does temperature of boiling point increase or decrease with altitude and why?
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.
304917
I believe that you mean water boiling at a lower-than-normal temperature when the atmospheric pressure is lower, such as at high altitudes........if this is what you meant, water boils when the 'vapor pressure' of the water, which is the amount of liquid water which evaporates into the air and which rises with temperature, becomes equal to the atmospheric pressure.  If you are in Colorado, for example, there is just less air to push against the top of the water, so it will boil off with less heat to push it out.
471496
Increasing air pressure increases the boiling point of a liquid. The boiling point is the temperature at which the saturated vapour of a liquid is equal to the external (atmospheric) pressure. Since saturated vapour pressure increases as temperature increases then the boiling point will also increase if the external pressure increases and vice versa.
7988
hydrogen bonds will increase the boiling point of a substance, all else being equal.\none way to see this is by looking at the boiling point of alcohols.\nthere is a near linear correlation between length fo the carbon chain and the boiling point for straight chain carbohydrate alcohols. as the chain gets shorter, the boiling point goes up faster than the linear relation would suggest, until you get to water  where hydrogen bonding is the most active and the boiling point jumps dramatically.
101164
This has been asked over and over recently. Is this part of an exam or a class?\n\nBoiling point decreases with altitude because there is less pressure. The water will boil when the vapor pressure equals the air pressure. \n\nBaguio city is about 1500-1600 meters above sea level, making its temperatures roughly 8 degrees C less than the sea level areas of the Phillipines. For every 1000 feet in elevation, the boiling point of water decreases about 1 degree C. Very roughly, Baguio city is at 4500 feet elevation. The boiling point of water at Baguio city should be about 4.5 degrees C less than 100 degrees C, or 95.5 degrees C.
786932
Boiling point is the temperature at which the vapor pressure of a liquid is equal to the atmospheric pressure.  Raising the temperature of a liquid increases the vapor pressure.  The higher the vapor pressure of a liquid already is, the lower the temperature required for it to boil.  Oxygen has a lower boiling point than hydrogen because it has a higher vapor pressure.  The reason for this is because there are less intermolecular forces holding oxygen together than there are intermolecular forces holding together hydrogen chloride.  In oxygen, there are weak London forces and nonpolar-covalent bonds.  In hydrogen chloride, there are London forces AND a polar-covalent bond.
947849
The higher the altitude, the lower the atmospheric pressure. The less atmospheric pressure that bears down on the surface of the liquid, the easier it is for water molecules to escape into the air. Thus, the water comes to its full rapid boil at a lower temperature in the mile-high city of Denver than it can in coastal Miami. For each thousand feet above sea level, the boiling point of water drops almost 2° F.
1097232
Have you heard of boiling and freezing points. Each substance has a boiling and a freezing point there is a different one for each substance. The freezing point of H20 (hydrogen and oxygen) is 32 degrees Fahrenheit and the boiling point is 212 degrees Fahrenheit. Now these temperatures could be different if the water has anything else in it changing the molecular structure. Things like salt, calcium, ect. So in your bottle story....The gas (common air) which has things like helium, carbon and oxygen is on top and your water is on the bottom. This could get confusing but essentially when you shake it up you added other molecules into the water that have a lower or higher freezing point. Same idea as when you have a partially frozen bottle of water and you shake it up and it defrosts. It also has to do with the first law of thermodynamics...Energy can not be created or destroyed just transferred. So some molecules do not have enough energy to bond with one another but when you shake up the bottle it transfers energy allowing them to bond with one another. Hope I didn't confuse you too much.
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.
130715
Adding table salt to water causes the water to boil at a higher temperature.\nThe three important concepts are the vapor pressure, the boiling point, and the freezing point.  For water at standard pressure (1 atmosphere), the boiling point occurs at 100 degrees Celsius, and the freezing point occurs at 0 degrees Celsius.   A Liquid will boil when the vapor pressure is equal to the atmospheric pressure. If we start with just barely boiling water and add some salt, the water will stop boiling.  The salt has lowered the vapor pressure of the solution.  To increase the pressure we need to add heat.  To add heat, we turn up the temperature.  It turns out that in the dilute solution case, the change in boiling temperature is proportional to the concentration of the add solute (salt).
