Hot liquid mixed with a cold liquid

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Discussion Overview

The discussion revolves around the behavior of temperature when a hot liquid is mixed with a cold liquid, specifically addressing the definition of temperature during the mixing process and the time it takes for the mixture to reach a constant temperature. The scope includes conceptual understanding and clarification of thermal dynamics in mixing liquids.

Discussion Character

  • Conceptual clarification, Debate/contested

Main Points Raised

  • One participant questions the textbook's statement that the temperature is "undefined for some time," suggesting that the temperature should first decrease before becoming constant.
  • Another participant argues that during the mixing process, the temperature can vary between the temperatures of the hot and cold liquids, indicating that it is not completely undefined.
  • Some participants note that the perspective on temperature change may depend on whether one is considering the hot or cold liquid, with the cold liquid's temperature increasing before stabilizing.
  • A request for further elaboration on the time it takes for mixing to occur is made, indicating a lack of familiarity with this aspect of the process.
  • A participant uses the analogy of baking a cake to illustrate that mixing is not an instantaneous process, implying that time is a factor in achieving a uniform temperature.

Areas of Agreement / Disagreement

Participants express differing views on the definition of temperature during the mixing process, with no consensus reached on whether the temperature can be considered undefined or variable. The discussion remains unresolved regarding the implications of time in the mixing process.

Contextual Notes

There are limitations in understanding the assumptions behind the textbook's terminology and the definitions of "undefined" in this context. The discussion does not resolve the mathematical or physical principles governing the mixing process.

Elena14
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My textbook says - When a hot liquid is mixed with a cold liquid, the temperature of the mixture -
"is undefined for some time and then becomes nearly constant".
Shouldn't the temperature first decrease and then become constant ? Why does it say "undefined" ?
 
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The mixing process takes some time during which a temperature reading can give 'anything' between Thot and Tcold. So it's not completely undefined.

Your perspective is apparently from the hot liquid ? Because for the cold liquid the temperature increases and then becomes constant !
 
BvU said:
The mixing process takes some time during which a temperature reading can give 'anything' between Thot and Tcold. So it's not completely undefined.

Your perspective is apparently from the hot liquid ? Because for the cold liquid the temperature increases and then becomes constant !

I haven't really come across this fact that the mixing process takes time. Will you please elaborate on this one?
 
Elena14 said:
I haven't really come across this fact that the mixing process takes time. Will you please elaborate on this one?
If you have ever baked a cake, you will know that mixing is one of the steps. That step is not instantaneous.
 

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