Don't believe it
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The freakiest thing I've seen was yesterday morning. I have a tarp on the garage floor to catch the caked snow that falls off the car at night in a pathetic effort to stop the foul black melt from flowing over everything else I have stacked in the garage. In the morning there's a pool of water at the garage door from the melt, and when I open the door it flows outside. I always get a broom and sweep it out of the way into a nearby (2 feet away) drain so I don't get a thicker and thicker ice slab building up. Yesterday, as I swept the water from the garage it almost immediately thickened, went slushy, then granular, and then within half a foot of the drain I was no longer pushing water but rolling a log of cookie-dough consistency frozen slush about 3 inches wide. Time was about 5-10 seconds from running water to the cookie dough event horizon. Back home to Australia in 4 weeks. Can. Not. Wait.
I heard it is 120 degrees Fahrenheit / 49 degrees Celsius in Australia. No comfy in between temperatures.
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I thought it rather sticked together via surface tension - hence why showerheads exist?
Regards, Rob Philpott.
Rob Philpott wrote:
I thought it rather sticked together via surface tension
Not quite. If this was true for any amount of water in the presence of gravity then you could devise a way to overturn a bucketful of water from a tall building and have it fall onto the ground as a single blob. At some critical mass, gravity (and random molecule movement) takes over and then the lower energy state of the fluid as a whole is to split into two (or more) droplets. The "other side of the coin" for the above statement is a leaky faucet. If you have a faucet that's giving a steady supply of water and slowly reduce the supply, at some point the surface tension is such that it's energetically favourable for the water to stop flowing as a "cylinder" and start flowing as a series of spheres (droplets). Actually, even in a showerhead, you can see that although the water comes out as a steady stream from each of the showerhead's holes, it becomes a series of droplets along the way. So, throwing any sizeable amount of water in the air in the presence of Earth's gravity will turn said amount of water into droplets.
Φευ! Εδόμεθα υπό ρηννοσχήμων λύκων! (Alas! We're devoured by lamb-guised wolves!)
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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
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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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
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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I saw a clip on the news last night where in the US, to demonstrate it's getting pretty chilly, they threw some boiling water in the air only to have it fall to earth as snow. Like a scene out of the dismal 'Day after tomorrow'. Really? So it's going to drop 100c in a second and also dissipate it's latent heat to solidify in the space of a second flat in air - a very good heat insulator? I'm having a very hard time accepting this. What says the CodeProject community?
Regards, Rob Philpott.
Actually, it does work. Remember the actual temperature isn't 0c. It is more like -25c It is really really cold. At this temp. Your spit will freeze before it hits the ground. I live here. We did this earlier this week. What is happening is the temp of the water is 100c it is hitting air that is -25c that is 125c wall. It is bursting the water immediately into droplets of steam. Immediate sublimation of the water. It is cool to do.
To err is human to really mess up you need a computer
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I heard it is 120 degrees Fahrenheit / 49 degrees Celsius in Australia. No comfy in between temperatures.
120F? Sounds comfy to me!
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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
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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It probably helped that you weren't suffering from culture
thermalshock 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
True :-)
Regards, Nish
Blog: voidnish.wordpress.com Latest article: C++ 11 features in Visual C++ 2013 Preview
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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.
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
:laugh:
Regards, Nish
Blog: voidnish.wordpress.com Latest article: C++ 11 features in Visual C++ 2013 Preview
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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.
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. :-D
Regards, Nish
Blog: voidnish.wordpress.com Latest article: C++ 11 features in Visual C++ 2013 Preview
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I saw a clip on the news last night where in the US, to demonstrate it's getting pretty chilly, they threw some boiling water in the air only to have it fall to earth as snow. Like a scene out of the dismal 'Day after tomorrow'. Really? So it's going to drop 100c in a second and also dissipate it's latent heat to solidify in the space of a second flat in air - a very good heat insulator? I'm having a very hard time accepting this. What says the CodeProject community?
Regards, Rob Philpott.
