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This phenomenon has been observed, but not in all circumstances. The "MPEMBA EFFECT" was originally published to consider possible causes. (see link}
What Actually Happens There are several things that can 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. Dissolved gasses also lower the freezing point. Since heated gas is less likely to contain dissolved gasses, it's more likely to freeze first. Water in the hot water pail evaporates at a much faster rate than the cold water. This does two things. First, the process of evaporation is endothermic, which means it takes energy for something to evaporate. As a molecule of water evaporates, it leaves the surface of the water and flies into the atmosphere. Thus, in simplified terms, the molecule converted heat energy into kinetic energy (energy of motion). Since the hot water evaporates quicker than the cold water, it loses heat energy quicker than the cold energy. Second, since some of the hot water evaporates away, there is less water left to have to freeze. The hot water pail will melt the surrounding snow. Later, as it begins to freeze, the snow around the pail will freeze back so that it more closely "touches" the pail. The cold water pail is then only sitting in fluffy airy snow, while the hot water pail is in a form fitting ice-crust. The ice-crust will obviously conduct the cold better that the airy snow. Other factors, such as convection currents (the movement made as hot water rises while cool water sinks) may or may not play a role in this odd phenomenon.
What else can I help you with?
Why does an ice cube melt faster in water than air?
One is the temperature of the water could be warmerSecondly when an ice cube is in water, conduction takes place. The kinetic energy of the water particles more time.moves to the ice causing it to melt. When in air radiation or convection must take place which will take
Would a sugar cube melt fast in a cold cup of water?
No, it wouldn't. a sugar cube would melt a lot faster in a cup of Hot water. the hot water helps it desolve more evenly than cold water.
Which warms up faster sand or water?
sand heats faster because it absorbs heat faster than water!!!!!!
Does a sphere shaped ice cube melt faster than a regular shaped ice cube?
A cylinder shaped ice cube will melt faster because it has a greater surface area than the rectangle-shaped ice cube has. Cubes of ice with less surface area will melt slower. Ice that has very low surface area has more ice concealed inside than it does on the outside. Therefore, ice cubes that have more surface area will melt faster... I hope this will help you.. :) ..
Does ice melt faster in air or water?
Been answered already.For the same temperaure, the ice will melt faster in the medium that extracts most heat from it.Now, compare the heat conductivity of water and air - you've got your answer!Water, because the heat is carried away up to 4x faster because water molecules are more tighly packed than air. === === There are many variables to this question. What is the temperature of the water? What is the temp of the air? Is either one moving or flowing? Is the air below freezing? An ice cube melts because the ambient layer of air or water around it is changed rapidly. Styrofoam cups and coolers are designed to slow this down. If you take ice that has a fan blowing on it, it will melt faster because the air removes this layer surrounding it and replaces it with a warmer layer.well, technically ice is water, so if the water is liquid, it would melt faster there, however if the air is warm that will melt it quickly too.AnswerThe ice cube in cup that is by itself will melt slower. Ice water will have less kinetic energy, so ice cube in ice water will melt faster. Compared to the cup, the temperature surrounding the cup is much higher than ice water and so kinetic energy will be higher. Thus, causing the ice to melt faster in cup. Thie answer bears on the temperature in the ambient air. If it is -50 C in the room the ice in the cup will not melt. It will, however, evaporate eventually. I guess the ice cube in the ice water would freeze, too, so in that case it's moot. HmmmWater will have more contact with the ice cube and absorbs heat better and hence, will be able to transport or transfer its heat to the cooler ice cube quicker. Initially, both air and water contact surfaces are equal in size. However, just as soon as melting of ice begins, the meltwater " skin " produced reduces the contact surface area of the surrounding warmer air, insulating slightly and absorbing some of the heat itself. As the meltwater flows down and off the ice cube, it is carrying some of that absorbed heat away from the ice, slowing down the overall melting process in air. Interestingly, ice cubes floating in water, will have both air and water contact surfaces. If you could study a side view of the melting ice cube, you would see that the portion below the water surface melts faster ( becomes smaller in size). To compensate for this loss of below-surface mass of the ice cube, it sinks slightly. It appears the air is winning the race but this is not true. The faster heat transfer of the water medium is actually pulling the cube down. This would be clearly demonstrated if you set the cube up (with an onion bag supporting net ) such that it was supported from dropping down lower and lower into the water as it melted. Then you would see the below surface portion virtually disappear. As this happens the top-heavy portion will want to turn turtle to compensate for the disappearing bottom half of the cube.it melts faster in water because I tried it before the person who said that should put more notes down....
Does water boil faster than salt water why?
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Why does antifreeze boil faster than water?
It does NOT boil faster than water. It has higher boiling point AND lower freezing point. - Antifreeze boils at about 197 c.
Will water boil faster if there is less of it?
A small amount of water will reach it's boiling point sooner than a large amount of water. It will not boil faster.
Does lemon water boil faster than salt water?
yes
Why does sparkling water boil faster than water?
there are already bubbles in it
Does salt water boil faster than water with pepper?
No, salt water does not boil faster than water with pepper. Adding salt or pepper to water may change its boiling point slightly, but the difference is not significant enough to affect the time it takes to boil.
Does lake water boil faster than tap water with salt?
possibly...
If the ice cube is in water will it melt faster than an ice cube by itself in a cup?
Yes; because the rushing water will use (erosion) to wear it away faster than the temperature surrounding the ice cube in the air will
Will salt water boil faster than vinegar or sugar?
yes
Does cold water boil faster than hot water?
No, hot water boils faster than cold water because it is already closer to the boiling point.
Will coke or water boil faster?
Coke will boil faster than Gatorade will because Coke has a lower boiling point. This means it will break down faster than Gatorade.
Which cube melts faster a frozen juice cube or a frozen water cube?
A frozen juice cube will likely melt faster than a frozen water cube due to the sugar content in the juice, which lowers its freezing point. The presence of sugar allows the juice cube to start melting at a lower temperature compared to a plain water cube.
