Time for water to boil at altitude?

Discussion in 'Computer Support' started by Dribbler, Oct 7, 2004.

  1. Dribbler

    Dribbler Guest

    Watching a TV programme about the Himalayas, they mentioned water takes
    longer to boil at altitude.
    Why is this? I think it must be something to do with pressure, but why and
    what is the principal?
    Thank you,
    Dribbler
    Dribbler, Oct 7, 2004
    #1
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  2. Dribbler

    Ron Martell Guest

    "Dribbler" <> wrote:

    >Watching a TV programme about the Himalayas, they mentioned water takes
    >longer to boil at altitude.
    >Why is this? I think it must be something to do with pressure, but why and
    >what is the principal?
    >Thank you,
    >Dribbler
    >


    Did they say it takes longer to get water to boil, or did they say
    that you have to boil things longer at high altitudes?

    The reduced air pressure means that water will boil at a lower
    temperature at high altitude. And once it reaches the boiling point
    it will not get any hotter - just boil faster.

    The lower boiling temperature means that things take longer to cook.
    So pasta that cooks in 10 minutes at sea level might require 12
    minutes or more to cook properly in boiling water at high altitude.


    Ron Martell Duncan B.C. Canada
    --
    Microsoft MVP
    On-Line Help Computer Service
    http://onlinehelp.bc.ca

    "The reason computer chips are so small is computers don't eat much."
    Ron Martell, Oct 7, 2004
    #2
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  3. Dribbler wrote:

    > Watching a TV programme about the Himalayas, they mentioned water takes
    > longer to boil at altitude.
    > Why is this? I think it must be something to do with pressure, but why and
    > what is the principal?
    > Thank you,
    > Dribbler
    >


    Homework?
    http://www.newton.dep.anl.gov/askasci/phy00/phy00162.htm
    =?ISO-8859-1?Q?R=F4g=EAr?=, Oct 7, 2004
    #3
  4. Dribbler

    Liz Guest

    "Dribbler" wrote
    > Watching a TV programme about the Himalayas, they mentioned water takes
    > longer to boil at altitude.
    > Why is this? I think it must be something to do with pressure, but why and
    > what is the principal?


    This is because the air pressure is lower at high elevations.
    Water at sea level boils at 100C and freezes at 0 degrees.
    At higher elevations, where atmospheric pressure is lower,
    water's boiling temperature is lower, so it takes longer to
    boil or cook things.
    Liz, Oct 7, 2004
    #4
  5. Dribbler

    Kenny Guest

    It boils at a lower temperature at altitude.

    Boiling occurs when the water is hot enough to have the
    same pressure as the surrounding air, so that it can form bubbles. As water
    is heated, its steam pressure rises, until it reaches the pressure of the
    surrounding air. At high altitudes, this air pressure is lower than at sea
    level, so the water doesn't have to get so hot to get to boiling.

    --

    Kenny


    "Dribbler" <> wrote in message
    news:4165afba$0$8474$...
    > Watching a TV programme about the Himalayas, they mentioned water takes
    > longer to boil at altitude.
    > Why is this? I think it must be something to do with pressure, but why and
    > what is the principal?
    > Thank you,
    > Dribbler
    >
    >
    Kenny, Oct 7, 2004
    #5
  6. Dribbler

    Dribbler Guest

    "Kenny" <> wrote in message
    news:...
    > It boils at a lower temperature at altitude.
    >
    > Boiling occurs when the water is hot enough to have the
    > same pressure as the surrounding air, so that it can form bubbles. As

    water
    > is heated, its steam pressure rises, until it reaches the pressure of the
    > surrounding air. At high altitudes, this air pressure is lower than at sea
    > level, so the water doesn't have to get so hot to get to boiling.


