Quick Question About Plastic Bottle Delfating

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Discussion Overview

The discussion revolves around the phenomenon of a plastic soda bottle deflating after being sealed, particularly focusing on the effects of temperature changes on air volume within the bottle. Participants explore the implications of thermal contraction in a closed system, relating to both theoretical and practical aspects of gas behavior.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant inquires about the temperature of the liquid in the bottle, suggesting that if it was warmer than room temperature, the air volume would contract as the temperature decreases after sealing the bottle.
  • Another participant clarifies that when the cap is closed, the system becomes closed, preventing air from entering or leaving, which leads to a reduction in air volume as the temperature drops.
  • A later reply emphasizes that the air inside the bottle contracts more as the temperature reduces, explaining why the soda volume appears unchanged while the air volume seems less.

Areas of Agreement / Disagreement

Participants generally agree on the role of temperature in affecting air volume within a closed system, but the discussion remains exploratory without a definitive conclusion on all aspects of the phenomenon.

Contextual Notes

Limitations include assumptions about the initial conditions of temperature and the specific properties of the materials involved, as well as the lack of detailed mathematical analysis regarding the volume changes.

QuantamMan
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Hi Guys,

I am new here, but I have a quick question.
I had a somewhat tepid liquid in a plastic soda plastic 2L bottle
When I tightened the cap to close it all was well and normal
After a day a portion of the top of the bottle deflated, as if oxygen was sucked out

Can someone explain this process?

Thank You
QM
 
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Was the water warmer than room temperature?

If yes, the temperature of the bottle and the water became equal after you closed the cap. The air volume contracted as its temperature went down. It couldn't get air from outside because the cap was closed.

http://en.wikipedia.org/wiki/Thermal_expansion"
 
Last edited by a moderator:
omoplata said:
Was the water warmer than room temperature?

yes, we have been having snowfall lately, it's cold right now
 
Here is a clearer and more correct explanation.

Let's assume when you closed the cap, the bottle, the air inside it, and the soda were at the same temperature. When you closed the cap, matter (air) couldn't move in or out of the bottle, so you made it a http://en.wikipedia.org/wiki/Closed_system" . So air contracted more as the temperature reduced. That's why the soda volume seemed to be the same but the air volume appeared to be less.

You can look up these terms in your science textbooks too.
 
Last edited by a moderator:

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