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01 Apr 14 - 10:42 AM (#3614254) Subject: BS: Celius -Fahrenheit From: Louie Roy Above zero degrees it is easy to convert Fahrenheit to Celsius or Celsius to Fahrenheit but at zero degrees there is a difference. When it is 32 degrees above Fahrenheit it is zero degrees Celsius. My question to the mudcatters if it is -40 degrees Fahrenheit do you add 32degrees to - 40 to get the correct reading for Celsius which then will be -72 degrees below zero |
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01 Apr 14 - 10:51 AM (#3614256) Subject: RE: BS: Celius -Fahrenheit From: Will Fly -40F = -40C -10F = -23C -20F = -29C -30F = -34C So - not a simple +/-32 arithmetic sum. |
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01 Apr 14 - 10:55 AM (#3614257) Subject: RE: BS: Celius -Fahrenheit From: Will Fly Sorry - forgot to add the equation: C = 5/9 (F-32) |
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01 Apr 14 - 10:56 AM (#3614259) Subject: RE: BS: Celius -Fahrenheit From: Dave the Gnome Simple way - Double it and add 30. Works roughly. Proper way, multiply by 9/5 and add 32. -40 is the only temp. that is the same in both I think. -40 x 9/5 = -72. Add 32 = -40. Farenheit to centigrade formula is (simple) subtract 30 and half it. Proper way, subtract 32 and multiply by 5/9. Seemples DtG |
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01 Apr 14 - 11:13 AM (#3614271) Subject: RE: BS: Celius -Fahrenheit From: Louie Roy Like I said above zero no problem It's below zero when things change |
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01 Apr 14 - 11:18 AM (#3614273) Subject: RE: BS: Celius -Fahrenheit From: Will Fly The formula works regardless of plus or minus. Subtract -32 from -40F. Answer = -72 Multiply by 5. Answer = -360 Divide by 9. Answer = -40 Simples. |
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01 Apr 14 - 11:19 AM (#3614274) Subject: RE: BS: Celius -Fahrenheit From: Will Fly Whoops - subtracted a minus from a minus in the first line! Should be: Subtract 32 from -40F. Answer = -72 Multiply by 5. Answer = -360 Divide by 9. Answer = -40 |
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01 Apr 14 - 12:23 PM (#3614288) Subject: RE: BS: Celius -Fahrenheit From: Dave the Gnome Can take a bit of time to get your head round it, LR. Just think that when you subtract something from a negative, it gets bugger, IE more negative and when you add something to a negative it gets smaller. IE less negative. Another way of putting what will said is -40 -32 = -72. Try it on a calculator - It works. Honest! DtG |
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01 Apr 14 - 12:31 PM (#3614293) Subject: RE: BS: Celius -Fahrenheit From: Musket I see if my tongue sticks to it. Easiest way of distinguishing between plus or very minus. |
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01 Apr 14 - 12:33 PM (#3614294) Subject: RE: BS: Celius -Fahrenheit From: Q (Frank Staplin) Above readings. 5 C = 41 F 10 C = 50 F 15 C = 59 F 20 C = 58 F 25 C = 77 F 30 C = 86 F 100 C = 212 F 177 C = 350 F (moderate oven) 200 C = 400 F 230 C = 450 F 290 C = 550 F (Broiling temperature) My outdoor thermometer has both scales. For the rest, why not use a google table or handy-dandy pocket calculator? |
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01 Apr 14 - 12:43 PM (#3614302) Subject: RE: BS: Celius -Fahrenheit From: MGM·Lion Q ~~ Your 20C equiv is 10 out - a typo I expect. A very helpful hint I got from a newspaper correspondent when forecasts started using C when my generation had all been brought up to F, was that for all practical "What will the weather be like, will I need a coat?" purposes, a simple formula to get a near-enough approximation was to double the C # & add 30: so that 10C would be about 50C, 20C would be approx 70F; near enough to know the temp for practical everyday purposes. Was v grateful for that aid to coping with the changeover. ~M~ |
