sch@dedalus.UUCP (Steve Holzworth) (04/30/85)
There is actually a scientific reason to boil cold water as opposed to hot (it may not be the pertinent reason, though). Cold water will boil FASTER (yep, that's right) than hot water. This is because the cold water contains more oxygen than the hot water (now what that does is beyond me). The above strange fact was passed on to the freshman chemistry class I took in college. For what its worth, the professor used to be a research chemist with Dupont. Steve Holzworth mcnc!ikonas!dedalus!sch
reid@Glacier.ARPA (Brian Reid) (05/10/85)
> There is actually a scientific reason to boil cold water as opposed to > hot (it may not be the pertinent reason, though). Cold water will boil > FASTER (yep, that's right) than hot water. This is because the cold water > contains more oxygen than the hot water (now what that does is beyond me). > The above strange fact was passed on to the freshman chemistry class I took > in college. I remain deeply skeptical. So much so, in fact, that I went in to my kitchen just now and did an actual experiment. (details of experiment at end of message for those who care). ---------------------------------------------------------------------------- Initial Time to Kilojoules joules/ <-- you can think of temp boil absorbed second this number as the Hot water 60F 204sec 184 901 "boiling efficiency" Cold water 135F 365sec 347 950 ---------------------------------------------------------------------------- The summary result is that hot water boils faster than cold water, as one might have expected. A joule/second is a watt, so what this means is that my 1200-watt burner was delivering 901 watts to the hot water and 950 watts to the cold water. The probable explanation for this is that the energy transfer rate levels off sharply as the water approaches boiling, because of evaporative loss, and that the cold water stays in the high-efficiency range for a larger percentage of the total time. Another way of looking at these numbers is that not only does hot water not boil faster than cold water, it actually takes LONGER, degree for degree, than cold water (by about half a percent). The experiment: cold water boil: run cold tap water for 2 minutes into pan; empty pan and quickly measure in one liter of cold tap water. Let stand for 60 seconds (to equalize temperature of water and pan), then measure temperature and place on preheated electric stove burner. Hot water boil: the same, but use hot tap water. Alternate cold, hot, cold, etc. three times, for a total of six measurements, allowing the burner to reheat for 1 minute in between measurements. The pan was a copper saucepan (lined with nickel) that weighs 616 grams. The specific heat of copper is 0.0949, which means that the pan's heat absorbtion was 5.8% of the water's (mass of nickel assumed to be negligible; specific heat of Nickel is 0.1035) -- Brian Reid decwrl!glacier!reid Stanford reid@SU-Glacier.ARPA
js2j@mhuxt.UUCP (sonntag) (05/10/85)
> Cold water will boil > FASTER (yep, that's right) than hot water. This is because the cold water > contains more oxygen than the hot water (now what that does is beyond me). > The above strange fact was passed on to the freshman chemistry class I took > in college. For what its worth, the professor used to be a research chemist > with Dupont. > Steve Holzworth I also recall hearing that hot water will freeze faster than cold water for unknown reasons. Frankly, I doubt both statements. -- Jeff Sonntag ihnp4!mhuxt!js2j "I said, 'Doc, a world war passed through my brain.' He said, 'Nurse, grab your pad, the boy's insane.'"-Dylan
glp@osu-eddie.UUCP (Georgia Pritchett) (05/11/85)
