Which boils faster, a covered pot of water or an uncovered pot ?
447649
While what everyone is saying is true, if you completely seal the pot the vapor pressure will continually increase and slow or even stop the boiling process (it will make the boiling point significantly higher.)  Actually, if you have an almost full pot in a hermetically sealed container you won't get a boil at all without some seriously massive temps.
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.
897076
Yes.  It also boils at a lower temp.
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.
1052162
On paper that has to be the answer but there is a concept of heat loss when boiling water comes in contact with cold water.\nThe loss is in the nature of steam. \nSteam is at a the temperature of boiling water. \nSo there is a loss of heat. The cold water ends up being less in quantity due to steam loss. \nSo the cold water cannot offset the heat of the boiling water, so the temperture will be higher than that of 50 Degrees.
774236
Water that is evaporating is not the same as water boiling. evaporation is the loss water from the surface that is still water in very small amounts that become suspended in the air. Boiling that occurs at 100c is a state change in the water where the bonds in the water lattice have been broken. The steam then coming in contact with the cooler surrounding air then rapidly cools and forms water droplets on cooler surfaces or in the air and just like fog is a saturation of the air with water and you can see it so you also can see the steam re condensing into water in the air.
253095
Did you try boiling water?
264462
Because steam is hotter than boiling water.
288379
It all depends on your altitude!because at higher altitudes, there is less pressure keeping the water in a liquid state, so it can boil at a lower temperature. For example, you can boil water on top of Mount Everest much quicker than at sea level. The standard boiling point at sea level, however, is around one hundred degrees Celsius.
1183481
Pure water.  The ice will have to melt before it could boil.  Water doesn't go through sublimation
48257
ummm, no, water doesn't always boil at 100C.  It boils at 100c at one atmosphere, water will boil at room temperature in a vacuum.  But, hot water will boil faster, it requires less energy to heat the water, and the less water you have to boil the faster it will reach the boiling point.
508420
in pressure cookers water is heated under  pressure due to witch boiling point of water increases.& it remains in liquid form over 100 degrees also. (over 100 degrees water changes its phase from liquid to gas).\nso the water in pressure cookers can give more heat compared to water in other vessals used for cooking.\n& u can cook faster
1154007
hmmm, interesting, I should imagine it's related in some way to the specific heat capacity of an egg vs that of water, as well as the entropic changes involved with the egg yoke and egg white denaturing....need to think more about this\n\nedit...I don't see the full relevance of this equilibrium argument, it merely describes the time taken for heat to permeate the egg, nothing about itsd heat capacity relative to water. That all the water is the same temp is due to its thermal conductivity. Granted in a practical environment time is a factor, because you would be losing heat to the environment from the system whilst keeping the water boiling. I think we need to lay down some assumptions. What kind of egg are we delaing with and is it to be hard or soft boiled (changes of state)
4765
Boiling is very rapid evaporation starting at the bottom of a container of water.\n\nEvaporation occurs fastest where there is the most heat (energy).  When we heat water to make it boil we heat it from the bottom so the evaporation occurs at the bottom of the pot.  As a result, large  bubbles of water vapor form at the bottom and rise to the surface in the boiling action.  If we applied the same heat to the top surface of the water it would evaporate just as quickly but we would not call it boiling because the bubbles would not form and rise to the surface.\n\nNormally evaporation occurs at a much slower rate than boiling because most evaporation occurs with room temperature water.\n\nEvaporation-is the escape of molecules from the liquid state to the gas or vapor state. In evaporation, molecules of higher-than-average kinetic energy escape from a liquid, leaving it cooler than it was before they escaped.\n\nBoiling-is the temperature at which the vapor pressure of a liquid is equal to the \nexternal pressure above the liquid.  When we give the boiling point of a liquid, we \nneed also to state the pressure.
734492
Heat = mass x specific heat of material x change of temperature.\nSpecific heat of water is 1. So the amount of heat needed to be added is the mass of the water x the amount of change needed to get to boiling. So cold water does not boil faster. \n\nsalt will cause it to take longer. \n\nPeople think that tea tastes betterr if you start with cold water, which holds more oxygen. As you heat the water, the oxygen comes out. This may look like boiling.
209491
On a mountain top the air pressure is a little lower.  If you ever went on top of one you might be one of those unfortunate souls who suffers from altitude sickness, gasping for breath.  Strange how a little less pressure and a little less atmosphere can effect us so much.\n\nAnyway, back to cooking.  At higher elevations water boils at a little lower temp than 100 C.  What this means is that if it boiled say at 80 C you cannot get it any hotter, it is boiling already.  So say you wanted to cook some spaghetti.  If you put your spaghetti in a cold water in a pot overnight, eventually it would get soft enough to eat.  It would be cold, but you could eat it.  On a mountain, cooking takes longer because  it is like cooking on medium heat instead of leaving the burner on high.  Either way it will cook, one will take longer than the other.
683444
Pressure cooking is a method of cooking in a sealed vessel that does not permit air or liquids to escape below a preset pressure. Because water's boiling point increases as the pressure increases, the pressure built up inside the cooker allows the liquid in the pot to rise to a temperature higher than 100 °C (212 °F) before boiling. The higher temperature causes the food to cook faster. Cooking times can be reduced by a factor of three or four. For example, shredded cabbage is cooked in one minute, fresh green beans take about five, small to medium-sized potatoes (up to 200 g) may be ready in five minutes or so and a whole chicken takes no more than twenty-five minutes. It is often used to simulate the effects of long braising or simmering in shorter periods of time.\n\nA safety valve releases steam when the pressure exceeds the safety limit for the cooker; usually the steam pressure lifts a weighted stopper allowing excess pressure to escape. There is usually a backup pressure release mechanism that may employ a number of different techniques to release pressure quickly if primary pressure release mechanism fails. One such method is in the form of a hole in the lid blocked by a plug of low melting-point alloy. If internal temperature (and hence pressure) gets too high, the metal plug will melt, resulting in a release of the pressure.\n\nA pressure cooker is often used by mountain climbers to compensate for the low atmospheric pressure at a very high altitude. Without it, water boils off before reaching 100 °C, leaving the food improperly cooked