    > Kenny


    Thankyou Kenny, you explain it so well!
    I appreciate all the replies, I feel rather daft for not knowing and for
    not being able to locate the answer myself on Google.
    Thanks!
    Dribbler
    Dribbler, Oct 7, 2004
    #6
  7. Dribbler

    Conor Guest

    In article <2Gi9d.289831$>, Liz says...
    > "Dribbler" wrote
    > > Watching a TV programme about the Himalayas, they mentioned water takes
    > > longer to boil at altitude.
    > > Why is this? I think it must be something to do with pressure, but why and
    > > what is the principal?

    >
    > This is because the air pressure is lower at high elevations.
    > Water at sea level boils at 100C and freezes at 0 degrees.
    > At higher elevations, where atmospheric pressure is lower,
    > water's boiling temperature is lower, so it takes longer to
    > boil or cook things.
    >

    Did you actually read that? The boiling point is lower thus requiring
    less heating up but it takes longer?


    --
    Conor

    Opinions personal, facts suspect.
    Conor, Oct 8, 2004
    #7
  8. Dribbler

    Plato Guest

    Dribbler wrote:
    >
    > Watching a TV programme about the Himalayas, they mentioned water takes
    > longer to boil at altitude.
    > Why is this? I think it must be something to do with pressure, but why and
    > what is the principal?


    Since a watched pot never boils put a lid on it.
    Plato, Oct 8, 2004
    #8
  9. Dribbler

    alan Guest

    "Dribbler" <> wrote in message
    news:4165afba$0$8474$...
    > Watching a TV programme about the Himalayas, they mentioned water takes
    > longer to boil at altitude.
    > Why is this? I think it must be something to do with pressure, but why and
    > what is the principal?
    > Thank you,
    > Dribbler
    >
    >

    I saw that too. It's wrong, or at least badly expressed Water will reach
    its boiling point quicker at altitude because the boiling point is reduced -
    lets say it boils at 95 rather than 100C. Food boiled at 95C will take
    longer to cook than at the normal 100C.

    Alan
    alan, Oct 8, 2004
    #9
  10. Dribbler

    Liz Guest

    "Conor" <> wrote
    > In article <2Gi9d.289831$>, Liz says...
    > > "Dribbler" wrote
    > > > Watching a TV programme about the Himalayas, they mentioned water takes
    > > > longer to boil at altitude.
    > > > Why is this? I think it must be something to do with pressure, but why and
    > > > what is the principal?

    > >
    > > This is because the air pressure is lower at high elevations.
    > > Water at sea level boils at 100C and freezes at 0 degrees.
    > > At higher elevations, where atmospheric pressure is lower,
    > > water's boiling temperature is lower, so it takes longer to
    > > boil or cook things.
    > >

    > Did you actually read that? The boiling point is lower thus requiring
    > less heating up but it takes longer?


    Do you have trouble understanding food takes longer to cook
    at a lower temperature?
    Liz, Oct 8, 2004
    #10
  11. Liz wrote:
    > "Conor" <> wrote
    >
    >>In article <2Gi9d.289831$>, Liz says...
    >>
    >>>"Dribbler" wrote
    >>>
    >>>>Watching a TV programme about the Himalayas, they mentioned water takes
    >>>>longer to boil at altitude.
    >>>>Why is this? I think it must be something to do with pressure, but why and
    >>>>what is the principal?
    >>>
    >>>This is because the air pressure is lower at high elevations.
    >>>Water at sea level boils at 100C and freezes at 0 degrees.
    >>>At higher elevations, where atmospheric pressure is lower,
    >>>water's boiling temperature is lower, so it takes longer to
    >>>boil or cook things.
    >>>

    >>
    >>Did you actually read that? The boiling point is lower thus requiring
    >>less heating up but it takes longer?