> > Cold water will boil > > FASTER (yep, that's right) than hot water. This is because the cold water > > contains more oxygen than the hot water (now what that does is beyond me). > > The above strange fact was passed on to the freshman chemistry class I took > > in college. For what its worth, the professor used to be a research chemist > > with Dupont. > > Steve Holzworth > > I also recall hearing that hot water will freeze faster than cold water > for unknown reasons. Frankly, I doubt both statements. > -- > Jeff Sonntag > ihnp4!mhuxt!js2j > "I said, 'Doc, a world war passed through my brain.' > He said, 'Nurse, grab your pad, the boy's insane.'"-Dylan *** REPLACE THIS LINE WITH YOUR MESSAGE *** I don't know about cold water boiling faster than hot, but the reason that hot will freeze faster than cold is that the molecules in hot water are more oriented towards the structure that they have in ice than the molecules in cold. So even though it may sound silly it really isn't. ---georgia
rep@panda.UUCP (Pete Peterson) (05/13/85)
In article <7285@Glacier.ARPA> reid@Glacier.ARPA (Brian Reid) writes: >> There is actually a scientific reason to boil cold water as opposed to >> hot (it may not be the pertinent reason, though). Cold water will boil >> FASTER (yep, that's right) than hot water. This is because the cold water >> contains more oxygen than the hot water (now what that does is beyond me). >> The above strange fact was passed on to the freshman chemistry class I took >> in college. > >I remain deeply skeptical. So much so, in fact, that I went in to my kitchen >just now and did an actual experiment. (details of experiment at end of >message for those who care). >---------------------------------------------------------------------------- > Initial Time to Kilojoules joules/ <-- you can think of > temp boil absorbed second this number as the >Hot water 60F 204sec 184 901 "boiling efficiency" >Cold water 135F 365sec 347 950 >---------------------------------------------------------------------------- > >The summary result is that hot water boils faster than cold water, as one >might have expected. A joule/second is a watt, so what this means is that my >1200-watt burner was delivering 901 watts to the hot water and 950 watts to >the cold water. The probable explanation for this is that the energy >transfer rate levels off sharply as the water approaches boiling, because of >evaporative loss, and that the cold water stays in the high-efficiency range >for a larger percentage of the total time. Another way of looking at these >numbers is that not only does hot water not boil faster than cold water, it >actually takes LONGER, degree for degree, than cold water (by about half a >percent). > Am I confused or do the first and last parts of this paragraph say opposite things about which boils faster? >The experiment: cold water boil: run cold tap water for 2 minutes into pan; >empty pan and quickly measure in one liter of cold tap water. Let stand for >60 seconds (to equalize temperature of water and pan), then measure >temperature and place on preheated electric stove burner. Hot water boil: >the same, but use hot tap water. Alternate cold, hot, cold, etc. three >times, for a total of six measurements, allowing the burner to reheat for >1 minute in between measurements. > >The pan was a copper saucepan (lined with nickel) that weighs 616 grams. The >specific heat of copper is 0.0949, which means that the pan's heat >absorbtion was 5.8% of the water's (mass of nickel assumed to be negligible; >specific heat of Nickel is 0.1035) >-- > Brian Reid decwrl!glacier!reid > Stanford reid@SU-Glacier.ARPA It appears that Brian's results agree with the counter-intuitive statement of the original article; the APPARENT disagreement results from an unusual use of the terms "hot" and "cold". Pete Peterson
fred@mnetor.UUCP (Fred Williams) (05/13/85)
