Does water boil quicker below sea level or at high altitude or the same at both?
601632
Water boiling has to do with air pressure.\n\nThe higher your elevation, the less pressure exerted on the water, so it can boil at a lower temperature.\n\nThe closer to sea level you get, the more air pressure there is, so it requires more energy to boil.  (Going lower then sea level will still increase the boiling temperature).\n\nIt's also important to note, that when water is boiling, it keeps a constant temperature.  So if you look at this graph of time vs average temperature....\n\n|.........../..\n|........../..\n|....------.... <---  Boiling Temperature\n|../...........\n|./............\n\nYou see that when the boiling occurs, the temperature does not increase.  Only when all the water is evaporated does the temperature increase.  This ALSO works for ice in water.  The water will remain at 0 degrees celcius till all the ice is melted.\n\nHope this helps you understand melting/boiling points.
383320
the idea isn't that water can't heat up when it boils at low pressure, but that it doesn't have to. no matter what temperature something is, its molecules are moving somewhat, and some of them escape as a gas. also, any gas always is condensing into a liquid or solid. when pressure and tempurature are constant, these processes reach equilibrium where they cancel each other out. at high temperature, more gasses escape, and at low pressure, less gases return to liquid. so at somewhat low temperature and relativly lower pressure, even though few gases relatively escape, even fewer return to liquid, so the net effect is that the liquid evaporates at low temperature. if the temperature were raised, it would boil even faster.
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.
438791
altitude.....higher altitude means lower air pressure.  Liquids, water included, vaporizes at lower temp when pressure lowers.  (a glass of water will boil at room temp in a vaccumn)
341576
Besides the loss of heat due to the difference with room temperature, we can also check how water specific heat behaves with temperature. \nThe specific heat is the amount of heat required to change a unit mass of a substance by one degree in temperature. This specific heat increases with temperature, so this indicates us that water at a higher temperature needs a bit more energy to rise 1º than water at lower temperature.\n\nSo the answer is yes, it will take more time to rise from 90º to 100º because of two reasons:\n1- There is more loss of heat in the water at 90º than water at 10º.\n2- Specific heat is higher in water at 90º than water at 10º.
132266
Ignore harsha.  A 1 atm decrease in pressure would mean zero pressure at 100 meters above sea level, which is absurd.\n\nPressure decreases as you rise because the total mass of the atmosphere weighing down on you decreases.  High pressure means you need more energy to make water boil, so at sea level the boiling point will be higher than it will be on a mountain top.
489650
No. Hot water will boil quicker because it is closer to water's boiling point. At sea level the bp of water is 100 C. (The boiling point is a little less at higher elevations). Once it gets heated to that it doesn't get hotter but rather it changes to a vapor. Cold water requires more energy over a longer period of time to heat it to the required temperature to reach its boiling point.
777060
Tap water. Dissolved salt raises the boiling point, so salt water  takes longer to boil.
514471
There is a difference between boiling and evaporating.\nAt 100 degrees water starts boiling. The temperature can not rise because al the energy you put in is used by the molecules to 'escape' and the water to change into gas. That is why damping water cools off. But water kan evaporate also at lower temperatures because molecules can 'escape'. The molecules are not as volatile as at 100 degrees, but they are volatile. Winds helps because the dryer the air, the easier it is to escape. Is the air humid, than the molecules can be caught in the water again. \nSorry I am not a chemist but I think this is it essentially.
232411
Salt only helps the boiling point rise a little. It will boil more rapidly. It will not decrease time it takes to reach boiling point.
696743
NO! water will boil faster in the water in an area  above 6,000 feet. At higher elevations, where the atmospheric pressure is much lower, the boiling point is also lower, so it means it will boil faster.\n\nFor example: The boiling point of water is 100 °C (212 °F) at standard pressure. On top of Mount Everest the pressure is about 260 mbar (26 kPa) so the boiling point of water is 69 °C. It means lesser time to arrive to its boiling point.\n\nIf you were to boil water on Mount Everest,it  would be the lowest boiling point in the world because of its high elevation and low air pressure. If you were to boil water at the Dead Sea, it would reach the highest boiling point on Earth due to the low elevation and high air pressure. \n\nElevation affects the boiling point because of the amount of air pressure pushing down on the surface of the water. At a higher elevation the pressure is less and at a lower elevation  it is higher. When the pressure is higher, the molecules must absorb more energy in order to change state from liquid to gas therefore requiring more energy (temperature).♥
124074
In short: Any solution will boil at a higher temperature than the pure solvent. \nBoiling point elevation is a colligative property. Use the formula provided by emilyrose. The addition of salt to water causes vapor pressure reduction of the water. This is because the addition of a non-volatile solute causes a reduction in the surface area available to water molecules, reducing the likelihood of evaporation. This vapor pressure lowering is described by Raoults Law (see link).\nInterestingly, if you have a salt solution, and you heat it till it boils, as the water evaporates, the boiling temperature of the solution will continuously increase, because its molality increases. Please see the link below for a more detailed discussion.
980701
In Denver. This is because at higher elevations there is less pressure in the atmosphere, so the water boils at a lower temperature.
474034
It decreases, as everyone said. The reason may be given like this: water at a given temperature is just a bunch of molecules wildly moving around. The temperature tells you just how fast. Evaporation (water drying up) happens because some of the fastest molecules escape into the surrounding air. Now, evaporation happens faster at higher altitude: that is because there is less air, the air molecules are less bunched together. This means a water molecule escaping into air is less likely to be bounced right back into the water. \n\nNow boiling occurs when evaporation is so violent that the water cannot hold itself together any more. Again, it will happen more easily in thin air, that is, at high altitudes.
356469
The lower the air pressure, the lower the boiling point of water.
966324
Ether has a higher saturated vapor pressure than water. Thus the former boils at a lower temperature than the latter.
2167
You can't make water boil by compressing it directly.  If you compress it, but allow the hest caused by compressing to leave, then you'll get nothing.  It is possible if you have an insulated system to compress it in such a way that temperature of the water rises, but at higher pressures, the temperature needed to boil water increases.  If the water, once heated by comprsession, were to be rapidy brought to a lower pressure through a throttling valve, it could be vaporized.\n\nBut really, if you want water to boil, you should *DECREASE* the pressure.  In out space, water at room temperature would instantly boil due to the low pressure involved.