8 ms·

0 degrees celsius + 0 degrees celsius -

170 points by iamelgringo 16y ago

loyd 16y ago
Is this a bug or a joke?
- keyle 16y ago
  It looks more like a bug. That, or it's a not funny joke.
- syncsynchalt 16y ago
  In terms of thermodynamics, it's correct. What makes you think it's a bug or a joke?
revolvingcur 16y ago
I didn't get correct answers for any of the "temperature math" problems I gave it. Something's screwy on the back end.
Myrth 16y ago
0 degrees celsius - 0 degrees celsius http://www.google.com/search?q=0+degrees+celsius+-+0+degrees+celsius http://www.google.com/search?q=0+degrees+celsius+-+0+degrees...
JangoSteve 16y ago
Digging a little deeper... (0 degrees Celsius) + (0 degrees Celsius) - (0 degrees Celsius) = 0 degrees Celsius (0 degrees Celsius) - (0 degrees Celsius) = 0 kelvin (0 degrees Celsius) + (0 kelvin) = 0 degrees Celsius The last 2 of the 3 are wrong, so I'd say this is definitley a bug. EDIT: I think I figured it out. It's converting everything after the first temperature to Kelvin, without converting the first temp to Kelvin, and then just doing the arithmetic on the numbers... 0C + 0C => 0C + 273K => 0 + 273 = 273 0C + 0C - 0C => 0 + 273 - 273 = 0 0C - 0C => 0 - 273 = -273 = 0K (ok, weird this one then converts back to K) 0C + 0K => 0 + 0 = 0 EDIT 2: While this does match the results seen by google, I think _delirium's solution is more likely the reason.
- fleitz 16y ago
  0C - 0C => 0 - 273 = -273 = 0K (ok, weird this one then converts back to K) Your math/logic is wrong, (A - A) => (B - A) you converted 0C to both 0 and 273. Convert everything to Kelvin and it all makes sense. It's non-intuitive because 0C indicates a positive amount of energy rather than no energy as 0K does.
  - JangoSteve 16y ago
    If you read my comment leading up to that, you'd see why I did it that way. But I agree with the other comment that it's more likely Google is just converting everything to Kelvin as it's canonical calculating form.
- iacvlvs 16y ago
  No. It's converting EVERYTHING to K, then doing the arithmetic, then converting the result to C. 0C + 0C = 273K + 273K = 546K = 273C 0C + 0C - 0C = 273K + 273K - 273K = 273K = 0C 0C - 0C => 273K - 273K = 0K 0C + 0K = 273K + 0K = 273K = 0C
- JangoSteve 16y ago
  Yup you guys are right. This is what I get for trying to overanalyze a problem at 3am.
poundy 16y ago
Wolfram Alpha beats Google on this! http://www.wolframalpha.com/input/?i=0+degrees+celsius+-+0+degrees+celsius http://www.wolframalpha.com/input/?i=0+degrees+celsius+-+0+d...
- ars 16y ago
  No it doesn't: http://www.wolframalpha.com/input/?i=0+degrees+celsius+%2B+0+degrees+F http://www.wolframalpha.com/input/?i=0+degrees+celsius+%2B+0...
_delirium 16y ago
It looks like it must be using kelvin as its canonical units: 0C + 0C = 273.15 K + 273.15 K = 546.3 K = 273.15 C The weirdness is that conversions like that don't work for units that have different zero points. Perhaps addition of temperatures isn't really well defined? If 273.15 K + 273.15 K does not equal 0 C + 0 C, despite 273.15 K = 0 C, it's not clear what addition "means" in this context. One restricted form of addition that makes sense (which maybe is what's intended?) is to consider the 1st temperature an actual temperature, and the 2nd temperature a temperature difference in units of degrees-C (or degrees-K, or degrees-F). So e.g.: "5 C warmer than 30 C" = 30 C + 5 C = 303.15 K + 5 K = 308.15 K = 35 C But then addition isn't commutative. The problem is that "degrees C" is overloaded here, to mean both a position on a scale, and the size of a unit on that scale, with no conventional short way of distinguishing which one you mean (which is one reason Kelvin was invented, since things aren't ambiguous if you put absolute zero at 0 K).
- nixme 16y ago
  Google can actually differentiate between the two meanings: degrees Celsius and Celsius degrees. As you explained, the query posed by the title is meaningless, but 0 degrees Celsius + 0 Celsius degrees is handled correctly: http://www.google.com/search?&q=0+degrees+celsius+%2B+0+celsius+degrees http://www.google.com/search?&q=0+degrees+celsius+%2B+0+...
  - _delirium 16y ago
    Ah, that's pretty interesting. It makes sense when you read the two phrasings next to each other, but it does seem like a pretty subtle wording difference. I think in practice people tend to differentiate which one is meant by context more than by "degrees Celsius" versus "Celsius degrees" being used consistently. Should Google should convert the query somehow? It seems like adding two temperatures in degrees Celsius is something that never really makes sense (or subtracting, multiplying, or dividing them), so faithfully executing it like they currently do is rarely what's intended.
    - ugh 16y ago
mhansen 16y ago
It's meaningless to add temperatures when the zero level is at +273. It's like adding years relative to 2010 years ago - it would be meaningless to add this year - 2010 - with (say) 1666 - the year of the Great Fire of London. It's meaningful to take differences (the Great Fire happened 344 years ago), but not to add. (Unless we converted to some kind of absolute time units e.g. years since the big bang) I'd say what it's doing - converting to an absolute scale then adding - makes sense.
- deleted 16y ago
  [deleted]
  - momokatte 16y ago
    "three degrees hotter" is an interval of three degrees, and not an absolute value along a scale. So you'd take your original temperature and add an interval of 3 degrees to it. 0 degrees Celsius has a heat value (273.15 K). If you double it (i.e. add 0 degrees Celsius to it), you get 546.3 K -- which is 273.15 degrees Celsius. What it really comes down to is that if you're going to perform math on temperatures for scientific reasons, use Kelvin. And if you're adjusting a temperature by an interval, leave out the units from the math completely.