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01 Apr 14 - 01:00 PM (#3614307) Subject: RE: BS: Celius -Fahrenheit From: brashley46 There are 180 Fahrenheit degrees between freezing and boiling; old Herr Fahrenheit assigned the zero value to the coldest temp he had ever experienced, which was 32 of his degrees below freezing. Celsius divided the difference between freezing and boiling to 100 of his degrees, and started the scale at freezing = zero. As a hospital worker in the Ontario system I got used to Celsius temperatures real quick. |
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01 Apr 14 - 01:03 PM (#3614309) Subject: RE: BS: Celius -Fahrenheit From: Q (Frank Staplin) Right, M. My poor typing. (10 C = 50 C? I guess we are all poor typists or proofers). Here in Calgary we must have clothes for -40 (C and F) and plus 30C on some summer days. I remember summers in New Mexico- At one of our favorite camping spots, ice in the water bucket at dawn and 90F in the afternoon. Aside- I put typers and my MS gave me the red underline, so I quickly changed it to typists- purists everywhere! |
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01 Apr 14 - 01:18 PM (#3614314) Subject: RE: BS: Celius -Fahrenheit From: Dorothy Parshall To convert almost anything except lead to gold I simply cannot bother with math! |
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01 Apr 14 - 03:28 PM (#3614336) Subject: RE: BS: Celius -Fahrenheit From: michaelr DtG -- "it gets bugger" LOL |
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01 Apr 14 - 04:15 PM (#3614354) Subject: RE: BS: Celius -Fahrenheit From: Nigel Parsons Brashley46: There are 180 Fahrenheit degrees between freezing and boiling; old Herr Fahrenheit assigned the zero value to the coldest temp he had ever experienced, which was 32 of his degrees below freezing. Celsius divided the difference between freezing and boiling to 100 of his degrees, and started the scale at freezing = zero. Close, but no ceeegar. Anders Celsius devised a scale in which the boiling point of pure water (at sea level) was 0 degrees, and the freezing point 100 degrees. These days we use the scale the other way around. When I was in school it (the modern version) was referred to as the centigrade scale. |
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01 Apr 14 - 04:20 PM (#3614356) Subject: RE: BS: Celius -Fahrenheit From: Mrrzy Right, -40 is -40 regardless of Celsius or Fahrenheit. I can finally think in both, rather than having to do the math. |
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01 Apr 14 - 04:24 PM (#3614360) Subject: RE: BS: Celius -Fahrenheit From: Dave the Gnome Well spotted, michaelr :-) It was an errr, errrmmm, deliberate pun... :D tG |
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01 Apr 14 - 08:11 PM (#3614405) Subject: RE: BS: Celius -Fahrenheit From: Joe_F Minus 40 has a number of other curious properties: The mercury freezes in the thermometer. Oak trees freeze to death. Your spit freezes before it hits the ground. I have heard that Herr Fahrenheit stuck his thermometer in freezing brine to mark 0, and then in his mouth, or somewhere, to mark 100. (He seems to have run a little hot.) If I were dictator, I would go for the Kelvin scale. Then there would be no nonsense about negative temperatures. Freezing, 273 K. Room temperature, 293 K. Boiling, 373 K. |
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01 Apr 14 - 08:27 PM (#3614407) Subject: RE: BS: Celius -Fahrenheit From: Bill D program for Windows users |
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01 Apr 14 - 08:34 PM (#3614408) Subject: RE: BS: Celius -Fahrenheit From: Steve Shaw Your spit freezes before it hits the ground. Not if you're three foot eight and spit downwards hard it doesn't. Unfortunately for those requiring neat packages, "freezing" is closer to 273.1K. |
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02 Apr 14 - 10:39 AM (#3614568) Subject: RE: BS: Celius -Fahrenheit From: Dave the Gnome Not if you're three foot eight and spit downwards hard it doesn't. Have you been watching me? DtG |
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02 Apr 14 - 11:50 AM (#3614583) Subject: RE: BS: Celius -Fahrenheit From: Tug the Cox Intersesting correspodences are 16C=61F....28C=82F. |
