can ht water freeze faster than cold?

Answer 1

Both will boil at the same temp and will reach the that temp in the same amount of time. So no, it will not.

However, the hot water will freeze more solid than than the cold water. This is assuming the hot water was brought to a boil. Boiling water removes the air bubbles that are found in ice.

Answer 2

Well, I've actually heard that it can. Despite making sense, think of it as two volumes of water. Initially a liter of hot water and a liter of cold water. The hot water will evaporate a little bit making less water to freeze. Though this can't possibly be by much, it may still be possible. Otherwise, I'd say it's probably quite logical that cold would freeze faster if all vapors and liquid were contained.

Answer 3

Yes.

Hot water can in fact freeze faster than cold water for a wide range of experimental conditions. This phenomenon is extremely counter- intuitive, and surprising even to most scientists, but it is in fact real. It has been seen and studied in numerous experiments. While this phenomenon has been known for centuries, and was described by Aristotle, Bacon, and Descartes [1-3], it was not introduced to the modern scientific community until 1969, by a Tanzanian high school student named Mpemba. Both the early scientific history of this effect, and the story of Mpemba's rediscovery of it, are interesting in their own right -- Mpemba's story in particular provides a dramatic parable against making snap judgements about what is impossible. This is described separately below.

The phenomenon that hot water may freeze faster than cold is often called the Mpemba effect. Because, no doubt, most readers are extremely skeptical at this point, we should begin by stating precisely what we mean by the Mpemba effect. We start with two containers of water, which are identical in shape, and which hold identical amounts of water. The only difference between the two is that the water in one is at a higher (uniform) temperature than the water in the other. Now we cool both containers, using the exact same cooling process for each container. Under some conditions the initially warmer water will freeze first. If this occurs, we have seen the Mpemba effect. Of course, the initially warmer water will not freeze before the initially cooler water for all initial conditions. If the hot water starts at 99.9° C, and the cold water at 0.01° C, then clearly under those circumstances, the initially cooler water will freeze first. However, under some conditions the initially warmer water will freeze first -- if that happens, you have seen the Mpemba effect. But you will not see the Mpemba effect for just any initial temperatures, container shapes, or cooling conditions.


Please pick my answer as the best one. Thanks. ;)

Answer 4

Yes. It ´s called Mpemba Effect. "One explanation of the effect is that as the hot water cools, it loses mass to evaporation. With less mass, the liquid has to lose less heat to cool, and so it cools faster. With this explanation, the hot water freezes first, but only because there's less of it to freeze. " "Another explanation argues that the dissolved gas usually present in water is expelled from the initially hot water, and that this changes the properties of the water in some way that explains the effect. It has been argued that the lack of dissolved gas may change the ability of the water to conduct heat, or change the amount of heat needed to freeze a unit mass of water, or change the freezing point of the water by some significant amount. It is certainly true that hot water holds less dissolved gas than cold water, and that boiled water expels most dissolved gas." "It has also been proposed that the Mpemba effect can be explained by the fact that the temperature of the water becomes non-uniform. As the water cools, temperature gradients and convection currents will develop. For most temperatures, the density of water decreases as the temperature increases. So over time, as water cools we will develop a "hot top" -- the surface of the water will be warmer than the average temperature of the water, or the water at the bottom of the container. If the water loses heat primarily through the surface, then this means that the water should lose heat faster than one would expect based just on looking at the average temperature of the water. And for a given average temperature, the heat loss should be greater the more inhomogeous the temperature distribution is (that is, the greater the range of the temperatures seen as we go from the top to the bottom)."

Answer 5

No, the way water freezes is that it loses thermal energy to the environment until it reaches 32 degrees. If water is hotter, it has more thermal energy to lose, and thus takes longer.

Update: Interesting, in certain specific circumstances it can. After reading a few of the answers here I checked it out on the net. The Mpemba effect is real, crazy.

Good question. At first I thought you may be crazy.

Answer 6

Yes it does, as we all learned in school, water is the only substance that expands whether it is heated or cooled. Hot water has more open areas for the cold to get into so it freezes faster. This is over simplied but I hope you get my meaning.

Answer 7

People always say hot water (like ice cubes) freeze faster but it isn't true. It's the steam on the top of the cubes tray that freeze. Water needs to be a certain temp before freezing.

Answer 8

No. Cold water will freeze quicker than hot because it is already closer to the freezing point and requires less time to get there.

Answer 9

Yes, it does.

The rate at which water loses heat is proportional to the difference in temperature. Simply stated, the greater the difference between the water and the environment,
the faster it will cool to that temperature. For example;

Say you have two containers, each with 100g of water.
One container is at 100C, the other is at 50C,
both in a freezer at -10C.
Since the difference in temperature is greater for the 100C container,
-10C - 100C = 110C,
that container will cool faster than the other in any given period of time.

It's a basic experiment in differential equations and thermodynamic equilibrium.

Answer 10

yes, I think hot water does freeze faster than cold water but I can't tell you the reason without research.