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

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On 12/30/2013 1:23 PM, Tegger 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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Evaporative cooling?
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plausible, and wrong." (H L Mencken)
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For what it's worth, right now as I type this at 7:24 PM Central Standard Time, Winnipeg is at -36 degrees Celsius (or about -33 F), and with the wind it feels like -51 deg. C. (or -60 F). We're hoping for milder temperatures toward the end of this week.
One thing more people should know, but don't, is that you can significantly improve your car's starting in cold weather by switching to synthetic motor oil for the winter.
Waxes that occur naturally in crude oil find their way through the refinery and into your motor oil. These waxes thicken up at colder temperatures, causing the oil to become much more viscous. Synthetic motor oils have very much less wax in them than conventional oils, and so they don't increase in viscosity as much with colder temperatures. So, by using a synthetic motor oil in your car during the winter, you'll improve starting because the oil will be thinner and allow faster cranking of the engine.
There was an oil change company that had a "Start and Go or We Pay the Tow" promotion on last winter. The idea was that you had them put Quaker State synthetic motor oil in your car, and if your car wouldn't start just because of the cold weather, they would pay to tow your car to the nearest garage. The catch was that they would only pay for one tow. If your car wouldn't start a second time, you needed to have a second oil change. Otherwise they wouldn't pay anything.
Still, using synthetic oil in the winter is a good idea to minimize hard starting problems; especially if you live or work in an area where you can't plug your car's block heater in. When I have an empty apartment, but no available parking spot, I tell prospective tenants about changing their oil to a synthetic over the winter months, but most of them are reluctant to rent an apartment without a parking spot and plug-in because they don't know how much difference the synthetic oil will make. I've tried it on my own car, and I'm convinced it does make a significant difference.
http://tinyurl.com/orthcrc
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On Tue, 31 Dec 2013 02:36:51 +0100, nestork

It's 9:38PM EST now. It's 44F (7C) with a 7MPH wind from the NNW. You can have that Winter crap! I had enough of it.

So are we. 60F would be nice. ;-)
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On 12/30/2013 7:36 PM, nestork wrote:

Re-filtering the oil also means that you will not have to purchase more of the same. Save some money while you are at it.
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<...snipped...>

<...snipped...>

I have over 31 years in fleet vehicle maintenance and about 8 years working on constructiofn equipment before that. You can do your own research and make your own decisions, but I would have serious reservations about switching back and forth between synthetic and regular engine oil, especially on engines that have accumulated a lot of miles. YMMV of course. the slightly easier starting provided by the lower cold viscosity of synthetic oils is nothing compared to the improvement made by the adoption of gear reduction starters by automotive manufacturers over the last decade or 2.
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'Larry W[_3_ Wrote:

Why would you have reservations about switching back and forth between synthetic and conventional motor oils?
And, why would the mileage on the car's engine have any effect on how the engine responds to that switching back and forth.
No, I don't have 30+ years of experience, but so far my car's engine doesn't seem to have responded negatively in any way to my doing that, and I've been doing it for years.
But, on the other side of the coin, I don't want to cause unnecessary damage to my car's engine either. What, if any, effect should I be looking for that indicates that I'm damaging my engine by switching to synthetic motor oil every winter?
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On Tuesday, December 31, 2013 11:57:45 PM UTC-5, nestork wrote:

I think today the consensus is that you can switch back and forth. ABout 35 years or so ago, when synthetic first started to move into the auto market, there was concern about the response of various seals to the differences in the oils. That an engine that had been run on conventional oil might develop seal leaks with synthetic. Whether that was true or not, IDK.
But IDK why you would switch back and forth based on season to begin with. For one thing, you'd have to do a lot of driving to run up miles in just winter on synthetic to require an oil change in spring. And the last few cars I've had all spec'd synthetic as required, or at least as the preferred year round oil. Given that synthetic performs better, lasts longer and costs about the same given the increased change intervals, the only reason I can see for using regular oil today in any modern car would be if it's burning oil so that more than normal topping off is needed.
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No direct serious damage but many sources say that this practice can lead to leaking seals. I've also heard stories of engines that after a long time running conventional oil, were switched to synthetic and then developed internal lubrication system blockages; the synthetic oil allegedly loosened a glop of sludge that had been harmlessly congealed somewhere in the engine but, freed by the synthetic oil's more agressive cleaning properties, broke loose and got lodged in a lube passage. You can take these stories with a grain of salt. Personally, the cost factor alone is enough to keep me from switching to synthetic oil for any vehicle that I personally drive. FYI my 96 Jeep Cherokee with 4.0 L six has 243,000 miles, burns no oil between oil changes, and the oil still looks fairly clean when I change it every 5000 miles. My old 78 Chevy pickup with 350 V8 reached over 320,000 with irregular oil changes, sometimes more than 6000 between them for sure, though it was not in as good shape as the jeep engine at comparable mileages. Even so I got rid of that truck because of rust and body problems; the engine was still running fine.
Now these are both old-school cast iron designis and pretty rugged. Some newer, high-revving engines may well spec synthetic oil or perform better with synthetic, but I would not switch back and forth between synthetic and conventional oil in any case.
It's probably worth noting that most of the syn oil manufacturers, unsurprisingly, say that their oil and conventional oils can be switched or mixed indiscriminately without any problems. However if you read a lot of car service forums or search on this subject you will see many reports of problems, admittedly mostly anectodtal, but a few with some logic and facts behind them. Your call. As I said, personally the cost alone is a deterrent enough for me.
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Larry W. - Baltimore Maryland - lwasserm(a)sdf. lonestar. org
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On 12/31/2013 10:57 PM, nestork wrote:

