# Philo's "Beyond Science" Question for the day.

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• posted on December 30, 2013, 2:46 pm
My car starts reliably to -20F . The temperature outside it -18F but the wind chill factor is -40F. Will my car start?
To all the science-minded people out there , the answer is "NO".
Explanation:
I am NOT going out to start it!

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• posted on December 30, 2013, 3:31 pm

Wind chill does not apply to engines. If ambient is -18 the engine will also be at -18 regardless of whether the wind is 1 mph or 500 mph.

I'll come over and hot-wire it, thus proving you wrong.
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Tegger

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• posted on December 30, 2013, 4:00 pm
On 12/30/2013 09:31 AM, Tegger wrote:

yes, I am sure everyone here knows that, I was just making a joke.

Nope, I've lived in WI most of my life and stuff like cold weather doesn't bother me.

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• posted on December 30, 2013, 4:19 pm
On 12/30/2013 11:00 AM, philo wrote:

On the other hand. The guys in Buffalo Air, in Alaska deal with wind chill. When an air plane lands, how long till the oil is too thick to restart? Wind chill is a serious factor.
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Christopher A. Young

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• posted on December 30, 2013, 4:28 pm
On Mon, 30 Dec 2013 11:19:36 -0500, Stormin Mormon

True. The wind chill does affect how quickly a warmed up engine cools down.

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• posted on December 30, 2013, 6:23 pm
snipped-for-privacy@aol.com wrote in wrote:

The phenomenon you're referring to is NOT "wind chill". The phenomenon you're referring to is simply air movement stripping away or minimizing any boundary layer, thus keeping the temperature gradient steeper than it would be if a boundary layer were allowed to establish and thicken. That's why an engine in the wind will cool faster than one in still air.
But either way, no engine will cool to BELOW AMBIENT, which is what the term "wind chill" implies. The sensation of a below-ambient temperature can only be felt by animate objects that generate their own heat. You, for instance.
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Tegger

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• posted on December 30, 2013, 6:32 pm
wrote:

No, it's *exactly* wind-chill. It's exactly the same process that makes you feel colder when the wind is blowing. Your body is required to make more heat to keep its temperature constant. The "off" engine doesn't generate heat, so gets colder, faster, in the wind.

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• posted on December 30, 2013, 6:59 pm
snipped-for-privacy@attt.bizz wrote in

The term "wind chill" is used to refer to the sensation of air /feeling/ colder than it actually is; it cannot apply to an inanimate object.

Your sentence does not appear to follow from my sentence that you quoted immediately before.
My corpse will be an inanimate object that will not generate its own heat and will thus be unable to feel "wind chill". Until I zombi-fy, of course.
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Tegger

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• posted on December 30, 2013, 7:43 pm
On 12/30/2013 12:59 PM, Tegger wrote:

That's true, but it is also true that a cold wind blowing on a hot object will cool it down faster.

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• posted on December 30, 2013, 8:06 pm

True but irrelevant.
You originally said the ambient temperature was -18 with a wind chill of -40, and implied that the wind chill would have some effect on the engine's ability to start. Wind chill will have NO effect on the engine at all. The engine knows it's -18 and no lower.
http://en.wikipedia.org/wiki/Wind_chill (krw appears to have been right that hastened cooling in wind is in fact also called "wind chill".)
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Tegger

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• posted on December 30, 2013, 8:08 pm
On 12/30/2013 02:06 PM, Tegger wrote:

That's correct, I don't think anyone here thinks anything different

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• posted on December 31, 2013, 12:47 am
On 12/30/2013 3:08 PM, philo wrote:

Now, hold on. I hate to put a wet blanket on this conversation, but Philo and Tegger and myself have said that wind chill doesn't prevent an engine from starting due to temps colder than the ambient. We did say that such engine cools faster than still air. You can't just go around telling people that we agree with each other. It's un-Democratic. What would Jesse and Al say? And Papa Obama? What would happen if EVERYONE agreed? Don't be telling me it's just a couple people. What would happen if EVERYONE agreed!
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Christopher A. Young

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• posted on December 30, 2013, 9:16 pm
wrote:

That depends on how long it's left in the wind. It takes a looong time for an engine to lose residual heat. It'll take much longer to reach that -18 if parked out of the wind. Parking a car in shelter can make a big difference.

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• posted on December 31, 2013, 12:44 am
On 12/30/2013 2:43 PM, philo wrote:

https://en.wikipedia.org/wiki/Wind_chill
The speed of cooling has different effects on inanimate objects and biological organisms. For inanimate objects, the effect of wind chill is to reduce any warmer objects to the ambient temperature more quickly.
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Christopher A. Young

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• posted on December 30, 2013, 10:56 pm
On 12/30/2013 01:59 PM, Tegger wrote:

So how come the wet bulb cools off more than the dry bulb on a sling psychrometer?
Isn't the wet bulb an inanimate object?
http://science-edu.larc.nasa.gov/SCOOL/psychrometer.html

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• posted on December 31, 2013, 5:56 am
On 12/30/2013 4:56 PM, Norman Bates wrote:

Evaportation, of course. I learned this during sixth grade science camp.

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• posted on December 31, 2013, 6:11 am
Irreverent Maximus wrote:

Hi, Well, if I park a car facing cold Northerly wind vs. facing the other way, one facing North is harder to start in the morning. In Chinese wind chill spells like this, "體感溫度" direct translation, "temperature feels like" which is usually lower than actual temperature. I am not Chinese.

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• posted on December 31, 2013, 7:27 am
On 12/31/2013 12:11 AM, Tony Hwang wrote:

Cold wind is colder than ambient, right? Energy only flows in one direction in thermo-dynamics when no extra energy is added. It is possible for a high wind to take away a bit more energy than it provides. However, it is still providing energy, so, the temperature difference will be minute unless the wind is measurably colder.
Works in reverse, too. A real high wind, even if cold, will heat an object. That's one hell of a wind, though. It is rather unlikely to cause that much friction. Though, super sonic craft...
This is in no way a succinct description and is rather piss poor in my opinion. Oh, well. Other things on my mind.

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• posted on December 31, 2013, 2:01 am
wrote:

Utter nonsense. The mechanism is *exactly* the same.

I can't help it if you're illiterate.

No, go back and think about that some more.

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• posted on December 31, 2013, 5:52 am
On 12/30/2013 12:59 PM, Tegger wrote:

Will the warm braiiinnnz change your temperature?