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02 Apr 14 - 08:19 PM (#3614708) Subject: RE: BS: Celius -Fahrenheit From: beeliner I have heard that Herr Fahrenheit stuck his thermometer in freezing brine to mark 0, and then in his mouth, or somewhere, to mark 100. (He seems to have run a little hot. Another theory is that he intended 0 to represent the coldest reading in an average year and 100 the warmest. |
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03 Apr 14 - 06:26 AM (#3614792) Subject: RE: BS: Celius -Fahrenheit From: Nigel Parsons The theory I've heard is that the lowest temperature which could be considered as a constant was the freezing point of salt water/sea water. This was used as the starting point. Boiling (pure) water was used for the other endpoint. I don't believe that the Fahrenheit system was ever intended to have a specific meaning for 100 degrees. A scale of 180 degrees (half a circle) made much more sense as it allowed each degree to be smaller (giving amost double the precision) and allowed division by a greater number of factors. |
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03 Apr 14 - 06:48 AM (#3614801) Subject: RE: BS: Celius -Fahrenheit From: IanC Bit of a problem with the seawater argument ... (from Wikipedia) The freezing point of seawater decreases as salt concentration increases. At typical salinity it freezes at about −2 °C (28 °F). The coldest seawater ever recorded (in a liquid state) was in 2010, in a stream under an Antarctic glacier, and measured −2.6 °C (27.3 °F). :-) |
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03 Apr 14 - 07:00 AM (#3614807) Subject: RE: BS: Celius -Fahrenheit From: Steve Shaw Which is why we salt icy roads in winter. |
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03 Apr 14 - 09:01 PM (#3615122) Subject: RE: BS: Celius -Fahrenheit From: Joe_F Not seawater, saturated brine (ice water with salt at the bottom). |
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04 Apr 14 - 10:17 AM (#3615273) Subject: RE: BS: Celius -Fahrenheit From: Steve Shaw And we get Danish Scurvy-grass, a neat little seaside plant, growing all along our motorway (heavily-salted in winter) central reservations. In flower right now. V. pretty! |
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04 Apr 14 - 01:06 PM (#3615323) Subject: RE: BS: Celius -Fahrenheit From: dick greenhaus An easier-to-remember conversion algorithm is: Add 40 to the temperature to be converted. Multipy by 5/9 if you'rr coverting from F to C, OR Multply by 9/5 if you're converting from C to F Subreact 40 and there's your answer |
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04 Apr 14 - 08:00 PM (#3615464) Subject: RE: BS: Celius -Fahrenheit From: McGrath of Harlow Changing the name from Centigrade to Celsius was a bit questionable. True enough the Swedish Scientist Anders Celsius was the one who though of having 100 degrees between the freezing and boiling point of water, but he had 0 as the boiling point and 100 as freezing point. |
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05 Apr 14 - 06:34 PM (#3615821) Subject: RE: BS: Celius -Fahrenheit From: GUEST Celsius, you're breakin' my heart, You're shakin' my comfidence daily... |
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05 Apr 14 - 07:33 PM (#3615831) Subject: RE: BS: Celius -Fahrenheit From: Dave MacKenzie The name got changed from Centigrade because Fahrenheit was based on a 100 degrees, even if nobody can remember what they were supposed to be, and it was realized that water only boils at 100 degrees at sea level. I still don't see the attraction of decimal arithmetic; Pre metric we counted in everything but tens, and it was much easier shopping for dozens when everuthing was in pence and shillings. |
