Notices
Results 1 to 8 of 8

Thread: Water is the only substance...

  1. #1 Water is the only substance... 
    Forum Freshman
    Join Date
    Jun 2006
    Posts
    14
    I found this on one science web site, and it realy confused me:

    "Water is the only substance that occurs at ordinary temperatures in all three phases: liquid, gas and solid."

    As far as I know, many, many substances can be in all three phases at ordinary temperatures. Am I right?


    Reply With Quote  
     

  2.  
     

  3. #2  
    Universal Mind John Galt's Avatar
    Join Date
    Jul 2005
    Posts
    14,168
    I shall answer you with a question.

    Which substances?


    Reply With Quote  
     

  4. #3  
    Forum Freshman
    Join Date
    Jun 2006
    Posts
    14
    Well, any substance that is liquid at standard conditions could be solidified if pressure is aplied, without change of temperature. If pressure is lowered, substance will vaporise. And, even if liquid state is stable, it will always have vapor pressure, and so some vapor will exist above liquid.

    Also substances that have melting point at about 10-20 degrees celsius can thus exist in S and L state at "ordinary" temperatures. And there is always vapor above L and S phases, however insignificant it might be. So even without changing pressure, you can achive all 3 states of mater inside "ordinary" temperatures.
    Reply With Quote  
     

  5. #4  
    Universal Mind John Galt's Avatar
    Join Date
    Jul 2005
    Posts
    14,168
    1. I would read into the statement you quote that atmospheric pressure is implied.
    2. I do not have the advantage of the context in which the quote is placed. However, I suspect they are talking about 'normal' general conditions, not micro-conditions.
    3. So, name any substance which can exist in all three phases under 'normal' conditions.
    Reply With Quote  
     

  6. #5  
    Forum Freshman
    Join Date
    Jun 2006
    Posts
    14
    But how can water exist in all three phases under normal conditions?
    Reply With Quote  
     

  7. #6  
    Forum Freshman ArchAngel's Avatar
    Join Date
    Jun 2006
    Posts
    8
    Quote Originally Posted by munja100
    But how can water exist in all three phases under normal conditions?

    Water vapor in the air of the steaming jungle, liquid water in the ocean, and frozen water falling as snow.

    Not the same conditions, but all are 'normal'.
    Reply With Quote  
     

  8. #7  
    Forum Professor river_rat's Avatar
    Join Date
    Jun 2006
    Location
    South Africa
    Posts
    1,510
    or at the triple point - 273.16K and a Vapour pressure of 611.73P where water vapour, ice and liquid water exist in a happy little equilibrium.
    As is often the case with technical subjects we are presented with an unfortunate choice: an explanation that is accurate but incomprehensible, or comprehensible but wrong.
    Reply With Quote  
     

  9. #8  
    Forum Professor Zwolver's Avatar
    Join Date
    May 2006
    Location
    Netherlands
    Posts
    1,667
    water has an increddibly high electromagnetic binding. this keeps water together as a liquid. It reacts as a hexogen when it freezes, and by heat or uv it turns to vapor.

    freezes at 0C° and turns to vapor at any heat... can be liquid between 0 and 100C° under 1 atm.

    water rules..
    Growing up, i marveled at star-trek's science, and ignored the perfect society. Now, i try to ignore their science, and marvel at the society.

    Imagine, being able to create matter out of thin air, and not coming up with using drones for boarding hostile ships. Or using drones to defend your own ship. Heck, using drones to block energy attacks, counterattack or for surveillance. Unless, of course, they are nano-machines in your blood, which is a billion times more complex..
    Reply With Quote  
     

Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •