Is is faster to make ice from cold water or from hot water?
461815
you do the experiment yourself places a cup of cold and hot water in your freezer, the hot water will freeze first, the\nhotter the water the faster it will freeze
297542
well lets see, if cold water is anything above 0 Centigrade and hot water is anything under boiling....my money is on the hot winning. What I can not understand is why you asked?
166782
The cold water froze about 10 or 15 minutes faster than the hot water, and there was no detectable difference between the boiled water and the other kind. Another old wives' tale thus emphatically bites the dust. Science marches on.
745215
The answer is yes. And I bet you want more of an explanation, which gets a little tricky. It would seem evident that cold water would freeze faster than warm water. But there have been raging debates in scientific circles over whether that's true or false. The fact is a lot of different factors contribute to how fast water freezes, including its beginning temperature.\n    Physicists writing in the journal Scientific American have waded into the fray and have probably come the closest to a satisfactory answer. Quoting Paul G. Hewitt in the book Conceptual Physics, the Scientific American writers believe that hot water will freeze faster than lukewarm water, but not faster than cold water. (Except under certain circumstances.)\n    According to Scientific American, water at 90° C will freeze before water that is 60° C. Below 60° C, however, there is a switch and the cooler water will freeze faster. For example, 30° C water will freeze faster than 60° C water. It has to do with the water evaporation of the hot water immersed in a cold environment. The rate of cooling by evaporation is way higher for hot water than for the cooling of lukewarm water.\n    Now, for those certain circumstances. When you put a pan of cold water and a pan of hot water in a freezer (both pans have equal masses of water), the hot water experiences this rapid evaporation AND freezing from below, which cools water on the bottom of the pan. Because the surface water is already warm or hot, the water at the bottom just sits there instead of rising, getting colder and colder. The water at the top experiences evaporation. The combined effect could make the hot water freeze faster than the cold water.
189354
I discussed this experiment with some of my colleagues and we think that the CO2 (carbon dioxide) causes a stirring effect which distributes the temperature more evenly in the soda. The ice cubes serve as nucleation sites for the bubbles (a place for bubbles to grow). As the bubbles grow and then release they cause the ice cubes to circulate in the liquid. This circulation causes the warmer layer below the ice to mix with the colder upper layer of soda and ice. Have you ever noticed that when you use a straw to drink a liquid that the liquid at at the bottom of the cup is warm and requires a stir to evenly distibute the cooling? The "still" beverages (water and tea have no bubbles) will have a cold layer on top next to the ice and a warmer layer on the bottom. This would cause the ice to melt slower.\n\nHere is an experiment to try. Allow some soda to get flat overnite, then try the experiment again.\n\nKeep in mind that temperature is the average kinetic energy of the particles in a substance, whereas heat is the total energy of all the particles. The air and water may have particles moving the same speeds, but the water has more heat because there are more particles. \n\nPicture it this way. The ice melts as fast moving particles slam into the slow moving ice particles. As in any collision, some of the energy is transferred to the ice particle, and with its new energy it can break out of the crystal and flow as a liquid water molecule. \n\nTo make the ice melt faster, you can use hotter (faster moving) particles to slam into it. This is why the ice melts faster on a hot day than a cold one. Alternatively, you can just use more collisions. The water is much more dense than the air, with many more particles per cubic millimeter. Thus even though the water molecules have the same kinetic energy as the air particles, there are many more of them hitting the ice each second, and the ice melts faster.
656503
It doesn't.  Ice melts more slowly on a colder surface because when ice melts it must draw heat from the surrounding environment, and when there is less heat available it takes longer.\n\n____________\nEdit: as a college science major, I can tell you it simply doesn't work that way.  However, there are a number of factors besides temperature that effect ice melting.  For example, if the piece of ice on the colder block was considerably thinner than the ice on the warmer block the one on the colder block might still melt faster.  In biology, we sometimes melt small amounts of liquid on ice because bad things happen if they get too warm, and two microliters of frozen liquid on ice generally melts faster than ten mililiters in warm (about 98˚F) water.\n\nAnother factor that effects melting point is solutes dissolved in the water before it was frozen.  Salt water freezes at a lower temperature, and consequently melts at a lower temperature, than pure water (that's why the salt the roads in the winter).  If there were a lot of salt dissolved in the piece of ice on the cold block, then depending on the temperatures of the two blocks, the one on the cold block might melt faster.\n\nIt's also possible that one or both pieces of ice weren't water at all.  There are plenty of clear liquids out there that melt at various temperatures.  A compound with a lower freezing point will tend to melt faster, possibly even at a lower temperature.\n\nAnother factor is the starting temperature of the ice.  In one of the biology labs at my school we have a freezer that's at -80˚C, and the normal ones at 4˚C.  If you take a piece of ice out of the -80˚C freezer and one out of the 4˚C freezer, they're both frozen, so they're both ice, but the one at -80 is a lot colder, and is going to take a lot longer to melt, even at a warmer temperature, because it has to warm back up to 0˚C before it can even start to melt.\n\nBut, of course, the obvious explanation is that either your teacher lied to you, or you lost track of which block was which at some point in the demo.