    - ugh 16y ago
      You are right, I was wrong, but I think Google’s behavior is less than optimal. See my new comment.
- ugh 16y ago
  Hm, well not really. It doesn’t give the answer the user wants to know. They should just convert the second degrees celsius to celsius degrees. (Ideally they should probably also add a ‘Did you mean …’-link with the alternative ála Wolfram Alpha.)
- sesqu 16y ago
  I started Deep Thought 2010 years ago. It consisted of two geographically distributed identical units, networked by means of ether. One I put in London, another in Mecca. The former was destroyed in the Great Fire of London, 344 years ago. How many years of processing has Deep Thought finished? 2010 + 1666. In general, yes, it is pointless to add times. But I wouldn't call it meaningless.
deleted 16y ago
[deleted]
rincewind 16y ago
The question is meaningless but google answers it in the best possible way
- deleted 16y ago
  [deleted]
- tome 16y ago
  Arguably it oughtn't to answer it at all. It's a bit like asking "Where do I end up if I start at Alpha Centurai and go one light year east?".
- jpr 16y ago
  I'd appreciate it more that it wouldn't answer it at all. Giving stupid answers to stupid questions is even stupider than asking the stupid question in the first place.
Vulture 16y ago
Nice finding, now try to tell them
thras 16y ago
The fact that people get out of secondary education with no real understanding of thermodynamics is a tragedy. Case in point: There is currently no discussion in this thread of the difference between extensive and intensive properties of matter (highly relevant to the error Google makes here).
brisance 16y ago
WolframAlpha gets it right http://www.wolframalpha.com/input/?i=0%20degrees%20celsius%20%2B%200%20degrees%20celsius http://www.wolframalpha.com/input/?i=0%20degrees%20celsius%2...
- syncsynchalt 16y ago
  Not really. Google's answer is correct, in as much as it can be without mentioning the materials involved.
cemerick 16y ago
Stunning and just a little bit sad that something like this hits #2 (almost surely #1 soon).
- praptak 16y ago
  How about upmodding some of the competing links from the top page or, better yet, http://news.ycombinator.com/newest http://news.ycombinator.com/newest ?
cperciva 16y ago
Looks right to me. Asking for 0 degrees celsius + 0 degrees celsius, or put another way, "what's twice as hot as freezing water?", is profoundly nonsensical, but 273.15 degrees celsius is the closest you can get to a sensible answer.
Twisol 16y ago
It sure looks really bizzare, but here it is broken down... "0 degrees celsius in kelvin" -> 0 degrees Celsius = 273.15 kelvin "273.15 kelvin + 273.15 kelvin in degrees Celsius" -> (273.15 kelvin) + (273.15 kelvin) = 273.15 degrees Celsius Hence: "0 degrees celsius + 0 degrees celsius" -> (0 degrees Celsius) + (0 degrees Celsius) = 273.15 degrees Celsius
praptak 16y ago
Yeah, "It is twice as hot today as it was yesterday."
DrStalker 16y ago
Ever tried to add two Unix Time values together? The results may look weird, but make sense if you know what you're actually adding. Same here.
mataap 16y ago
Temperature is an intensive quantity, not an extensive quantity.
billhasmail 16y ago
Whether "degrees Celsius" refers to a point on the Celsius scale or an interval is ambiguous and is usually determined by context. Although attempts at conventions have existed the effect of typing rather than writing was not considered when they were created and so those conventions are largely ignored. In this case there is no context so google uses "degrees celsius" and "celsius degrees" to distinguish between a scale point and an interval which is a nice natural language solution in my opinion. To better see what is happening try: 0 degrees celsius + 10 celsius degrees 0 degrees celsius + 10 degrees celsius 0 celsius degrees + 10 celsius degrees
doki_pen 16y ago
If you take the absolute temperatures of 0 C in actual heat and add them together, you would have a cumulative heat of 273.15 C. Makes perfect sense.
balding_n_tired 16y ago
Well, shoot, with enough ice cubes we can reverse global warming.
TWAndrews 16y ago
Seems like arthmatic with temperatures is just broken. This querey: "5 degrees c + 1 degree f in fahrenheit" yields: "501.67 degrees Fahrenheit"
deleted 16y ago
[deleted]
Marticus 16y ago
Moral of the story: Google is a bunch of cheeky bastards. It took me a while to understand the reasoning behind that as points on a scale versus actual temperature values ("Celsius degrees" versus "degrees Celsius," respectively). Googling "0 Celsius degrees + 0 Celsius degrees" returns 0 Kelvin, which would be expected given the technicality in wording.
dstein 16y ago
As a rant, it annoys me to no end that C is the SI unit for Coulomb, yet everyone uses C as Celcius. Someone should fix that.
- slug 16y ago
  Well, afaik, people use ºC and not just C.
hippich 16y ago
what you expect is to add 0 temperature difference to 0 temperature value. What it actually calculate - sum of two temperature values. it's matter of notation imho
danielrhodes 16y ago
Even more confusing: http://www.google.com/search?aq=f&ie=UTF-8&q=0+degrees+fahrenheit+%2B+0+degrees+fahrenheit http://www.google.com/search?aq=f&ie=UTF-8&q=0+degre...
hc 16y ago
http://en.wikipedia.org/wiki/Affine_space http://en.wikipedia.org/wiki/Affine_space