Believe it or not, hot water freezes faster than cold water. It sounds totally dumbass, but it's true. This is a well-known phenomenon that has been noted over the centuries by multiple people. Recently, someone came up with a plausible explanation why (see https://medium.com/the-physics-arxiv-blog/d8a2f611e853[^]) And yes, some places in the world (like Alaksa) are cold enough for hot water to freeze before it hits the ground. You can easily din youtube videos of this by obvious amateurs who wouldn't know what Photoshop was if it introduced itself. So it is believable.
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I saw a clip on the news last night where in the US, to demonstrate it's getting pretty chilly, they threw some boiling water in the air only to have it fall to earth as snow. Like a scene out of the dismal 'Day after tomorrow'. Really? So it's going to drop 100c in a second and also dissipate it's latent heat to solidify in the space of a second flat in air - a very good heat insulator? I'm having a very hard time accepting this. What says the CodeProject community?
Regards, Rob Philpott.
Freezes so fast, the ice is still warm. :)
XAlan Burkhart
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I saw a clip on the news last night where in the US, to demonstrate it's getting pretty chilly, they threw some boiling water in the air only to have it fall to earth as snow. Like a scene out of the dismal 'Day after tomorrow'. Really? So it's going to drop 100c in a second and also dissipate it's latent heat to solidify in the space of a second flat in air - a very good heat insulator? I'm having a very hard time accepting this. What says the CodeProject community?
Regards, Rob Philpott.
I did not believe it either but gave it a try Tuesday morning when the temp was 6 degrees. Water won't work (tried it), hot water won't either (tried that). It has to be almost boiling and yes it will in the air turn into a cloud of steam with very little ice/snow hitting the ground. I also took near boiling water and tossed on a concrete slab. Most of it disappeared in the cloud of steam. Very little hit the concrete where it made a splash pattern in ice that steamed away in a few seconds leaving dry concrete. Now I am waiting till summer when I can get some eggs and do some cooking. And folks say there is nothing fun to do in Atlanta, GA !
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I saw a clip on the news last night where in the US, to demonstrate it's getting pretty chilly, they threw some boiling water in the air only to have it fall to earth as snow. Like a scene out of the dismal 'Day after tomorrow'. Really? So it's going to drop 100c in a second and also dissipate it's latent heat to solidify in the space of a second flat in air - a very good heat insulator? I'm having a very hard time accepting this. What says the CodeProject community?
Regards, Rob Philpott.
Though counter intuitive, hot water actually freezes faster than cold water... http://en.wikipedia.org/wiki/Mpemba_effect[^]
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I saw a clip on the news last night where in the US, to demonstrate it's getting pretty chilly, they threw some boiling water in the air only to have it fall to earth as snow. Like a scene out of the dismal 'Day after tomorrow'. Really? So it's going to drop 100c in a second and also dissipate it's latent heat to solidify in the space of a second flat in air - a very good heat insulator? I'm having a very hard time accepting this. What says the CodeProject community?
Regards, Rob Philpott.
Some food for thought: It takes 1 calorie to lower 1 gram of water 1 degree C. But it takes 80 calories to turn 1 gram of 0C water to ice (which is why ice cools liquids so well) Roughly, it is taking more energy to cool the water to freezing, if it is truly boiling. Regardless, air is not a great conductor, but cold air, with a high wind chill, can SIMULTANEOUSLY steal some of the moisture, like it does to chap your lips, and quickly lower the water temperature. Keeping in mind, that man-made snow is made by spraying WATER into the air and having it fall as snow, means this is quite possible at freezing temperatures. At temperatures SIGNIFICANTLY BELOW freezing, I would assume hotter water could certainly be used. Oh, and the wives tail about putting HOT water in the Freezer to make ice cubes faster comes to mind. THE ONLY WAY it could work, is that it forces the thermostat inside the freezer to register a higher temperature, and to kick in MUCH MORE COOLING in the same period of time. This of course, assumes you test this in the same freezer on 2 separate runs. In effect, you are revving the engine of the freezer because of putting hot water in it. (again not boiling water, but the key thing is that 80 calories to freeze is larger than the temperature to cool of hot water, it becomes part of the limiting factor). Admittedly, if both trays were put in at the same time, the cooler water should certainly freeze faster.