billvon 3,110 #101 February 8, 2011 >Why do you say that? >0.5 C = 0.9 F Sorry, meant to say that "20.1C isn't really different than 20C" (i.e. one significant digit different.) Quote Share this post Link to post Share on other sites
kallend 2,146 #102 February 8, 2011 Quote But zero is based on the lowest possible temp that salt water can remain liquid. You know what salt water is right? The majority of the water on the earth is salt water. The lowest temperature at which NaCl/H2O can remain liquid is -21.2C or -6.15F.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
sundevil777 102 #103 February 8, 2011 Quote Quote But zero is based on the lowest possible temp that salt water can remain liquid. You know what salt water is right? The majority of the water on the earth is salt water. The lowest temperature at which NaCl/H2O can remain liquid is -21.2C or -6.15F. Mr Fahrenheit's reference temp wasn't a sodium chloride salt water mix, it was an ammonium chloride salt water mix. Geez! do your research! People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am Quote Share this post Link to post Share on other sites
quade 4 #104 February 8, 2011 QuoteMr Fahrenheit's reference temp wasn't a sodium chloride salt water mix, it was an ammonium chloride salt water mix. Which, if you think about it, was actually quite ingenious considering it predates even experimental refrigeration by about 25 years and commercial creation of ice by about 125 years. He uses a frigorific mixture of existing ice, water and ammonium chloride which then automatically lowers its temperature and stabilizes which can then be used to set the calibration point of zero. That had to be close to magic in the early 1700s.quade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
popsjumper 2 #105 February 8, 2011 Quote The lowest temperature at which NaCl/H2O can remain liquid is -21.2C or -6.15F. Hmmmmm...interesting. I didn't know that (or forgot). I'm going to dig around to find out why that is. Well, I can already that this is going to be tough in a way. The first reference I looked at said molecules contain heat. Should I contact the writer and ask just how much heat a molecule actually contains? but from the same article, I get this: "As ice begins to freeze out of the salt water, the fraction of water in the solution becomes even lower, and the freezing point drops further! However, this doesn't continue indefinitely. At some point the solution will become saturated with salt. This happens for salt in water at -21.1°C, which therefore is the coldest a saturated solution of salt and water can get. At that temperature, the salt begins to crystallize out of solution, along with the ice, until the solution completely freezes. The frozen solution is a mixture of separate salt (NaCl·2H2O) crystals and ice crystals. This heterogeneous mixture is called a eutectic mixture." John, Do you know Tamara? http://van.physics.illinois.edu/qa/listing.php?id=1722 My reality and yours are quite different. I think we're all Bozos on this bus. Falcon5232, SCS8170, SCSA353, POPS9398, DS239 Quote Share this post Link to post Share on other sites
Abedy 0 #106 February 8, 2011 Quote [reply "Du bist ein Spinner" = You're a fruitcake/ douche bag... "You are a spinner" means something entirely different to me. Well, "Morning Mist" means something totally different to most Germans compared to what comes to an English native' mind. See: You cannot put a single word out of context and - more important - out of another language that simple The GERMAN word "Spinner" (note that the first letter is a capital) means first hand "fruitcake" or "dumbass" NOWADAY in GERMAN. The term itself has undergone considerable changes during the centuries. It indeed derives from "spinnen" which means to produce a thread or yarn by spinning wool fibres using a "Spinnrad". Terms like these were used in the fairy tales of the Grimm brothers, for example. But again: I wrote a proper German sentence and had the decency to translate it into English as properly as I could. If you want to tell me I wrote something wrong be assured it ain't so. If you, however, just made a funny remark, than please accept my apologies; I then missed the pun cause I looked for an explaining emoticon The sky is not the limit. The ground is. The Society of Skydiving Ducks Quote Share this post Link to post Share on other sites
