why does it heat faster than cold?
914272
what is the question???? II
432623
It depends on the temperature of the water and the air but if they are the same, then the ice in the water will melt faster because water is a better conductor for heat.
163247
The faster they move, the warmer the liquid gets. Then they make the liquid evaporate because they mix with the molecules of the air.
180504
Heat is actually a microscale form of kinetic energy. The molecules of a hot object are in rapid motion; the hotter, the higher the average speed. If the object is gaseous the motion consists of free-path travel and collisions with other molecules. If it is liquid the paths between collisions are shorter, and if solid the motion is vibrational with no secular movement. \nIn conduction, heat is transferred by collisions between molecule populations with different average speeds. The transfer continues until both populations have the same average speed. \nIn convection, heat is transferred by mixing fluids of differing temperature. The mixing can be forced or driven by density differences caused by temperature difference. It is not necessary that molecular collisions occur in convection, since mixing alone changes the average molecular speeds.\nIn radiation, the molecular motion is converted to microwave or infrared energy by rigid motion of molecules or flexing of molecular bonds (ref.). Shorter wavelengths (light, UV, X-rays, gamma rays) are produced at higher temperatures where atomic electrons and nuclei may become involved. Radiative energy is not considered heat, but is converted to heat by absorption.
414204
hot molecules contain greater potential energy and as this converts to ke at a faster rate they can move around a lot faster
819186
In very simple terms, nature does not like imbalance.  Heat is a quantity of energy.  So the hot thing has more energy than the cold thing.  The imbalance is got rid of by the hot thing giving up energy, and the cold thing absorbing it.
360729
It doesn't.  The t(exp 4)(temperature difference to the 4th power) law works here.  The higher temperature water will cool faster than the cooler water, however, when it reaches the temperature that the cooler water was in in the first place, it will cool at the same rate the cooler water cooled with.
17452
Hot air is less dense than cold air, assuming that volume is held constant, because the molecules in the heated air move more and faster than in cold air.  Think about a room filled with people.  If the people move around quickly (as molecules in heated air), then the people will spread out more and make more room between eachother (which would be lower density).  Since the hot air is less dense, and more dense objects are "more affected" by gravity, then the warm air is "lighter".
456301
Air is more dense when cold.
481035
its the other way round. a thing is hot if its molecules are moving with a higher thermal velocity (prop to T^1/2). if you heat something its molecular vibrations go up in turn increasing its temperature.
731331
I've heard that its the boiling water that freezes first. \n\nI think because the water molecules are hot (i.e. they are moving fast) the energy (or heat) will escape (move to equilibrium with other items in the freezer) at a faster rate than the water molecules in colder cup of water. \n\nBut really I'm mostly guessing with my explanation.
241754
Thermal intertia.  It works the other way too, cold water boils quicker than hot water.  The reason is when hot water is placed into the ice cube tray it immediately begins cooling.  Then when you put it into the freezer it continues to accelerate more and more quickly to the low temp desired.  Cold water would begin warming as soon as it gets put into the tray and then you have to cool it back down (opposite direction heating takes more energy)
1017824
Hot water will drop in temperature at a faster rate, but the cold water will freeze first except under certain circumstances in a phenomenon known as the Mpemba Effect\n\nhttp://math.ucr.edu/home/baez/physics/General/hot_water.html\nfor more details on the phenomenon
62870
Cold Water. - Most of the time. \nI have tried and tested this before (Tap Water). The hot water normaly takes about 10 minutes longer. When using Tempratures like 30 degrees and 70 degrees this will begin to vary and warm water might start freezing faster than cold water. \n\nWarm water can in fact sometimes freeze faster than Cold water but it very much depends on the conditions.\n\nWhat you are thinking of is the Mpemba effect. This could be due to a number of factors including but not limited to Evaporation (less water needed to be freezed), Dissolved Gasses and Convection.\n\nFor a lengthy but thorough explanation see the link below.\n(Very reliable references) \nhttp://math.ucr.edu/home/baez/physics/General/hot_water.html
714524
Well,  Hot & Cold are not only subjective (What's Hot for he is cold for me) and relative.  Better to think of temperature.\n\nTemperature is the measure of average kinetic energy.  The hotter, the more energy and vice versa.  \n\nAlso, as temperature is an average, some of the "hot" water may be cold.  In fact, there could be a several molecules that are frozen - we'd never know - but the average temperature is "hot."\n\nWhen you mix them heat is transfered from the high average kinetic energy water, "Hot," to the low average kinetic energy water, "Cold."  The "Cold" water absorbs the heat in the transfer and the results is as follows...\n\nThe "Hot" water is cooled, and the "Cold" water is warmed.  The results is 24 oz's of water that has an average kinetic energy, or temperature, higher than that of the "Cold" water, and lower than that of the "Hot."
741531
some cold, some hotter
739180
Warm water is absorbed easier into the body.  Cold water takes longer to absorb, therefore burning more calories.