239557
My friend did one that answered the question : "Which melts ice faster: Salt or spices?"\n\nShe experimented with salt and spices like cinnimon, peprika, chili powder, red pepper...\n\nIt was pretty cool. The title we came up with was "Salt or Spice Melts the Ice?" \n\nSalt melted it the fastest.
353832
The answer depends on many variables, including:\n   - How hot is the hot water?\n   - How cold is the cold water?\n   - How cold is the freezing environment?\n   - What is the humidity in the freezing environment?\n   - Are the water containers covered or not?\n\nThere is a famous experiment in which boiling water in an uncovered container exposed to dry, barely-below-freezing air froze before a container of the same amount of room-temperature water in the same conditions.\n\nThis only happened because much of the hot water evaporated in the first few minutes, leaving a much smaller mass of water in the "hot water" container than in the "cold water" container.\n\nIt is not hard to show that a small mass loses heat faster than a large mass. So, ultimately, the "hot water" froze first.\n\nIf you run the same experiment with sealed containers, the cold water freezes faster because it has the same mass and less heat to lose before freezing.
67706
Yes. It takes more time for hot water to freeze - the cooling process takes longer when you start from a higher temperature.\n\nDifferent liquids freeze at different temperatures.\n\nIt depends how cold the place where you're putting the boiling water is, how much boiling water there is, etc.\n\nI think that each liquid has a specific temperature at which it freezes - it may not be associated with thickness.
291269
Cold water has more dissolved gases in it than hot water.  Any dissolved solutes cause the freezing point of water to be lower than pure water with nothing dissolved in it.\n\nThis means if your power goes out in the wintertime and it is about 32 degrees F outside, the water in your hot water pipes is more likely to freeze than the water in your cold water pipes.  This is because the freezing point of the water in your hot water pipes is higher than the freezing point of the water in your cold water pipes.\n\nSpeed isn't being considered here.  The cooling process is assumed to be slow so that the pipes are in thermal equilibrium with surroundings.\n\nAlso check out this link.  It is from the Alaska Science Forum.  They can explain the water pipes problem more correctly than me and they have more personal experience with the phenomenon.\nhttp://www.gi.alaska.edu/ScienceForum/ASF4/440.html
135812
Well for an eight year old....(sounds like an intelligent one to me though)... The reason water freezes slower is because the particles of salt and sugar get in the way of water making a ice crystal.  Salt takes longer because when dissolved it "ionizes" or breaks apart into 2 particles while sugar remains as one.  Salt having two particles it is able to disturb more molecules of water from making ice crystals. I hope that helps! It excites me to here a child of such a young age interested in such things.
868477
water freezes at 32 degrees Fahrenheit, and 0 degrees Celsius\n\nthe colder the faster
680279
Technically a process can require the addition or extraction/removal of heat ENERGY.\n\nI cannot off the top of my head recognize a chem formula any longer, but adding oxygen to any system is oxidation and generates its own heat.  Tehcnically even iron rusting generates heat, just a very small amount, since any metal "rusting" is just it oxidizing.  \n\nAs far as the ice cubes, simply the removal of heat will not cause water molecule to become ice crystals,  I apologize, but I forget why.  I remember an experiment I saw and tried.  In a very clean container, pour distilled water. Now cover that container with another container that does not touch the first.  (Like putting a big bowl over a smaller bowl with the distilled water.  The water stays liquid all the way down to around -20 C.  But if you damage the stablility of the bowl by say gently tapping the side, the water will then turn to a solid.\n\nSnow in clouds form when the water molucle has a dust mote or other item to cling to and begin forming the ice crystal which eventually gets heavy enough to possibly fall all the way to the ground.
209676
Neither can freeze.  Boiling water is 200+ degrees F.  Room temp is roughly 70 degress F.  Now, if you meant does something at room temp freeze faster than something that is at boiling (water), then the answer is, in general, yes.
496282
No.  You would have to heat the cold water up to the temperature that the hot water is at and then go past it to get to the boiling point.  It works in reverse when freezing.  Hot water will not freeze faster than cold, because you have to remove heat just to get to the point the cold water is already at.\n\nThe cool part is you can do this experiment at home.  Put two pans on to boil, one with cold the other with hot, and see which one boils first.  You don't have to take my word for it.
53097
well, ice is solid, water is liquid, and air is gas, and the potential energy increases as the stages change.  in other words, air is the warmest, water next, and ice last.  air being the warmest will warm up the ice faster and therefore melt it quicker.\n\nthe only reason that i can see why it'd be in water is if there's been a sudden change in temperature and the water is still warm but the air is cooler (cold front after a week of mid 60s or 70s weather).
787766
There is no set speed because ice melts from the outside first. A solid block of ice, 1000g, will melt more slowly than 1000g of ice cubes, which will melt slower than 1000g of crushed ice. The more surface area exposed, the faster it melts. Also, it depends on the temperature of the ice. Ice from a -5C freezer will melt faster then ice from a -30C freezer.\n\nYou have asked this question twice. Why don't you carry out an experiment and find it our for yourself, using a kitchen scale, a timer, and a thermometer?