wolfriverjoe 1,523 #107 February 8, 2011 Quote Quote Quote But zero is based on the lowest possible temp that salt water can remain liquid. You know what salt water is right? The majority of the water on the earth is salt water. The lowest temperature at which NaCl/H2O can remain liquid is -21.2C or -6.15F. Mr Fahrenheit's reference temp wasn't a sodium chloride salt water mix, it was an ammonium chloride salt water mix. Geez! do your research! Ok, thanks (both of you) for the correction. I had always thought it was a NaCl solution. Edit to add: That doesn't change the fact that there was a valid freezing point for zero F."There are NO situations which do not call for a French Maid outfit." Lucky McSwervy "~ya don't GET old by being weak & stupid!" - Airtwardo Quote Share this post Link to post Share on other sites
SivaGanesha 2 #108 February 8, 2011 In most cases the metric system makes sense but this is one area where they messed up big time. Fahrenheit had a very reasonable approach, setting 0 to be the minimum and 100 the maximum temperature recorded during a year in the European city in which he lived. Although there are certainly some places where it gets colder and other places where it gets hotter, the majority of human experience is within those values and this seems a reasonable scale to use for weather/room temperature/etc. An additional convenient feature is that blood temperature is 98.6 degrees F so anything over 100 begins to put one into dangerous fever territory--making a simple rule of thumb. For scientific purposes, Kelvin makes the most sense. Celsius just doesn't have much to recommend it. 0 is set to the freezing point of water and 100 to the boiling point of water. The problem is that the only time, in human life, when the boiling point of water really comes into play is while cooking. And if one is in fact cooking, there are much higher temperatures that also come into play, so using the boiling point of water as some sort of baseline seems a bit arbitrary to me."It's hard to have fun at 4-way unless your whole team gets down to the ground safely to do it again!"--Northern California Skydiving League re USPA Safety Day, March 8, 2014 Quote Share this post Link to post Share on other sites
quade 4 #109 February 8, 2011 QuoteFahrenheit had a very reasonable approach, setting 0 to be the minimum and 100 the maximum temperature recorded during a year in the European city in which he lived. No. This is incorrect. See; http://en.wikipedia.org/wiki/Fahrenheit#Historyquade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
SivaGanesha 2 #110 February 8, 2011 QuoteNo. This is incorrect. See; http://en.wikipedia.org/wiki/Fahrenheit#History There seem to be many theories: http://www.wisegeek.com/what-is-the-history-of-the-fahrenheit-scale.htm However the link you provided suggests that human body temperature was key to Fahrenheit's scale. So my basic point--that Fahrenheit was interested in creating a scale with benchmarks corresponding to temperatures of real interest in human life--still stands even if that is the correct theory."It's hard to have fun at 4-way unless your whole team gets down to the ground safely to do it again!"--Northern California Skydiving League re USPA Safety Day, March 8, 2014 Quote Share this post Link to post Share on other sites
SivaGanesha 2 #111 February 8, 2011 QuoteHowever the link you provided suggests that human body temperature was key to Fahrenheit's scale. So my basic point--that Fahrenheit was interested in creating a scale with benchmarks corresponding to temperatures of real interest in human life--still stands even if that is the correct theory. Also the link you provided seems to suggest that Fahrenheit realized that the freezing point of water is much more significant in ordinary human life than the boiling point of water--and, again, I'd agree with that. But, yes, it seems it was probably more complex than just taking the highest and lowest temps in a year and calling them 100/0."It's hard to have fun at 4-way unless your whole team gets down to the ground safely to do it again!"--Northern California Skydiving League re USPA Safety Day, March 8, 2014 Quote Share this post Link to post Share on other sites
popsjumper 2 #112 February 8, 2011 Quote Quote Quote "Du bist ein Spinner" = You're a fruitcake/ douche bag... "You are a spinner" means something entirely different to me. If you want to tell me I wrote something wrong be assured it ain't so. If you, however, just made a funny remark, than please accept my apologies; No apologies necessary!My reality and yours are quite different. I think we're all Bozos on this bus. Falcon5232, SCS8170, SCSA353, POPS9398, DS239 Quote Share this post Link to post Share on other sites