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05 Apr 14 - 08:06 PM (#3615841) Subject: RE: BS: Celius -Fahrenheit From: Steve Shaw We had a maths teacher at school (in the mid-60s, I hasten to add) who was vehemently opposed to anything decimal. He declared that the system we then had for currency and measurement, based on twelve, was much more useful, in that 12 can be divided by 2, 3, 4 and 6, whereas ten can be divided only by 2 and 5. His downfall, of course, was that we have ten digits on our hands, which lent a degree of awkwardness to counting in twelves. He did have an answer to that for the missing two, though, which I won't convey now: suffice to say that we were an all-boys school... |
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05 Apr 14 - 08:20 PM (#3615846) Subject: RE: BS: Celius -Fahrenheit From: McGrath of Harlow 5 fingers on 2 hands, that makes 12. (And apropos of nothing, Anne Boleyn had six fingers on each hand.) Duodecimal is in principle much better, but the language we use is tied to decimal (20, 30 etc), and so is our system of numerals. A pity we abandoned existing duodecimal elements such as pennies and shillings and inches and feet. Probably no going back now. |
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05 Apr 14 - 08:33 PM (#3615851) Subject: RE: BS: Celius -Fahrenheit From: Steve Shaw Probably? No shit, Sherlock! :-) |
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06 Apr 14 - 03:17 AM (#3615899) Subject: RE: BS: Celsius -Fahrenheit From: Joe Offer Changing 90 degrees f to celsius? Go to Google and enter 90 degrees f in c. |
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06 Apr 14 - 04:41 AM (#3615916) Subject: RE: BS: Celius -Fahrenheit From: Doug Chadwick Intersesting correspodences are 16C=61F....28C=82F. ....give or take a bit. 16oC = 60.8oF 28oC = 82.4oF The problem with the Celsius scale is that 1 degree is such a large change in temperature. From experience, 1 degree Fahrenheit appears to be the "sensible" change in temperature. If I think "it's getting a bit warm/cold in here" then the temperature has changed by about 1oF (assuming that I'm not in a draught). Hence the unusual number of 180 degrees between freezing and boiling compared to Celsius's convenient 100 degrees. DC |
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06 Apr 14 - 07:27 AM (#3615990) Subject: RE: BS: Celsius -Fahrenheit From: Steve Shaw Good point, Doug. So we're lumbered with point fives and stuff now. Even my car computer does centigrade in point fives. Still, there's no going back. Probably. ;-) |
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06 Apr 14 - 06:20 PM (#3616263) Subject: RE: BS: Celsius -Fahrenheit From: McGrath of Harlow The one part of the metricising mania started by the French Revolution was effectively halted was when it comes to time. The ten day week they called the "decade" never caught on. And we've still an intransigant duodecimal relic in the 24 hours in a day, and 12 months in a year. The puzzle of course is where 60 seconda in a minute and 60 minutes in an hour came from. |
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07 Apr 14 - 09:55 AM (#3616379) Subject: RE: BS: Celsius -Fahrenheit From: Ringer "The puzzle of course is where 60 seconda in a minute and 60 minutes in an hour came from." Babylon, I understand. Incidentally, the way I heard it, Mr Farenheit used salt/ice as zero, and the temperature of his dog's arse as 100. Then he found pure water froze at 32 and, extending his straight line towards the hot, found that water boiled at 212. |
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07 Apr 14 - 08:39 PM (#3616622) Subject: RE: BS: Celsius -Fahrenheit From: Joe_F 360 is a nice number -- divisible by 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20,.... It is also close to the number of days in a year. If you have just drawn a circle, the easiest way to divide its circumference is into six 60-deg arcs: just march around using the same compass setting. |
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08 Apr 14 - 05:54 PM (#3616802) Subject: RE: BS: Celsius -Fahrenheit From: Rapparee Out here in the Wild, Arid, High Desert country, it can go from -35F to +104F at various times (no, not in the same hour or day!). Folks will say stuff like, "Yeah, it's fifteen below, but it's a dry cold" or "It's 103, but it's a dry hear." My butt! It's -15 or it's +103. Either way it's too cold or too hot. Temperature only means something in relation to something else -- the boiling point of lead, when you need a parka, or the temperature at which certain chemicals will melt together to form a propellant for your home-made rocket. |
