131dd565-088b-45ae...@v5g2000pre.googlegroups.com...
> We measured the circumference of the balloons
> every 30 minutes.
My guess is there is something funny in how you got your carbon
dioxide. Maybe it was hotter than the other gasses, and cooling
added to an *apparent* deflation. How many balloon of each gas?
David A. Smith
Bruce Sinclair
Most rubbers (and many plastics IIRC ?) are more permeable to CO2. Example
.. you inflate your car tyres with air. Tyre manufacturers recomend
nitrogen. After a while of filling them with air, you pretty much have 100 %
N. :)
Why ? The CO2 and O (slower I think ?) escapes faster. Why ? Perhaps it
'dissolves' in the rubber then permeates ?
I'm sure someone can confirm/deny :)
sydscience
Five balloons of each gas. We used two different sources of CO2 on
two separate occasions - one from a compressed CO2 bottle; another by
reaction between sodium bicarbonate and acetic acid - just to
eliminate the possibility of contamination. Results are the same in
each case.
Frank
osmotic pressure the carbon dioxide balloons would have deflated slower.
DuPont had used this phenomenon in a carpet underlay product where
polyester foam was inflated with a high molecular weight gas.
Maybe some interaction of carbon dioxide or oil it may contain to
plasticize or open up the latex.
N:dlzc D:aol T:com (dlzc)
"Bruce Sinclair"
<bruce.s...@NOSPAMORELSEagresearch.NOTco.NOTnz> wrote in
message news:498f6951$0$19495$c5fe31e7@read01-hal...
... as a boondoggle to get more money, in many cases.
> After a while of filling them with air, you pretty much have
> 100 % N. :)
> Why ? The CO2 and O (slower I think ?) escapes faster.
> Why ?
The oxygen oxidizes stuff on the inside, that is why the oxygen
disappears from inside tires.
> Perhaps it 'dissolves' in the rubber then permeates ?
>
> I'm sure someone can confirm/deny :)
http://books.google.com/books?id=IhDFIj-PoucC&pg=PA48&lpg=PA48&dq=balloon+latex+diffuse+rapidly+co2+OR+carbon-dioxide&source=web&ots=_Ib_fjHAbh&sig=jf7hwFKOF9x_rx89W2c5UAZ3BDw&hl=en&ei=UXePSaPrOYzQMcORoZEL&sa=X&oi=book_result&resnum=5&ct=result#PPA49,M1
... bottom of page 48 and bottom of page 49. Says it difuses at
a rate of 0.5 cc / minute through a latex pulmonary artery
catheter.
Seems to be a known behavior, but I have found no "why" for the
OP's question. Partial pressures won't be the answer, since the
percentage of CO2 in the atmosphere is much higher than is that
of helium... and its average speed will be lower due to its
molecular mass.
David A. Smith
Craig
(Bruce Sinclair) wrote:
> In article <m_Hjl.5079$%w3.3...@newsfe14.iad>, "N:dlzc D:aol T:com \(dlzc\)"
>
>
>
> <dl...@cox.net> wrote:
> >Dear sydscience:
I can't confirm, but I can offer a related observation. I often
inflate hydrogen balloons for my chemistry class. Regular latex
balloons hold hydrogen gas just fine, at least for an hour or two.
One day, I was looking for another gas and got the bright idea to try
the house natural gas (which the bunsen burners usually run on). I
simply could not get the latex balloons to inflate, and I smelled
gas. Clearly, they were much more permeable to methane etc.. It
wasn't CO2, but it at least seems reasonable to me that chemically
selective permeability of the balloon might be an issue. In other
words, the size and/or molar mass of the gas may not be the only factor
(s) affecting its rate of diffusion out of the balloon. Perhaps Mylar
might be worth a try as a comparison?
- Craig
Ernieman
"Craig" <cage...@aol.com> wrote in message
news:9929ecf5-4aab-41c9...@t39g2000prh.googlegroups.com...
- Craig
Permeability of gases through plastics films is a complex topic. One of the
"rules of thumb" is that increased solubility of the gas in a plastic is
likely to mean inceased permeation rate. Since "like dissolves like", the
solubility is likely to increase from He to CO2, to methane.
Ernie
Ron Jones
How did you try to fill the balloons with natural gas? At the tap or with a
pump - tap won't work, natural gas pressure is too low to inflate any
balloon - about 7" water (IIRC) = about 0.25psi.
--
Ron Jones
Process Safety & Development Specialist
Don't repeat history, unreported chemical lab/plant near misses at
http://www.crhf.org.uk Only two things are certain: The universe and
human stupidity; and I'm not certain about the universe. ~ Albert
Einstein
Bill Penrose
That's surprising, but depending on the balloon material, the
permeability of gases is due more to their 'solubility' in the
membrane material, not the size of the gas molecules. Helium is not
very soluble in organic materials, and may actually escape through
pores, but CO2 would have to dissolve in the membrane and diffuse away
on the other side.
