Does warm water freeze quicker than cold water.?

Question

If a bucket of warm water was thrown down a path in order to make a slide, would it freeze the slide quicker than if you poured cold water down it?

Answer 1

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.
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.)
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.
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.

Answer 2

"There are several things that help the hot pail freeze faster than the cold pail. Here are what is thought to be the most significant factors: The hot water is more likely to be supercooled. This means that the hot water's temperature is more likely to cool to temperatures below zero degrees Celsius. In the cold non-supercooled water, ice crystals form and float to the top, forming a sheet of ice over the top of the water, creating an insulating layer between the cooler air and the water. This ice sheet also stops evaporation. In the hot water that has become supercooled (thus, no longer hot) the water, when it does freeze, freezes throughout, creating more or less of a slush before freezing solid. Why is hot water more likely to be supercooled? Because hot water is less likely to contain tiny gas bubbles. Gas bubbles form from dissolved gasses as the water cools. When the hot water was heated, these dissolved gasses may have been driven out. In cold water, ice crystals use the tiny bubbles as starting points for formation (in physics, we call them nucleation points). But in the hot water, there are no bubbles, so there aren't as many starting points for the ice crystals." Google your question and you'll be presented with lots of answers.

Answer 3

This has been debated for centuries. There are some technical reasons why, under certain conditions, hot water may actually freeze faster than cold water. But there are so many variables and unknowns, that laboratory experiments have never conclusively proven this to be true.

In general I'd stick with cold water. But if you want to make an already-frozen surface more slippery...possibly hot water would soften any rough surface features and result in a smoother surface once it refreezes.

Either way, it's gonna be hilarious when someone falls.

Answer 4

Under certain conditions, yes. The reason is that warm water
will evaporate faster than cold water. With the same amount of water and a wide surface area for 2 samples of water( a wide
soup bowl for example) and enough of a temperature
differential, the warmer water may be able to evaporate
enough so that if and when it catches up to the temperature of the colder water before each freezes with a quantity difference significant enough for the originally warmer water, being less in amount than the other, it will procede to freeze sooner than the other.

Answer 5

It probably would freeze a bit faster, but the difference would be insignificant. Something about the movement of the atoms being faster in the warmer water.

In your experiment with the slide it may not work because you'll raise the surface temp of the slide.

Answer 6

Hot water can in fact freeze faster than cold water for a wide range of experimental conditions, but I think it depends on the situation.

Answer 7

No. It would cool quickly, but there is no reason as to why warm water would freeze any faster than cold water. I'd expect the opposite to be true.

Answer 8

Yes warm water would freeze faster

Answer 9

If so, as some people like to argue, it would defy all the laws of thermodynamics and various other physical laws. Think about it... in order for water to freeze, heat must be removed. This takes time.... more heat, more time required to remove it. I would love someone to explain to me how this old wive's tale got started. Probably Al Gore.

Answer 10

This is the so-called Mpemba effect, when an African schoolboy found that ice cream formed faster from a hot mix than a cold mix.

Look it up.