In article <7285@Glacier.ARPA> reid@Glacier.ARPA (Brian Reid) writes: >> There is actually a scientific reason to boil cold water as opposed to >> hot (it may not be the pertinent reason, though). Cold water will boil >> FASTER (yep, that's right) than hot water. This is because the cold water >> contains more oxygen than the hot water (now what that does is beyond me). >> The above strange fact was passed on to the freshman chemistry class I took >> in college. > >I remain deeply skeptical. So much so, in fact, that I went in to my kitchen >just now and did an actual experiment. (details of experiment at end of >message for those who care). >---------------------------------------------------------------------------- I am amazed that someone actually wasted time doing this. > Initial Time to Kilojoules joules/ <-- you can think of > temp boil absorbed second this number as the >Hot water 60F 204sec 184 901 "boiling efficiency" >Cold water 135F 365sec 347 950 >---------------------------------------------------------------------------- > >The summary result is that hot water boils faster than cold water, as one >might have expected. A joule/second is a watt, so what this means is that my >1200-watt burner was delivering 901 watts to the hot water and 950 watts to >the cold water. The probable explanation for this is that the energy >transfer rate levels off sharply as the water approaches boiling, because of >evaporative loss, and that the cold water stays in the high-efficiency range >for a larger percentage of the total time. . . . Newton's law of cooling describes this well. Does anyone I don't mean to be insulting to anyone, but really! Cheers, Fred Williams
devine@asgb.UUCP (Robert J. Devine) (05/13/85)
> There is actually a scientific reason to boil cold water as opposed to > hot (it may not be the pertinent reason, though). Cold water will boil > FASTER (yep, that's right) than hot water. This is because the cold water > contains more oxygen than the hot water (now what that does is beyond me). > The above strange fact was passed on to the freshman chemistry class I took > in college. Actually, I believe it is the other way. Hot water FREEZES faster than cold water. My chem TA had an argument with a professor over that point and won. What is this doing in net.cooks....? Bob Devine
leann@ames.UUCP (LeAnn Thompson) (05/14/85)
> > Cold water will boil > > FASTER (yep, that's right) than hot water. This is because the cold water > > contains more oxygen than the hot water (now what that does is beyond me). > > The above strange fact was passed on to the freshman chemistry class I took > > in college. For what its worth, the professor used to be a research chemist > > with Dupont. > > Steve Holzworth > > I also recall hearing that hot water will freeze faster than cold water > for unknown reasons. Frankly, I doubt both statements. > -- > Jeff Sonntag > ihnp4!mhuxt!js2j > "I said, 'Doc, a world war passed through my brain.' > lskdjfl dkjfkdls;alsdkfjklasjdfljasldj;flasjf l;jsf;ksjflksjf He said, 'Nurse, grab your pad, the boy's insane.'"-Dylan
macrakis@harvard.ARPA (Stavros Macrakis) (05/14/85)
Could we PLEASE kill this discussion? I have learned nothing from it besides the willingness of people to repeat nonsensical folklore. -s PS Did you know that Lacoste shirts ACTUALLY HAVE crocodile leather mixed into the cotton for strength?
nm34@sdcc12.UUCP (nm34) (05/15/85)
> -s > > PS Did you know that Lacoste shirts ACTUALLY HAVE crocodile leather > mixed into the cotton for strength? Speaking of reptiles, does anyone have any good recipes for alligator or crocks? Surely someone in the the old South will have thought of something to so with the old beasts... Andy Bindman
esg@mtx5b.UUCP (E.S.Gokhman) (05/15/85)
Water that has been boiled and then cooled to the temperature of the cold water will take longer to boil again. Hot water that was not cooled will take shorter time. Water that boiled once may take longer to boil again, and I think that what proffessor was reffering to. .