    >
    >
    > Do you have trouble understanding food takes longer to cook
    > at a lower temperature?
    >
    >


    That explains why a pressure cooker cooks much faster.
    :)
    =?ISO-8859-15?Q?Brian_H=B9=A9?=, Oct 8, 2004
    #11
  12. Dribbler

    Old Gringo Guest

    Dribbler wrote:
    > Watching a TV programme about the Himalayas, they mentioned water takes
    > longer to boil at altitude.
    > Why is this? I think it must be something to do with pressure, but why and
    > what is the principal?
    > Thank you,
    > Dribbler
    >
    >

    Here is the fun part: http://www.biggreenegg.com/boilingPoint.htm

    --
    Old Gringo George
    Just West Of Nowhere
    Enjoy Life And Live It To Its Fullest
    Freedom For The World <http://www.nuboy-industries.com/>
    Old Gringo, Oct 8, 2004
    #12
  13. On Fri, 08 Oct 2004 09:29:51 GMT, "alan"
    <> wrote :

    >
    >"Dribbler" <> wrote in message
    >news:4165afba$0$8474$...
    >> Watching a TV programme about the Himalayas, they mentioned water takes
    >> longer to boil at altitude.
    >> Why is this? I think it must be something to do with pressure, but whyand
    >> what is the principal?
    >> Thank you,
    >> Dribbler
    >>
    >>

    >I saw that too. It's wrong, or at least badly expressed Water will reach
    >its boiling point quicker at altitude because the boiling point is reduced -
    >lets say it boils at 95 rather than 100C. Food boiled at 95C will take
    >longer to cook than at the normal 100C.
    >
    >Alan
    >

    Actually, it's just badly expressed.

    Water boils at a lower temperature at altitude as you say, so if
    boiled on a normal domestic stove would actually boil quicker, but on
    the mountainside, they normally use small hexamine or spirit stoves
    with lower heat output, and there is usually wind that takes away lots
    of the small amount of heat generated, so YES, it usually does take
    longer to boil at altitude, even though it boils at a lower
    temperature.

    And YES, it will also take longer to cook after boiling, because the
    temperature is lower.

    And yes, a cup of tea made at very high altitude tastes ghastly!
    Peter Wilkins, Oct 8, 2004
    #13
  14. In article <MHA9d.290160$>,
    "Liz" <> wrote:
    >
    >"Conor" <> wrote
    >> In article <2Gi9d.289831$>, Liz says...
    >> > "Dribbler" wrote
    >> > > Watching a TV programme about the Himalayas, they mentioned water takes
    >> > > longer to boil at altitude.
    >> > > Why is this? I think it must be something to do with pressure, but why and
    >> > > what is the principal?
    >> >
    >> > This is because the air pressure is lower at high elevations.
    >> > Water at sea level boils at 100C and freezes at 0 degrees.
    >> > At higher elevations, where atmospheric pressure is lower,
    >> > water's boiling temperature is lower, so it takes longer to
    >> > boil or cook things.
    >> >

    >> Did you actually read that? The boiling point is lower thus requiring
    >> less heating up but it takes longer?

    >
    >Do you have trouble understanding food takes longer to cook
    >at a lower temperature?


    I am not sure if I have trouble understanding food takes longer to
    cook at a lower temperature.

    --
    Lady Chatterly

    "OK, I know I've been away for a while, so maybe I missed something.
    Is Lady Chatterly a bot?" -- oldami
    Lady Chatterly, Oct 9, 2004
    #14
  15. "Conor" <> wrote in message
    news:...
    > In article <2Gi9d.289831$>, Liz

    says...
    > > "Dribbler" wrote
    > > > Watching a TV programme about the Himalayas, they mentioned

    water takes
    > > > longer to boil at altitude.
    > > > Why is this? I think it must be something to do with pressure,

    but why and
    > > > what is the principal?

    > >
    > > This is because the air pressure is lower at high elevations.
    > > Water at sea level boils at 100C and freezes at 0 degrees.
    > > At higher elevations, where atmospheric pressure is lower,
    > > water's boiling temperature is lower, so it takes longer to
    > > boil or cook things.
    > >

    > Did you actually read that? The boiling point is lower thus

    requiring
    > less heating up but it takes longer?


