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0 degrees celsius + 0 degrees celsius -

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Re: 0 degrees celsius + 0 degrees celsius -

#41

Post by sesqu »

woodall wrote: post #35
_delirium wrote: post #7

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…

You just screwed me all up. 32 F + 32 F = 64 F 0 C + 0 C = 0 C HOWEVER it should equal about 17.78 degrees Celsius. Now we 17.78/2 = 8.89 C = 282.04 kelvin. That is suspiciously close the to 0 C = 273.15 K- however it is also not that close. My whole understanding of temperature has been flip upside down. Wait. This is why I am not an engineer. If we add a glass of liquid that is at 0C/32F/273K to another glass of li…

  10 °C = 50 °F (temperature)
  10 °C = 18 °F (temperature difference)
Celsius and Fahrenheit date to before temperature was understood to have a lower limit. Both measure only temperature difference from their respective zero points, with the conversion to energetic temperature demanding that one knows where the zero points are. The conversion is implicit in common use, so that

  10 °C + 10 °C = 273.15 K + 10 °C + 10 °C = 273.15 K + 20 °C = 20 °C
edit: changed substantially

Re: 0 degrees celsius + 0 degrees celsius -

#42

Post by serichsen »

antileet wrote: post #27
_delirium wrote: post #7

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…

Seems it is easy enough to confuse even Wolfram Alpha http://www.wolframalpha.com/input/?i=0+degrees+kelvin+%2B+0+... Funnily enough the original query is handled well[1] by W|A: http://www.wolframalpha.com/input/?i=0+degrees+celsius+%2B+0... And the query that fails in Wolfram Alpha, works fine in Google's Calculator: http://www.google.com/search?sourceid=chrome&ie=UTF-8&#3... :) 1: By "well", we probably mean accor…

Actually, Wolfram Alpha is doing a sensible thing in each case: it is not adding the temperatures, it is comparing them, resp. calculating the difference, when you give different scales. You can see that in the output, where it says "difference".

The confusion is all on your side.

Re: 0 degrees celsius + 0 degrees celsius -

#43

Post by billhasmail »

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

Re: 0 degrees celsius + 0 degrees celsius -

#44

Post by shdon »

sesqu wrote: post #41
woodall wrote: post #35

Earlier quoted context omitted.

You just screwed me all up. 32 F + 32 F = 64 F 0 C + 0 C = 0 C HOWEVER it should equal about 17.78 degrees Celsius. Now we 17.78/2 = 8.89 C = 282.04 kelvin. That is suspiciously close the to 0 C = 273.15 K- however it is also not that close. My whole understanding of temperature has been flip upside down. Wait. This is why I am not an engineer. If we add a glass of liquid that is at 0C/32F/273K to another glass of li…

10 °C = 50 °F (temperature) 10 °C = 18 °F (temperature difference) Celsius and Fahrenheit date to before temperature was understood to have a lower limit. Both measure only temperature difference from their respective zero points, with the conversion to energetic temperature demanding that one knows where the zero points are. The conversion is implicit in common use, so that 10 °C + 10 °C = 273.15 K + 10 °C + 10 °C =…

And thus 32 °F = 16 °F, which, with conventional mathematics, can only be satisfied if °F = 0. Express this in English as "Fahrenheit is nothing", which is something that every European already knows. That's why we use Celsius :P

Re: 0 degrees celsius + 0 degrees celsius -

#45

Post by bruceboughton »

ugh wrote: post #21
_delirium wrote: post #19

Earlier quoted context omitted.

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…

They should convert the query because that’s exactly what people want to know when they type in those kinds of queries.

>> when they type in those kinds of queries

If I wanted to know 50 degrees Celsius + 35 Celsius degrees, I would probably omit the units and just ask for 50 + 35. I find it unlikely that many users actually run into this problem.

Re: 0 degrees celsius + 0 degrees celsius -

#46

Post by ugh »

bruceboughton wrote: post #45
ugh wrote: post #21

Earlier quoted context omitted.

They should convert the query because that’s exactly what people want to know when they type in those kinds of queries.

>> when they type in those kinds of queries If I wanted to know 50 degrees Celsius + 35 Celsius degrees, I would probably omit the units and just ask for 50 + 35. I find it unlikely that many users actually run into this problem.

It’s no big deal, sure.

Re: 0 degrees celsius + 0 degrees celsius -

#47

Post by sesqu »

mhansen wrote: post #9

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…

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.

Re: 0 degrees celsius + 0 degrees celsius -

#49

Post by michael_dorfman »

sesqu wrote: post #47
mhansen wrote: post #9

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…

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.

In general, yes, it is pointless to add times. But I wouldn't call it meaningless.

For extremely large values of "in general." The only edge case where it appears to be meaningful is the one you pointed out, where one of your endpoints is the origin of the scale. If you had started Deep Thought at literally any other point in time, the addition would fail.

Re: 0 degrees celsius + 0 degrees celsius -

#50

Post by sesqu »

michael_dorfman wrote: post #49
sesqu wrote: post #47

Earlier quoted context omitted.

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.

In general, yes, it is pointless to add times. But I wouldn't call it meaningless. For extremely large values of "in general." The only edge case where it appears to be meaningful is the one you pointed out, where one of your endpoints is the origin of the scale. If you had started Deep Thought at literally any other point in time , the addition would fail.

The addition wouldn't fail; it would just not be very useful. Interval scales do support addition, which comes in handy when you want to, say, calculate the center of mass for interesting events.

What would fail would be trying to determine the factor by which 2010 is later than 1666.

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