RAF Moustache Story?
Mike Tighe
possible dangers of smoking in a fast jet jogged my memory to an old
tale, and I want to know if it is true...
The story goes back to the days when some RAF fast jet aircrew still
sported extravagant handlebar moustaches. On a long flight, a pilot
or nav ate his packed lunch, which happened to be a round of cheese
sandwiches. Then, when he put his oxygen mask back on, he selected
100% and accidentally started a small grease fire in his facial
hair...
Now, I know the perils of someone stupid using oil on the threads when
connecting up high pressure oxygen bottles (don't try that at home!),
so this is probably not completely impossible - but did it really
happen, and if so, has anyone seen the story in a flight safety mag or
biography?
Mike Tighe
Speaking from the bottom left
hand corner of the big picture.
Dweezil Dwarftosser
wrote:
>The story goes back to the days when some RAF fast jet aircrew still
>sported extravagant handlebar moustaches. On a long flight, a pilot
>or nav ate his packed lunch, which happened to be a round of cheese
>sandwiches. Then, when he put his oxygen mask back on, he selected
>100% and accidentally started a small grease fire in his facial
>hair...
>
>Now, I know the perils of someone stupid using oil on the threads when
>connecting up high pressure oxygen bottles (don't try that at home!),
>so this is probably not completely impossible - but did it really
>happen, and if so, has anyone seen the story in a flight safety mag or
>biography?
I don't know if that happened or not - but I did know a rather
dim-witted crew chief that would put a drop of LOX in his hat and pull
it down over his ears. This often resulted in a hair oil/oxygen
connection that would *pop* the hat off his head.
I'm told he's on life-long daily medication these days...
- John T.
Mary Shafer
> The story goes back to the days when some RAF fast jet aircrew still
> sported extravagant handlebar moustaches. On a long flight, a pilot
> or nav ate his packed lunch, which happened to be a round of cheese
> sandwiches. Then, when he put his oxygen mask back on, he selected
> 100% and accidentally started a small grease fire in his facial
> hair...
In the last year or two there was an article in Approach about a Naval
Aviator who set his moustache on fire with the O2 system. He'd used
the wrong kind of moustache wax. He had to have skin grafts to repair
the damage. This wasn't the first such story I'd read in a reliable
source; I think the RAF was the leader in discovering the
incompatibility of petroleum-based moustache waxes and O2, but the US
forces have continued to do research on the problem.
--
Mary Shafer NASA Dryden Flight Research Center, Edwards, CA
SR-71 Flying Qualities Lead Engineer Of course I don't speak for NASA
sha...@reseng.dfrc.nasa.gov DoD #362 KotFR
URL http://www.dfrc.nasa.gov/People/Shafer/mary.html
For personal messages, please use sha...@ursa-major.spdcc.com
Tarver Engineering
Mary Shafer wrote in message ...
>mik...@dircon.co.uk (Mike Tighe) writes:
>
>> The story goes back to the days when some RAF fast jet aircrew still
>> sported extravagant handlebar moustaches. On a long flight, a pilot
>> or nav ate his packed lunch, which happened to be a round of cheese
>> sandwiches. Then, when he put his oxygen mask back on, he selected
>> 100% and accidentally started a small grease fire in his facial
>> hair...
>
>In the last year or two there was an article in Approach about a Naval
>Aviator who set his moustache on fire with the O2 system. He'd used
>the wrong kind of moustache wax. He had to have skin grafts to repair
>the damage. This wasn't the first such story I'd read in a reliable
>source; I think the RAF was the leader in discovering the
>incompatibility of petroleum-based moustache waxes and O2, but the US
>forces have continued to do research on the problem.
I think you will find that all oxygen gages for torches say "use no oil",
and that predates the stupidity displayed by the RAF.
John
wal...@oneimage.com
>On Fri, 05 Feb 1999 02:03:53 GMT, mik...@dircon.co.uk (Mike Tighe)>wrote:
>>sported extravagant handlebar moustaches. On a long flight, a pilot
>>or nav ate his packed lunch, which happened to be a round of cheese
>>sandwiches. Then, when he put his oxygen mask back on, he selected
>>100% and accidentally started a small grease fire in his facial
>>hair...
>>connecting up high pressure oxygen bottles (don't try that at home!),
>>so this is probably not completely impossible - but did it really
>>happen, and if so, has anyone seen the story in a flight safety mag or
>>biography?
>>I don't know if that happened or not - but I did know a rather
>dim-witted crew chief that would put a drop of LOX in his hat and pull
>it down over his ears. This often resulted in a hair oil/oxygen
>connection that would *pop* the hat off his head.
>>I'm told he's on life-long daily medication these days...
>>- John T.
Here's a real-life maoustache story for y'all; I was there. In the 326 FIS
we had a pilot with a semi-handle bar 'stash; within regs, that is. He came
down from a flight in a 102 with a scorched face and had a hair-raising story
about his chapsticked lips cathcing fire from the Deuce's 100% oxygen (that's
all we had - there was no diluter mode). I was 'Life Support Officer' - read
Personel Equipment Officer - then and was in on the investigation and report.
Unfortunately it wasn't quite true. He had felt the need for a cigarette and
had neglected to shut off the oxygen flow. His coffin nail lasted but a second
or so and startled the hell out of him plus gave him mere first degree burns.
He was very lucky! (Clay, if you're out there - Hi!)
Walt BJ ftr plt ret
IanDTurner
official flight safety publication (recently), and it was certainly featured in
a training film whilst I was at Halton in 1985.
LOX can provide a bit of perverse entertainment. I remember a mate of mine
finding a dead rabbit once - dipped it in LOX and shattered it with a hammer (
sick but true )
Ian
Paul J. Adam
<sha...@reseng2.dfrc.nasa.gov> writes
>I think the RAF was the leader in discovering the
>incompatibility of petroleum-based moustache waxes and O2, but the US
>forces have continued to do research on the problem.
It surprised me (it shouldn't have, but it did) to hear how careful you
had to be with cosmetics when flying.
Given that as a twentysomething male I've never even considered that as
an issue or a problem, I can all too easily see pilots having problems
with petroleum-based lip balm and other such substances.
Meanwhile, Hazel can tell you with alarming accuracy the contents of
everything she puts on her skin: I'd think you'd have a much easier time
getting her into an oxygen-rich environment than me.
--
There are four kinds of homicide: felonious, excusable, justifiable and
praiseworthy...
Paul J. Adam pa...@jrwlynch.demon.co.uk
Mary Shafer
> In article <u0u2x03...@reseng2.dfrc.nasa.gov>, Mary Shafer
> <sha...@reseng2.dfrc.nasa.gov> writes
> >I think the RAF was the leader in discovering the
> >incompatibility of petroleum-based moustache waxes and O2, but the US
> >forces have continued to do research on the problem.
>
> It surprised me (it shouldn't have, but it did) to hear how careful you
> had to be with cosmetics when flying.
>
> Given that as a twentysomething male I've never even considered that as
> an issue or a problem, I can all too easily see pilots having problems
> with petroleum-based lip balm and other such substances.
I carefully wipe off my lipstick before snugging the O2 mask up, but
that's more to keep from smearing it all over me and the mask than
because I worry about setting my lips on fire. I've never heard of a
woman having a problem with lipstick and O2, or makeup and O2, in an
airplane and surely something like this would have been newsworthy
enough to appear in one of the many magazines I get.
Gord Beaman
--cut--
>I carefully wipe off my lipstick before snugging the O2 mask up, but
>that's more to keep from smearing it all over me and the mask than
>because I worry about setting my lips on fire. I've never heard of a
>woman having a problem with lipstick and O2, or makeup and O2, in an
>airplane and surely something like this would have been newsworthy
>enough to appear in one of the many magazines I get.
I've been looking this thread over and noticed that your last sentence
came as close as anything to what's been my experience...for seven
years I flew the Fairchild C-119 Boxcar all over the north, and as far
east as Greece. With around 7,000 hours in it I've had lots of time to
play with the oxygen system. The fact that I was in my early twenties
then helps (young and stoopid).
I've found that if you fill your lungs with 100% oxygen then light up
a cigarette you can blow out gently and get the cig to emit a little
flame. If you drop a lit butt into a Dixie cup then blow into it you
can, with a little work, make the cigarette butt catch on
fire...that's about it, these stories about hair oil blowing your hat
off, cheese fires in your beard etc are just silly stories dreamed up
by silly teenagers. Think about it for a minute...where would the
ignition come from?...gee...
--
Gord Beaman
PEI, Canada
Tex Bennett
wrote:
>Well, the mention on another thread on the relaxing effect versus the
>possible dangers of smoking in a fast jet jogged my memory to an old
>tale, and I want to know if it is true...
>
>The story goes back to the days when some RAF fast jet aircrew still
>sported extravagant handlebar moustaches. On a long flight, a pilot
>or nav ate his packed lunch, which happened to be a round of cheese
>sandwiches. Then, when he put his oxygen mask back on, he selected
>100% and accidentally started a small grease fire in his facial
>hair...
I read this story several years ago in the RAF in house Flight Saftey
magazine "Air Clues" - so if Wg Cmdr Spry says it's true that's good
enough for me. However, I'm sure it was a Shacklebomber back seater.
Gord Beaman
--cut--
>The ignition source is your
>body heat. Its a little bit of high school chemistry if I can remember back
>that far. If you want to know how hostile a 100% Oxygen environment is just
>talk to any of the technicians and firefighters who watched a RAAF P3 burn
>after a few Rust Particles entered the aluminium tubing of the Oxy system.
>
>Rock
>
>
"The ignition source is your body heat" you say?...I see...so you're
telling me that if I take a bite out of a sandwich (buttered) then
take a lungful of 100% oxygen that I'll explode?!...sure I will
sonny...sure I will...cripes, if 100% oxygen were that dangerous then
you wouldn't dare breathe it...don't you suppose there's any fatty
substance available inside your body?...why is it that these kids
dearly love to say startling things like 'microwave ovens heat from
the inside out' or hot water will freeze quicker than cold water (and
vice versa). I think they're likely thinking to themselves 'this guy
thinks I'm real smart'...yeh...sure kid...we do indeed...yes...
SL Nyveen
> "The ignition source is your body heat" you say?...I see...so you're
> telling me that if I take a bite out of a sandwich (buttered) then
> take a lungful of 100% oxygen that I'll explode?!...sure I will
> sonny...sure I will...cripes, if 100% oxygen were that dangerous then
> you wouldn't dare breathe it...don't you suppose there's any fatty
> substance available inside your body?...why is it that these kids
> dearly love to say startling things like 'microwave ovens heat from
> the inside out' or hot water will freeze quicker than cold water (and
> vice versa). I think they're likely thinking to themselves 'this guy
> thinks I'm real smart'...yeh...sure kid...we do indeed...yes...
I'm the last guy in the world to start believing urban folklore, but...
Hot water does freeze more quickly than cold. Really. While it does not
do so under ideal experimental conditions, it will in real life.
Remember the following facts before I launch into my explanation:
- Hot water is less dense than cold for temperatures above 4 C
- Temperature is a simple way of saying "average heat of all molecules in
a given volume".
To explain how, lets look at the ideal conditions first:
1) Take equal amounts, by mass, of cold water and hot water, each in an
expandable, closed container with no airspace. Place them in a freezer on
top of perfectly insulated pads, so no heat will be lost through contact
with the floor of the freezer.
