Tominator Posted October 2, 2006 Report Share Posted October 2, 2006 Re: O.K. scientists................. You must in a low lying area Don. Ice forms at 32f. No magic, your windshield was at least 32. Quote Link to comment Share on other sites More sharing options...
Master_Chief Posted October 2, 2006 Report Share Posted October 2, 2006 Re: O.K. scientists................. Here's the deal on windchill The only effect windchill has on inanimate objects, such as car radiators and water pipes, is to shorten the amount of time for the object to cool. The inanimate object will not cool below the actual air temperature. For example, if the temperature outside is -5 degrees Fahrenheit and the windchill temperature is -31 degrees Fahrenheit, then your car's radiator will not drop lower than -5 degrees Fahrenheit. Quote Link to comment Share on other sites More sharing options...
Strut10 Posted October 2, 2006 Author Report Share Posted October 2, 2006 Re: O.K. scientists................. [ QUOTE ] Here's the deal on windchill The only effect windchill has on inanimate objects, such as car radiators and water pipes, is to shorten the amount of time for the object to cool. The inanimate object will not cool below the actual air temperature. For example, if the temperature outside is -5 degrees Fahrenheit and the windchill temperature is -31 degrees Fahrenheit, then your car's radiator will not drop lower than -5 degrees Fahrenheit. [/ QUOTE ] Yep. And, Chris..........I am in a low lying area. But my Jeep sits 50 feet from the thermometer's sensory unit. I can see a degree or two difference maybe. But not 5 or 8 degrees difference. Some good thoughts and theories, folks. But I'm not sold on any of them. Quote Link to comment Share on other sites More sharing options...
Tominator Posted October 2, 2006 Report Share Posted October 2, 2006 Re: O.K. scientists................. [ QUOTE ] But my Jeep sits 50 feet from the thermometer's sensory unit. [/ QUOTE ] OK, so what you're telling me is that your thermometer's sensory unit is more accurate than the properties of physics. Sounds like Pennsylvanian schoolin' right there. There's only one way you get the liquid form of H2O into a solid form; lower it to 32 degrees, pure and simple. Quote Link to comment Share on other sites More sharing options...
GWSmith Posted October 2, 2006 Report Share Posted October 2, 2006 Re: O.K. scientists................. Do you know what the Dew Point has been the last couple of nights??? And BTW...previous comments were unscientifically derived from Webcrawler/Wikipedia Quote Link to comment Share on other sites More sharing options...
wtnhunt Posted October 2, 2006 Report Share Posted October 2, 2006 Re: O.K. scientists................. [ QUOTE ] Maybe it was below freezing during the night when it formed, and didn't have enough time to melt before you got in your truck. Either that or your thermometer is reading wrong. [/ QUOTE ] That right there makes perfect sense. Quote Link to comment Share on other sites More sharing options...
Exturkinator Posted October 2, 2006 Report Share Posted October 2, 2006 Re: O.K. scientists................. [ QUOTE ] That was the overnight low. I'm tellin' ya............I have 2 precision thermometers and a regular big old round one with a deer picture on it. They all collaborate........within a 1-2 degree variance (way less for the 2 electronic ones). The thermo's also jive with my ma-in-law's which is approximately 300 yards away. They are right. This is freaky!! [/ QUOTE ] Be sure your thermometers are located well away from the physical structure of the house, otherwise they can pick up heat from the house (or any other object that retains heat) by convection and thereby read higher temperatures than the actual ambient... I'm changing my vote to Professor Plumb in the kitchen with poison.,... Quote Link to comment Share on other sites More sharing options...
Texan_Til_I_Die Posted October 2, 2006 Report Share Posted October 2, 2006 Re: O.K. scientists................. I suspect that there was enough moisture in the air to create some freezing fog up high in the atmosphere where the temps were well below freezing, then it settled down to the ground. Probably too warm for it to stick to most surfaces without melting, but it appears your windshield may have been cold enough to keep it from melting until you witnessed it. Quote Link to comment Share on other sites More sharing options...
10acboy Posted October 2, 2006 Report Share Posted October 2, 2006 Re: O.K. scientists................. did you drive the Jeep yesterday? maybe the trip home cooled the windshield to below 32 and did not warm up fast enough to the outside temp and that is why you had the slush on the windshield this morning. I'm no scientist but that's the only theory that I can come up with. Quote Link to comment Share on other sites More sharing options...
