Warm Water Expansion: Facts & Questions

  • Context: High School 
  • Thread starter Thread starter wikoh
  • Start date Start date
  • Tags Tags
    Water
Click For Summary

Discussion Overview

The discussion revolves around the properties of water, particularly its expansion when heated and its unique behavior when frozen. Participants explore the implications of these properties for life and compare water to other substances with similar characteristics. The conversation includes theoretical and conceptual aspects of water's behavior across different temperature ranges.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants assert that warm water expands, while cooling water contracts until it freezes, at which point it expands again due to the formation of crystalline structures.
  • It is noted that pure water reaches its maximum density at approximately 4 degrees Celsius.
  • Participants discuss the unusual nature of water's expansion when frozen, questioning whether it is odd for a substance to expand at multiple temperature points.
  • Some contributions highlight the polar nature of water molecules as a reason for its unique expansion properties when freezing.
  • There is mention of the potential implications of water's properties for extraterrestrial life, suggesting that life may be water-based due to these unique characteristics.
  • Participants inquire about other substances that exhibit similar expansion properties, with some examples provided, including materials with negative coefficients of thermal expansion.
  • Technical details are shared regarding materials that exhibit negative thermal expansion, including polymers and oxides, along with explanations of the mechanisms behind these properties.

Areas of Agreement / Disagreement

Participants generally agree on the unique properties of water and their significance for life, but there are multiple competing views regarding the implications and comparisons to other substances. The discussion remains unresolved regarding the broader implications of these properties.

Contextual Notes

Some claims about the behavior of water and other materials depend on specific conditions and definitions, which are not fully explored in the discussion. The relationship between temperature and expansion is complex and may vary among different substances.

Who May Find This Useful

This discussion may be of interest to those studying chemistry, biology, environmental science, or materials science, particularly in relation to the properties of water and its role in life and the environment.

wikoh
Messages
2
Reaction score
0
In a Time article about global warming they say warm water expands, but water expands when it's frozen - is it both ways 'round?
 
Physics news on Phys.org
Yes, warm water expands, just like warming anything.

And, as you cool water, it contracts- until it starts to freeze- then, because it forms rather large crystals it suddenly expands (have you ever stopped to think how much of life depends on that fact?). If you continue to cool ice after it has completely frozen, it will contract again.
 
Pure water has its maximum density at about 4 degrees C.
 
I've read that water is quite an odd substance in that it expands when it freezes. Is this true, and is this thing to expand at two (or more) far-apart levels of temperature also odd?
 
wikoh said:
I've read that water is quite an odd substance in that it expands when it freezes. Is this true, and is this thing to expand at two (or more) far-apart levels of temperature also odd?
Yes and yes. And extremely fortunate for life as we know it, as HallsofIvy alludes to.

It has to do with the polar nature of water - one end of the molecule is positively charged, the other is negatively charged. When they get clsoe together and start to line up (i.e. crystalize), they don't line up in the most compact pattern, they line up according to their charge attractions, which takes up more room. This results in water taking up *more* room as it crystalizes, rather than less as with most other molecules and elements.
 
wikoh said:
I've read that water is quite an odd substance in that it expands when it freezes. Is this true, and is this thing to expand at two (or more) far-apart levels of temperature also odd?
Yes and yes. And extremely fortunate for life as we know it, as HallsofIvy alludes to.

And because it is both unique and highly beneficial to life, this is a very compelling reason why extra-terrestrial life is very likely to be water-based.
 
Are there any other similar substances to water with similar properities?
-scott
 
Just to add on what's already been said, why is water so essential to life? Well if it didn't expand when it was frozen then its density would not decrease. I'm sure everyone is familiar with ice cubes that are less dense then water floating on the surface. If ice did not do not then there would be an awful positive feedback loop that would freeze more of the world's ocean waters. The frozen water on hte surface is able to be heated by the sun's radiation, but if were not able to float it would sink to the bottom.
 
second party interested...

scott_alexsk said:
Are there any other similar substances to water with similar properities?
-scott


Hello, I'm also very interested to know if there are any other substances that expand, albeit over a narrow (yet life-preserving) temperature range.
 
  • #10
There are several materials with a negative coefficient of expansion (Google: negative CTE). Many composites and fibers (eg: kevlar) exhibit at least one axis with negative CTE. Polymers like HDPE exhibit negative CTE over small temperature ranges. But probably the most widely studied materials are the oxides (including many silicates and related zeolites), following the discovery of uniform negative CTE in zirconium tungstate (and subsequently in related oxides).

With polymers, the negative CTE usually from thermally breaking cross-linkages between chains. In the oxides, the culprit is usually the rotational modes of the M--O--M bonds.
 
Last edited:
  • #11
expressed gratitude

many thanks
 

Similar threads

High School Pumping water upwards into a large water tank
  • · Replies 6 ·
Replies
6
Views
3K
High School Why does increasing the height of a water tower increase water pressure?
  • · Replies 16 ·
Replies
16
Views
7K
Graduate Fluid Dynamics and Global Warming
  • · Replies 6 ·
Replies
6
Views
2K
Undergrad What happened to the boiling water
  • · Replies 13 ·
Replies
13
Views
4K
High School Will there be water coming out of the last hole?
  • · Replies 17 ·
Replies
17
Views
2K
Undergrad Oil-Water-Salt - What's the force at work here?
  • · Replies 5 ·
Replies
5
Views
17K
Tidal friction and global warming
  • · Replies 10 ·
Replies
10
Views
4K
High School Why does hot water rise to the top of a water heater?
  • · Replies 66 ·
3
Replies
66
Views
6K
High School Problem with understanding deriving Torricelli's law
  • · Replies 14 ·
Replies
14
Views
3K
High School Discovering the Mystery Behind the Direction of Water Swirl in Your Sink
  • · Replies 3 ·
Replies
3
Views
2K