2) Under these conditions, no evaporation can take place, so the number of
molecules remains the same in each container. Heat loss takes place
purely through contact with air molecules in the freezer. Given that the
cold water has less heat to lose to reach freezing temperature, it should
freeze first.
No, lets look at real life:
1) Take equal volumes, say 1 L, of cold water and hot water and place them
in perfectly insulated buckets. Place these buckets in the freezer.
2) First, the volumes are the same but the hot water, less dense, will
have fewer molecules in it. This accelerates cooling - all will agree
that a thimle of hot water freezes before six L of cold water would,
right?
3) The temperature of the hot water is higher than the temperature of the
cold (tautology, but so what - it makes the point). So the hot water has
more molecules of any given heat content (= energy). Therefore, the hot
water will have more molecules reach the heat content (= energy) required
to break intermolecular bonds. Thus the hot water will have more
molecules evaporate from its surface than will the cold water. This
reduces the mass of the water in the hot water bucket. (Lets ignore what
happens to evaporated water - it will condense equally in both buckets and
on the freezer walls.)
4) Loss of high energy molecules (= evaporation) will continue to lower
the average heat (=temperature) of the hot water more than the same
process in the cold water. At some point, this will equalize temperatures
in the two buckets.
5) By the time the temperatures in the two buckets equal one another,
there is less of the water that was the hot water than there is of what
was the cold water. There was less to start with and this has been
exacerbated by evaporation.
6) Both buckets are the same temperature, but there is less "hot" water.
Ergo, it has less heat to lose before freezing and it will freeze first.
Note that the real-life effect will be more pronounced with a wood
(insulating) bucket than with aluminum (conducting) buckets since with
conductive buckets, heat is lost to the ground and the air (through the
sides) without reducing mass.
See?
Laurie Nyveen lawr...@dsuper.nett
_____________________________________________________________________
Editor, Netsurfer Digest - http://www.netsurf.com/nsd/index.html
101 Sqn opus-in-progress - http://www.dsuper.net/~lawrence/index.html
DNRC Minister of Adding "ue" to Words That End in "log"
"All we are, basically, are monkeys with car keys."
- Grandma Woody (Northern Exposure)
Please remove the extra "t" to e-mail me. Sorry.
Rock
>
>I've been looking this thread over and noticed that your last sentence
>came as close as anything to what's been my experience...for seven
>years I flew the Fairchild C-119 Boxcar all over the north, and as far
>east as Greece. With around 7,000 hours in it I've had lots of time to
>play with the oxygen system. The fact that I was in my early twenties
>then helps (young and stoopid).
>
>I've found that if you fill your lungs with 100% oxygen then light up
>a cigarette you can blow out gently and get the cig to emit a little
>flame. If you drop a lit butt into a Dixie cup then blow into it you
>can, with a little work, make the cigarette butt catch on
>fire...that's about it, these stories about hair oil blowing your hat
>off, cheese fires in your beard etc are just silly stories dreamed up
>by silly teenagers. Think about it for a minute...where would the
>ignition come from?...gee...
>--
>Gord Beaman
>PEI, Canada
Ok Gord heres a challenge. Get a pair of greasy overalls and put them on.
Now fill a room with pure oxygen such as what happens if you spill LOX. Now
walk in and ........ Its something I wouldn't want to risk just because
someone else hasn't suffered third degree burns. The ignition source is your
body heat. Its a little bit of high school chemistry if I can remember back
that far. If you want to know how hostile a 100% Oxygen environment is just
talk to any of the technicians and firefighters who watched a RAAF P3 burn
after a few Rust Particles entered the aluminium tubing of the Oxy system.
Rock
wal...@oneimage.com
electricity would provide the spark. Along the rust in lines bit we had a small
fire in the oxygen mask test system at RGAFB; it was metal paricles blown down the
line by the oxygen from a suddenly opened valve, according to the
experts who invetsigated it. I was OIC of the Life Support Shop when and where it
happened back about 1961.
BTW some of our denser ramp rats used to stomp on spilled LOX and make it go bang
on the asphalt ramp - until their NCO saw what they were doing. Nothing like a little
'extra instruction' to get their attention.
Rock
>>
>"The ignition source is your body heat" you say?...I see...so you're
>telling me that if I take a bite out of a sandwich (buttered) then
>take a lungful of 100% oxygen that I'll explode?!...sure I will
>sonny...sure I will...cripes, if 100% oxygen were that dangerous then
>you wouldn't dare breathe it...don't you suppose there's any fatty
>substance available inside your body?...why is it that these kids
>dearly love to say startling things like 'microwave ovens heat from
>the inside out' or hot water will freeze quicker than cold water (and
>vice versa). I think they're likely thinking to themselves 'this guy
>thinks I'm real smart'...yeh...sure kid...we do indeed...yes...
>--
>Gord Beaman
>PEI, Canada
Hey Gord,
Settle down. My point is that there is a danger present. If there wasn't
some basis in the theory why does the RAAF have a policy of no make up of
any kind for all aircrew and why did that USN pilot have a helmet fire when
he used the wrong type of hair Gel (suffering severe burns to his head) as
reported in our flight safety magazine here in Aus. And why does the RAAF
insist on all technicians handling LOX wear dedicated overalls that are
guaranteed clean of grease. And how come we use silicon grease on all oxygen
systems??????
If you have so much faith in the fact that you wont explode into flames go
ahead and do my little experiment. I will keep to a grease free environment
thanks very much.
Rock
Andrew Yeung
Beaman) wrote:
>the inside out' or hot water will freeze quicker than cold water (and
Hot water actually freezes quicker. The latent heat of vaporization
coupled with the convection currents of the steam help to remove more
heat faster.
Gord Beaman
--cut--
>1) Take equal amounts, by mass, of cold water and hot water, each in an
>expandable, closed container with no airspace. Place them in a freezer on
>top of perfectly insulated pads, so no heat will be lost through contact
>with the floor of the freezer.
>
it up much easier by wiping all that out and saying 'hot water will
not freeze quicker than cold water unless you start manipulating
conditions to make it happen'...you can make almost anything happen if
you manipulate enough parameters enough.
I prefer the reasonable mature adult method of reasoning problems out.
That you seem to prefer the trick-ridden approach merely lends
credence to the pertinent statement about this in my original post.
Emmanuel Gustin
>I think you will find that all oxygen gages for torches say "use no oil",
>and that predates the stupidity displayed by the RAF.
IIRC NASA lost two rocket-engined X-series test aircraft because
the wrong type of gaskets was used for connectors on LOX lines.
Emmanuel Gustin
Bubba
land in Florida then?
Hot water freeze faster than cold my ass!!!
Andrew Yeung wrote in message <36bd23cc...@news.pacific.net.sg>...
Jim Erickson
>On contrary, that is the experimental method: controlling all
>variables except the one being tested.
Laurie,
I just picked up this thread and Gord Beaman has you beat. He is
absolutely right, cold water will freeze faster than hot unless you
start to manipulate the parameters. Your claim to follow the
experimental method is specious. First, you conveniently ignore the
issue of surface to volume ratios and the amount of exposed surface
which are critical factors in heat transfer or evaporative cooling. I
suspect there are surface to volume ratios and exposed surface areas
that will produce the phenomenon you describe, but there are many that
will not.
Second, your argument depends on having a perfect, or near perfect
insulator, otherwise heat transfer through the sides of the container
will profoundly influence the results as you admit in your mention of
the difference between aluminum and wooden buckets. Where in the "real
world" are you going to get that perfect insulator?
Third, your argument is not experimental, it's a theoretical statement
that is not backed up by any quantitative figures. If you want your
argument to be convincing you ought to present some numbers that support
your thesis that the higher evaporative cooling rate of a hot liquid
will result in a greater net loss rate of heat in the liquid than the
evaporation rate for a cold liquid. As it is, you simply assert that
what you say is true.
Fourth, you ignore the question of what is a hot and what is a cold
liquid. Would you argue that 5°C water will freeze faster than 4°C?
How about 20°, or 50° or 80°? At what point does your argument prevail?
Jim Erickson
David E. Oakley
wal...@oneimage.com wrote:
> >
> If the atmosphere is anything like it is here in Colorado static
> electricity would provide the spark. Along the rust in lines bit we had a small
> fire in the oxygen mask test system at RGAFB; it was metal paricles blown down the
> line by the oxygen from a suddenly opened valve, according to the
> experts who invetsigated it. I was OIC of the Life Support Shop when and where it
> happened back about 1961.
> BTW some of our denser ramp rats used to stomp on spilled LOX and make it go bang
> on the asphalt ramp - until their NCO saw what they were doing. Nothing like a little
> 'extra instruction' to get their attention.
> Walt BJ ftr plt ret
> >
Walt
We denser ramp rats are easily amused. 8-)
What we were taught in one or another of our fire safety classes was that as the percent
of O2 goes up, the kindling temperature goes down. For very high concentrations of O2,
the kindling temperature for some materials gets very close to ambient. No spark
required, it just goes bang. 8-)
David
Andrew Yeung
Beaman) wrote:
>lawr...@dsuper.nett (SL Nyveen) wrote:
>--cut--
Tarver Engineering
Emmanuel Gustin wrote in message <79l42i$e80$1...@fu-berlin.de>...
Ooops. :)
I could see one, but two?
John
Maury Markowitz
> I started out arguing your post point by point but I think I can sum
> it up much easier by wiping all that out and saying 'hot water will
> not freeze quicker than cold water unless you start manipulating
> conditions to make it happen'.
Manipulating the conditions? Put two ice cube trays in your freezer, one
with warm water, one cold. Try it for yourself Gord.
> I prefer the reasonable mature adult method of reasoning problems out.
I prefer experimentation, human reasoning is fallible.
Maury
Paul J. Adam
> BTW some of our denser ramp rats used to stomp on spilled LOX and make it go
>bang
>on the asphalt ramp - until their NCO saw what they were doing. Nothing like a
>little
>'extra instruction' to get their attention.
The "pure 02" TINS I heard was a guy who'd been doing a tank inspection
at a steelworks: a big oxygen tank, drained for inspection and checking.
The technician in question went into the tank, with thorough antispark
and antistatic precautions, and did the interior check.
Of course, it was _cold_ in there, so he'd dressed very warmly.
The check complete, he came out, closed the tank, made sure all was safe
and the high-oxygen environment of the tank was sealed off and protected
from hazard.
That done - cold, tired and miserable - he lit a cigarette.
Of course, he was wearing several thick layers of clothing, which were
saturated with oxygen, and he burned like a torch. His shocked comrades
tried to smother the flames, but his sweater and fleece jacket and all
the rest of his clothing contained suxh a high level of oxygen that
smothering it did no good at all.
Erickson Lab
Maury Markowitz wrote:
OK, I'm not Gordon Beaman, but I doubt that he will mind. Here's a "quick and
dirty" experiment.
I added 1.0 ml of distilled water to each of four 1.5 ml open topped
polypropylene tubes. The starting water temperature varied as follows:
tube 1: 60°C (140° F)
tube 2: 42°C (107° F)
tube 3: 21°C (70° F)
tube 4: 5°C (41° F)
At time zero, the four tubes were placed in a -80°C freezer (I didn't have the
patience to use the -20°C) and I monitored the phase transition at various
times.
