Naked Science Forum
Life Sciences => The Environment => Topic started by: pippystardust on 27/03/2012 21:41:18

if it is 0 degrees celcius outside and the weatherman says that it will be twice as cold tomorrow ...what will the temperature be tomorrow ?

If the temperature is zero degrees C and the weatherman says it will be twice as cold tomorrow ...what will the temperature be tomorrow ?

It will be cold enough that you need a better weatherman.

137° C

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You have started two topics.
It is generally frowned upon to start two identical threads.
(Now merged).

If the temperature is zero degrees C and the weatherman says it will be twice as cold tomorrow ...what will the temperature be tomorrow ?
Well, that weatherman can't be correct because 0 degrees C = 273.15 K, and twice as cold will then be 136.575 K, or 136.575 degrees C. I think the whole world would come to a stop if it were to become that cold...

Stands to reason it will be 16F.
Probably.

Obviously, it will be 245.8 degrees.

If 70°F (21°C) is considered "comfortable".
So... 0°C would be 21 degrees Cold.
So, twice as cold would have to be 21°C, or 6°F

why are some people being so literal ? the weatherman didn't REALLY say that...its a hypothetical question !

What about windchill?

What about windchill?
Windchill is an attempt by weathermen to "dumbdown" science so they can make meaningless statements like "twice as cold" [;D]
It's pretty qualitative.

even though this is a bit of fun why are people just coming up with figures and no explanation of how they came up with it ? Int that a teensy bit pompous to assume that everyone will accept that they are correct?
Its not a very scientific way of presenting something either is it? if you presented an essay like that without backing up claims then you would either fail or get the essay returned unmarked

even though this is a bit of fun why are people just coming up with figures and no explanation of how they came up with it ? Int that a teensy bit pompous to assume that everyone will accept that they are correct?
I think that is part of the fun... and allows one to puzzle over the answer.
"Twice as hot" is a pretty simple concept, take the temperature on your favorite temperature scale, Kelvin, Celsius, or Fahrenheit, and double it, although scientifically speaking, one should use Kelvin for such a comparison.
"Twice as cold" is much more ambiguous because if you double a temperature, you get something hotter.
Obviously
2 x 0°C = 0°C.
½ x 0°C = 0°C.
137° C
Well, that weatherman can't be correct because 0 degrees C = 273.15 K, and twice as cold will then be 136.575 K, or 136.575 degrees C. I think the whole world would come to a stop if it were to become that cold...
Both these are the same, using half the temperature in Kelvin (http://en.wikipedia.org/wiki/Kelvin), rather than "twice as cold".
Stands to reason it will be 16F.
Probably.
0°C = 32°F. So, half that temperature in Fahrenheit is 16°F, or 8.89°C
Keep in mind that Fahrenheit (http://en.wikipedia.org/wiki/Fahrenheit) is widely used in the USA for ambient temperatures.
Obviously, it will be 245.8 degrees.
Hmmm... [:o] [?]
Ok, on the Rankine Scale (http://en.wikipedia.org/wiki/Rankine_scale), 0°C = 491.67 °R.
Half of 491.67 °R = 245.8°R
[xx(]
If 70°F (21°C) is considered "comfortable".
So... 0°C would be 21 degrees Cold.
So, twice as cold would have to be 21°C, or 6°F
Here I tried to redefine what "cold" means. In this case, anything below your "optimum" temperature is considered "cold", and anything above it is "hot". So, once one gets a "cold scale", it is easy enough to double it.
In a Geezeresque fashion, let me try another answer using the Delisle Scale. (http://en.wikipedia.org/wiki/Delisle_scale). This scale has the advantage over the other scales in that the larger the number, the colder the temperature.
So,
0°C = 150°De (http://en.wikipedia.org/wiki/Delisle_scale).
One can then easily calculate that twice as cold would simply be 150°De x 2 = 300°De, or −100.00°C, or −148.00°F.
See what you get for asking such a question in a "Science Forum" [:o)]

Good spot on the Rankine!

Good spot on the Rankine!
0 degrees is O degrees in ANY scale so what is twice as cold as 0 degrees? its not about what you consider "cold" its what 0 degrees is !
I will reword my question in a boring way
"What is twice as cold as 0 degrees?" (in ANY scale)
PS just so thst you know that I am actually thinking scientifically...I assume that the upper most temp on the scale makes a difference to the answer !

It's an expression i guess?
And a good thing to philosophize over, over a beer :)
I don't know, what is 'zero'?

"What is twice as cold as 0 degrees?" (in ANY scale)
0 degrees :p

O°C is about 20° lower than a comfortable temperature so twice as cold would be 20°C

I would say that the weatherman is speaking figuratively (=metaphorically) rather than figuratively (=numerically).
One measure for "twice as cold" would be to measure the heat loss through each square cm of bare skin.
 If the weather is "twice as cold" you would lose twice as much heat through each square cm of skin.
 Since heat is carried away more effectively by moving air than still air, on a windy day you could be "twice as cold" and the temperature could be unchanged at 0C.
This is what the various Wind Chill formulae attempt to estimate.
See: https://en.wikipedia.org/wiki/Wind_chill

Once I asked a question along something of this line in 3 different math forums and they seemed to agree with you guys:
http://mymathforum.com/elementarymath/340359askabouthotcold.html
http://www.mathisfunforum.com/viewtopic.php?id=23897
http://mathhelpboards.com/prealgebraalgebra2/askabouthotcold21312.html

why are some people being so literal ? the weatherman didn't REALLY say that...its a hypothetical question !
We didn't know that.

In a Geezeresque fashion, let me try another answer using the Delisle Scale.. This scale has the advantage over the other scales in that the larger the number, the colder the temperature.
I heard recently that Anders Celsius developed a temperature scale where the fixed points were the freezing and boiling points of water  only his system had freezing point=100°, and boiling point =0°. So it had the same direction as the Delisle scale...
This scale was turned upside down in 1743 by JeanPierre Christin, to produce the Celsius scale we use today (well, Europeans and Scientists use it, anyway).
See: https://en.wikipedia.org/wiki/Celsius

What about windchill?
Windchill is an attempt by weathermen to "dumbdown" science so they can make meaningless statements like "twice as cold" [;D]
It's pretty qualitative.
No, it is quantitative. Wind chill is the difference between actual ambient and the still, dry air temperature that would produce the same rate of heat loss from moist skin at 30°C. It is tabulated as a function of wind speed, temperature and humidity in most survival manuals and physiology textbooks.