realpet 0 #113 February 8, 2011 Quotee told that Australia set a 2-year period to convert. During the 2-year period, they could use either system but at the end of the 2-year period they could no longer use anything in the old system. Sorry for late reply, pre-second time reading this thread. Last time I was in Australia (somewhere around 90's) the total conversion was not implemented. Car speeds kilometers per hour but person's heigh was still feet/inches. Don't know if they have grown to metric system nowadays... - Petri * * Coming from a country using the S/I system for almost everything except (for some weird reason) car tires and tv screen sizes (latter ones nowadays seen also at sizes of 18.5" etc) Quote Share this post Link to post Share on other sites
realpet 0 #114 February 8, 2011 Quote>The Fahrenheit scale is more "precise" since the difference between two neighbouring >Fahrenheit grades is less that the difference between two neighbouring Celsius grades. That's what I like about it. For some of what I do (brewing, for example) the extra accuracy comes in handy; 70F really is different than 71F during fermentation, and 150F really is different from 151F during the mash. That problem is solved by adding a decimal point, but then a) you sort of have too much accuracy (20.5C really isn't different than 21C) and b) all your displays have to add a decimal point and another digit. I notice this because I do use both. I got some super cheap heating/cooling controllers designed for the EU, so they are 220 volt and display in C. Everything else in my notes is in F. Extra accuracy is needed but it is too much :) ? One of the reasons I prefer SI/metric system (on top of the obvious one that the school system teaches it) is the decimal thingie. A couple of examples: 1 kilometer is 1000 meters, 1 meter = 100 cm = 1000 mm). 1 mile (wait - is it nautical, statute or survey one?) is 5280 feet (except the 1st one, see below). Presenting fractions over a kilometer is dead easy 1.35562 km equals to 1 kilometer, 355 meters and 62 centimeters 1 mile is 5280 feet unless it is the nautical one in which case it is one minute of arc of latitude along any meridian meaning that 1.34462 miles is either 1.34462 * 5280 feet or 1.34462 * 1852 meters (or 1.34462 * approximately 6,076 feet) Oil barrel: http://en.wikipedia.org/wiki/Oil_barrel#Oil_barrel So on SI adding accuracy equals more or less to adding decimals. In Imperial hazzle accuracy equals to switching to another definition of measure that is split so some weird amount of partions ;-). Quote Share this post Link to post Share on other sites
sundevil777 102 #115 February 8, 2011 I find it strange that in Canada, vehicle fuel economy is not measured as kilometers/liter, they use liters/100 km. That is the inverse of miles/gallon as in the US. That is odd that they inverted it, instead of just using metric units. Is it the same in other metric countries?People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am Quote Share this post Link to post Share on other sites
billvon 3,110 #116 February 9, 2011 >Extra accuracy is needed but it is too much :) ? Two digits in the centigrade scale is not sufficiently accurate. Three digits (two plus a tenths place) is too much. >One of the reasons I prefer SI/metric system (on top of the obvious one that the >school system teaches it) is the decimal thingie. OK. 72.5 degrees F is 72 and a half degrees. How is that different from 20.5C? Quote Share this post Link to post Share on other sites
JohnnyMarko 1 #117 February 9, 2011 Quote>Extra accuracy is needed but it is too much :) ? Two digits in the centigrade scale is not sufficiently accurate. Three digits (two plus a tenths place) is too much. >One of the reasons I prefer SI/metric system (on top of the obvious one that the >school system teaches it) is the decimal thingie. OK. 72.5 degrees F is 72 and a half degrees. How is that different from 20.5C? Because you forgot to use the scientific term 'decimal thingie' Quote Share this post Link to post Share on other sites
popsjumper 2 #118 February 9, 2011 QuoteOK. 72.5 degrees F is 72 and a half degrees. How is that different from 20.5C? by 2 degrees CMy reality and yours are quite different. I think we're all Bozos on this bus. Falcon5232, SCS8170, SCSA353, POPS9398, DS239 Quote Share this post Link to post Share on other sites
Abedy 0 #119 February 9, 2011 Quote I find it strange that in Canada, vehicle fuel economy is not measured as kilometers/liter, they use liters/100 km. That is the inverse of miles/gallon as in the US. That is odd that they inverted it, instead of just using metric units. Is it the same in other metric countries? The value is also measured/given in litres per 100 km in Germany, Austria, Switzerland etc. When looking at displays at car dealers you'll find values for "city traffic", "out of city" (highways etc) and "mixed" but these values are - miraculously! - lower than day-to-day observations in real life BTW: At the moment CO2 emission (in grams per kilometre) are state of the art and required to be given. The EU set standards and goals to be achieved, let's wait what this will bring for the nature...The sky is not the limit. The ground is. The Society of Skydiving Ducks Quote Share this post Link to post Share on other sites