Why not try 'canned air'? That's actually a polyfluoro-something-or-
other with a very high molecular weight. It's also soluble in organic
substances. See how that works. (Note: this is a hypothesis that can
be tested a la the scientific method.) The hardware store and computer
stores stock it.
It's also kind of funny to see balloons that fall like cinder blocks.
Dangerous Bill
Craig
It was exactly as simple as you suspect. I just walked up to the tap
and held the balloon around it, expecting that to do the job.
You're right - house natural gas pressure doesn't inflate a balloon
very well. It seems my starry-eyed idea was doomed for more than one
reason.
I just tried it again to refresh my memory. Indeed, the balloon
inflates a pathetic amount, consistent with the pressure being fairly
low. I hold the balloon tightly to the open tap, inflate it as best I
can, and twist the base to make it reasonably "airtight". I then
close the tap and squeeze the barely-inflated balloon. It deflates
and I smell gas. This off-the-shelf (latex?) balloon is clearly
permeable to natural gas.
- Craig
dlzc
On Feb 9, 4:27 pm, Bill Penrose <dangerousb...@gmail.com> wrote:
> On Feb 8, 12:35 pm, sydscience <nkconr...@mydurango.net> wrote:
>
> > My daughter did her science experiment measuring
> > the deflation rates of latex balloons filled with helium,
> > carbon dioxide and compressed air. The carbon
> > dioxide balloons deflated fastest but we have no idea
> > why. Does anyone know the reason that carbon
> > dioxide filled balloons deflate faster than helium or
> > compressed air?
>
> That's surprising, but depending on the balloon
> material, the permeability of gases is due more to
> their 'solubility' in the membrane material, not the
> size of the gas molecules. Helium is not very soluble
> in organic materials, and may actually escape
> through pores, but CO2 would have to dissolve in the
> membrane and diffuse away on the other side.
I wonder if the latex membrane depends in part on adsorbed water to
fill the pores? How does cured latex behave in ultra-dry conditions?
David A. Smith
Mark Thorson
>
> I just tried it again to refresh my memory. Indeed, the balloon
> inflates a pathetic amount, consistent with the pressure being fairly
> low. I hold the balloon tightly to the open tap, inflate it as best I
> can, and twist the base to make it reasonably "airtight". I then
> close the tap and squeeze the barely-inflated balloon. It deflates
> and I smell gas. This off-the-shelf (latex?) balloon is clearly
> permeable to natural gas.
You didn't smell natural gas. You smelled an odorant
added to the gas (butyl mercaptan).
Ron Jones
Methane does not smell. It's permeable to ethanethiol. ;-)
Ron Jones
You want Xenon to do that. Might be a tad expensive...
Dirk Bruere at NeoPax
Every so often they take a dead skunk, liquidise it and throw it in the
methane tanks at HQ
--
Dirk
http://www.transcendence.me.uk/ - Transcendence UK
http://www.theconsensus.org/ - A UK political party
http://www.onetribe.me.uk/wordpress/?cat=5 - Our podcasts on weird stuff
Dirk Bruere at NeoPax
> Bill Penrose wrote:
>> On Feb 8, 12:35 pm, sydscience <nkconr...@mydurango.net> wrote:
>>> My daughter did her science experiment measuring the deflation rates
>>> of latex balloons filled with helium, carbon dioxide and compressed
>>> air. The carbon dioxide balloons deflated fastest but we have no idea
>>> why. Does anyone know the reason that carbon dioxide filled balloons
>>> deflate faster than helium or compressed air?
>> That's surprising, but depending on the balloon material, the
>> permeability of gases is due more to their 'solubility' in the
>> membrane material, not the size of the gas molecules. Helium is not
>> very soluble in organic materials, and may actually escape through
>> pores, but CO2 would have to dissolve in the membrane and diffuse away
>> on the other side.
>>
>> Why not try 'canned air'? That's actually a polyfluoro-something-or-
>> other with a very high molecular weight. It's also soluble in organic
>> substances. See how that works. (Note: this is a hypothesis that can
>> be tested a la the scientific method.) The hardware store and computer
>> stores stock it.
>>
>> It's also kind of funny to see balloons that fall like cinder blocks.
>>
>> Dangerous Bill
>
> You want Xenon to do that. Might be a tad expensive...
I did it with Xenon once. Very impressive and very expensive.
I had considered breathing it to see if my voice changed, but didn't
have enough.
Mark Thorson
>
> I did it with Xenon once. Very impressive and very expensive.
> I had considered breathing it to see if my voice changed, but didn't
> have enough.
I wonder if that would have been dangerous.
How quickly could xenon be cleared from the
lungs?
Dirk Bruere at NeoPax
I though about that, and decided that if I fainted from lack of O2 I
needed someone to hold me upside down while doing a bit of CPR.
Craig
The precision of my speech stands duly corrected. :)
I've never been involved in the formulation of natural gas for lab
use, but I would tend to suppose that the odorant is probably only a
tiny fraction of the mixture. If the balloon were permeable only to
the odorant, then squeezing the balloon would result in the expulsion
of the odor but not the rest. Since most of the balloon deflated, I
feel forced to conclude that either:
(i) the balloon is also permeable to methane
(ii) the odorant makes up a very large percentage of the gas mix
I feel that (i) is more likely to be correct, but with this crowd, I
am suddenly feeling the need to write as precisely as
possible... :)
- Craig
Craig
wrote:
> Mark Thorson wrote:
> > Dirk Bruere at NeoPax wrote:
> >> I did it with Xenon once. Very impressive and very expensive.
