Why Does Water Show Maximum Density at 277K?

  • Context: Undergrad 
  • Thread starter Thread starter shaviprem
  • Start date Start date
  • Tags Tags
    Density Maximum
Click For Summary

Discussion Overview

The discussion centers around the phenomenon of water exhibiting maximum density at approximately 277 K (4°C) and whether this behavior is unique to water or observed in other substances. The scope includes theoretical explanations and conceptual clarifications regarding the properties of water and its molecular structure.

Discussion Character

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

Main Points Raised

  • Some participants note that water has a maximum density at around 4°C, which is significant because it is the only substance where maximum density does not occur when solidified.
  • One participant references a source stating that water expands upon freezing, increasing in volume by about 9%, which contributes to ice being less dense than liquid water.
  • Another participant suggests that the polar nature of water molecules may explain its unique properties and speculates that other polar substances might exhibit similar behaviors.
  • There is a mention of the implications of water's density properties on environmental phenomena, such as ice fishing and the prevention of lakes freezing solid due to convection currents.
  • One participant discusses the unique crystal structure of ice, which is believed to be less dense than liquid water, leading to the observed density changes below 4°C.

Areas of Agreement / Disagreement

Participants generally agree that water's maximum density occurs at 4°C and that this property is linked to its molecular structure. However, there is no consensus on whether other substances exhibit similar behavior, and the discussion includes varying interpretations of the underlying reasons for water's properties.

Contextual Notes

Some statements rely on external sources, and the accuracy of those claims is not verified within the discussion. The exploration of other polar substances as potential analogs to water's behavior remains speculative.

shaviprem
Messages
2
Reaction score
0
i have had this problem for some time. why exactly does water show a maximum density at about 277 K. and is it the only substance to show such a behaviour.
 
Science news on Phys.org
From http://www.simetric.co.uk/si_water.htm

"When water freezes it expands rapidly adding about 9 % by volume. Fresh water has a maximum density at around 4° Celsius. Water is the only substance where the maximum density does not occur when solidified. As ice is lighter than water, it floats."
----------------
Now, I can not speak for the accuracy of that statement, but that's what that link says.
 
pallidin said:
From http://www.simetric.co.uk/si_water.htm

"When water freezes it expands rapidly adding about 9 % by volume. Fresh water has a maximum density at around 4° Celsius. Water is the only substance where the maximum density does not occur when solidified. As ice is lighter than water, it floats."
----------------
Now, I can not speak for the accuracy of that statement, but that's what that link says.

The reason for water's remarkable properties are usually traceable to the fact that it is such a polar molecule. I would imagine that other polar molecular substances might have similar properties. It would be a place to start looking, anyway.

-Dan
 
shaviprem said:
i have had this problem for some time. why exactly does water show a maximum density at about 277 K. and is it the only substance to show such a behaviour.
If that were not true, we couldn't go ice fishing.
 
?? That is true - the max density is at 4C (277K) and it decreases from there, which makes ice float. That's also what keeps lakes from freezing solid: 4C water being the least dense, sets up a convection, circulating ground heat.

My understanding was that the crystal structure(s) is unique in being less dense than the liquid state and below 4C, the molecules start to line-up, decreasing the density.
 
Last edited:

Similar threads

Undergrad Calculating vapor pressure from Boltzmann distribution?
  • · Replies 0 ·
Replies
0
Views
2K
Undergrad Confusion on Callen's Maximum Work Theorem
  • · Replies 7 ·
Replies
7
Views
2K
High School Calculating vacuum -- These numbers do not make sense
  • · Replies 30 ·
2
Replies
30
Views
4K
High School Why does hot water rise to the top of a water heater?
  • · Replies 66 ·
3
Replies
66
Views
5K
Undergrad How can the maximum entropy and minimum energy principles be physical?
  • · Replies 13 ·
Replies
13
Views
4K
Undergrad How does evaporation generate cooling? Swamp coolers edition
  • · Replies 32 ·
2
Replies
32
Views
4K
Undergrad How to find the change in volume of a solid to a liquid
  • · Replies 3 ·
Replies
3
Views
2K
High School Does movement affect H2O freezing temperature?
  • · Replies 16 ·
Replies
16
Views
7K
Undergrad How can visible gas bubbles remain intact inside frozen water?
  • · Replies 8 ·
Replies
8
Views
2K
Undergrad Volume of water consumed by vacuum
  • · Replies 5 ·
Replies
5
Views
2K