The results:
At t = 6 min the 5°C sample (#4) was frozen solid. The 21°C sample (#3) was
almost frozen. The others were still ~1/2 liquid, with tube #1 having the
larger volume of liquid.
At t = 8 min both the 5°C and 21°C samples were frozen solid. The 42° (#2)
and 60°C (#1) tubes still contained some liquid water with tube 1 containing
the larger amount.
At t = 10 min all four samples appeared to be frozen solid.
The experimental method--ya gotta love it!
Jim Erickson
Gord Beaman
>In <36bdd5e1...@news1.sympatico.ca> Gord Beaman wrote:
>> I started out arguing your post point by point but I think I can sum
>> it up much easier by wiping all that out and saying 'hot water will
>> not freeze quicker than cold water unless you start manipulating
>> conditions to make it happen'.
>
> Manipulating the conditions? Put two ice cube trays in your freezer, one
>with warm water, one cold. Try it for yourself Gord.
>
I don't think so Maury, if my wife saw it she'd ask and I'd feel just
too silly telling her why. She, being a sensible sort, would look
askance at me and say, 'Oh really?...I see...hummm'. Then for some
time after I'd catch her looking at me with a quizzical expression on
her face. It's likely that for months after that she'd check me over
before I went downtown for unlaced shoes, unraised zippers and other
signs of mental wear.
>> I prefer the reasonable mature adult method of reasoning problems out.
>
> I prefer experimentation, human reasoning is fallible.
>
>Maury
>
Doesn't make for good old horse sense Maury, you're really taking a
chance when you rely on the results of expermentation without running
those results through the good old 'is this answer reasonable' common
sense filter. But, hey, whatever turns your crank...speaking of which,
are you 'still' of the opinion that the pistons are arranged around
the propshaft vice the crankshaft?...gee...
Gord Beaman
--cut--
>
>OK, I'm not Gordon Beaman, but I doubt that he will mind. Here's a "quick and
>dirty" experiment.
>
>I added 1.0 ml of distilled water to each of four 1.5 ml open topped
>polypropylene tubes. The starting water temperature varied as follows:
>
>tube 1: 60°C (140° F)
>tube 2: 42°C (107° F)
>tube 3: 21°C (70° F)
>tube 4: 5°C (41° F)
>
>At time zero, the four tubes were placed in a -80°C freezer (I didn't have the
>patience to use the -20°C) and I monitored the phase transition at various
>times.
>
>The results:
>
>At t = 6 min the 5°C sample (#4) was frozen solid. The 21°C sample (#3) was
>almost frozen. The others were still ~1/2 liquid, with tube #1 having the
>larger volume of liquid.
>
>At t = 8 min both the 5°C and 21°C samples were frozen solid. The 42° (#2)
>and 60°C (#1) tubes still contained some liquid water with tube 1 containing
>the larger amount.
>
>At t = 10 min all four samples appeared to be frozen solid.
>
>The experimental method--ya gotta love it!
>
>Jim Erickson
>
If I ever need lab work done I'll surely remember your facility.
SL Nyveen
> I added 1.0 ml of distilled water to each of four 1.5 ml open topped
> polypropylene tubes. The starting water temperature varied as follows:
>
> tube 1: 60°C (140° F)
> tube 2: 42°C (107° F)
> tube 3: 21°C (70° F)
> tube 4: 5°C (41° F)
>
> At time zero, the four tubes were placed in a -80°C freezer (I didn't have the
> patience to use the -20°C) and I monitored the phase transition at various
> times.
>
> The results:
>
> At t = 6 min the 5°C sample (#4) was frozen solid. The 21°C sample (#3) was
> almost frozen. The others were still ~1/2 liquid, with tube #1 having the
> larger volume of liquid.
>
> At t = 8 min both the 5°C and 21°C samples were frozen solid. The 42° (#2)
> and 60°C (#1) tubes still contained some liquid water with tube 1 containing
> the larger amount.
>
> At t = 10 min all four samples appeared to be frozen solid.
>
> The experimental method--ya gotta love it!
Cool!
Try any or all of these now, if you don't mind:
1) stick the tubes in a styrofoam block to limit heat loss through the plastic.
2) use the -20 C freezer. The rate of cooling probably affects the amount
of evaporative cooling that can occur in a given time.
3) use boiling water vs. water at room temperature.
4) use containers that allow greater surface area.
Ogden Johnson III
: I've got a bride in Brooklyn for sale.
The bloom is off the romance this early?
OJ III
Jim Erickson
>1) stick the tubes in a styrofoam block to limit heat loss through the plastic.
>2) use the -20 C freezer. The rate of cooling probably affects the amount
>of evaporative cooling that can occur in a given time.
>3) use boiling water vs. water at room temperature.
>4) use containers that allow greater surface area.
>Laurie Nyveen
Sorry Laurie, I don't have the time to check a whole range of variable
just to test a crazy hypothesis. I'm not convinced that hot water will
freeze faster than cold under any conditions, let alone common ones.
I'm not saying it's impossible, just that if it can occur, it likely
requires a very special set of conditions. Which was Gord Beaman's
point IIRC.
BTW, I did the old ice cube tray in the freezer trick at home last
night. One tray with 6 slots filled with hot tap water, 2 empty slots
in the middle, and 6 slots filled with cold tap water. The answer: the
cold water cubes froze first. Of course you could argue that I was a
biased experimentor since I knew that was going to be the result, but
hey, what can you do?
Jim Erickson
Jim Erickson
>>with warm water, one cold. Try it for yourself Gord.
>I don't think so Maury, if my wife saw it she'd ask and I'd feel just
>too silly telling her why. She, being a sensible sort, would look
>askance at me and say, 'Oh really?...I see...hummm'. Then for some
>time after I'd catch her looking at me with a quizzical expression on
>her face. It's likely that for months after that she'd check me over
>before I went downtown for unlaced shoes, unraised zippers and other
>signs of mental wear.
>>> I prefer the reasonable mature adult method of reasoning problems out.
>
>> I prefer experimentation, human reasoning is fallible.
>
>>Maury
>
>Doesn't make for good old horse sense Maury, you're really taking a
>chance when you rely on the results of expermentation without running
>those results through the good old 'is this answer reasonable' common
>sense filter. But, hey, whatever turns your crank...
>Gord Beaman
Maury, if you're going to toss aside reason for experimental results,
you really ought to do the experiment first. I risked embarrassment and
scorn and did the experiment at home last night. The cold water cubes
froze first.
Jim Erickson
Maury Markowitz
> The experimental method--ya gotta love it!
Indeed, now try it with ice cube trays, as I noted.
Maury
Maury Markowitz
> Thank you Jim, I would have expected nothing less than your results.
> If I ever need lab work done I'll surely remember your facility.
Har!
Lemme ask Gord, have YOU tried the experiment that I outlined? No?
Let's see your next message...
> I don't think so Maury, if my wife saw it she'd ask and I'd feel just
> too silly telling her why.
You're scared to experiment because of your wife? Sorry Gord, that's a
pretty lame excuse IMHO.
> Doesn't make for good old horse sense Maury
I must only assume that you haven't done much modern physics. "good old
horse sense" is wrong almost 100% of the time. "good old horse sense" is
great for things weighing between 1 and 1000 pounds, travelling at speeds
between 1cm/s and about 50km/h. Beyond that it tends to fail more and more
rapidly until it becomes quite the opposite of reality.
"good old horse sense" says that you can brace yourself against your
steering wheel in case of an accident. It makes lots of sense until I ask
you to hold out your arms and run as fast as you can into a brick wall.
"good old horse sense" says that sound travels faster in denser mediums.
"good old horse sense" says that particles are little balls spinning like
tops flying through space.
> chance when you rely on the results of expermentation without running
> those results through the good old 'is this answer reasonable' common
> sense filter
In a single sentance you've just rejected the last three centuries of
scientific progress. As a (failed) physicist let me assure you that the
rest of the world labours under no such illusions about the worthyness of
the human brain in terms of the "reasonableness" of the way the universe
"should" work. All of the great experiments in science are those that
result in the opposite of what "common sense" would tell you - the
photoelectic effect. blackbody radiation, the Stern-Gerlach experiment, the
Aspect/Bell Inequallity measurement, the quantum boiling pot etc etc etc.
The fact the the real world works nothing like what "common sense" suggests
is a property some philosophers of science have used to suggest that
science is an infinite enterprise.
Do the experiment Gord. I have. It froze quicker. You can "reason" all
you want, you'll still be wrong. If you're worried about your wife looking
at you funny, show her this message and tell her I'm crazy.
Maury
Maury Markowitz
> sense filter. But, hey, whatever turns your crank...speaking of which,
> are you 'still' of the opinion that the pistons are arranged around
> the propshaft vice the crankshaft?...gee...
I just noticed this.
I don't remember this topic at all, although I've seen you speaking about
it in the past. Please provide pointers to the thread in question.
Maury
Jim Erickson
> I must only assume that you haven't done much modern physics. "good old
>horse sense" is wrong almost 100% of the time. "good old horse sense" is
>great for things weighing between 1 and 1000 pounds, travelling at speeds
>between 1cm/s and about 50km/h. Beyond that it tends to fail more and more
>rapidly until it becomes quite the opposite of reality.
Maury, Are the ice cubes in your freezer part of the old fashioned
Newtonian world of physics or of the small-scale relativistic world of
modern physics that you're hinting at here? At the macroscopic level of
MY freezer, things are modeled quite well by the old fashioned physics.
>> chance when you rely on the results of expermentation without running
>> those results through the good old 'is this answer reasonable' common
>> sense filter
> In a single sentance you've just rejected the last three centuries of
>scientific progress. As a (failed) physicist let me assure you that the
>rest of the world labours under no such illusions about the worthyness of
>the human brain in terms of the "reasonableness" of the way the universe
>"should" work. All of the great experiments in science are those that
>result in the opposite of what "common sense" would tell you - the
>photoelectic effect. blackbody radiation, the Stern-Gerlach experiment, the
>Aspect/Bell Inequallity measurement, the quantum boiling pot etc etc etc.
>The fact the the real world works nothing like what "common sense" suggests
>is a property some philosophers of science have used to suggest that
>science is an infinite enterprise.
Actually Gord has stated one of the most useful rules in scientific
research. It's always a good idea to ask, does this make sense?
Sometimes, as in relativistic physics or quantum mechanics, we know
enough to say that the common sense answers are likely wrong, but when
you deal with macroscopic "real world" items, common sense is a good,
but not infallible, guide. Certainly in biology, molecular biology, and
biological chemistry most things obey common sense rules.
I also take issue with the claim that all great scientific discoveries
came about in the face of common sense. Mendel's genetic experiments,
Darwin's evolutionary theory, the germ-theory of disease, the
chromosomal basis of heredity, the demonstration of DNA as the
hereditary molecule, the structure of DNA etc etc etc. violate no common
sense principles, and I've found that the layman can rather easily
comprehend these concepts if they are explained clearly and simply in
common sense terms.
> Do the experiment Gord. I have. It froze quicker. You can "reason" all
>you want, you'll still be wrong. If you're worried about your wife looking
>at you funny, show her this message and tell her I'm crazy.