realpet 0 #120 February 9, 2011 Quote>OK. 72.5 degrees F is 72 and a half degrees. How is that different from 20.5C? Not that much in temperature. That's why my example was about lenght in which I tought the benefit of decimal system was more clear. Quote Share this post Link to post Share on other sites
virgin-burner 1 #121 February 9, 2011 QuoteI find it strange that in Canada, vehicle fuel economy is not measured as kilometers/liter, they use liters/100 km. That is the inverse of miles/gallon as in the US. That is odd that they inverted it, instead of just using metric units. Is it the same in other metric countries? never heard of that, so i assume it's liters/100km everywhere else that is metric.“Some may never live, but the crazy never die.” -Hunter S. Thompson "No. Try not. Do... or do not. There is no try." -Yoda Quote Share this post Link to post Share on other sites
VincePetaccio 0 #122 February 9, 2011 The whole miles/gallon thing makes it hard for me to judge aircraft fuel economy based on a gallons/hour metric.Come, my friends! 'Tis not too late to seek out a newer world! Quote Share this post Link to post Share on other sites
VincePetaccio 0 #123 February 9, 2011 QuoteQuote>The Fahrenheit scale is more "precise" since the difference between two neighbouring >Fahrenheit grades is less that the difference between two neighbouring Celsius grades. That's what I like about it. For some of what I do (brewing, for example) the extra accuracy comes in handy; 70F really is different than 71F during fermentation, and 150F really is different from 151F during the mash. That problem is solved by adding a decimal point, but then a) you sort of have too much accuracy (20.5C really isn't different than 21C) and b) all your displays have to add a decimal point and another digit. I notice this because I do use both. I got some super cheap heating/cooling controllers designed for the EU, so they are 220 volt and display in C. Everything else in my notes is in F. Extra accuracy is needed but it is too much :) ? One of the reasons I prefer SI/metric system (on top of the obvious one that the school system teaches it) is the decimal thingie. A couple of examples: 1 kilometer is 1000 meters, 1 meter = 100 cm = 1000 mm). 1 mile (wait - is it nautical, statute or survey one?) is 5280 feet (except the 1st one, see below). Presenting fractions over a kilometer is dead easy 1.35562 km equals to 1 kilometer, 355 meters and 62 centimeters 1 mile is 5280 feet unless it is the nautical one in which case it is one minute of arc of latitude along any meridian meaning that 1.34462 miles is either 1.34462 * 5280 feet or 1.34462 * 1852 meters (or 1.34462 * approximately 6,076 feet) Oil barrel: http://en.wikipedia.org/wiki/Oil_barrel#Oil_barrel So on SI adding accuracy equals more or less to adding decimals. In Imperial hazzle accuracy equals to switching to another definition of measure that is split so some weird amount of partions ;-). Both temperature scales are equally precise (accuracy and precision are different things). The F scale has greater whole-unit resolution between boiling and freezing temperatures of water, but the C scale can resolve equally well (or better) by adding a decimal point. Accuracy, precision, and resolution are functions of the measuring tools, not of the scale used.Come, my friends! 'Tis not too late to seek out a newer world! Quote Share this post Link to post Share on other sites
JohnMitchell 16 #124 February 9, 2011 Quote Celsius just doesn't have much to recommend it. 0 is set to the freezing point of water and 100 to the boiling point of water. The problem is that the only time, in human life, when the boiling point of water really comes into play is while cooking. But many of our measures are based on H2O. Specific gravity uses water as a standard 1.000. One cubic centimeter of water = one gram, another "not coincidence." Seriously, we should use Kelvin, but it will take a lot of work to change people over. Quote Share this post Link to post Share on other sites
JohnMitchell 16 #125 February 9, 2011 Quote The whole miles/gallon thing makes it hard for me to judge aircraft fuel economy based on a gallons/hour metric. How fast ya flyin'? Lemme grab a pencil. Now . . . is that statute MPH or Knots? Quote Share this post Link to post Share on other sites
