Notices
Results 1 to 6 of 6
Like Tree3Likes
  • 1 Post By Gummpy
  • 1 Post By MeteorWayne
  • 1 Post By Gummpy

Thread: A few questions :)

  1. #1 A few questions :) 
    New Member
    Join Date
    Jul 2012
    Posts
    3
    Hello i just wanted to ask a few questions about things that bothered me.

    1.Hot air is heavier than cold air, is it same with water? Hot water is heavier than cold water?

    2.Helium-3 - Wikipedia, the free encyclopedia is it real and useful?


    ampwitch likes this.
    Reply With Quote  
     

  2.  
     

  3. #2  
    Comet Dust Collector Moderator
    Join Date
    Mar 2011
    Location
    New Jersey, USA
    Posts
    2,848
    1. Hot air is less dense than cold air (in the atmosphere).
    2. Water becomes more dense as it cools to about 39F (4C) then starts to get less dense as it cools further. That's why ice forms on the surface of a lake, not the bottom. Very important, that fact!
    3. Yes Helium 3 is real. It is useful, but only very small quantities are available.


    Ascended likes this.
    Reply With Quote  
     

  4. #3  
    New Member
    Join Date
    Jul 2012
    Posts
    3
    thanks a lot its cool when there is a place to ask such questions with such fast answers. thanks again.
    GuessWho likes this.
    Reply With Quote  
     

  5. #4  
    Forum Bachelors Degree Kerling's Avatar
    Join Date
    Jul 2012
    Location
    Copenhagen
    Posts
    440
    Helium-3 is real, and really expensive :P
    Reply With Quote  
     

  6. #5  
    Forum Ph.D.
    Join Date
    Jul 2011
    Posts
    984
    Quote Originally Posted by Gummpy View Post
    Hello i just wanted to ask a few questions about things that bothered me.

    1.Hot air is heavier than cold air, is it same with water? Hot water is heavier than cold water?

    2.Helium-3 - Wikipedia, the free encyclopedia is it real and useful?
    How did you get the notion that hot air is heavier than cold air? When anything is heated it expands so the same mass takes up more space. Thus it is less dense. Everyday demonstrations of this effect: smoke rising from a fire, hot air balloons.

    Water behaves the same as everything else, that is cool water is more dense than hot water, except as it approaches the freezing point. This is because of the inherent shape of the water molecule. As they cool water molecules arrange themselves into hexagons with an open space in the middle of each one. This arrangement takes up more space than liquid water.
    Reply With Quote  
     

  7. #6  
    Forum Bachelors Degree Kerling's Avatar
    Join Date
    Jul 2012
    Location
    Copenhagen
    Posts
    440
    If I remember well enough warmer water has in fact a slightly higher density then cold water. And around 4 degress celsius the density of that water is larger then that of warmer water. That is why lakes don't immediatly freeze up. The cold water drops to the bottom of the lake, and the warmer water gets pushed up. Only untill the entire lake is at 4 degrees can it begin to freeze over. That is why in still water the deeper parts take longer to freeze. And that when it is frozen, the water beneath it is often a few degrees above freezing! Also for a large volume of water to continue to become cold it explains why the thick ice evnetually can 'span' itself over the water. But this doesn't happen very often.
    Reply With Quote  
     

Similar Threads

  1. yes im still going to ask questions..
    By Brandon in forum Personal Theories & Alternative Ideas
    Replies: 16
    Last Post: September 19th, 2011, 03:23 PM
  2. 2 Questions
    By Always.Asking in forum Astronomy & Cosmology
    Replies: 6
    Last Post: June 25th, 2010, 05:41 PM
  3. A Few Questions...
    By marcut in forum Astronomy & Cosmology
    Replies: 6
    Last Post: November 9th, 2008, 06:19 PM
  4. questions
    By A-guy in forum Earth Sciences
    Replies: 2
    Last Post: April 29th, 2007, 11:50 AM
  5. BB Questions
    By Mike NS in forum Astronomy & Cosmology
    Replies: 62
    Last Post: October 20th, 2006, 02:11 PM
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
  •