>Maury
Now we know why you're a "failed" (experimental) physicist! (grin)
Jim Erickson
Steve Pickering
<T...@btinternet.com> writes
>On Fri, 05 Feb 1999 02:03:53 GMT, mik...@dircon.co.uk (Mike Tighe)
>wrote:
>
>>Well, the mention on another thread on the relaxing effect versus the
>>possible dangers of smoking in a fast jet jogged my memory to an old
>>tale, and I want to know if it is true...
>>
>>The story goes back to the days when some RAF fast jet aircrew still
>>sported extravagant handlebar moustaches. On a long flight, a pilot
>>or nav ate his packed lunch, which happened to be a round of cheese
>>sandwiches. Then, when he put his oxygen mask back on, he selected
>>100% and accidentally started a small grease fire in his facial
>>hair...
>
>I read this story several years ago in the RAF in house Flight Saftey
>magazine "Air Clues" - so if Wg Cmdr Spry says it's true that's good
>enough for me. However, I'm sure it was a Shacklebomber back seater.
I seem to remember many moons ago a flying clothing worker at Coningsby
getting a 'good show' because he spotted that a future F-4 driver had
put Vaseline on his face which had smeared all over his oxy mask and
"COULD" have caused an explosion.
--
Steve P. St Andrews, Fife. Scotland (56.20.35 N 002 46.90 W)
Ex RAF Survival Equipment Fitter
Check 6 - Phantoms Phorever
S. Evans
>
> >> Manipulating the conditions? Put two ice cube trays in your freezer, one
> >>with warm water, one cold. Try it for yourself Gord.
>
> >askance at me and say, 'Oh really?...I see...hummm'. Then for some
> >time after I'd catch her looking at me with a quizzical expression on
> >her face. It's likely that for months after that she'd check me over
> >before I went downtown for unlaced shoes, unraised zippers and other
> >signs of mental wear.
>
> >>> I prefer the reasonable mature adult method of reasoning problems out.
> >
> >> I prefer experimentation, human reasoning is fallible.
> >
> >>Maury
> >
> >Doesn't make for good old horse sense Maury, you're really taking a
> >those results through the good old 'is this answer reasonable' common
>
> >Gord Beaman
>
> Maury, if you're going to toss aside reason for experimental results,
> you really ought to do the experiment first. I risked embarrassment and
> scorn and did the experiment at home last night. The cold water cubes
> froze first.
>
> Jim Erickson
Jim,
The error that Maury made was that this experiment is really a trick.
First you measure equal amounts of water. This is the important part.
The amount of water to compare must be equal before the heating. Next
pour one of the measures into a container that will go into the
freezer. With the other measure, heat it to a boil, then pour that
water into another container (ice cube tray, whatever) and place the two
into the freezer. The water that was boiling will often freeze first.
Why? Because there is less water. Some of it boiled off. I think The
Science Guy did this on Public Television (PBS) not too long ago.
Steve Evans
Gord Beaman
Ok Maury...here's the pertinent post...
=======================================
> Gord Beaman claimed:
>> Also I don't agree that there's very little
>> difference between the prop shaft and the crankshaft,
>> no self respecting pilot/engineer/mechanic would
>> confuse the two or use one in place of the
>> other...sorry...
> Yes, but that's Erik's point - that he feels Ford is
> NOT a "pilot/engineer/mechanic". And other
> non-"pilot/engineer/mechanic"'s that I know refer to
> spinners as nose cones, and prop shafts as crank shafts.
> Specifically the later one, where indeed the two
> _are_ many times the same thing.
>
> Maury
Jeff Crowell
Maury Markowitz wrote:
> Manipulating the conditions? Put two ice cube trays in your freezer, one
>with warm water, one cold. Try it for yourself Gord.
But the "why" is important, Maury.
All this "convective currents" bullhooey is just that. Eventually the warm
water
cools down (at a faster rate due to greater delta T) to match the temp of
the
water that started out cooler. Same-same all from there. The reason the
water that started out warm (or hot) freezes faster is that there is now
less
'hot' water than 'cold' water due to evaporation.
It's just another way of cheating, or stating the conditions deceptively.
Jeff
Jeff Crowell
Paul J. Adam wrote:
>Of course, he was wearing several thick layers of clothing, which were
>saturated with oxygen, and he burned like a torch. His shocked comrades
>tried to smother the flames, but his sweater and fleece jacket and all
>the rest of his clothing contained suxh a high level of oxygen that
>smothering it did no good at all.
Absotively! Then there's the mining stories, in a similar vein. (sorry)
It is not unheard of for miners (or others, for that matter) to work
in an atmosphere which is explosive without coming to harm, then
coming out into clean normal air for a break. They "light up"
(literally) and their chests explode because their lungs are filled with
the explosive mixture still.
Yick!
Jeff
Gord Beaman
>In <36bfb28b...@news1.sympatico.ca> Gord Beaman wrote:
>> Thank you Jim, I would have expected nothing less than your results.
>> If I ever need lab work done I'll surely remember your facility.
>
> Har!
>
> Lemme ask Gord, have YOU tried the experiment that I outlined? No?
>Let's see your next message...
>
>> I don't think so Maury, if my wife saw it she'd ask and I'd feel just
>> too silly telling her why.
>
> You're scared to experiment because of your wife? Sorry Gord, that's a
>pretty lame excuse IMHO.
>
Well, old chap, your using this remark against me this way is the only
lame item here, you don't really suppose I was being serious when I
said it do you now?...talk about opportunism!...guess in future I
won't use anything but very short plain sentences with little words
when I'm speaking to you.
>> Doesn't make for good old horse sense Maury
>
> I must only assume that you haven't done much modern physics. "good old
>horse sense" is wrong almost 100% of the time. "good old horse sense" is
>great for things weighing between 1 and 1000 pounds, travelling at speeds
>between 1cm/s and about 50km/h. Beyond that it tends to fail more and more
>rapidly until it becomes quite the opposite of reality.
>
If you say so ace...
> "good old horse sense" says that you can brace yourself against your
>steering wheel in case of an accident.
Might to a kid who has no life experiences perhaps...how old did you
say you were?...
<some drivel deleted here>
>
>
> All of the great experiments in science are those that
>result in the opposite of what "common sense" would tell you
If you say so ace...
> Do the experiment Gord. I have. It froze quicker. You can "reason" all
>you want, you'll still be wrong.
>
>Maury
>
Bullshit...it couldn't possibly freeze quicker...look Maury, if you
take two EQUAL amounts of water (at the same temp), heat one sample to
say 50C, cool the other to 2C, put them both in the cooler. Now you
claim that the warmer one will freeze first?...as Bernie says
"Bwhaaaaaahhaaaa"...
Hell, even though the hot one loses it's temp at a higher RATE (while
its hotter), eventually they'll get to the same temp (maybe before the
cool one freezes (which I doubt)) how do you explain one losing temp
faster than the other NOW?...they're at the same temp, they have the
same amount of water...tell me bright boy?...do some magical higher
physics machinations which have nothing to do with common sense and
tell me how this could happen...while you're at it tell me how one
sample will lose FIFTY degrees while another exactly the same size is
losing TWO degrees...I say again (loudly) bullshit sir...
Jeff Crowell
>> Manipulating the conditions? Put two ice cube trays in your freezer,
one
>> with warm water, one cold. Try it for yourself Gord.
But the 'why' is important, Maury.
All this 'convective currents" bullhooey is just exactly that. When the
hot and cold samples are placed in the freezer, the hot water cools off
faster than the cold--a simple convection problem so far. More delta T,
faster flow of heat (Q). But after a while, the 'hot' water catches up to
(cools down to the same temperature as) the cold. And it is
samee-samee-all from here.
The hot water really will freeze faster, by the way.
The hot water freezes faster because there is less water to freeze.
A meaningful fraction of it evaporated during the cooling-off period
(for small sample sizes).
But you may not be able to measure the differences in your
freezer.
Jeff
Jim Erickson
>Jim,
>The error that Maury made was that this experiment is really a trick.
>First you measure equal amounts of water. This is the important part.
>The amount of water to compare must be equal before the heating. Next
>pour one of the measures into a container that will go into the
>freezer. With the other measure, heat it to a boil, then pour that
>water into another container (ice cube tray, whatever) and place the two
>into the freezer. The water that was boiling will often freeze first.
>Why? Because there is less water. Some of it boiled off. I think The
>Science Guy did this on Public Television (PBS) not too long ago.
>Steve Evans
Thanks for pointing this out Steve. What is different here from what
Laurie Nyveen stated earlier, is that the evaporation occurs before the
water ever enters the freezer. Thus the hot sample contains much less
water than the cold sample when they enter the freezer, so the hot
sample has the chance of freezing faster. It's really no different from
putting a thimble full of boiling water and a bucket of cold into the
freezer and asking; which freezes first?
The common-sense, and physically correct, bottom line is that if you
want to make ice cubes, start with cold water. It's also a lot easier
on any frozen meats or vegetables you've got in the freezer.
Jim Erickson
SL Nyveen
> Hell, even though the hot one loses it's temp at a higher RATE (while
> its hotter), eventually they'll get to the same temp (maybe before the
> cool one freezes (which I doubt)) how do you explain one losing temp
> faster than the other NOW?...they're at the same temp, they have the
> same amount of water...tell me bright boy?
They don't have the same amount of water when they reach the same temp.
The hotter one has less, because more has evaporated. That was my
original point.
> ...do some magical higher
> physics machinations which have nothing to do with common sense and
> tell me how this could happen...while you're at it tell me how one
> sample will lose FIFTY degrees while another exactly the same size is
> losing TWO degrees...I say again (loudly) bullshit sir...
Here you seem to be confusing temperature with heat - although it can be a
semantic error, I'll grant you.
Imagine each molecule has heat content that can be defined as a number.
The temperature of a liquid is the average number among all molecules.
The heat is the sum of all molecules. (And with evaporation, the
molecules with higher numbers leave - leaving behind a lower average and a
lower sum.)
I performed the experiment myself this afternoon. I used 1/3 cup of water
near boiling and water at room temperature. I poured the water into two
Fireking measuring cups and stuck them in my freezer on top of towels (to
remove the cooling effect of the shelf). I checked the water at 7 min, 20
min, 40 min, 60 min, and every 5 min thereafter.
I had an odd, but telling, result. The room temperature water displayed
ice crystals first, but the hot water froze solid first. Why? Probably
because there was less hot water left, and thus less latent heat to lose
in freezing. (No, I did not mix up the containers...).
There appear to be as many results here as there are experimenters. I
think this is because the variables can effect the outcome drastically.
Variable include:
- Temperature difference between samples
- absolute starting temperatures
- surface area
- conductive cooling (container material and insulative properties)
- temperature of cooling medium (freezer air)
and more...
I don't call these variables "tricks", however, since that's not what they
are. There's definitely a curve waiting to be drawn here among the
variables - on one side the hotter water freezes first; on the other, the
cooler water does. My experiment, with the cooler water reaching 0
degrees first, but the lesser volume of the hot water, with less latent
heat, catching up to and passing the former in the race to lose latent
heat, seems to have cut very finely near that imaginary curve.
My conclusion? Hot temperature water _can_ freeze faster than cooler
water given the right starting conditions, but won't always. I suspect
you need to start with truly hot water and compare it to tepid water. I
mean, no one's arguing with Gord that 52-degree water will freeze before
2-degree water, right?
Mary Shafer
story of "hot water freezing before cold" in "On Food And Cooking".
