Boiling water in a plastic bottle

I've tried it with the cap on and I was able to get it very hot but not to a rolling boil. I think the bottle started leaking then melting. Les Stroud was able to get it to a rolling boil with the cap off hence, letting the gas escape. I plan to try it with the cap off the next time I go camping.
 
The video makes no sense. The water will be able to absorb the heat with or without the cap, and leaving the cap on just leaves no escape for gas, setting it up for a possible steam explosion when you open the bottle / the bottle breaks.
 
sounds like a great way to get cancer...all those plastic compunds under high heat leeching into your water supply...
 
It seems to me the title is misleading. He's not boiling water, he's making it hot.

It also seems to me that the cap is the weak point, as there are two layers of plastic at the thread area. This would leave the outer layer, the cap, removed from the cooling effects of the liquid.

I've boiled water in a paper bag before, so this is just another example. If you wanted to boil water in plastic, you'd have to take off the cap and set the bottle upright.

.
 
He's heating it to a boiling temperature, though it's not visually "boiling" and with no air it can't do the rolling boil that we associate. I think he's heating it more to kill bacteria and other critters that may be in the water.

No matter *if* there is plastic leeching into the water I'd say in a survival situation it many be worth the chance.
 
znode said:
The video makes no sense. The water will be able to absorb the heat with or without the cap, and leaving the cap on just leaves no escape for gas, setting it up for a possible steam explosion when you open the bottle / the bottle breaks.
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Water dosen't expand much when heated so no it won't explode. The cap is to make sure there's no air inside, which cannot abosrb heat as well as water, thus the part of plastic contacting air will melt.
 
jzmtl said:
Water dosen't expand much when heated so no it won't explode. The cap is to make sure there's no air inside, which cannot abosrb heat as well as water, thus the part of plastic contacting air will melt.
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Exactly - the trick here is the water is cooling the plastic as the fire is heating the plastic (and through the plastic, the water inside).

The asumpion is that the type of plastic used in the video (different plastics have differrent properties), will melt at the temperature of the fire, but not at the temperature of boiling (or very hot) water. Therefore, as long as the water can draw heat away from the plastic faster than the fire can pump heat into the plastic, it won't melt.

On the other hand, air can not draw heat away fast enough - so any plastic with the fire on one side, and air on the other side will heat above its melting temp.
 
So how do you know the water reached boiling or not? Take a sip - wait for the diarrhea?
 
David E said:
Yeah, I read that on Snopes, too ! (debunked)

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I did a search on Snopes using "Lexan" and another using "nalgene" and got no results.

On the other hand, several university studies have issues about a mutigenic chemical, BPA, leaching from Lexan when that plastic is exposed to harsh chemicals and very hot water. The owner of the rights to Lexan and the manufacturers say its all nonsense, as supported by every study paid for by the plastics industry. No problem if you're not gonna' have (more) kids.

I'm with mete. Bring a metal cup or can or pot -- even some aluminum foil. Drop hot rocks in a water-filled hole or bark container or hollowed-out log.


Oh, and it doesn't have to boil to kill the baddies. That's just a sign it's hot "enough."
 
jzmtl said:
Water dosen't expand much when heated so no it won't explode.
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Then you are mistaken.

No, it initially doesn't expand very much - UNTIL it gets to boiling. Then, it would involve a 1200x volume expansion due to the water -> gas phase change.

In fact, the boiling point would be higher than 100 degrees Celsius while you keep the cap closed, due to the pressure. But once you open the cap... boom. (Well, more like "puff" and a jet of hot water.)

This method would be fine to just heat water to a warm temperature (though still dangerous, because it'd be hard to judge). But "boiling" water in a closed container, as the video title claims, is completely retarded and Darwin-awards-worthy.
 
WonderMonkey said:
He's heating it to a boiling temperature, though it's not visually "boiling" and with no air it can't do the rolling boil that we associate.
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He's definitely not heating it to a boiling temperature. Boiling MAKES its own air. That's the definition of vaporization.

Now, with the cap closed, the boiling temperature under pressure will be higher than 100 degrees Celsius. But if the plastic bottle doesn't explode before visible gas is produced, you WILL be able to see visible gas.

If he were to have heated to 1atm boiling temperature, there would have been an instant rush of bubbling, and the scalding water will jet/gush out of the bottle when he opened the cap (as a shaken bottle of soft drink would).
 
Thomas Linton said:
The owner of the rights to Lexan and the manufacturers say its all nonsense, as supported by every study paid for by the plastics industry.
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Uhm... Haven't you and I had this discussion before?