Smitteken Posted October 2, 2006 Report Share Posted October 2, 2006 Re: O.K. scientists................. Actually liquids can freeze at higher temperatures it pressure is increased. Water freezes at 32 F at 1 atmosphere of pressure. So in a high pressure situation it will freeze at a higher temp. Also the specific heat capacity of certain substances such as metal and glass allow them to hold temperatures differently. Quote Link to comment Share on other sites More sharing options...
Bond Posted October 2, 2006 Report Share Posted October 2, 2006 Re: O.K. scientists................. Temperature is the measure of average heat in the air. Some places might be hotter than 38.5 some places, such as your windshield might be colder than 38.5. That's the only thing I can think of. Quote Link to comment Share on other sites More sharing options...
Guest luckyman4 Posted October 2, 2006 Report Share Posted October 2, 2006 Re: O.K. scientists................. Are your thermometers mounted on or near something that could be a heat source, such as your home? Try putting them closer to the jeep. Is there frost anywhere else? If there is no other frost anywhere, except on the jeep, then for some reason the jeep is colder (insert alien theory - its cold in outer space) OR ice is forming on your jeep at colder than 32 degrees. We make water stay water at less than 32 degrees all the time by adding salt to it - maybe there is something on your jeep that mixes with the water to make it form ice above 32 degrees, but I don't know of anything that does that, lol. Quote Link to comment Share on other sites More sharing options...
Guest bucknutt Posted October 2, 2006 Report Share Posted October 2, 2006 Re: O.K. scientists................. ICE?!?!.. i'm still tryin to figure out how to get rid of these dang skeeters! Quote Link to comment Share on other sites More sharing options...
Leo Posted October 3, 2006 Report Share Posted October 3, 2006 Re: O.K. scientists................. [ QUOTE ] Actually liquids can freeze at higher temperatures it pressure is increased. Water freezes at 32 F at 1 atmosphere of pressure. So in a high pressure situation it will freeze at a higher temp. Also the specific heat capacity of certain substances such as metal and glass allow them to hold temperatures differently. [/ QUOTE ] This is the right answer. Quote Link to comment Share on other sites More sharing options...
Smitteken Posted October 3, 2006 Report Share Posted October 3, 2006 Re: O.K. scientists................. [ QUOTE ] [ QUOTE ] Actually liquids can freeze at higher temperatures it pressure is increased. Water freezes at 32 F at 1 atmosphere of pressure. So in a high pressure situation it will freeze at a higher temp. Also the specific heat capacity of certain substances such as metal and glass allow them to hold temperatures differently. [/ QUOTE ] This is the right answer. [/ QUOTE ] Sorry I'm a dork...eh...I mean chemist. Quote Link to comment Share on other sites More sharing options...
Guest HaDeRonDa Posted October 4, 2006 Report Share Posted October 4, 2006 Re: O.K. scientists................. Without gettting too technical because there is no reason to do so. Like it or not your thermometer does not read windshield temperature (glass) Let's not talk about it's quality or calibration. It was 32 F at some time for the ice to form. Hey, I was just thinking. Now you know the thermometer needs to be calibrated or replaced. Quote Link to comment Share on other sites More sharing options...
Strut10 Posted October 4, 2006 Author Report Share Posted October 4, 2006 Re: O.K. scientists................. [ QUOTE ] Without gettting too technical because there is no reason to do so. Like it or not your thermometer does not read windshield temperature (glass) Let's not talk about it's quality or calibration. It was 32 F at some time for the ice to form. Hey, I was just thinking. Now you know the thermometer needs to be calibrated or replaced. [/ QUOTE ] Agreed.....the thermometer reads air temp. Still, there is no way that windshield temp can independently go below air temp. The thermometers are right (within a few 1/10's of a degree). What I have done is relocated one sensory unit to within a few feet of where my Jeep is parked and away from any outside source of residual, stored heat. We're supposed to have some upper 30's coming up in the next few nights. We'll see what happens. Quote Link to comment Share on other sites More sharing options...
Exturkinator Posted October 4, 2006 Report Share Posted October 4, 2006 Re: O.K. scientists................. [ QUOTE ] What I have done is relocated one sensory unit to within a few feet of where my Jeep is parked and away from any outside source of residual, stored heat. We're supposed to have some upper 30's coming up in the next few nights. We'll see what happens. [/ QUOTE ] Oh man I can stand the anticipation.... It is building up inside me like the steam in Old Faithful... (Im serious, not kidding - I love science experiments)... Quote Link to comment Share on other sites More sharing options...
