Blame global warming. Yeah, that's it. Global warming.
Physics time!
- Thread starter BigPoppa
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Would that not be global cooling?
Nope, it's gotta be global warming. Ask Rachel mad cow.
We have a weiner!
Got to dock some Google search points, but you are correct. Kudos for taking the time to look it up.
On a clear night with ambient close to, but not quite at, freezing temperature, moisture can form ice if it loses enough energy through radiation faster than heat is absorbed by the moisture.
'Coulda swore it was magic.
Bonus question for you: in ancient times, one society knew how to use this effect to make ice cream in the desert. What society, and how did they do it?
Oh geez, my brain.
Okay, that is still a pretty scientific answer. Can you break it down further for us common folk? It's a clear night and it's a little above freezing. There is moisture in the air like normal. Radiation from the... moon... sun... does something and we suddenly have ice.
Further research:
All objects constantly emit radiation, usually in the infrared spectrum. Most objects are therefore bathed in infrared radiation from their surroundings, and the net rate of heat loss by radiation roughly equals the rate at which radiation is absorbed.
During the daytime, the sky is filled with scattered sunlight (mainly in the blue spectrum) and so a car parked outside receives radiant energy from above. However, when parked in the open on a clear night, there is nothing between the car and outer space, which is close to absolute zero temperature, so the car receives negligible radiation from space. However, it is still radiating its own energy and so its temperature starts to drop.
Windscreens are relatively thin and have little heat energy stored in them. Glass is also a poor conductor, so it is hard for residual heat to flow into it from elsewhere in the body of the car. If the rate of heat flow into the glass by convection from the surrounding air is less than the rate at which it loses energy by radiation, then its temperature can drop until it is below freezing, even if the air temperature is above zero.
Touch of frost
Damnit. I never took Physics or Engineering in college. I only took the math. I should have taken both.
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Google search:
The ancient Persians used this phenomenon to freeze water overnight in the desert by pouring it into shallow trays in deep, well insulated holes exposed to the night sky above. The ice was then stored in special insulated and evaporatively cooled buildings called yakhchals to be served to the nobility on request.
It is believed that Arabs who had conquered Persian Empire at the time took the age-old Persian refreshment called Sharbat and enriched the existing mix of fruit syrup and snow chilled honey with milk and sugar.
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Black body sky...
"Latent Heat Of Crystallization"..........it takes a little energy BOOST to kick water from liquid to solid!!
chrome-extension://oemmndcbldboiebfnladdacbdfmadadm/http://folk.uio.no/tomvs/minerals/geo4910/Crystallization.pdf
chrome-extension://oemmndcbldboiebfnladdacbdfmadadm/http://folk.uio.no/tomvs/minerals/geo4910/Crystallization.pdf
"Latent Heat Of Crystallization"..........it takes a little energy BOOST to kick water from liquid to solid!!
Or is that backwards? From your article:
"But for the liquid to crystallize, the liquid has to get rid of the energy difference between the liquid and solid states of matter". So subtract energy, not boost it?
I think I'm more comfortable with the 'magic' or 'goddam witch craft' answers.
Exactly, but I just want to peak their interest, not scare them off by going into that depth of the detail.
Dude, what i don't get is you can say "Black-body sky," and "latent heat," and NOT instantly draw a crowd. In both cases the universe is practically shouting at you to pay attention to something important. It is literally like God is saying, "Hey, kid! Here's the keys to the universe! Taker her for a spin. Go on, really wring it out and see what she'll do!" and yet ... most folk's eyes just glaze over and they wonder how they can check their social media without appearing overly rude.
Just turn the defrost on, and see how "physics" affects the frost on your windshield.
Then go grab milk and tampons like she asked you to do an hour ago.
Then go grab milk and tampons like she asked you to do an hour ago.
Hot water freezes quicker than cool water in a freezer meaning it takes some energy to convert from liquid to solid......."BOOST" was a poor choice of words though!!
Mind blowing! I had heard that over the years but never really thought much about it. Now, looking it up its amazing that scientists still don't definitively understand why. The Mpemba Effect. Cool and unusual.
So, a real world application. It's been very cold around here as of late. Because of this Effect a warm naked person straying outside would freeze to death sooner than an already cooled naked corpse. That is good to know and should be a warning to everyone not to wander about naked when it's freezing outside.
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