I know it has been beaten to death- do a search. Unless you are amazingly stupid and clean it with dryno or toss it in a fire, without special equipment you can not get a quantity of BPA out of Lexan that is sufficent to have any long term effects on an adult male. It will drop your sperm count, but it won't make you sterile- it is an estrogen analog. Oh, wait- if you milk has rBST in it and you drink enough, THAT estrogen analog will have the same results.

Now, putting a plastic bottle over a fire... I'm not sure I agree with Les on this. This will leach a number of nasty chemicals into the water, yes, but short term dehydration vs plus a fraction of a percent on you risk of developing cancer or having two tailed sperm for a few weeks is pretty much a no brainer. But if it is your ONE (1) container, I'll risk the water rather than risk loosing the container until I can make one out of wood or bark that I can use boiling stones in.
 
ironraven said:
Uhm... Haven't you and I had this discussion before?

I know it has been beaten to death- do a search. Unless you are amazingly stupid and clean it with dryno or toss it in a fire, without special equipment you can not get a quantity of BPA out of Lexan that is sufficent to have any long term effects on an adult male. It will drop your sperm count, but it won't make you sterile- it is an estrogen analog. Oh, wait- if you milk has rBST in it and you drink enough, THAT estrogen analog will have the same sults.
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We may have this discussion repeatedly.

I invite anyone to do a Goggle on "lexan" or "nalgene" and "BPA", look only at university studies, and draw their own conclusions. Case Western Reverve U. was not using Draino or boiling water. The conditions are public record. And BPA leach out has been found with far less extreme conditions than the CWRU situation. The primary issue is birth defects. And they were looking at branded stuff, not the ????? Lexan-like stuff coming from China.

What I don't get is why run ANY risk when HDPE (Type 2 PE) is cleared by everyone (well, except the black helicopter crowd) and when washing Lexan (type 7 PE) by hand with liquid dish detergent seems to eliminate BPA leaching?
 
znode said:
He's definitely not heating it to a boiling temperature. Boiling MAKES its own air. That's the definition of vaporization.

Now, with the cap closed, the boiling temperature under pressure will be higher than 100 degrees Celsius. But if the plastic bottle doesn't explode before visible gas is produced, you WILL be able to see visible gas.

If he were to have heated to 1atm boiling temperature, there would have been an instant rush of bubbling, and the scalding water will jet/gush out of the bottle when he opened the cap (as a shaken bottle of soft drink would).
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Right. I suppose I should have said "open air" or "standard" boiling temperature.
 
Thomas, one can find plenty of studies that suggest that saccharine can cause cancer, and a few that suggest that high doses of vitamin C can cause miscarriages. (And it can, you just need to drink a couple of gallons of it and it would do a decent job of digesting you.) Hell, tylenol can cause, in a tiny number of cases involving insanely large doses, liver damage in embryos. We are talking about probabilities that are so slight at the exposure levels of a normal human that they don't count- the EMF off an electric blanket has the same odds of causing birth defects.

If the risk was as real as your side in this make it sound, how come there are so few test tube and artificial insemination babies with defects? There was lexan involved in all of them. This is the "aluminum causes Alzheimer's" scare all over again.

And we do agree that the best route is hand washing. It is the easiest way to put this whole issue to bed- read the tag, follow the washign directions. Failure to RTFM should be painful.
 
znode said:
Boiling MAKES its own air.
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Wow, how did I miss this last night...

Boiling converts liquid water into water vapor, yes, but it doesn't "make" anything. There is no new compound being created, there is no compound being broken. Just a fairly common compound undergoing a state change. But even then, it "makes" water vapor, which while a component part of the collection of gases called air is not air. That is like saying that you are a spleen. :P

What it does create is pressure becuase the vaporized form of most compounds has lower density. And a heated vapor, due to the higher excitation of molecules, has a lower density and increases pressure.

Sloppy, sloppy, sloppy. This kind of thinking leads to interesting trips to the ER to get your backside stitched up after accidentally sitting on a knife. :)
 
ironraven said:
Boiling converts liquid water into water vapor, yes, but it doesn't "make" anything.
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The "air" is my fault. I was thinking gas, but typed air instead. Either way, it doesn't detract from my point.

The "make" however, is completely semantic pedantry. You make ice by freezing water. You make water vapor by boiling water. "Make" is one of the most versatile words in the English lexicon, and there doesn't need to be chemical or nuclear reactions for something to be colloquially "made", especially seeing that the audience I'm writing to isn't a physics forum.

ironraven said:
Sloppy, sloppy, sloppy. This kind of thinking leads to interesting trips to the ER to get your backside stitched up after accidentally sitting on a knife.
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Me? Lapses in the language, maybe. I know my phase transitions plenty well, though. For example:

ironraven said:
the vaporized form of most compounds has lower density.
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Most? I don't think there's a single counterexample. The sheer entropy increase at time of vaporization dictates that it will have lower density.
 
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