In case you haven’t noticed, it is as cold in Canada (and soon some parts of the USA) as it gets at the South Pole at times:
The video author writes:
Woke up to a balmy -41C (-41.8°F) this morning in South Porcupine, ON. Thought I’d share what happens when you mix boiling water and a water gun and take it outside for a few shots.
Watch:
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Sounds like we all have short memories. A similar polar vortex breakout happened also in January1985 shortly after a very warm spell along the east coast of North America in December 1984. Could the past warm spell in November in Northern Asia be behind our current cold spell [or the current warm high over Northern Pacific?] These events are both similar to SSW[, Sudden Stratospheric Warming ]which have been happening in December / January every other year but have been happening more frequently now .
http://en.wikipedia.org/wiki/Winter_1985_Arctic_outbreak
http://www.thegatesnotes.com/Books/Personal/The-Bet?WT.mc_id=12_13_2013_TheBet
The recent very cold temperatures in North America provide a preview of how a colder climate affects people. More people die.
Excess winter mortality rates increase and the poor suffer the most.
Fortunately in North America we have cheap natural gas due to shale fracking.
In Europe the enviro-extremists have been fighting shale fracking and natural gas is many times more expensive.
OK, to hear from the engineering majors, hot water does indeed freeze faster and it is exactly thermodynamics which causes it. It has to do with the triple point cliffs and the fact that the number of calories associated with a 1 degree temperature drop is much less than the number of calories associated with a phase change, so the fact that more of the hot waters goes to vapor (a phase change) cools the water more rapidly, making it freeze slightly more quickly.
I’ve done the hot water/cold water test with coffee urn water (around 190F) versus tap water. In all cases, the tap water froze first. I used insulated containers to prevent any change in conducting surfaces. However, I did notice that the really hot water lost a decent amount of mass due to evaporation. Should that loss be large enough, say around 1/4 of the original mass, you’d likely get a hot water freezing faster than cold water scenario.
Of course, really hot water has much fewer dissolved gases in it, which I think makes it unlikely to supercool, unlike relatively cold water. I have had fun with supercooled liquids with my kids, having them agitate a container of really cold liquids in the freezer which then formed crystals almost immediately.
So yes, the Mpemba effect is real (of course; it’s demonstrable), but all things being equal- and that’s a challenge in a fluid/gas mixtures at different temperatures- the cold water will freeze faster than the hot water, assuming that you don’t lose sufficient mass from evaporation.
wow, imagine that.. water freezing in freezing temperatures.. WHO’DA THOUGHT!?