908777
Temperature is temperature no matter what elevation or altitude you are at - no need to know it.\n\nIf you want to correct station pressure readings to sea level for a weather station, then it may be helpful. The most practical and a reasonably accurate method though is to simply set your barometer several times (making small adjustments) to the sea level pressure using data from a good surface chart during daytime on a nice day with a weak pressure gradient (when it'll be very similar over tens of miles). Here is a good site for observations the past hour:\n\nhttp://www-frd.fsl.noaa.gov/mab/metar\n\nThey say data are experimental and not always accurate blah blah blah - but I never saw an error in METAR listings for any of the stations nor their locations - though you have to be able to read METAR reports. E-mail me if you wish regarding this.\n\nWhatever the case, Topozone is good if you want your elevation for any particular reason:\n\nhttp://www.topozone.com
897109
atmospheric pressure decreases as altitude increases.\n(think about gravity)\n\nan object that floats is less dense than the fluid it floats in.\n"A piece of the object weighs less than a piece of the fluid the same size."
1114805
You've taken the first step in a good scientific inquiry.  You observed a phenomenon and began trying to explain it.  Now you can work toward an answer.  You could see if sugar (glucose?  sucrose?) is a molecule similar to salt for elevating the boiling point of water. (It depresses the freezing point like salt does.)  You could try measuring water just as it boils, and then with the same instrument, measure sugar-water just as it boils, and see if it really is elevated.  You can learn more about the subject by reading.  The melting point of glucose (C6 H12 O6) is 113 degrees Centigrade, higher than the boiling point of water.\n\nThen you can formulate theories as possible explanations.  You've started doing that.  Then you can investigate those.  Here's another.  Perhaps dissolving sugar is an endothermic reaction.  Mix some sugar and water which are both at the same temperature.  Does the temperature of the mixture change?\n\nIt takes a certain amount of energy to raise the temperature of water.  Look up the definition of calorie.  It takes additional energy to convert it from its liquid state to its gaseous state.\n\nIt often takes some discontinuity for a supercooled solution to freeze or form crystals, or for a superheated solution to boil.  The bottom of the pot has such discontinuities, and particularly irregular parts of the pot are where boiling likely starts.  When you add granulated sugar, you are adding lots of discontinuities.  What happens when you add dissolved sugar instead of granulated sugar?\n\nKeep good records, sign and date your notes and get them witnessed periodically.  They could be your first steps toward a very good science fair project or perhaps a bigger discovery and a patent.  Then, tell the world I helped you along.  That would REALLY make my day!
105979
the boiling point of water at sea level is 212 deg F. the boiling point of water in the mountains is different because the column of air is not as "tall" as it is at sea level. the boling point is when the vapor pressure of a heated liquid exceeds the atmospheric pressure. sea level has a certain atmospheric pressure and thus a certain boiling point for water. at high altitudes the pressure is less and below sea level the pressure is greater.
150195
at sea level water boils at 100 deg C\nat elevation like up a mountain it will boil at a lower temp because the pressure is lower. I think water boils at about 70 deg C on everest.
15822
It mainly depends on the pressure (if we are talking about pure water). The higher the pressure, the higher the boiling point - it can be much lower (ex. high in the mountains) or much higher than 100 degrees C (the boiling point under normal atmospheric pressure). If we don't talk about pure water, then adding other chemicals (for example, table salt - sodium chloride) can raise the boiling point as well.
554161
As answer 4 implies, it defies simple description and modeling, since the lapse rate (rate of change of temperature with altitude) depends on air humidity, and of course that can vary. Up to about 11 KM altitude you can approximate the lapse rate as 6.5 C per km (ref. 1), but that applies to an "international standard atmosphere" which may not exist in your application.\nLooking at the diagrams at the bottom of the page in ref. 2, you can see how a typical real-world weather situation (warm water-laden air blowing onto the shore and passing over a mountain) has a more complex temperature profile.