Mach1 Posted October 4, 2006 Report Share Posted October 4, 2006 Re: O.K. scientists................. [ QUOTE ] Actually liquids can freeze at higher temperatures it pressure is increased. Water freezes at 32 F at 1 atmosphere of pressure. So in a high pressure situation it will freeze at a higher temp. Also the specific heat capacity of certain substances such as metal and glass allow them to hold temperatures differently. [/ QUOTE ] You must have taken a Physics class at the wonderful SIUE. This was my first thought when I read the initial post. Quote Link to comment Share on other sites More sharing options...
Strut10 Posted October 4, 2006 Author Report Share Posted October 4, 2006 Re: O.K. scientists................. [ QUOTE ] Oh man I can stand the anticipation.... It is building up inside me like the steam in Old Faithful...... [/ QUOTE ] You really need to talk to someone....... Quote Link to comment Share on other sites More sharing options...
jcwa Posted October 4, 2006 Report Share Posted October 4, 2006 Re: O.K. scientists................. I found this. Question: Is it possible for frost to form when the ambient temperature is above 0° C (32 °F).? If so, please explain how this happens. Answer: Yes and no: It depends on how you define "ambient temperature", and, of course whether the temperature is below the frost point. You see, when temperatures are officially recorded for hourly weather observations and climate reports, they are measured at a height of between 1.25 and 2 metres (4.1 and 6.6 ft) above the ground in special shelters, called Stevenson screens. (The shelter is named after the father of writer and poet Robert Louis Stevenson.) Meteorologists call this temperature the "surface temperature," and it is what is reported on the radio and TV (and internet and newspapers, reports, etc.). The distinction is important for the following reason. During clear and calm nights, the temperature at the ground or some surface near the ground can become much cooler than the "surface temperature". The radiation of heat away from the ground is the cause of this drop. The coldest air, therefore, forms near the ground, and being heavier than the air above it remains there. If we were to make measurements of temperature from the surface to the height of the official "surface temperature" measurement every few centimetres or inches, we would find the air temperature increases as we move upward from the ground. Meteorologists call this a surface temperature inversion. Since cold air is heavy air, in the absence of wind, the coldest air will remain nearest the ground, thus allowing surface temperatures to continue to fall. Thus, under such conditions -- clear and calm nights -- the ground temperature may fall below the freezing point while the temperature measured officially at was still above freezing. This is particularly common in the autumn and winter when nights are long allowing more time for cooling to occur. Now frost is a covering of ice crystals on the surface produced by the depositing of water vapor to a surface cooler than 0° C (32° F). The deposition occurs when the temperature of the surface falls below the frost point. Similarly, dew forms when the air or surface temperature falls below the dew point temperature. (Note that the water vapor goes directly from gas to ice. Therefore, frost is not frozen dew.) Thus, if the temperature on the ground or an object such as a bush or a car windshield near the ground falls below the frost point, frost crystals may form. But the measured "surface temperature" may still be above freezing. This is the most common way in which frost may form when the official surface temperature is still above the freezing point. Quote Link to comment Share on other sites More sharing options...
Strut10 Posted October 4, 2006 Author Report Share Posted October 4, 2006 Re: O.K. scientists................. Nice bit of research. The sensory unit I re-installed yesterday is set to the same elevation as my Jeep's windshield. So, plausible as your info is, it should not factor into my equation now. I'm starting to feel like Exturkinator, now. Maybe I need to talk to somebody................ Quote Link to comment Share on other sites More sharing options...
Griz Posted October 4, 2006 Report Share Posted October 4, 2006 Re: O.K. scientists................. Ice! Wow...I wish we had that. instead I'm still getting a sun tan with temps reaching to 98... Go figure... Quote Link to comment Share on other sites More sharing options...
Exturkinator Posted October 4, 2006 Report Share Posted October 4, 2006 Re: O.K. scientists................. Alright Strut, what's the verdict here - we're dying out here.... we need some edumacations... Quote Link to comment Share on other sites More sharing options...
Strut10 Posted October 4, 2006 Author Report Share Posted October 4, 2006 Re: O.K. scientists................. [ QUOTE ] Alright Strut, what's the verdict here - we're dying out here.... we need some edumacations... [/ QUOTE ] 52 degrees and change for a low last nite. No data to report, sir. Supposed to get into the 30's tomorrow nite and Friday nite, too. Gotta build the suspense. Quote Link to comment Share on other sites More sharing options...
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