Strange behavior of the density of the water around the freezing point

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Discussion Overview

The discussion revolves around the unusual behavior of water's density near the freezing point, particularly the phenomenon where water reaches its maximum density at approximately 4 degrees Celsius, contrary to typical expectations of density decreasing with temperature. The conversation includes theoretical explanations, illustrative analogies, and inquiries about molecular behavior.

Discussion Character

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

Main Points Raised

  • Some participants propose that water expands as it approaches freezing due to the alignment of its polar molecules forming a crystalline structure.
  • One participant notes that the maximum density of water occurs at around 4 degrees Celsius, attributing this to the polar nature of water molecules.
  • Another participant highlights that this behavior is specific to pure water and does not apply to seawater or water with dissolved substances.
  • A participant questions why water is less dense at 2 degrees Celsius than at 4 degrees Celsius, suggesting that hydrogen bonding dynamics may play a significant role.
  • There is a request for more diagrammatic illustrations to explain the molecular shape's effect on water's density behavior.

Areas of Agreement / Disagreement

Participants express varying degrees of understanding and curiosity about the topic, with some agreeing on the basic principles while others raise questions and seek further clarification. No consensus is reached on the underlying mechanisms or the specifics of the density behavior.

Contextual Notes

Participants mention the need for diagrams to illustrate molecular interactions, indicating that visual aids may be necessary to fully grasp the concepts discussed. There is also an acknowledgment that the discussion primarily pertains to pure water, with implications that other types of water may behave differently.

Who May Find This Useful

This discussion may be of interest to individuals exploring the properties of water, students studying chemistry or physics, and those curious about the implications of molecular behavior on physical properties.

bolbol2054
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please is there a topic that discuss with illustration factor that causes Strange behavior of the density of the water around the freezing point
 
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Can you be more specific?
Do you mean why it begins to expand?

That's fairly simple; water begins to expand because its poles are trying to line up so it can form a crystaline matrix.

Get ten people to crowd together in the centre of a room with their arms outstretched. They could probably crowd together pretty closely - outstretched arms overlapping and intertwined - if you herded them together.

Now, with their arms still outstretched, tell them to move around so they can hold hands with each other. They won't be able to grab each others' hands until they step back a pace or two. They'll take up more of the room.
 
I presume you mean the fact that the maximum density is around +4 degrees centigrade?

This is due to the highly polar nature of the water molecule because of its shape.

Please note this is only applies to fresh water ie pure water. Water with dissolved material eg seawater does not exhibit this phenomenon.
 
i meant with strange behavior that water contradicts the role of decreasing density due to increasing temperatur at a range from 0 c degree to 4 c degree
 
Studiot said:
I presume you mean the fact that the maximum density is around +4 degrees centigrade?

This is due to the highly polar nature of the water molecule because of its shape.

yes sir that's exactly what i meant but i want to know with more diagramatic illustration the effect of molecule's shape on this behaviour i thought that such basic phenomena had a lot of discussion in previous threads
 
Is your question, why is water less dense at 2C than at 4C even though it isn't ice?

Heck if I know. I'm not a chemist. But as an aspiring odds-maker, my money says that an increase in the time that hydrogen in one molecule temporarily bonds to oxygen in another dominates over the thermal agitation that would separate them.

Was that the question? If so, I wonder what the density curve of supercooled water looks like.
 
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