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oh my god, saying "it's too cold to snow" is like saying "I am not the boss of my company" 
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Chris Maunder wrote: If I hear another person say it's too cold to snow I'm going to send them outside, no gloves, no coat, no shoes, and ask them to take a good look around.
That was what Dave C told me on my first day in Canada. That in winter it doesn't snow more when it's at its coldest. Never understood the thinking behind that. 
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It happens because the maximum amount of water vapor air can hold goes down as it gets colder. That's why the heaviest snowfall is when it's only slightly below freezing; and why while states like Tennessee and North Carolina don't get as much total snow as we do in Pennsylvania or Ohio they're prone to occasional massive storms when the freeze line crashes into warm humid gulf air over their heads. OTOH because it blows around the dry powder that falls when it's colder can be more of a PITA because you have to keep shovelling it over and over again than the wet snow that will stay in place once it's down. On the gripping hand because most of Canada gets cold enough that the snow pack never melts off till spring the cumulative impact of lots of small snow storms when it's really cold still turns into really thick layers covering the ground everywhere.
Did you ever see history portrayed as an old man with a wise brow and pulseless heart, waging all things in the balance of reason?
Is not rather the genius of history like an eternal, imploring maiden, full of fire, with a burning heart and flaming soul, humanly warm and humanly beautiful?
--Zachris Topelius
Training a telescope on one’s own belly button will only reveal lint. You like that? You go right on staring at it. I prefer looking at galaxies.
-- Sarah Hoyt
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Thanks, I believe Dave explained something similar to me. It makes sense when you think of it.
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It probably helped that you weren't suffering from culturethermal shock when I repeated it. 
Did you ever see history portrayed as an old man with a wise brow and pulseless heart, waging all things in the balance of reason?
Is not rather the genius of history like an eternal, imploring maiden, full of fire, with a burning heart and flaming soul, humanly warm and humanly beautiful?
--Zachris Topelius
Training a telescope on one’s own belly button will only reveal lint. You like that? You go right on staring at it. I prefer looking at galaxies.
-- Sarah Hoyt
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True
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The flakes are smaller the colder it gets (not as sticky) and when it's been cold for a long time open bodies of water start freezing over so there's less fuel. And yeah, the absolute humidity is lower hence less water per cubic meter of air, but given a water supply it'll snow, especially if the wind is blowing. Lower water density, but more volume of air per second means lots of water still available to make your day a mess.
And this is e same Dave who wandered around downtown with me when it was -5C in a tshirt. I almost turned around and got back on the plane then and there.
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Chris Maunder wrote: And this is e same Dave who wandered around downtown with me when it was -5C in a tshirt. I almost turned around and got back on the plane then and there.
You sound like the wimps who thought I was out of my mind not wearing a coat on Tuesday; on your first day off the plane I'd've done the exact same thing except I'd also be wearing shorts (assuming I wasn't on my way too/from the office anyway). -5C is around the middle of my preferred temperature for shoveling snow; warm enough I can still get away with just a tshirt and denim shorts for a few hours, cool enough I don't need to worry about overheating because I'm working too hard. (The latter is bad because the amount of my shirt that gets soaked in sweat ends up too large and then turns into a giant heat sucker as it tries to evaporate and freeze at the same time.)
Did you ever see history portrayed as an old man with a wise brow and pulseless heart, waging all things in the balance of reason?
Is not rather the genius of history like an eternal, imploring maiden, full of fire, with a burning heart and flaming soul, humanly warm and humanly beautiful?
--Zachris Topelius
Training a telescope on one’s own belly button will only reveal lint. You like that? You go right on staring at it. I prefer looking at galaxies.
-- Sarah Hoyt
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Dan Neely wrote: I can still get away with just a tshirt and denim shorts for a few hours
One can never get away with denim shorts unless one is Jessica Simpson in the Dukes of Hazzard movie.
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Yeah - been doing a fair bit of shoveling / ice cracking at -10 in a T-shirt these past few weeks.
The only exercise I can get these days.
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Chris Maunder wrote: Yeah - been doing a fair bit of shoveling / ice cracking at -10 in a T-shirt these past few weeks.
Was about to ask why you don't get a snow blower.
Chris Maunder wrote: The only exercise I can get these days.
That answered it. 
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Chris Maunder wrote: And this is e same Dave who wandered around downtown with me when it was -5C in a tshirt. I almost turned around and got back on the plane then and there
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The convection currents in the warm water help in the rapid heat exchange which is why warm water is used.
(I don't have a citation other than a colleague who showed me the explanation online yesterday)
“That which can be asserted without evidence, can be dismissed without evidence.”
― Christopher Hitchens
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Ah! An interesting new angle...
Regards,
Rob Philpott.
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Not quite - boiled water has dissolved gasses removed, and will freeze faster.
When you heat water on a stove to boiling point, you will see bubbles form for some time before the water reaches the boiling point. This is dissolved gases coming out of solution, and if you capture the bubbles, you will see that their content is not H2O. Once the water reaches boiling point ("rolling boil"), then the water is changing phase and the content of gas emitted is water vapor (H2O).
Water (even boiling water) that has the dissolved gases removed will freeze faster than warm or even cold water.
Never moon a werewolf.
- Harvey
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Thanks - (in danger of being a complete pain in the arse) has this theory been peer reviewed scientifically?
I ask this as having just done a quickish google there do appear to be a few theories none of which have been conclusively proven correct.
e.g. Mpemba theory[^]
“That which can be asserted without evidence, can be dismissed without evidence.”
― Christopher Hitchens
modified 8-Jan-14 9:45am.
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When taking engineering courses it was explained by the fact the hot water is losing energy already where as cold water has to start losing heat(energy). Poor man's explanation after 30 plus years of forgetting. At the time we calculated the "proof".
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That is saying that energy loss has momentum. I don't think that is true, and it should be relatively easy to prove in a lab. [Haven't done it myself...]
Never moon a werewolf.
- Harvey
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As I say I do not remember exactly what the science was but I remember doing the calculations.
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Not saying that energy loss has momentum, but technically, fluid temperature is very closely related to the average momentum of the water molecules - if I recall correctly, temperature (being a measure of internal water energy) is proportional to the average kinetic energy of the water molecules (or something along those lines), which in turn is proportional to the average of the square of the molecules' momentum.
So I would say that heated water, having a higher average molecular kinetic energy, exchanges higher amounts of energy with its environment, therefore in turn loses more energy to it (and cools faster).
Then again, I may be wrong in that. I seem to have forgotten most of the thermodynamics I've been taught.
Φευ! Εδόμεθα υπό ρηννοσχήμων λύκων!
(Alas! We're devoured by lamb-guised wolves!)
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H.Brydon wrote: Not quite
"the Mpemba effect" 
Bastard Programmer from Hell 
If you can't read my code, try converting it here[^]
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Was gonna post this, but I was beaten to it. Good link. 
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it is actually so that hot water freezes more quickly than cold water, although it is not yet known why.
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