ps@celerity.UUCP (Pat Shanahan) (05/15/85)
> I don't know about cold water boiling faster than hot, but the > reason that hot will freeze faster than cold is that the molecules in hot > water are more oriented towards the structure that they have in ice than the > molecules in cold. So even though it may sound silly it really isn't. > > ---georgia How does the hot water manage to freeze without turning into cold water first? -- ps (Pat Shanahan) uucp : {decvax!ucbvax || ihnp4 || philabs}!sdcsvax!celerity!ps arpa : sdcsvax!celerity!ps@nosc
reid@Glacier.ARPA (Brian Reid) (05/17/85)
Pete Peterson writes, in response to my report of my water-boiling experiment: > Am I confused or do the first and last parts of this paragraph say opposite > things about which boils faster? > .... > It appears that Brian's results agree with the counter-intuitive statement > of the original article; the APPARENT disagreement results from an unusual > use of the terms "hot" and "cold". > > Pete Peterson Very funny. Yes, the real reason is that it was late at night when I typed the data into the machine, and I had burned my fingers on one of the hot pans, and as a result I got distracted and got the "hot" and "cold" temperatures reversed. Not even in California is 60F "hot" while 135F is "cold". Here is the true table, which has the "Initial temp" numbers unreversed: Initial Time to Kilojoules joules/ <-- you can think of temp boil absorbed second this number as the Hot water 135F 204sec 184 901 "boiling efficiency" Cold water 60F 365sec 347 950 -- Brian Reid decwrl!glacier!reid Stanford reid@SU-Glacier.ARPA
reid@Glacier.ARPA (Brian Reid) (05/17/85)
> I am amazed that someone actually wasted time doing this. > ... > Newton's law of cooling describes this well. Does anyone > I don't mean to be insulting to anyone, but really! > > Cheers, Fred Williams I knew what the result would be, of course, but there is so little hard data flying around the network that it seemed to me that some certified truth would be a refreshing change. Remember the situation in European science in the 16th century, when it was considered unscholarly to do experiments, because everyone "knew" what the answers would be? Then Gallileo (allegedly) went and dropped a cannonball and a cork from the tower of Pisa, in spite of the advice of his peers that "I was amazed that someone actually wasted time doing this." There are plenty of situations in the kitchen where the actual science involved is so subtle, and so different from the laboratory, that instincts and college-learned chemical "truth" do not always apply. For this reason I am a great believer in trying things to see what will happen, even when I am certain that I know what will happen. -- Brian Reid decwrl!glacier!reid Stanford reid@SU-Glacier.ARPA
tron@fluke.UUCP (Peter Barbee) (05/18/85)
In article <1414@mtx5b.UUCP> esg@mtx5b.UUCP (E.S.Gokhman) writes: >Water that has been boiled and then cooled to the temperature >of the cold water will take longer to boil again. Hot water >that was not cooled will take shorter time. Water that >boiled once may take longer to boil again, and I think that >what proffessor was reffering to. >. What? Really?? Why??? Peter B
inc@fluke.UUCP (Gary Benson) (05/18/85)
In reply to this gem: > > Water that boiled once may take longer to boil again, and I think that > > what proffessor was reffering to. Peter Barbee replies: > What? Really?? Why??? May I help answer these pressing questions? Here are the official answers as found in a mayonnaise jar on the back porch of Funk & Wagnall's: Yup! YUP!! Dunno, but if I say it twicet, it must be wright!!! C'mon Pete, you knew the answers all along! <<<<FLAMERS NOTE: Use of the word "mayonnaise" in this posting qualifies it for inclusion in net.cooks. Thank you.>>>>> *** HEY COMMODORE, WHAT IS IT? *** -- Gary Benson * John Fluke Mfg. Co. * PO Box C9090 * Everett WA * 98206 MS/232-E = = {allegra} {uw-beaver} !fluke!inc = = (206)356-5367 _-_-_-_-_-_-_-_-ascii is our god and unix is his profit-_-_-_-_-_-_-_-_-_-_-_
wetcw@pyuxa.UUCP (T C Wheeler) (05/22/85)
R a eferences: <707@dedalus.UUCP> <865@mhuxt.UUCP> <293@osu-eddie.UUCP>, <288@celerity.UUCP>
wetcw@pyuxa.UUCP (T C Wheeler) (05/22/85)
There certainly is a great deal of discussion concerning hot and cold water freezing and boiling. All I know is that if I put the coffee on in the morning using hot water, the coffee is ready when I finish showering. If I use cold water, the coffee is not ready. Please don't start a discussion about making coffee. As long as it is hot, black, and strong, I will drink it. I'm not hung up on how its made or, within reason, how it tastes, I use it for my pshycological jump start in the morning. Further, if I put cold water in the ice tray, the water SEEMS to freeze faster, plus, the fridg doesn't have to work so hard trying to slow down a bunch of hot and bothered molecules. Doesn't this belong in net.physics? T. C. Wheeler