He refers to the SciAm article that confirmed the empirical
observations of the schoolboy who first noticed the phenomenon. He
also presents the data he himself collected in the process of doing
these experiments.
In brief, if you put two open trays of equal amounts of water, one hot
and one cold, in the freezer, on a clean shelf, at the same time, the
hot water will sometimes freeze faster. However, if you then let the
ice thaw and remeasure the water, you will find that you have less
water from the hot water tray. The hot water has evaporated. This is
why it froze sooner--there's measurably less of it. Sometimes not
enough evaporated and the cold water froze at the same time or sooner
than the hot water.
If you cover the trays, or use covered containers, the cold water will
_always_ freeze first.
--
Mary Shafer NASA Dryden Flight Research Center, Edwards, CA
SR-71 Flying Qualities Lead Engineer Of course I don't speak for NASA
sha...@reseng.dfrc.nasa.gov DoD #362 KotFR
URL http://www.dfrc.nasa.gov/People/Shafer/mary.html
For personal messages, please use sha...@ursa-major.spdcc.com
Mary Shafer
> Much as I have to provice references....
This should be "Much as I hate to provide references....
I just got back from the other building and it's cold and rainy and
windy and my fingers weren't working very well. It's really miserable
living somewhere that doesn't have much weather, only climate, because
one isn't nearly so prepared for the bad stuff as those who get it all
the time. My usually adequate demin jacket is soaked to the lining
and I'm still looking for my umbrella because I've got to go to my car
and leave (I refuse to be trapped here, waiting for the rain to stop).
Gord Beaman
--cut--
>
>In brief, if you put two open trays of equal amounts of water, one hot
>and one cold, in the freezer, on a clean shelf, at the same time, the
>hot water will sometimes freeze faster. However, if you then let the
>ice thaw and remeasure the water, you will find that you have less
>water from the hot water tray. The hot water has evaporated. This is
>why it froze sooner--there's measurably less of it. Sometimes not
>enough evaporated and the cold water froze at the same time or sooner
>than the hot water.
>
>If you cover the trays, or use covered containers, the cold water will
>_always_ freeze first.
>
>--
>Mary Shafer
Thank you Mary...what I find difficult to believe is that a litre of
water will lose so much water due to evaporation (unless you boiled
the hell out of it) that you could even notice the difference in the
freezing point between the 'lesser' amount and the 'larger' amount.
Let's say you put a litre of water at 75 deg C in one pan and a litre
of water say 5C in another...ok now, how much 'less' water is there in
the hot pan?...damned little less I'd say, are you telling me that
'that' much less water will make the ~litre reach 0C 'before' the
litre of 5C water?...of course the 'hot' pan will lose a little more
due to evaporation as it cools down, but will it lose enough to wipe
out that huge difference in temperature?...my common horse sense says
nah!, not a snowball's chance...and besides all that it's no fair to
start out with a different amount of water...we need to start out with
a fixed amount of water at the same temp...however, I think the cold
water will win anyway.
Squeaks
Bubba wrote in message <79o47d$ldc$1...@server2.wans.net>...
snip
>the inside out' or hot water will freeze quicker than cold water (and
>Hot water actually freezes quicker. The latent heat of vaporization
>coupled with the convection currents of the steam help to remove more
>heat faster.
IIRC, the misconception on this thread revolves around the fact that the
rate of _evaporation_ is greater for hot water than for cold. This
initially gives a greater _rate_ of cooling for hot water, but the rate
slows down as the water cools, so by the time it gets to the original
temperature of the "cold" water sample, the cold water is approaching
freezing.
QED, the cold water freezes first, but the hot water had a greater initial
rate of cooling. My grammar school physics lessons were too long ago to
remember precisely, but it may be Boyle's Law that holds the key?
Cheers,
John Eacott
The Helicopter Service Australia
Andrew Yeung
Beaman) wrote:
>Bullshit...it couldn't possibly freeze quicker...look Maury, if you
>take two EQUAL amounts of water (at the same temp), heat one sample to
>say 50C, cool the other to 2C, put them both in the cooler. Now you
>claim that the warmer one will freeze first?...as Bernie says
Try the experiment, 1 at BP, one at room temp.
Andrew Yeung
Beaman) wrote:
>Let's say you put a litre of water at 75 deg C in one pan and a litre
>of water say 5C in another...ok now, how much 'less' water is there in
>the hot pan?...damned little less I'd say, are you telling me that
>'that' much less water will make the ~litre reach 0C 'before' the
>litre of 5C water?...of course the 'hot' pan will lose a little more
>due to evaporation as it cools down, but will it lose enough to wipe
>out that huge difference in temperature?...my common horse sense says
>nah!, not a snowball's chance...and besides all that it's no fair to
>start out with a different amount of water...we need to start out with
>a fixed amount of water at the same temp...however, I think the cold
>water will win anyway.
Try BOILING water, RPT try BOILING water. And appreciate the
difference.
Andrew Yeung
<eac...@helicopterservice.com.au> wrote:
>QED, the cold water freezes first, but the hot water had a greater initial
>rate of cooling. My grammar school physics lessons were too long ago to
>remember precisely, but it may be Boyle's Law that holds the key?
Isn't Boyle's law one of the gas laws?
Tarver Engineering
Jim Erickson wrote in message <36C04E...@columbia.edu>...
>>Try any or all of these now, if you don't mind:
>
>>1) stick the tubes in a styrofoam block to limit heat loss through the
plastic.
>
>>2) use the -20 C freezer. The rate of cooling probably affects the amount
>>of evaporative cooling that can occur in a given time.
>
>>3) use boiling water vs. water at room temperature.
>
>>4) use containers that allow greater surface area.
>
>>Laurie Nyveen
>
>
>Sorry Laurie, I don't have the time to check a whole range of variable
>just to test a crazy hypothesis. I'm not convinced that hot water will
>freeze faster than cold under any conditions, let alone common ones.
>I'm not saying it's impossible, just that if it can occur, it likely
>requires a very special set of conditions. Which was Gord Beaman's
>point IIRC.
If you use an upright freezer and the system cycles hard you can get hot
water to freeze faster, but all things are not equal then.
John
Tarver Engineering
Mary Shafer wrote in message ...
>Mary Shafer <sha...@reseng2.dfrc.nasa.gov> writes:
>
>> Much as I have to provice references....
>
>This should be "Much as I hate to provide references....
Sorry, spelling flames are not allowed.
John
keeg...@perkin-elmer.com
gbe...@bigfoot.com wrote:
> Bullshit...it couldn't possibly freeze quicker...look Maury, if you
> take two EQUAL amounts of water (at the same temp), heat one sample to
> say 50C, cool the other to 2C, put them both in the cooler. Now you
> claim that the warmer one will freeze first?...as Bernie says
> "Bwhaaaaaahhaaaa"...
>
> Hell, even though the hot one loses it's temp at a higher RATE (while
> its hotter), eventually they'll get to the same temp (maybe before the
> cool one freezes (which I doubt)) how do you explain one losing temp
> faster than the other NOW?...they're at the same temp, they have the
> same amount of water...tell me bright boy?...do some magical higher
> physics machinations which have nothing to do with common sense and
> tell me how this could happen...while you're at it tell me how one
> sample will lose FIFTY degrees while another exactly the same size is
> losing TWO degrees...I say again (loudly) bullshit sir...
Not completely bullshit, but somewhat of a trick. Never tried this myself,
but the hot water will freeze quicker because the hot water evaporates more
as it is cooling and so at the end the amount of water is not equal. I am not
sure what the starting conditions have to be before this will work. It is
supposed to work better if the water is put into an insulated container.
Wooden water bucket instead of a metal one.
Stephen Keegan
-----------== Posted via Deja News, The Discussion Network ==----------
http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
Maury Markowitz
> But the 'why' is important, Maury.
Yes thank you, I didn't realize after five years of honors physics that
the reasons things happened weren't important! :-)
Maury
Jim Erickson
>Much as I haTe to proviDe references, John McGee details the entire
>story of "hot water freezing before cold" in "On Food And Cooking".
>He refers to the SciAm article that confirmed the empirical
>observations of the schoolboy who first noticed the phenomenon. He
>also presents the data he himself collected in the process of doing
>these experiments.
Mary,
I found "On Food and Cooking: the science and lore of the kitchen" by
Harold McGee (1984) in the library but could find no mention of the hot
v. cold water issue. I also checked Scientific American without
success. Our library had a very good index for Sci Am from 1946 to 1978
and I couldn't find any listings under water, ice, or freezing that fit
the bill. We have no good index for the more recent volumes but my
cursory glances through the later Amateur Scientist section indices
didn't help either. Of course, the stuff could well be there and I may
just have missed it (I spent half an hour trying to find the keys that
were right on top of my desk a couple of days ago). On the other hand,
perhaps you were thinking of another book. Any further help you could
offer would be appreciated.
Jim Erickson
Maury Markowitz
> Steve Evans wrote:
I didn't get his post - my server loses a full 1/3rd of the messages on
the net. UUNet really is a terrible hack.
> >Jim,
> >The error that Maury made was that this experiment is really a trick.
Oh come on! I am not in "error", the experiment works, I've don't it
myself. Nor is it a "trick", if you put the ice cube trays in the freezer,
this is likely to happen. I'm tried of people effectively implying that
I'm being intellectually dishonest.
Maury
Tarver Engineering
Maury Markowitz wrote in message ...
Gat a refund, you were cheated.
John
Gord Beaman
--cut--
>> >Jim,
>> >The error that Maury made was that this experiment is really a trick.
>
> Oh come on! I am not in "error", the experiment works, I've don't it
>myself. Nor is it a "trick", if you put the ice cube trays in the freezer,
>this is likely to happen. I'm tried of people effectively implying that
>I'm being intellectually dishonest.
>
>Maury
>
I can only assume that you meant 'done' and 'tired'...now then, I can
suggest a sure fire way to prevent people from implying that
Maury...take a guess?...and btw what's your answer re the
crankshaft/propshaft?...and have you yet given up calling a spinner a
nosecone?...<hoowee>!...hate to kick a guy when he's down but you're
such an easy target!...
Gord Beaman
-cut--
>
>IIRC, the misconception on this thread revolves around the fact that the
>rate of _evaporation_ is greater for hot water than for cold. This
>initially gives a greater _rate_ of cooling for hot water, but the rate
>slows down as the water cools, so by the time it gets to the original
>temperature of the "cold" water sample, the cold water is approaching
>freezing.
>
>rate of cooling. My grammar school physics lessons were too long ago to
>remember precisely, but it may be Boyle's Law that holds the key?
>
Gord Beaman
--cut--
>
>Try BOILING water, RPT try BOILING water. And appreciate the
>difference.
Yes Andrew, that will do it I'm sure...probably help if you leave it
at boiling for a half hour too...and I 'appreciate' your offering...
Mary Shafer
Look in McGee's second book, then. The SciAm article was by Jearl
Walker, to narrow down the time span. It's definitely post-78; Walker
was with SciAm in the '90s, I think.
Try the alt.folklore.urban FAQ and archive, too.
Mary Shafer
> Thank you Mary...what I find difficult to believe is that a litre of
> water will lose so much water due to evaporation (unless you boiled
> the hell out of it) that you could even notice the difference in the
> freezing point between the 'lesser' amount and the 'larger' amount.
