Temperature Question

[claymore]

If the temperature is zero outside today and it's going to be twice as cold tomorrow, how cold will it be?

 

[powerskipper]

00
as twice 0 is 0 /forums/images/graemlins/grin.gif

 

[jimi]

is that celcius, fahrenheit or kelvin?

 

[drawp]

Freezing is 32 deg Farenheit in old money. Twice as cold (half as hot?) would be 16 deg Farenheit which would be -8.8888888888888888889 deg C. Do I get an elephant stamp?

 

[claymore]

Well - I suppose we'll just have to wait until tomorrow

 

[claymore]

Jings furst para then youse - tha's ra baith oan yiz awake - whits happnin?

 

[Lakesailor]

Too cold to go out.

 

[ongolo]

well, in physics there is no cold, there is only a lack of heat.

zero Celsius is about 273 Kelvin. And zero Celsius is hot as hell relative to absolue zero or 0 Kelvin, if you dont believe it double it to 273 celsius and see what I mean.

But I am sure, you have a much more logical solution.

)

lets hear it

Ongolo

 

[jimi]

acshully was going to go sailing but it wiz so cold I changed the oil & impeller instead whilst basking in the warmth of the eberspacher

 

[Sammo]

Well Winfried

As a heating engineer all I can say is it`s not bloody lack of heat enough.
Let`s get some snow on the ground, after all I`ve got a
boat to maintain.

........................
BooBooHoo.

 

[Rowana]

Cold is a frog on an ice bound pool
Cold is the tip of an eskimo's tool
Cold is charity
And that' bloody chilly
But not as cold as our poor Willy
He's dead, poor b***ard !

/forums/images/graemlins/frown.gif /forums/images/graemlins/frown.gif /forums/images/graemlins/frown.gif

 

[VicS]

I would interpret " twice as cold " as meaning that the heat loss from the body is doubled.

you can calculate the heat loss from the formula:

K = (10.45 + sq. root v - v)(33 - t)

where K is the heat loss, in Kilogram calories, per sq. metre of exposed skin in 1 hour,
v is the wind speed in metres per second,
t is the temperature in degrees C,

(The temperature of bare skin is assumed to be 33C)

So, at the same wind speed, the rate of heat loss will be doubled if the term (33-t) is doubled. If the current temperature is 0C then that will be occur at -33C.

Alternatively, at the same temperature, the heat loss will be doubled when (10.45 + sq.root v - v) is doubled. (I'll leave you to do the maths)

Or of course from a combination of both effects.

Having got a value (or expression) for the rate of heat loss, K, you can calculate the "Windchill eqivalent temperature, Te, from the equation:

Te = 33 - K/22.04.

I hope that helps, at least you can while away the afternoon compiling your own windchill chart. A nice little spreadsheet exercise.

 

[Cornishman]

minus zero?

 

[claymore]

I didn't really think it was as cold today as it was yesterday and I cannot make Vics spreadsheet hang together!

 

[philmarks]

Cold = Brass monkey has problem

Therefore twice as cold = two brass monkeys have problem(s)

 

[VicS]

Re: Correction.... apologies

The formula for calcuating heat loss should have been

K = (10.45 + 10xsq.root v - v)(33-t)

I left the 10 out before the sq.root v as a result of concentrating to hard on trying to find a sq.root sign.

 

[claymore]

Re: Correction.... apologies

hmm - just as I thought. So does that make it warmer tomorrow or colder?

 

[VicS]

Re: Correction.... apologies

If the temperature's lower it'll be colder. If it's windier it'll feel colder. If the temperature is lower and it's winder it'll be colder and feel even colder still.

At the moment it looks very cold (rather white) here and the forecast is for it to get colder and whiter. There's no Gulf stream to keep the south east warm!