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Author Topic: How Is Wind Chill Factor Calculated ?  (Read 9020 times)

Offline neilep

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How Is Wind Chill Factor Calculated ?
« on: 08/10/2009 17:43:33 »
Burrrrrrp...Farrrrrrrrrrt !!...sorry...I have wind !!

As a sheepy I am course very used to weathering the elements..being stuck in a field and all that !  Yep, being stuck in a  field all year round when it's blowing a gale really bloody cheers me up no end !!



Look here's some windmill thingys.....



Windmill Thingies

nice eh...being delivered next Tuesday.

Windmill thingies collect magic from the wind and turn it into faerie power that makes your doorbell work !..This is true !

Sometimes when I hear the weather forecast they say things like the wind chill factor will be etc etc !!

What's that all about and how do they calculate it ?..is there a breeze chill factor ?  a rain chill factor ? a snow chill factor ? an X-factor ?

whajafink ?


hugs & shmishes


mwah mwah mwah mwah !



neil
Sheepy With A High Hug Warmth Factor
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx


 

Offline SkepticSam

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How Is Wind Chill Factor Calculated ?
« Reply #1 on: 08/10/2009 20:32:12 »
I gather you are a sheep and therefore you are asking this on behalf of you farmer. I say that because sheep don't suffer from wind chill (as such) your coat (hair, fur) traps air and acts as an insulator unless you are wet or have been sheared.

Your poor farmer doesn't have the luxary of a nice woolen coat so he may need to know about windchill. But then again unless he's farming in Alaska, Canada or the arctic he can simply be clever enough to know that when the wind blows he will feel Colder and dress apropriately.

So what's going on with windchill? If you expose your naked self to the wind you feel colder. This is because your body is always giving off moisture, sweating. This moisture has to evaporate, and that process of evaporation from liquid to gas causes a cooling effect. This is heightened by the wind.  I think the process is more accurately known as latent heat of vapourisation and is covered by one of the gas laws... Is it boyles law?

This is a link to a windchill chart.
windchill chart [nofollow]

Do you know the first person to use windchill in a UK forecast? Well if he is to be believed, and why shouldn't he, it was Philip Eden. I'm sure I heard him say he regrets doing it.
 

Offline litespeed

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How Is Wind Chill Factor Calculated ?
« Reply #2 on: 12/11/2009 18:58:26 »
Temperature v Windchill Factor.

I grew up where it could be cold with and without wind. Zero degrees F was cold. During such times the temperature would change very little, moment to moment, but the wind might or might not be blowing.  I would look at the thermometer to see it was zero F outside, and I could judge for myself the wind conditions.

I think Windchill was invented by people who live inside away from both wind and cold so they could claim how bad is their climate. Simply wait for a temporary wind bluster and announce an additional 20 degrees F colder.

Yuppified balderdash. But then as a fully wooly denizen of the very deep freeze, you already knew that, suspects me.....
« Last Edit: 12/11/2009 19:01:58 by litespeed »
 

Offline Madidus_Scientia

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How Is Wind Chill Factor Calculated ?
« Reply #3 on: 12/11/2009 21:32:17 »
Temperature v Windchill Factor.

I grew up where it could be cold with and without wind. Zero degrees F was cold. During such times the temperature would change very little, moment to moment, but the wind might or might not be blowing.  I would look at the thermometer to see it was zero F outside, and I could judge for myself the wind conditions.

I think Windchill was invented by people who live inside away from both wind and cold so they could claim how bad is their climate. Simply wait for a temporary wind bluster and announce an additional 20 degrees F colder.

Yuppified balderdash. But then as a fully wooly denizen of the very deep freeze, you already knew that, suspects me.....

Living in such a cold place, have you ever heard of a fan? It's a device used in places outside your own little world that people use to cool down when it's hot. It doesn't actually change the temperature at all, but it does increase wind chill factor.

Maybe you've done this; when your food is too hot to eat, you hold it on the fork near your mouth and blow on it, you are giving it wind chill factor. The more air moving over it, the faster it will lose heat to the air. The temperature of the air remains constant, of course.

But I guess it wouldn't be the first time you've considered well established science to be yuppified balderdash.
 

Offline Karsten

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How Is Wind Chill Factor Calculated ?
« Reply #4 on: 12/11/2009 22:09:26 »
Temperature v Windchill Factor.

I grew up where it could be cold with and without wind. Zero degrees F was cold. During such times the temperature would change very little, moment to moment, but the wind might or might not be blowing.  I would look at the thermometer to see it was zero F outside, and I could judge for myself the wind conditions.

I think Windchill was invented by people who live inside away from both wind and cold so they could claim how bad is their climate. Simply wait for a temporary wind bluster and announce an additional 20 degrees F colder.

Yuppified balderdash. But then as a fully wooly denizen of the very deep freeze, you already knew that, suspects me.....

I am sorry, I LIVE in an area that gets around -40F occasionally (Southern QC)and I go outside every day. Sometimes longer - sometimes shorter. There is a DISTINCT difference between the effect of air on your exposed skin when the wind is blowing and when it is not. -20F is bearable in no wind and with good clothes. Zero F and strong wind is hard to withstand unless you expose absolutely no skin. You ignore this and go outside in far below freezing weather with whipping wind, you loose some skin or part of your ear or nose in a very short time. Even my dog "knows" that and responds accordingly.

Whether the current wind chill scale makes sense or whether people understand when and how it applies can be debated, but to say it was invented to claim your climate is worse seems silly. Moving air cools you down faster than standing air of the same temperature. I would think the wind chill factor and scale was invented by someone who recognized that not telling people about the wind can injure/kill those who go outside preparing only for the temperature and not for wind and temperature.