>
> Let's say you put a litre of water at 75 deg C in one pan and a litre
> of water say 5C in another...ok now, how much 'less' water is there in
> the hot pan?...damned little less I'd say, are you telling me that
> 'that' much less water will make the ~litre reach 0C 'before' the
> litre of 5C water?...of course the 'hot' pan will lose a little more
> due to evaporation as it cools down, but will it lose enough to wipe
> out that huge difference in temperature?...my common horse sense says
> nah!, not a snowball's chance...and besides all that it's no fair to
> start out with a different amount of water...we need to start out with
> a fixed amount of water at the same temp...however, I think the cold
> water will win anyway.
This isn't such a profound problem that it can only be studied in labs
or something. I've provided a reference, with data, and if you don't
accept that, you need to provide your own data, not just say you don't
believe it when you obviously haven't even looked at the reference,
let alone collected any data yourself. It's not just Gordon that's
doing this, but all of you. Let's see less arguing and more
information.
Rather than tell us what you think must happen, try it yourself and
report the data here. If it doesn't agree with McGee and Jearl
Walker, you may have to look at the references yourself to be sure
you're doing the same experiment, of course. McGee used recording
thermocouples but manual thermometers will work just fine, although
all the door opening will slow things down. You need a clean shelf
(no frost) and identical ice cube trays or shallow dishes. You can go
ahead and do the covered containers at the same time if you've got a
large freezer. Your scale should be accurate to the nearest gram or
so and I don't think you need a liter of water, as most ice cube trays
don't hold nearly that much.
As you'd know if you'd looked at the reference, the evaporation
doesn't happen in boiling the water. All the experiments I've seen
reported use equal amounts of water poured into the trays, eliminating
any effects of boiling the water. It happens in the freezer, where a
shallow tray (with a relatively large surface area) was used. The
effect is markedly more pronounced in self-defrosting freezers, by the
way.
For those without access to McGee or SciAm, try the FAQ and archive
for alt.folklore.urban, as this question has come up repeatedly in
that newsgroup.
Mary Shafer
All the experiments I've seen use the same amounts of hot and cold
water going into the freezer. Unless it's going to be boiled in the
freezer, length of boiling time has nothing to do with this
experiment.
Michael Kelly Perdue
>
> Much as I have to provice references, John McGee details the entire
> story of "hot water freezing before cold" in "On Food And Cooking".
Speaking of those dagburn references, here's one from the Physics'
FAQ on the subject:
http://www.public.iastate.edu/~physics/sci.physics/faq/hot_water.html
Complete with more of those pesky references! :-)
Kelly Perdue
"I've attended the Indy 500. That's formula one, not stock cars,
but the idea's the same" -- Dan Quayle
Jim Erickson
>> >difference.
>
>> Yes Andrew, that will do it I'm sure...probably help if you leave it
>> at boiling for a half hour too...and I 'appreciate' your offering...
>All the experiments I've seen use the same amounts of hot and cold
>water going into the freezer. Unless it's going to be boiled in the
>freezer, length of boiling time has nothing to do with this
>experiment.
Without having read the references (yet) I'm betting that what is so
paradoxical about this phenomenon is that it works best when the hot
water is VERY hot. The critical factor is the amount of water that
evaporates in the freezer from the hot sample. This will be maximized
at temperatures where the vapor pressure of water is high, since it's
the vapor pressure that determines evaporation rate. For example,
water's maximum vapor pressure is at 100°C (760 Torr) and it's minimum
is at O°C (~5 Torr). There is a rapid fall off in vapor pressure with
temperature, however, so that by the time it cools to 60°C the vapor
pressure is only 20% of the maximum. In essence, if you do the
experiment with 20° and 60° water, I would bet the cold sample wins
everytime. If you use 95° water enough water vaporizes to reduce the
amount of water to the point where the hot sample can win out.
One subtle point from Mary's previous message that bears repeating, is
that the water must be weighed before putting it in the freezer. Mass
does not vary with temperature, but density does. If you simply use
equal volumes, the near boiling sample starts out with only ~ 96% of the
water in the cold (4-20°C) sample because the hot water is less dense.
(Below 4°, the colder the water, the less dense it becomes.)
Jim Erickson
Maury Markowitz
> Yes Andrew, that will do it I'm sure...probably help if you leave it
> at boiling for a half hour too...and I 'appreciate' your offering...
Metal objects that fly in the air? Suuuure little boy, I 'appreciate'
you offering...
Give it up Gord, now you're just sounding cranky.
Maury
Gord Beaman
>gbe...@pei.sympatico.ca (Gord Beaman) writes:
>
>> and...@pacific.net.sg (Andrew Yeung) wrote:
>> --cut--
>> >
>> >Try BOILING water, RPT try BOILING water. And appreciate the
>> >difference.
>>
>> Yes Andrew, that will do it I'm sure...probably help if you leave it
>> at boiling for a half hour too...and I 'appreciate' your offering...
>
>All the experiments I've seen use the same amounts of hot and cold
>water going into the freezer. Unless it's going to be boiled in the
>freezer, length of boiling time has nothing to do with this
>experiment.
>--
>Mary Shafer
...Mary Mary!...is this an off day for you?...I honestly hate to take
a person of your standing to task but....
Please allow me to defend myself, did you not read several posters
who mentioned the fact (and it is fact) that a litre of hot water has
'less' water than a litre of cold?...gee, I hope you aren't going to
argue that point?...less 'mass' I mean of course...
Second point, I was being sarcastic Mary, I meant that it would be to
his advantage to BOIL some water away!...gee...isn't this the whole
damned point?, that there's less water in the 'hot' sample therefore
it'll freeze quicker?...
And I did go to A.U. Legends and read the article by Jearl Walker, the
experiment described uses water at 95C and 75C and suggests using
'wooden buckets'. It also mentions that a litre of water will lose as
much as (iirc) 26% during cooling from 100C to 0C.
S. Evans
Did not mean to imply that you were using some trick. I meant that
there was a "trick" to this process, it was more than just the
temperature of the water. The outcome of the experiment would probably
be different if both samples were placed in sealed containers.
In another post, I saw you reference your education, and it is obvious
you have the backgroud to understand the entire thing better than I do.
I struggled through college, spent some time in the navy, channel surf
the TV, once in a while catching some show called the Science Guy that I
am sure is aimed at 10 year olds. So don't take what I said personally.
Steve Evans
Maury Markowitz wrote:
>
> In <36C0A4...@columbia.edu> Jim Erickson wrote:
> > Steve Evans wrote:
>
> I didn't get his post - my server loses a full 1/3rd of the messages on
> the net. UUNet really is a terrible hack.
>
Jim Erickson
>Maury,
>Did not mean to imply that you were using some trick. I meant that
>there was a "trick" to this process, it was more than just the
>temperature of the water. The outcome of the experiment would probably
>be different if both samples were placed in sealed containers.
I might as well offer an apology to Maury as well, for suggesting that
he didn't do the experiment before opining about it. On the other hand,
he did say some silly things about the nature of science....(grin)
The cold water will freeze first if the experiment is done in sealed
containers. In that case there is no evaporative cooling, thus no loss
of mass from the hot sample, and the sample with the lowest amount of
energy (the cold one) will freeze first.
>In another post, I saw you reference your education, and it is obvious
>you have the backgroud to understand the entire thing better than I do.
>I struggled through college, spent some time in the navy, channel surf
>the TV, once in a while catching some show called the Science Guy that I
>am sure is aimed at 10 year olds. So don't take what I said personally.
>Steve Evans
Hey don't underestimate "Bill Nye, the Science Guy", it is an excellent
program. Yes, it's aimed at kids, but the science is pretty darn good,
and it is entertaining. I try to watch it whenever I'm home sick, and
I've been in molecular biology for close to 20 years. Enjoy it.
Jim Erickson
Mary Shafer
> Second point, I was being sarcastic Mary, I meant that it would be to
> his advantage to BOIL some water away!...gee...isn't this the whole
> damned point?, that there's less water in the 'hot' sample therefore
> it'll freeze quicker?...
And how's he going to boil it in the freezer, Gordon? I've never seen
a freezer with burners inside. Equal weights into the freezer doesn't
sound like boiling some of it off before putting it in will matter
much.
However, I will point out that, up to a point, the longer you boil tap
water, the fewer dissolved gasses it has in it (which is why tea made
with water that's boiled for a while tastes so flat). It is possible
that the gasses might have some effect on freezing rate, although I
don't know which way the change would go.
Curtis McRae
Geez - can't you people go back to talking about airplanes? As long as I
have cubes for my drink that's all I'm concerned about ;->
Curt
-usually a lurker-
Jim Erickson
>have cubes for my drink that's all I'm concerned about ;->
>Curt
>-usually a lurker-
What do you think I did with the ice cubes I made? Funny thing, the hot
water cubes tasted better than the cold ones. Or were those the
poly-water cubes?
Jim Erickson
Tarver Engineering
Mary Shafer wrote in message ...
>
>> Second point, I was being sarcastic Mary, I meant that it would be to
>> his advantage to BOIL some water away!...gee...isn't this the whole
>> damned point?, that there's less water in the 'hot' sample therefore
>> it'll freeze quicker?...
>
>And how's he going to boil it in the freezer, Gordon? I've never seen
>a freezer with burners inside. Equal weights into the freezer doesn't
>sound like boiling some of it off before putting it in will matter
>much.
Maybe you should go to Maury's house and see his freezer.
>However, I will point out that, up to a point, the longer you boil tap
>water, the fewer dissolved gasses it has in it (which is why tea made
>with water that's boiled for a while tastes so flat). It is possible
>that the gasses might have some effect on freezing rate, although I
>don't know which way the change would go.
How about if you boil away all the hot water and call it magic? Then you
could claim that when you freeze hot water is dissapears. :)
John
Gord Beaman
--cut--.
>
> Metal objects that fly in the air? Suuuure little boy, I 'appreciate'
>you offering...
>
sorry, care to explain?.
> Give it up Gord, now you're just sounding cranky.
>
>Maury
>
Cranky?!...is this a freudian slip perhaps?...in any case it's the
closest you've come to mentioning the questions that I've been asking
you for awhile...(and after I searched Dejanews at your suggestion
too!).
Jim Erickson has stated his thoughts much better than I can mine and
mine match his. Mary has pretty well summed up the situation
too...here's her 'summation' so to speak:
>....... However, if you then let the
>ice thaw and remeasure the water, you will find that you have less
>water from the hot water tray. The hot water has evaporated. This is
>why it froze sooner--there's measurably less of it. Sometimes not
>enough evaporated and the cold water froze at the same time or sooner
>than the hot water.
>If you cover the trays, or use covered containers, the cold water will
>_always_ freeze first.
>--
>Mary Shafer
Yes Mary and your source Jearl Walker also states in part:
> If equal masses of water are taken at two starting
>temperatures, more rapid evaporation from the hotter one may diminish
>its mass enough to compensate for the greater temperature range it must
>cover to reach freezing.
Which pretty well agrees with what you state above...you'll notice
that he leaves himself an out though '...from the hotter one MAY
diminish it's mass enough...'. I do note, however, that he says you
need to use insulated containers and the water samples need to be 95C
and 50C (75C in one sample), hardly 'cold' in my estimation...