    Like so many, the poster was chronically unable to be unambiguous.
    Because of the reduced boiling point at high altitude, the pot will
    come to the boil quicker, assuming equal power inputs. However,
    because of the lower boiling point at high altitude, food may have to
    remain at boiling temperature for longer to become "cooked" in the
    culinary sense.

    Franz
    Franz Heymann, Oct 9, 2004
    #15
  16. "Liz" <> wrote in message
    news:MHA9d.290160$...
    > "Conor" <> wrote
    > > In article <2Gi9d.289831$>, Liz

    says...
    > > > "Dribbler" wrote
    > > > > Watching a TV programme about the Himalayas, they mentioned

    water takes
    > > > > longer to boil at altitude.
    > > > > Why is this? I think it must be something to do with pressure,

    but why and
    > > > > what is the principal?
    > > >
    > > > This is because the air pressure is lower at high elevations.
    > > > Water at sea level boils at 100C and freezes at 0 degrees.
    > > > At higher elevations, where atmospheric pressure is lower,
    > > > water's boiling temperature is lower, so it takes longer to
    > > > boil or cook things.
    > > >

    > > Did you actually read that? The boiling point is lower thus

    requiring
    > > less heating up but it takes longer?

    >
    > Do you have trouble understanding food takes longer to cook
    > at a lower temperature?


    That was not what you said. You have subtly tried to say something
    new now.

    Franz
    Franz Heymann, Oct 9, 2004
    #16
  17. "Kenny" <> wrote in message
    news:...
    > It boils at a lower temperature at altitude.
    >
    > Boiling occurs when the water is hot enough to have the
    > same pressure as the surrounding air,


    No. At the top surfce of the water, its pressure is always exactly
    equal to the atmospheric pressure.
    What you meant to say is that it boils when its vapour pressure
    becomes equal to that of the atmosphere.

    [snip]

    Franz
    Franz Heymann, Oct 9, 2004
    #17
  18. Dribbler

    Liz Guest

    "Franz Heymann" wrote
    > "Liz" <> wrote in message
    > news:MHA9d.290160$...
    > > "Conor" <> wrote
    > > > In article <2Gi9d.289831$>, Liz

    > says...
    > > > > "Dribbler" wrote
    > > > > > Watching a TV programme about the Himalayas, they mentioned

    > water takes
    > > > > > longer to boil at altitude.
    > > > > > Why is this? I think it must be something to do with pressure,

    > but why and
    > > > > > what is the principal?
    > > > >
    > > > > This is because the air pressure is lower at high elevations.
    > > > > Water at sea level boils at 100C and freezes at 0 degrees.
    > > > > At higher elevations, where atmospheric pressure is lower,
    > > > > water's boiling temperature is lower, so it takes longer to
    > > > > boil or cook things.
    > > > >
    > > > Did you actually read that? The boiling point is lower thus

    > requiring
    > > > less heating up but it takes longer?

    > >
    > > Do you have trouble understanding food takes longer to cook
    > > at a lower temperature?

    >
    > That was not what you said. You have subtly tried to say something
    > new now.


    If that is saying something new, you must be extremely lonely.
    Liz, Oct 10, 2004
    #18
  19. Dribbler

    Liz Guest

    "Lady Chatterly" wrote:
    >
    > I am not sure if I have trouble understanding food takes longer to
    > cook at a lower temperature.


    Then you'll need a computer science degree to use a microwave oven.

    --
    How do you make Yankee Bean Soup? Add one bean on a string
    to a boiling pot of water. Yank the bean out, and serve.
    Liz, Oct 10, 2004
    #19
  20. Dribbler

    Liz Guest

    "Brian H¹©" wrote
    > Liz wrote:
    > >
    > > Do you have trouble understanding food takes longer to cook
    > > at a lower temperature?

    >
    > That explains why a pressure cooker cooks much faster.
    > :)


    Did you know that "microwave sickness" are stress syndrome
    and high blood pressure. :)

    http://www.manatwork.com/_working_net.html
    Liz, Oct 10, 2004
    #20
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