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08 Apr 14 - 07:40 PM (#3616815) Subject: RE: BS: Celsius -Fahrenheit From: Bill D I have learned...memorized... and relearned & re-memorized that 5/9th formula for 60 years. I'm glad they just DO it these days. Besides, I doubt that many folks anymore CAN multiply by 5/9ths and 9/5ths in a reasonable amount of time. I see the advantages of both systems, and it may be that I just grew up doing F, but it 'seems' easier having more whole #s rather than sticking .5s to be accurate. No matter, I have my programs to convert furlongs to fortnights ...and C to F anytime it's relevant. |
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08 Apr 14 - 07:59 PM (#3616817) Subject: RE: BS: Celsius -Fahrenheit From: Steve Shaw I know all the C/F equivalents by heart for all values likely to be encountered either here in Bude or on my holidays (preferably spent in Mediterranean summers when I can afford 'em, which is not often). So anything from minus ten to plus 40 Celsius. We once got to minus nine in Bude a few winters ago. Very rare. The highest on record it's ever been in Bude is plus 32. It happened twice in 1976 and once in my garden in August 1995. The hottest weather I've ever been in was in Perth, Australia a few years ago when it got to plus 36 (in April, not their hottest time of year), though it did push that in London in 1976 once or twice at the end of June. My climatic experiences are a good match for my equable temperament, I feel. |
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09 Apr 14 - 09:54 AM (#3616891) Subject: RE: BS: Celsius -Fahrenheit From: Ringer Dick greenhaus' algorithm (Date: 04 Apr 14 - 01:06 PM), "add 40, multiply, subtract 40" is astonishing! It works both for converting C to F and also F to C. I've been working with math all my life and the sheer beauty of Dick's method overwhelms me. (Perhaps I should get out more.) |
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09 Apr 14 - 10:07 PM (#3617104) Subject: RE: BS: Celsius -Fahrenheit From: BK Lick Have to agree with Ringer -- and I'm embarrassed to say I have a PhD in math. |
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10 Apr 14 - 05:01 AM (#3617162) Subject: RE: BS: Celsius -Fahrenheit From: Nigel Parsons Okay, Dick's method works, but it took a while to see why. You have two striaght line graphs plotting temperatures in degrees C & degrees F. These intersect at -40. Adding 40 to any quoted temperature moves the intersection point to Zero degrees. Multiplying by 5/9 (or 9/5) gives the correction for the slope of the graph (1 in 100 or 1 in 180). Subtract 40 to reset the intersection point of the graphs. Much easier that the equation I learnt in school: (F-32)/9=C/5 Unfortunately I've had that equation in my mind for 40+ years, so it won't be easy to replace! |
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10 Apr 14 - 11:33 PM (#3617425) Subject: RE: BS: Celsius -Fahrenheit From: BK Lick Hmm...I can't seem to grok what the x and y axes represent in the two straight line graphs that intersect at -40. |
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11 Apr 14 - 12:32 AM (#3617437) Subject: RE: BS: Celsius -Fahrenheit From: GUEST,NightWing, without a cookie BK, make the x-axis degrees Fahrenheit and the y-axis be "degrees". One line will be degrees C, the other degrees F. It works the same if you make the x-axis be Celsius. BB, NightWing |
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11 Apr 14 - 02:39 AM (#3617452) Subject: RE: BS: Celsius -Fahrenheit From: BK Lick OK, I get that. Then the slope of the degrees F line is 1 and the slope of slope of the degrees C line is 5/9. But what's the meaning of "the correction for the slope of the graph (1 in 100 or 1 in 180)?" |