Now here's the 'statement' that he uses to explain why, when the hot
sample reaches the temp of the cooler sample, they don't 'match' for
the rest of the journey:
>Every "proof" that hot water can't freeze faster assumes that the state of
>the water can be described by a single number. Remember that
>temperature is a function of position. There are also other factors besides
>temperature, such as motion of the water, gas content, etc. With these
>multiple parameters, any argument based on the hot water having to pass
>through the initial state of the cold water before reaching the freezing
>point will fall apart. The most important factor is evaporation.
He just makes this statement then carries on with no further
justification of this mysterious 'function of position' whatever that
is, motion of the water (?), gas content (?). There is one other
little lulu in there, let's see if I can find it,...yeh, here tiz:
>The cooling effect of evaporation is twofold. First, mass is carried off so
>that less needs to be cooled from then on. Also, evaporation carries off
>the hottest molecules, lowering considerably the average kinetic energy
>of the molecules remaining.
Isn't this just a fancy way of saying 'It's cooling off'?...(the last
para I mean).
In conclusion, this doesn't look much like 'data' to me, seems pretty
clear that he's just making statements like I did Mary, mind you, he's
likely a scientist and is 'allowed' to make statements, although I
have only your word on this...
Andrew Yeung
<sha...@reseng2.dfrc.nasa.gov> wrote:
>gbe...@pei.sympatico.ca (Gord Beaman) writes:
>
>> and...@pacific.net.sg (Andrew Yeung) wrote:
>> --cut--
>> >
>> >Try BOILING water, RPT try BOILING water. And appreciate the
>> >difference.
>>
>> Yes Andrew, that will do it I'm sure...probably help if you leave it
>> at boiling for a half hour too...and I 'appreciate' your offering...
>
>All the experiments I've seen use the same amounts of hot and cold
>water going into the freezer. Unless it's going to be boiled in the
>freezer, length of boiling time has nothing to do with this
>experiment.
Yes, it's absolutely got nothing to do with boiling away water. The
point is *boiling* water which has just been taekn off will have at
least 98 - 100 degs of temp. If you've the time to do 60 degs and all,
try boiling water.
dmb...@my-dejanews.com
gbe...@bigfoot.com wrote:
>
> >....... However, if you then let the
> >ice thaw and remeasure the water, you will find that you have less
> >water from the hot water tray. The hot water has evaporated. This is
> >why it froze sooner--there's measurably less of it. Sometimes not
> >enough evaporated and the cold water froze at the same time or sooner
> >than the hot water.
>
The point he's making here is that given initial conditions
that vary in one way* (one sample is hotter than the other),
the hotter sample *never passes through* the same point as the
colder sample. The temperature gets to be the same as colder
sample, but by then there has been evaporation, so the mass
is different. I think you got that bit.
> >If you cover the trays, or use covered containers, the cold water will
> >_always_ freeze first.
> >--
> >Mary Shafer
>
> Yes Mary and your source Jearl Walker also states in part:
>
A better statement would be *sealed* containers, rather than
covered ones. Then the evaporative losses don't occur. It's
possible for a "covered" container to allow evaporative losses.
>
> Which pretty well agrees with what you state above...you'll notice
> that he leaves himself an out though '...from the hotter one MAY
> diminish it's mass enough...'. I do note, however, that he says you
> need to use insulated containers and the water samples need to be 95C
> and 50C (75C in one sample), hardly 'cold' in my estimation...
>
He doesn't say you have to use the two specified temperatures - they
are examples.
This caveat isn't an "out" it's an admission that there are other,
un-controlled variables, like the rate of conductive losses that
may eliminate the advantage that evaporation gives the hot water.
It's honesty, not duplicity.
> Now here's the 'statement' that he uses to explain why, when the hot
> sample reaches the temp of the cooler sample, they don't 'match' for
> the rest of the journey:
>
So you do get it. Why are you being difficult?
>
> He just makes this statement then carries on with no further
> justification of this mysterious 'function of position' whatever that
> is, motion of the water (?), gas content (?).
Call it "state" if it makes you feel better.
> There is one other
> little lulu in there, let's see if I can find it,...yeh, here tiz:
>
> >The cooling effect of evaporation is twofold. First, mass is carried off so
> >that less needs to be cooled from then on. Also, evaporation carries off
> >the hottest molecules, lowering considerably the average kinetic energy
> >of the molecules remaining.
>
> Isn't this just a fancy way of saying 'It's cooling off'?...(the last
> para I mean).
>
I'm not sure about this, but I think there's more to "temperature" than
mere 1/2 mv2 - what about molecular vibration, rotation, inter-molecular
bonding?
> In conclusion, this doesn't look much like 'data' to me, seems pretty
> clear that he's just making statements like I did Mary, mind you, he's
> likely a scientist and is 'allowed' to make statements, although I
> have only your word on this...
The paper is interesting but doesn't describe an experiment that can
be independently verified. I would expect:
an accurate description of the physical set-up, including
bucket material, shape, water mass, measurement method.
Results! Temp vs. time, Temp vs mass, vapour pressures, etc.
Range of starting temperatures would be nice, too.
Basically, the only thing the paper says is that if you stick
a bucket of water outside in the cold then five different
physical processes are involved in determining how quickly
the water remaining in the bucket freezes.
You're in Canada, it's cold at this time of the year - try
it out.
Take two buckets...
;-)
David
Michael Kelly Perdue
> However, I will point out that, up to a point, the longer you boil tap
> water, the fewer dissolved gasses it has in it (which is why tea made
> with water that's boiled for a while tastes so flat). It is possible
> that the gasses might have some effect on freezing rate, although I
> don't know which way the change would go.
More from the Physic's FAQ at
http://www.public.iastate.edu/~physics/sci.physics/faq/hot_water.html:
Forth Factor: Dissolved Gasses
Water always contains dissolved gases such as oxygen and carbon
dioxide. These impurities have the effect of lowering its freezing
point. When water is heated, much of these gases are driven out
because their solubility in water is less at higher temperatures.
When the hot water cools it then has less dissolved gas than water
which was not heated so it has a higher freezing point and freezes
first. This is often cited as a an important factor but no references
to experimental evidence or quantitative analysis have been given.
Kelly Perdue
"We trained hard, but it seemed that every time we were beginning to
form up into teams, we would be reorganized. I was to learn later in
life that we tend to meet any new situation by reorganizing; and a
wonderful method it can be for creating the illusion of progress
while producing confusion, inefficiency, and demoralization."
-Petronius Arbiter, 210 BC
Jeff Crowell
Gord Beaman wrote:
>Thank you Mary...what I find difficult to believe is that a litre of
>water will lose so much water due to evaporation (unless you boiled
>the hell out of it) that you could even notice the difference in the
>freezing point between the 'lesser' amount and the 'larger' amount.
What may be giving you the trouble, Gord, is that the vast
majority of the heat transfer required to cool and freeze the
water is the heat transfer necessary to freeze the water
once it has reached 0 Celsius.
Digressing a bit, 'heat' and 'temperature' are very different
things, at least in the engineering and scientific worlds. Heat
is energy in motion, basically. 'Sensible heat' is heat transfer
that results in temperature change. 'Latent heat' is heat
transfer that results in phase change (fusion is solid to liquid
and back, vaporization is liquid to vapor and back).
While it takes 4 Joules to change the temperature of one
gram of liquid water one degree Celsius (sensible heat),
it takes 334 Joules to convert one gram of liquid water at
zero C to one gram of ice at zero C (latent heat of fusion).
So it doesn't take much of a mass change to effect a real
difference in freeze times.
Ain't science wonderful?
Jeff
Tarver Engineering
dmb...@my-dejanews.com wrote in message <79unac$qh0$1...@nnrp1.dejanews.com>...
>> >If you cover the trays, or use covered containers, the cold water will
>> >_always_ freeze first.
>> >--
>> >Mary Shafer
>>
>> Yes Mary and your source Jearl Walker also states in part:
>>
>
>A better statement would be *sealed* containers, rather than
>covered ones. Then the evaporative losses don't occur. It's
>possible for a "covered" container to allow evaporative losses.
I recomend against boiling warter in a sealed container. :)
John
Maury Markowitz
> Did not mean to imply that you were using some trick. I meant that
> there was a "trick" to this process
I'm sorry, but I simply don't agree. I don't see this as any more a
"trick" than the fact that water is denser as a liquid than as a solid (in
normal setups). It's a property of the system, and an interesting and
seemingly odd one. These are the exact sorts of experiements that lead to
a deeper understanding of nature, whereas most science teaching today spews
forth "pat" answers like everything is solved.
For instance we "all know" that microwaves heat things by shaking (or
spinning) the water molecules in them, right? Well last night my friend
was rather proud of himself because he got his question read on Discovery.
The question is simple, why don't flies die in a microwave? Clearly if the
explaination of how the oven works was correct then the fly would die, thus
there must be some deeper functioning that people are glossing over.
And to me this is exactly the same case as water in the freezer. The
_fact_ that this effect happens is unquestionable, and the interesting
thing is the _why_. However this thread has degenerated into bating and
not-terribly subtle personal attacks. Facinating in itself I suppose.
> the TV, once in a while catching some show called the Science Guy that I
> am sure is aimed at 10 year olds. So don't take what I said personally.
I don't, I was not referring to you specifically, although reading it
again it does seem that way, so I offer my appologies.
By the way, I think Bill Nye is one of the best shows on TV, even if it
is for kids. I watch it every weekend, and learn something most every
show. Last week's on bouyancy was fun (although that stuff I knew) and the
week before's on wetlands was excellent - including explainions of flooding
events and such.
Maury
dmb...@my-dejanews.com
"Tarver Engineering" <jta...@tminet.com> wrote:
>
>
> I recomend against boiling warter in a sealed container. :)
>
I never said that the water had to be boiling. The
important point is that sealing the container prevents
evaporative (mass) loss.
Oh, and I suggest you look at an old fangled cooking
device called a "pressure cooker". That takes "boiling
water" very happily.
Maury Markowitz
> > Metal objects that fly in the air? Suuuure little boy, I 'appreciate'
> >you offering...
> >
> I have no idea what this above refers to...care to elucidate?...oops
> sorry, care to explain?.
I don't have to, you've clearly grasped the sacrasm in the statement.
> Cranky?!...is this a freudian slip perhaps?...in any case it's the
> closest you've come to mentioning the questions that I've been asking
> you for awhile...(and after I searched Dejanews at your suggestion
> too!).
I haven't seen these questions. What are they? Keep in mind my server
loses a full third of the mail in most all groups.
> >ice thaw and remeasure the water, you will find that you have less
> >water from the hot water tray. The hot water has evaporated. This is
> >why it froze sooner--there's measurably less of it. Sometimes not
> >enough evaporated and the cold water froze at the same time or sooner
> >than the hot water.
>
> >If you cover the trays, or use covered containers, the cold water will
> >_always_ freeze first.
Yes. Does this answer your question?
Odd, this appears to be a reply to someone else. It seems that the
messages were concatted.
Maury
Jim Erickson
>What may be giving you the trouble, Gord, is that the vast
>majority of the heat transfer required to cool and freeze the
>water is the heat transfer necessary to freeze the water
>once it has reached 0 Celsius.
>While it takes 4 Joules to change the temperature of one
>gram of liquid water one degree Celsius (sensible heat),
>it takes 334 Joules to convert one gram of liquid water at
>zero C to one gram of ice at zero C (latent heat of fusion).