> >> I had considered breathing it to see if my voice changed, but didn't
> >> have enough.
>
> > I wonder if that would have been dangerous.
>
> > How quickly could xenon be cleared from the
> > lungs?
>
> I though about that, and decided that if I fainted from lack of O2 I
> needed someone to hold me upside down while doing a bit of CPR.
>
I had exactly the same concerns. Then I saw videos of people actually
doing it, although using sulfur hexafluoride.
Adam Savage from the Mythbusters tried it:
http://www.youtube.com/watch?v=d-XbjFn3aqE
However, that clip doesn't show what happens afterwards. The
continued presence of Adam on the show suggests that he lived
somehow. :)
The clip below shows someone inhaling SF6 and then simply breathing a
few times to clear the lungs. (This isn't posted by the copyright
holder, but it was the best I found demonstrating what happens after
inhaling SF6.)
http://www.youtube.com/watch?v=HIXEzj08MwE
I think the guy on the left in the clip above is Steve Spangler.
Spangler definitely demonstrated this on the Ellen show:
http://www.youtube.com/watch?v=2qlb8X_ffO8
Again, you can see that Ellen exhales a few times and clears the stuff
out of her lungs.
I'm convinced that, if you're careful, you can do this without the
need to hang upside down. I haven't yet gotten around to trying this
myself.
- Craig
Bill Penrose
> I wonder if the latex membrane depends in part on adsorbed water to
> fill the pores? How does cured latex behave in ultra-dry conditions?
No idea. We did experiments on selective permeation about 10 years ago
and the appropriate background reading to accompany it. The conclusion
was that it's a bad idea to use straight permeation. It's too
unpredictable and subject to too many factors.
Certainly silicone, which can absorb up to 13% water, changes its
properties, but we never looked at latex.
DB
Mark Thorson
>
> Certainly silicone, which can absorb up to 13% water, changes its
> properties, but we never looked at latex.
What kind of silicone is that? PDMS silicone is
very hydrophobic.
Bill Penrose
So it seems, to liquid water anyway. Water vapor goes through PDMS
like it wasn't there. I used to measure gas supersaturation in water
with a coil of PDMS tubing. From the pressure that developed in the
tube, the partial pressure of O2 + N2 relative to atmospheric was
derived by subtracting the water vapor partial pressure at that
temperature. Our method was similar to this:
www.chelanpud.org/HCP/Studies/2001%20Report.pdf (page 10)
We could use PDMS for humidification of gases, except that Nafion
tubing works better.
PDMS is sometimes added to other polymers to improve vapor
permeability.
www.siliconespectator.com/articles/September_2008.pdf
DB
N:dlzc D:aol T:com (dlzc)
"Bill Penrose" <danger...@gmail.com> wrote in message
news:643afdaf-51d2-4436...@n5g2000prc.googlegroups.com...
...
> So it seems, to liquid water anyway. Water vapor
> goes through PDMS like it wasn't there. I used to
> measure gas supersaturation in water with a coil
> of PDMS tubing.
I've had similar experience with copper tubing. Dry an air
stream to -100degfF dewpoint, and shut it off for a few days. By
the time you start air flow again, the humidity will have climbed
quite a bit.
David A. Smith
Mark Thorson
>
> On Feb 11, 12:24 pm, Mark Thorson <nos...@sonic.net> wrote:
> > Bill Penrose wrote:
> >
> > > Certainly silicone, which can absorb up to 13% water, changes its
> > > properties, but we never looked at latex.
> >
> > What kind of silicone is that? PDMS silicone is
> > very hydrophobic.
>
> So it seems, to liquid water anyway. Water vapor goes through PDMS
> like it wasn't there. I used to measure gas supersaturation in water
That's permeability, not water absorption. PDMS silicone
has one of lowest water absorptions of any polymer.
Certainly not anywhere close to 13%, not for unmodified
PDMS or methyl-phenyl silicones.
It is, however, among the most permeable polymers to
water, gases, solvents, etc. It will have a high
absorption of hydrophobic solvents, but almost no
absorption of water.
Bill Penrose
> ...That's permeability, not water absorption. PDMS silicone
> has one of lowest water absorptions of any polymer.
I defer. I couldn't find any info to back up my statement, so I have
to assume it's a misfiled memory thing.
DB
Michael Moroney
>> It's also kind of funny to see balloons that fall like cinder blocks.
>You want Xenon to do that. Might be a tad expensive...
Sulfur hexafluoride. Cheaper and a higher MW than Xenon.
Bruce Sinclair
.. *but* a known green house gas :) :)
Dirk Bruere at NeoPax
I wonder what fluorine impurities one might encounter in a "bad" batch
of SF7?