# Naked Science Forum

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

Title: Can we get "twice as cold" as 0 degrees C?
Post 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 ?
Title: Re: Can we get "twice as cold" as 0 degrees?
Post by: pippystardust on 27/03/2012 21:48:16
If the temperature is zero degrees C  and the weatherman says it will be twice as cold tomorrow ...what will the temperature be tomorrow ?
Title: Re: Can we get "twice as cold" as 0 degrees?
Post by: Bored chemist on 27/03/2012 22:13:51
It will  be cold enough that you need a better weatherman.
Title: Re: Can we get "twice as cold" as 0 degrees?
Post by: CliffordK on 27/03/2012 22:16:51
-137° C
Title: Re: Can we get "twice as cold" as 0 degrees?
Post by: pippystardust on 28/03/2012 00:21:15
11 views   no suggestions yet !
Title: Re: Can we get "twice as cold" as 0 degrees?
Post by: CliffordK on 28/03/2012 02:18:24
You have started two topics.
It is generally frowned upon to start two identical threads.

(Now merged).
Title: Re: Can we get "twice as cold" as 0 degrees?
Post by: Nizzle on 28/03/2012 11:20:39
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...
Title: Re: Can we get "twice as cold" as 0 degrees?
Post by: Sprool on 28/03/2012 14:40:15
Stands to reason it will be 16F.
Probably.
Title: Re: Can we get "twice as cold" as 0 degrees?
Post by: Geezer on 28/03/2012 15:30:59
Obviously, it will be 245.8 degrees.
Title: Re: Can we get "twice as cold" as 0 degrees?
Post by: CliffordK on 28/03/2012 22:25:40
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

Title: Re: Can we get "twice as cold" as 0 degrees?
Post by: pippystardust on 29/03/2012 19:37:05
why are some people being so literal ? the weatherman didn't REALLY say that...its a hypothetical question !
Title: Re: Can we get "twice as cold" as 0 degrees?
Post by: chris on 29/03/2012 19:46:44
Title: Re: Can we get "twice as cold" as 0 degrees C?
Post by: Geezer on 29/03/2012 21:16:25

Windchill is an attempt by weathermen to "dumb-down" science so they can make meaningless statements like "twice as cold"   [;D]

It's pretty qualitative.
Title: Re: Can we get "twice as cold" as 0 degrees C?
Post by: pippystardust on 30/03/2012 09:33:15
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
Title: Re: Can we get "twice as cold" as 0 degrees C?
Post by: CliffordK on 31/03/2012 00:37:37
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)]
Title: Re: Can we get "twice as cold" as 0 degrees C?
Post by: Geezer on 31/03/2012 02:30:32
Good spot on the Rankine!
Title: Re: Can we get "twice as cold" as 0 degrees C?
Post by: pippystardust on 03/04/2012 00:26:01
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 !
Title: Re: Can we get "twice as cold" as 0 degrees C?
Post by: yor_on on 07/04/2012 15:44:46
It's an expression i guess?
And a good thing to philosophize over, over a beer :)

I don't know, what is 'zero'?
Title: Re: Can we get "twice as cold" as 0 degrees C?
Post by: Nizzle on 10/04/2012 10:27:00
"What is twice as cold as 0 degrees?"     (in ANY scale)

-0 degrees :p
Title: Re: Can we get "twice as cold" as 0 degrees C?
Post by: syhprum on 07/12/2017 00:27:41
O°C is about 20° lower than a comfortable temperature so twice as cold would be -20°C
Title: Re: Can we get "twice as cold" as 0 degrees C?
Post by: evan_au on 07/12/2017 07:59:20
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
Title: Re: Can we get "twice as cold" as 0 degrees C?
Post by: Monox D. I-Fly on 13/01/2018 02:58:12
Once I asked a question along something of this line in 3 different math forums and they seemed to agree with you guys:
http://www.mathisfunforum.com/viewtopic.php?id=23897
Title: Re: Can we get "twice as cold" as 0 degrees C?
Post by: Tomassci on 02/06/2018 08:28:35
why are some people being so literal ? the weatherman didn't REALLY say that...its a hypothetical question !

We didn't know that.
Title: Re: Can we get "twice as cold" as 0 degrees C?
Post by: evan_au on 02/06/2018 09:03:16
Quote from: CliffordK
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 Jean-Pierre Christin, to produce the Celsius scale we use today (well, Europeans and Scientists use it, anyway).
See: https://en.wikipedia.org/wiki/Celsius
Title: Re: Can we get "twice as cold" as 0 degrees C?
Post by: alancalverd on 02/06/2018 12:58:26