>So it doesn't take much of a mass change to effect a real
>difference in freeze times.
>Ain't science wonderful?
>Jeff
The only problem here is that you seem to have proven that you have to
heat up ice water to freeze it. The latent heat of fusion is the energy
required to convert a solid to a liquid. To go from liquid to solid you
have to take away energy, so it's -334 J to convert 1 gm liquid water at
0° to ice.
Your overall point is correct. It's a lot easier energetically, and
thus faster in this case, to cool 1 g of water from 10° to 0° C (40
Joules lost from the water) than to freeze the water once you get to
zero degrees (334 Joules lost from the water.)
Jim Erickson
Jim Erickson
> For instance we "all know" that microwaves heat things by shaking (or
>spinning) the water molecules in them, right? Well last night my friend
>was rather proud of himself because he got his question read on Discovery.
>The question is simple, why don't flies die in a microwave? Clearly if the
>explaination of how the oven works was correct then the fly would die, thus
>there must be some deeper functioning that people are glossing over.
> And to me this is exactly the same case as water in the freezer. The
>_fact_ that this effect happens is unquestionable, and the interesting
>thing is the _why_. However this thread has degenerated into bating and
>not-terribly subtle personal attacks. Facinating in itself I suppose.
Be careful before you discard the ideas we "all know" are true, or
someday you may end up buying a perpetual motion machine. There is a
lot of solid data supporting the idea of how microwaves heat matter. I
don't know specifically what expt. you are refering to but I'm guessing
that a fly survived a zapping of some minutes in a microwave. Why? I
bet the answer has to do with the wavelength of the microwaves and the
fact that a fly is small. I can't remember all the principles off hand
but small objects may or may not get heated up depending on their size
and position relative to the microwave source. It's the same phenomenon
that causes hot and cold spots in the food you heat. This was a big
problem with the first generation of microwave ovens that had a fixed
microwave source. Basically there were fixed standing waves and thus
hot and cold spots in the oven. This was largely fixed in terms of
objects the size of foods, by having a rotating, rather than a fixed
source of microwaves, but I suspect the problem persists on a smaller
scale.
The lesson: don't be too quick to discard established facts, even if
they don't seem to fit with your experimental data. You've probably
overlooked something. Both human reasoning and experiments are
fallible. I can assure you, based on a lot of personal experience, that
conclusive experiments are often very difficult to design and to do.
Jim Erickson
Jeff Crowell
Jim Erickson <jw...@columbia.edu> wrote in message
36C31C...@columbia.edu...
>The only problem here is that you seem to have proven that you have to
>heat up ice water to freeze it
What, you're gonna hold a mere minus sign agin' me?
While little details such as minus signs are indeed important,
Jim, I submit no one who read the post in question thought I was
suggesting adding heat to freeze something...
It does, in fact, take 334 Joules to freeze a gram of liquid water
to ice. The minus sign (or lack thereof) simply has to do with
the frame of reference.
Getting back to flaming moustaches, I was told the same tale
re: moustache wax and oxygen as the original poster, but the
PR who told us about it (he also related warnings about
petroleum-based lip balm) made a point of saying that no
flamage took place--the burns were chemical in nature, not
caused by an actual fire.
This makes more sense to me than fireballs in oxygen masks.
Jeff
Jim Erickson
>>The only problem here is that you seem to have proven that you have to
>>heat up ice water to freeze it
>What, you're gonna hold a mere minus sign agin' me?
I should have put a (grin) after that sentence. It was obvious you knew
what you you were talking about.
>While little details such as minus signs are indeed important,
>Jim, I submit no one who read the post in question thought I was
>suggesting adding heat to freeze something...
On this thread? I dunno.... ;)
>It does, in fact, take 334 Joules to freeze a gram of liquid water
>to ice. The minus sign (or lack thereof) simply has to do with
>the frame of reference.
>Getting back to flaming moustaches, I was told the same tale
>re: moustache wax and oxygen as the original poster, but the
>PR who told us about it (he also related warnings about
>petroleum-based lip balm) made a point of saying that no
>flamage took place--the burns were chemical in nature, not
>caused by an actual fire.
>This makes more sense to me than fireballs in oxygen masks.
Me too.
Jim Erickson
David Hyde
: Getting back to flaming moustaches, I was told the same tale
: re: moustache wax and oxygen as the original poster, but the
: PR who told us about it (he also related warnings about
: petroleum-based lip balm) made a point of saying that no
: flamage took place--the burns were chemical in nature, not
: caused by an actual fire.
OTOH, let's go back to the "Approach" article Mary Shafer referred
to. It was the Sept/Oct 1994 issue, titled "Helmet Fire".
The author writes about getting a flattop and using hair gel to get the
"cruise 'do" he was after...petroleum-based hair gel.
"[I pulled] the oxygen mask from my face to allow oxygen to flow
under my visor and clear the fumes.
"The resultant explosion literally blew the helmet apart and off my head."
...
"My BN just stared wide-eyed, gestruing to the flames engulfing my head."
Doesn't sound like chemical burns to me.
I knew my packrat habits would come to use eventually.
Dave 'packing crates' Hyde
na...@glue.umd.edu
RAH15/?
LesB
[non-GB]
>>The cooling effect of evaporation is twofold. First, mass is carried off so
>>that less needs to be cooled from then on. Also, evaporation carries off
>>the hottest molecules, lowering considerably the average kinetic energy
>>of the molecules remaining.
*Hottest molecules*? No such thing. Just that some are more
energetic than others and *escape* the boundary more easily..
[GB]
>Isn't this just a fancy way of saying 'It's cooling off'?...(the last
>para I mean).
Yup. But another, *sideways* theory occurs to me Gord. As the hot
water is cooling down in the fridge, it is giving off heat. This
raises the temperature of the cold water standing beside it thereby
letting the hot water overtake the cold in the freezing race and get
to zero first. Its so simple I'm surprised nobody has thought of it
yet. ;-)
You just keep on going Gord, its a fascinating thread and you're doing
a great job of winding all these others up. Love it. And not one
mention of Migs or anything! Ooops. . . .
LesB
{take out one to mail}
EE Canberra Tribute Site
http://www.netcomuk.co.uk/~lesb/canberra.html
Tarver Engineering
Maury Markowitz wrote in message ...
>In <36C1F6...@larscom.com> "S. Evans" wrote:
>> Did not mean to imply that you were using some trick. I meant that
>> there was a "trick" to this process
<snip>
> For instance we "all know" that microwaves heat things by shaking (or
>spinning) the water molecules in them, right? Well last night my friend
>was rather proud of himself because he got his question read on Discovery.
>The question is simple, why don't flies die in a microwave? Clearly if the
>explaination of how the oven works was correct then the fly would die, thus
>there must be some deeper functioning that people are glossing over.
I think we will all pass on meals cooked in your microwave. How many flies
do you have in there?
John
Tarver Engineering
dmb...@my-dejanews.com wrote in message <79v4v0$6kq$1...@nnrp1.dejanews.com>...
>In article <79uukb$f0s$1...@remarQ.com>,
> "Tarver Engineering" <jta...@tminet.com> wrote:
>>
>>
>> I recomend against boiling warter in a sealed container. :)
>>
>
>I never said that the water had to be boiling. The
>important point is that sealing the container prevents
>evaporative (mass) loss.
The evaporation is the basis of Maury's theory. The URL that was posted
claims 16% loss of mass makes the experiment work. Of course this is for
outdoor freezing.
>Oh, and I suggest you look at an old fangled cooking
>device called a "pressure cooker". That takes "boiling
>water" very happily.
Wrong, the boiling point is increased for a pressure cooker and that portion
above the boiling temperature is released.
John
Jim Erickson
>> For instance we "all know" that microwaves heat things by shaking (or
>>spinning) the water molecules in them, right? Well last night my friend
>>was rather proud of himself because he got his question read on Discovery.
>>The question is simple, why don't flies die in a microwave? Clearly if the
>>explaination of how the oven works was correct then the fly would die, thus
>>there must be some deeper functioning that people are glossing over.
>I think we will all pass on meals cooked in your microwave. How many flies
>do you have in there?
>John
ROFL! I knew somebody would work flying back into this thread!
Jim Erickson
Tarver Engineering
Dweezil Dwarftosser wrote in message
<36c3ab69...@news.rdu.bellsouth.net>...
>On Thu, 11 Feb 1999 07:56:50 -0800, "Tarver Engineering">That's the first time I ever saw someone TYPE with a midwest accent!
><G>
I write the way I talk, that is why I can't spell. Well, I have to go warsh
the dishes. :)
John
I can't hep it.
>
>- John T.
Gary Watson
Does a fly land on the ceiling by looping or rolling inverted??
Gary Watson
Gary Watson
I just flew out of LAX Tuesday night, for the past week while in San Diego,
I heard nothing but warnings about "the mother of all rainstorms coming soon
to the LA area". The main part of the system went through us a LAX in about
30 minutes. Of course when one lives in the land of perpetual sunshine...
any rain is big rain.
ps do any cars in California have working turn signals?
GW
Mary Shafer wrote in message ...
>Mary Shafer <sha...@reseng2.dfrc.nasa.gov> writes:
My usually adequate demin jacket is soaked to the lining
>and I'm still looking for my umbrella because I've got to go to my car
>and leave (I refuse to be trapped here, waiting for the rain to stop).
>
Dweezil Dwarftosser
wrote:
>While we are on flies...
>Does a fly land on the ceiling by looping or rolling inverted??
>Gary Watson
Dunno - but my kids blind them with a laser pointer, then blast away.
( With a rubber band. ) They spiral into the ground.
- John T.
Dweezil Dwarftosser
<jta...@tminet.com> wrote:
>I recomend against boiling warter in a sealed container. :)
That's the first time I ever saw someone TYPE with a midwest accent!
<G>
- John T.
Andrew Yeung
>In article <79uukb$f0s$1...@remarQ.com>,
> "Tarver Engineering" <jta...@tminet.com> wrote:
>>
>>
>> I recomend against boiling warter in a sealed container. :)
>>
>
>I never said that the water had to be boiling. The
>important point is that sealing the container prevents
>evaporative (mass) loss.
>
>Oh, and I suggest you look at an old fangled cooking
>device called a "pressure cooker". That takes "boiling
>water" very happily.
It's not sealed... there's a safety valve to release excess
pressure... :)
Jeff Crowell
>: Getting back to flaming moustaches, I was told the same tale
>: re: moustache wax and oxygen as the original poster, but the
>: PR who told us about it (he also related warnings about
>: petroleum-based lip balm) made a point of saying that no
>: flamage took place--the burns were chemical in nature, not
>: caused by an actual fire.
David Hyde wrote
>OTOH, let's go back to the "Approach" article Mary Shafer referred
>to. It was the Sept/Oct 1994 issue, titled "Helmet Fire".
>The author writes about getting a flattop and using hair gel to get the
>"cruise 'do" he was after...petroleum-based hair gel.
>
>"[I pulled] the oxygen mask from my face to allow oxygen to flow
>under my visor and clear the fumes.
>"The resultant explosion literally blew the helmet apart and off my head."
>...
>"My BN just stared wide-eyed, gestruing to the flames engulfing my head."
>
>Doesn't sound like chemical burns to me.
>
>I knew my packrat habits would come to use eventually.
No argument from me, Dave, just relating my own experience,
or lack thereof.
Jeff