« Last Edit: 12/11/2009 22:11:45 by Karsten »
 

Offline litespeed

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How Is Wind Chill Factor Calculated ?
« Reply #5 on: 12/11/2009 22:16:29 »
Madi - You wrote: "...when your food is too hot to eat, you hold it on the fork near your mouth and blow on it, you are giving it wind chill factor...the temperature of the air remains constant, of course."

Oh Jeeze. The entier purpose of blowing air over hot food is transfer heat to the air. But the temperature of the air does not remain constant. It INCREASES as the food is cooled, which is the entire point of the exercise.

But I digress. Do you believe planetary climate was warmer in the Roman era then now?



 

Offline litespeed

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How Is Wind Chill Factor Calculated ?
« Reply #6 on: 12/11/2009 22:22:04 »
Karsten

Temperature is relatively stable, but wind speed varies second to second. How in the hell could you rely on a Weather Babe telling you the wind chill factor when the wind is in constant change.

You won't do that. You will note the actual temperature from your own thermometer and will also notice whether it is windy or not. I just do not see you googling wind chill for zip code xxxxx. Anyway, in such extreme circumstance any sane person will not rely on the local weather babe at all.  Going out in such circumstances imposes pre-selected survival gear. Even if the wind is zero, one must ASSUME it will not stay that way.

I got the hell out of Chicago for several reasons. Not the least of which was the need to keep survival gear in the car during Winter at all times.
« Last Edit: 12/11/2009 22:28:48 by litespeed »
 

Offline Madidus_Scientia

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How Is Wind Chill Factor Calculated ?
« Reply #7 on: 13/11/2009 11:53:11 »
Madi - You wrote: "...when your food is too hot to eat, you hold it on the fork near your mouth and blow on it, you are giving it wind chill factor...the temperature of the air remains constant, of course."

Oh Jeeze. The entier purpose of blowing air over hot food is transfer heat to the air. But the temperature of the air does not remain constant. It INCREASES as the food is cooled, which is the entire point of the exercise.

But I digress. Do you believe planetary climate was warmer in the Roman era then now?





Yes, but the moving air is the same temperature as the room. Yet it cools the food down faster when it's moving.

WTF does the climate of the Roman era have to do with this thread? You have hijacked enough threads on that topic already, there is no need to do it with entirely unrelated threads.
 

Offline litespeed

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How Is Wind Chill Factor Calculated ?
« Reply #8 on: 14/11/2009 17:46:37 »
Karsten

You tell us you live in a Cold Place. Although I no longer live in a Cold Place I am curious what indoor temperature you recommend as appropriate in such conditions. In my Temperate Place, I usually open all the sliding glass doors when the temperature rises to 65F in order to let in all that warm air!
 

Offline Karsten

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How Is Wind Chill Factor Calculated ?
« Reply #9 on: 14/11/2009 18:49:11 »
Karsten

You tell us you live in a Cold Place. Although I no longer live in a Cold Place I am curious what indoor temperature you recommend as appropriate in such conditions. In my Temperate Place, I usually open all the sliding glass doors when the temperature rises to 65F in order to let in all that warm air!

Depends on what you are doing and who you ask. I am fine with 60F as long as I am physically active. 65 for more stationary activities. My girl-friend and her daughter prefer MUCH warmer and it is a constant struggle. But, unlike me, they don't wear PP long underwear from November through April. Not all rooms are the same temperature either.

If the house stands empty for a long time I keep it just above freezing. Frozen pipes are a drag.

To bring this back to at least remotely concern the original post: If it is windy, it shows even inside the house. Drafts are worse than colder temperatures. I also don't like forced air systems a whole lot for that reason. They make me feel colder even though they heat the house. I prefer radiant heat by far. Moving warm air from the warm air ducts gets me colder than standing 60F air.
 

Offline litespeed

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How Is Wind Chill Factor Calculated ?
« Reply #10 on: 14/11/2009 19:03:44 »
Karsten.  You are a woman after my own heart!  Years ago I lived on a houseboat in Norfolk. The interior seldom rose above 55 degrees in winter, except on weekends when the kerosene heater might catch up a bit. I LIKE it cold at night.

However, during the working week I did find it a bit bracing to shower with a 55 degree bathroom! And the water flow was less then about one gallon per minute. I still miss the simplicity.  My wardrobe of cloths was about three feet wide, and I always wore a jacket and tie to work.

My total living space in Winter [I closed off the Pilot House] was about 8x30 = 240 square feet. Never felt deprived and did it for three years. I am STILL nostalgic! And you are correct about radiant heat. Forced air heat pumps seem an exercise in futility.

« Last Edit: 14/11/2009 19:06:13 by litespeed »
 

Offline Karsten

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How Is Wind Chill Factor Calculated ?
« Reply #11 on: 14/11/2009 21:11:19 »
Litespeed: Don't get too excited, I am a man.
 

Offline litespeed

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How Is Wind Chill Factor Calculated ?
« Reply #12 on: 14/11/2009 21:29:53 »
Karsten,

No second quessing on this side. The time honored method to keep pipes from freezing is to open a cold fawcet and let it drip over night.  In the old days we had an electric pump in a pit outside the house. Nothing more then a 100 watt light bulb was needed to ensure nothing froze.

The important thing is to identify places in the water system that are open to the cold air, and then to insulate them. Still, just letting ground water temperature water move slowly through the system is sufficient.

Sorry about the gender missunderstanding....
 

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How Is Wind Chill Factor Calculated ?
« Reply #12 on: 14/11/2009 21:29:53 »

 

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