Steve Cargill Posted January 29, 2004 Share Posted January 29, 2004 Just a timely reminder. Don't be tempted to scrape, or even push (unless you are VERY careful) the snow and ice off your car paintwork. The ice is pretty hard and can easily scrape your paintwork If your car looks like mine and seems to attract stone chips and cats claws (bleeding mess they leave, scratches all over the car and fur balls under the spoiler) then it probably doen't matter too much. Quote Link to comment Share on other sites More sharing options...
Timwildman Posted January 29, 2004 Share Posted January 29, 2004 Try telling that to the little sh!ts that were using the top of the supra, as the best supply of sonw in the road last night. (they couldn't reach the roofs of all the people carriers/ 4*4's) Quote Link to comment Share on other sites More sharing options...
blackmax Posted January 29, 2004 Share Posted January 29, 2004 Just what I thought... I went out to my car this morning armed with my FREE BP supplied scraper..... After one... Ssssccchhhhhhrrrrrrrsssshhh across the windsceen I was back in to get a can full of water (tepid of course). Is it right that hot water freezes before cold water..?? Go figure..? Quote Link to comment Share on other sites More sharing options...
Whitesupraboy2 Posted January 29, 2004 Share Posted January 29, 2004 i thought the idea of using cold water, was too not have such a big temperature change as too make ur window glass crack! i may be wrong but im sure i read that somewhere Quote Link to comment Share on other sites More sharing options...
Rob Posted January 29, 2004 Share Posted January 29, 2004 Originally posted by blackmax Just what I thought... I went out to my car this morning armed with my FREE BP supplied scraper..... After one... Ssssccchhhhhhrrrrrrrsssshhh across the windsceen I was back in to get a can full of water (tepid of course). Is it right that hot water freezes before cold water..?? Go figure..? Yes thats true. The water molecules are more agitated and further apart in hot water, this extra space between the molecules allows more "cold" in, and lowers the temp quicker, thus trapping the "cold" in between the molecules. Honest. Never argue with science. Quote Link to comment Share on other sites More sharing options...
Supraguy Posted January 29, 2004 Share Posted January 29, 2004 Erm k.. then when the "hot" water is cooling to a freezing state, wouldnt the molecules slow in contrast to the temperature of the water? Those molecules being so densely packed is what makes liquids turn to solids. So, that hot water needs to cool to that avg temp tap water before freezing, right? I just dont see how hot water can turn solid "freeze" by skipping the temps in between. (making it faster) Those fast moving molecules need to slow down all the same to freeze, no? Im obviously not too busy here at work today. Quote Link to comment Share on other sites More sharing options...
Patrick_Devlin Posted January 29, 2004 Share Posted January 29, 2004 If you rapidly freeze a liquid from hot the crystalline structure will tend to be more coarse than that of a liquid cooled slowly. Not sure if it means that a hot liquid will freeze quicker than a cool one though! The liquid cant skip temperatures, but there may be the case that certain aspects, maybe impurities in the water will cause crystallization to occur quicker. I dont know, it sounds as if I'm talking out of my arse! I've confused myself! Quote Link to comment Share on other sites More sharing options...
Keith C Posted January 29, 2004 Share Posted January 29, 2004 When pouring warm (NOT hot/boiling) water on a windscreen, pour on the metal a couple of inches above the glass - this will then run down the screen clearing it, but also cools the water at the same time, preventing screen damage. Works an absolute treat, and will clear a window in seconds. Quote Link to comment Share on other sites More sharing options...
blackmax Posted January 29, 2004 Share Posted January 29, 2004 hot water freezes before cold water All I can remember is it's called the Mpemba effect... Anyone remember from school the reasons..? Quote Link to comment Share on other sites More sharing options...
Supraguy Posted January 29, 2004 Share Posted January 29, 2004 I have heard of this.. Im just looking for the tech reason why it happens. Given my example of molecules, etc. Quote Link to comment Share on other sites More sharing options...
SimonB Posted January 29, 2004 Share Posted January 29, 2004 Here you go:- New Scientist Quote Link to comment Share on other sites More sharing options...
lpher Posted January 29, 2004 Share Posted January 29, 2004 Ehhmm....you guys are for real? You really pour hot/warm water on the windscreen to get the ice off? At the temperatures were getting here sometimes...that would be like pissing your pants to keep warm! Why not use a tool designed for scraping ice of windshields instead? @lpher Who has an electrical preheater-system in his Supra Quote Link to comment Share on other sites More sharing options...
trooper Posted January 30, 2004 Share Posted January 30, 2004 Symapthies to you @lpher living in Norway in those temperatures. I lived in Sweden for five years and the cold is no fun. Back in England it gets to Zero and everyone panics. In my ignorance, I poured water onto my screen when I first got to Sweden and instead of having a bit of ice I then had LOADS of ice. One lesson learnt. I then scraped with my Halfords scraper, which broke. Went and bought a proper scraper. A friend of mine, equally unused to low temperatures, poured water onto his frozen garage door lock... and then couldn't get in for days. We have it easy here and I'm glad of that. Here's to Blighty Quote Link to comment Share on other sites More sharing options...
pulse Posted January 30, 2004 Share Posted January 30, 2004 Quite simply, hot water freezes faster than cold water (if you need ice blocks quickly, put hot water in your freezer. Just ignore the steam that will then freeze all over the surface of it and make a mess). More important than that, though, is the temperature differential that WILL shatter your windscreen/windows if it goes from cold->hot too fast. Probably not what you want on a cold winter's morning. -p Quote Link to comment Share on other sites More sharing options...
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