Here is some info:
During the entirety of my 38 year work career I was provided with a company car or van. I always got the oil changed right on schedule and used ONLY conventional oil.
Most of the cars were replaced between 80,000 and 130,000 miles and had no signs of engine wear.
The very last one had about 150,000 miles on it and was just starting to use a little oil between changes. I can assure you I used the van hard and it was loaded with tools and parts.
My conclusion is that conventional oil does a good job if changed per the vehicle manufacturer's spec. Though you very well might get even more engine life with synthetic oil...by the time a vehicle has 150,000 on it there are many other things that need attention and at that point major repairs are not going to be worth it.
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On 12/30/2013 7:11 PM, Larry W wrote:

I worked on some cooling towers for one of the 4,000 ton chilled water units in a chilled water plant at a hospital complex and the fan blades were the size of the props on a C-130 cargo plane. ^_^
TDD
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On 12/30/2013 12:23 PM, Tegger wrote:

Spray water on the inanimate warm object and then wind chill may become a factor. The way I understand wind chill is that sweat evaporating off a living thing will cause it to loose heat much faster than if there is no movement of air. The thing about nonliving things is that those things don't "feel" the cold unless it's Mr.Data or other sentient android possessing artificial nerve endings and artificial sweat glands. ^_^
TDD
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On Tuesday, December 31, 2013 11:37:42 AM UTC-5, The Daring Dufas wrote:

Wind chill doesn't imply anything cooling below ambient.
The sensation of a below-ambient

But inanimate objects can be effected by it as well. Put a bottle of water that at room temp outside when it's 20F. It's going to freeze faster with a lower wind chill number.
>

Yes, that can result in it goind below ambient. But you don't have to spray it on. Many inanimate objects can have water evaporation without spraying additional water on.
The way I understand wind chill is that sweat evaporating off

Most people aren't sweating when it 20F outside, but evaporation increases the effect. The US model for wind chill doesn't include evaporation, only temperature and windspeed.
The thing about nonliving things is that those

That's true, but they can still be effected by it, even though they don't feel it.
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On 12/31/2013 11:50 AM, snipped-for-privacy@optonline.net wrote:

No, not by definition. Wind will carry heat odd the engine faster, but the wind chill (feels like) factor the weatherman gives is only for humans that have feelings, not inanimate objects with no nerve endings. It is the evaporative effect that makes you feel xolder than the temperature indicated on the thermometer.

Yes, that is why they give those numbers on the weather reports. They are always below ambient.

Huh? Of course you are sweating. It you stop sweating you will die. It is a matter of degree. They even make special underware to wick away the moisture under you winter clothing.

But what you are talking about is heat transfer and laws of physics, especially convection. The weatherman wind chill factor is only applied to humans and how they feel from the moving air across the skin.
Looks like we are talking about different things.
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The "wind chill" reported by weather services does include evaporation but it also includes the cooling effects of moving air. You don't think the fan in your computer is in there to make noise, do you?
Nerve endings aren't required.

Nope. It's usually below ambient but the numbers they're quoting now also include the moisture evaporation you mentioned above. These numbers include the effects of humidity, which can and often do make it "warmer" than ambient. Evaporation works both ways.

There is exceedingly little sweat on uncovered skin in winter, unless you're really working out.

The numbers are based on how fast human skin will freeze (frostbite). It does include a small loss to evaporation but also includes the direct loss due to the wind.

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On 12/31/2013 6:25 PM, snipped-for-privacy@attt.bizz wrote:

When they use the term "wind chill" it is below ambient. You are correct though, that they factor in humidity but usually call it "real feel" temperature as there is no chill..
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So was I. I'm not actually going to come over and hot-wire your car.
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On 12/30/2013 12:24 PM, Tegger wrote:

I know...in this weather you'd have to cold wire it.
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Good point.
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On Monday, December 30, 2013 10:31:21 AM UTC-5, Tegger wrote:

If the wind is 500 mph, the engine would be warmer than -18 degrees due to the heat caused by air friction.
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