170 points by iamelgringo 16y ago

loyd 16y ago

Is this a bug or a joke?

keyle 16y ago
It looks more like a bug. That, or it's a not funny joke.
syncsynchalt 16y ago
In terms of thermodynamics, it's correct. What makes you think it's a bug or a joke?

revolvingcur 16y ago

I didn't get correct answers for any of the "temperature math" problems I gave it. Something's screwy on the back end.

Myrth 16y ago

0 degrees celsius - 0 degrees celsius http://www.google.com/search?q=0+degrees+celsius+-+0+degrees+celsius http://www.google.com/search?q=0+degrees+celsius+-+0+degrees...

JangoSteve 16y ago

Digging a little deeper... (0 degrees Celsius) + (0 degrees Celsius) - (0 degrees Celsius) = 0 degrees Celsius (0 degrees Celsius) - (0 degrees Celsius) = 0 kelvin (0 degrees Celsius) + (0 kelvin) = 0 degrees Celsius The last 2 of the 3 are wrong, so I'd say this is definitley a bug. EDIT: I think I figured it out. It's converting everything after the first temperature to Kelvin, without converting the first temp to Kelvin, and then just doing the arithmetic on the numbers... 0C + 0C => 0C + 273K => 0 + 273 = 273 0C + 0C - 0C => 0 + 273 - 273 = 0 0C - 0C => 0 - 273 = -273 = 0K (ok, weird this one then converts back to K) 0C + 0K => 0 + 0 = 0 EDIT 2: While this does match the results seen by google, I think _delirium's solution is more likely the reason.

fleitz 16y ago
0C - 0C => 0 - 273 = -273 = 0K (ok, weird this one then converts back to K) Your math/logic is wrong, (A - A) => (B - A) you converted 0C to both 0 and 273. Convert everything to Kelvin and it all makes sense. It's non-intuitive because 0C indicates a positive amount of energy rather than no energy as 0K does.
- JangoSteve 16y ago
  If you read my comment leading up to that, you'd see why I did it that way. But I agree with the other comment that it's more likely Google is just converting everything to Kelvin as it's canonical calculating form.
iacvlvs 16y ago
No. It's converting EVERYTHING to K, then doing the arithmetic, then converting the result to C. 0C + 0C = 273K + 273K = 546K = 273C 0C + 0C - 0C = 273K + 273K - 273K = 273K = 0C 0C - 0C => 273K - 273K = 0K 0C + 0K = 273K + 0K = 273K = 0C
JangoSteve 16y ago
Yup you guys are right. This is what I get for trying to overanalyze a problem at 3am.

