Why does air release differently from a slightly open versus a wide open mouth?

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Discussion Overview

The discussion revolves around the phenomenon of air release from the mouth, specifically comparing the sensations and effects of air released through a slightly open mouth versus a wide open mouth. Participants explore the implications of airflow speed, temperature, and humidity in this context.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that a thinner, faster stream of air from a slightly open mouth pulls more cold air from the surroundings, leading to a cooler sensation.
  • Others argue that the temperature of the air released from the mouth remains constant regardless of the stream's speed, suggesting that the perceived temperature difference is due to evaporative cooling effects on damp surfaces.
  • A participant mentions that they can release hot air even when the mouth is only slightly open, indicating that airflow speed may play a role in the sensation of warmth.
  • Another participant notes that the air exhaled has 100% relative humidity, which affects its ability to cool the skin through evaporation, implying that the sensation of coolness is related to the humidity of the air being pulled in from the environment.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between airflow, temperature, and humidity, with no clear consensus reached on the mechanisms at play.

Contextual Notes

Some claims depend on assumptions about airflow dynamics and environmental conditions, such as humidity levels and temperature, which remain unresolved in the discussion.

kartikwat
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Whay is it that when we release air from our mouth when it is little open then the cold air is released but when we release air from large open mouth hot air is released.
 
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kartikwat said:
Whay is it that when we release air from our mouth when it is little open then the cold air is released but when we release air from large open mouth hot air is released.
The thinner faster stream pulls more cold air from surroundings with it.
 
kartikwat said:
Whay is it that when we release air from our mouth when it is little open then the cold air is released but when we release air from large open mouth hot air is released.

I can release hot air even when it is opened very little. I think you meant opened little and blowing fast.
 
Releasin air from mouth

adjacent said:
I can release hot air even when it is opened very little. I think you meant opened little and blowing fast.

Ya you are correct
 
I think that you will find that the air coming from your mouth has the same temperature as it had in your mouth regardless of the speed of the stream. The difference is in the effect on a damp surface. The amount of evaporative cooling that takes place on that surface is in direct proportion to the square of the wind velocity
 
klimatos said:
I think that you will find that the air coming from your mouth has the same temperature as it had in your mouth regardless of the speed of the stream. The difference is in the effect on a damp surface. The amount of evaporative cooling that takes place on that surface is in direct proportion to the square of the wind velocity

That's true, but I think it's mostly what I said in post #2. When put your finger close to the mouth, then a thin fast stream still feels warm. When you move the finger away it becomes colder, because more cool air is pulled with the stream.
 
A.T. said:
because more cool air is pulled with the stream.

It's 105°F (about 41°C) here right now. Where's the cool air coming from?
 
klimatos said:
It's 105°F (about 41°C) here right now. Where's the cool air coming from?
In this case it's not about being colder, but about having less humidity. You breath has 100% relative humidity, so it cannot evaporate the sweat from your finger, no matter how fast you blow. To feel cold the stream must pull with it some less humid air from the surroundings.
 

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