poundy 16y ago

Wolfram Alpha beats Google on this! http://www.wolframalpha.com/input/?i=0+degrees+celsius+-+0+degrees+celsius http://www.wolframalpha.com/input/?i=0+degrees+celsius+-+0+d...

ars 16y ago
No it doesn't: http://www.wolframalpha.com/input/?i=0+degrees+celsius+%2B+0+degrees+F http://www.wolframalpha.com/input/?i=0+degrees+celsius+%2B+0...

_delirium 16y ago

It looks like it must be using kelvin as its canonical units: 0C + 0C = 273.15 K + 273.15 K = 546.3 K = 273.15 C The weirdness is that conversions like that don't work for units that have different zero points. Perhaps addition of temperatures isn't really well defined? If 273.15 K + 273.15 K does not equal 0 C + 0 C, despite 273.15 K = 0 C, it's not clear what addition "means" in this context. One restricted form of addition that makes sense (which maybe is what's intended?) is to consider the 1st temperature an actual temperature, and the 2nd temperature a temperature difference in units of degrees-C (or degrees-K, or degrees-F). So e.g.: "5 C warmer than 30 C" = 30 C + 5 C = 303.15 K + 5 K = 308.15 K = 35 C But then addition isn't commutative. The problem is that "degrees C" is overloaded here, to mean both a position on a scale, and the size of a unit on that scale, with no conventional short way of distinguishing which one you mean (which is one reason Kelvin was invented, since things aren't ambiguous if you put absolute zero at 0 K).

nixme 16y ago
Google can actually differentiate between the two meanings: degrees Celsius and Celsius degrees. As you explained, the query posed by the title is meaningless, but 0 degrees Celsius + 0 Celsius degrees is handled correctly: http://www.google.com/search?&q=0+degrees+celsius+%2B+0+celsius+degrees http://www.google.com/search?&q=0+degrees+celsius+%2B+0+...
- _delirium 16y ago
  Ah, that's pretty interesting. It makes sense when you read the two phrasings next to each other, but it does seem like a pretty subtle wording difference. I think in practice people tend to differentiate which one is meant by context more than by "degrees Celsius" versus "Celsius degrees" being used consistently. Should Google should convert the query somehow? It seems like adding two temperatures in degrees Celsius is something that never really makes sense (or subtracting, multiplying, or dividing them), so faithfully executing it like they currently do is rarely what's intended.
  - ugh 16y ago

mhansen 16y ago

It's meaningless to add temperatures when the zero level is at +273. It's like adding years relative to 2010 years ago - it would be meaningless to add this year - 2010 - with (say) 1666 - the year of the Great Fire of London. It's meaningful to take differences (the Great Fire happened 344 years ago), but not to add. (Unless we converted to some kind of absolute time units e.g. years since the big bang) I'd say what it's doing - converting to an absolute scale then adding - makes sense.

deleted 16y ago
[deleted]
- momokatte 16y ago
  "three degrees hotter" is an interval of three degrees, and not an absolute value along a scale. So you'd take your original temperature and add an interval of 3 degrees to it. 0 degrees Celsius has a heat value (273.15 K). If you double it (i.e. add 0 degrees Celsius to it), you get 546.3 K -- which is 273.15 degrees Celsius. What it really comes down to is that if you're going to perform math on temperatures for scientific reasons, use Kelvin. And if you're adjusting a temperature by an interval, leave out the units from the math completely.
  - ugh 16y ago
    You are right, I was wrong, but I think Google’s behavior is less than optimal. See my new comment.
ugh 16y ago
Hm, well not really. It doesn’t give the answer the user wants to know. They should just convert the second degrees celsius to celsius degrees. (Ideally they should probably also add a ‘Did you mean …’-link with the alternative ála Wolfram Alpha.)
sesqu 16y ago
I started Deep Thought 2010 years ago. It consisted of two geographically distributed identical units, networked by means of ether. One I put in London, another in Mecca. The former was destroyed in the Great Fire of London, 344 years ago. How many years of processing has Deep Thought finished? 2010 + 1666. In general, yes, it is pointless to add times. But I wouldn't call it meaningless.

deleted 16y ago

[deleted]

rincewind 16y ago

The question is meaningless but google answers it in the best possible way

deleted 16y ago
[deleted]
tome 16y ago
Arguably it oughtn't to answer it at all. It's a bit like asking "Where do I end up if I start at Alpha Centurai and go one light year east?".
jpr 16y ago
I'd appreciate it more that it wouldn't answer it at all. Giving stupid answers to stupid questions is even stupider than asking the stupid question in the first place.

Vulture 16y ago

Nice finding, now try to tell them

thras 16y ago

The fact that people get out of secondary education with no real understanding of thermodynamics is a tragedy. Case in point: There is currently no discussion in this thread of the difference between extensive and intensive properties of matter (highly relevant to the error Google makes here).

brisance 16y ago

WolframAlpha gets it right http://www.wolframalpha.com/input/?i=0%20degrees%20celsius%20%2B%200%20degrees%20celsius http://www.wolframalpha.com/input/?i=0%20degrees%20celsius%2...

syncsynchalt 16y ago
Not really. Google's answer is correct, in as much as it can be without mentioning the materials involved.

cemerick 16y ago

Stunning and just a little bit sad that something like this hits #2 (almost surely #1 soon).

praptak 16y ago
How about upmodding some of the competing links from the top page or, better yet, http://news.ycombinator.com/newest http://news.ycombinator.com/newest ?

cperciva 16y ago

Looks right to me. Asking for 0 degrees celsius + 0 degrees celsius, or put another way, "what's twice as hot as freezing water?", is profoundly nonsensical, but 273.15 degrees celsius is the closest you can get to a sensible answer.

Twisol 16y ago

It sure looks really bizzare, but here it is broken down... "0 degrees celsius in kelvin" -> 0 degrees Celsius = 273.15 kelvin "273.15 kelvin + 273.15 kelvin in degrees Celsius" -> (273.15 kelvin) + (273.15 kelvin) = 273.15 degrees Celsius Hence: "0 degrees celsius + 0 degrees celsius" -> (0 degrees Celsius) + (0 degrees Celsius) = 273.15 degrees Celsius

praptak 16y ago

Yeah, "It is twice as hot today as it was yesterday."

DrStalker 16y ago

Ever tried to add two Unix Time values together? The results may look weird, but make sense if you know what you're actually adding. Same here.

mataap 16y ago

Temperature is an intensive quantity, not an extensive quantity.

billhasmail 16y ago

Whether "degrees Celsius" refers to a point on the Celsius scale or an interval is ambiguous and is usually determined by context. Although attempts at conventions have existed the effect of typing rather than writing was not considered when they were created and so those conventions are largely ignored. In this case there is no context so google uses "degrees celsius" and "celsius degrees" to distinguish between a scale point and an interval which is a nice natural language solution in my opinion. To better see what is happening try: 0 degrees celsius + 10 celsius degrees 0 degrees celsius + 10 degrees celsius 0 celsius degrees + 10 celsius degrees

doki_pen 16y ago

If you take the absolute temperatures of 0 C in actual heat and add them together, you would have a cumulative heat of 273.15 C. Makes perfect sense.

balding_n_tired 16y ago

Well, shoot, with enough ice cubes we can reverse global warming.

TWAndrews 16y ago

Seems like arthmatic with temperatures is just broken. This querey: "5 degrees c + 1 degree f in fahrenheit" yields: "501.67 degrees Fahrenheit"

deleted 16y ago

[deleted]

Marticus 16y ago

Moral of the story: Google is a bunch of cheeky bastards. It took me a while to understand the reasoning behind that as points on a scale versus actual temperature values ("Celsius degrees" versus "degrees Celsius," respectively). Googling "0 Celsius degrees + 0 Celsius degrees" returns 0 Kelvin, which would be expected given the technicality in wording.

dstein 16y ago

As a rant, it annoys me to no end that C is the SI unit for Coulomb, yet everyone uses C as Celcius. Someone should fix that.

slug 16y ago
Well, afaik, people use ºC and not just C.

hippich 16y ago

what you expect is to add 0 temperature difference to 0 temperature value. What it actually calculate - sum of two temperature values. it's matter of notation imho

danielrhodes 16y ago

Even more confusing: http://www.google.com/search?aq=f&ie=UTF-8&q=0+degrees+fahrenheit+%2B+0+degrees+fahrenheit http://www.google.com/search?aq=f&ie=UTF-8&q=0+degre...

hc 16y ago

http://en.wikipedia.org/wiki/Affine_space http://en.wikipedia.org/wiki/Affine_space