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

  • Context: High School 
  • Thread starter Thread starter kartikwat
  • Start date Start date
  • Tags Tags
    Air
Click For Summary
SUMMARY

The discussion centers on the phenomenon of air release from the mouth, specifically contrasting the temperature and humidity of air expelled through a small versus a wide opening. When air is released through a narrow opening, it creates a faster stream that pulls in cooler, less humid air from the surroundings, resulting in a cooling effect. Conversely, a wide opening allows for a slower stream, which can feel warmer due to the lack of evaporative cooling from the surrounding air. The temperature of the air expelled remains consistent with that in the mouth, but the perceived temperature changes based on the airflow dynamics.

PREREQUISITES
  • Understanding of airflow dynamics
  • Basic knowledge of temperature and humidity concepts
  • Familiarity with evaporative cooling principles
  • Awareness of relative humidity effects on temperature perception
NEXT STEPS
  • Research airflow dynamics and its impact on temperature perception
  • Study the principles of evaporative cooling in different environments
  • Explore the effects of humidity on thermal comfort
  • Investigate how airflow velocity influences heat transfer
USEFUL FOR

This discussion is beneficial for physicists, meteorologists, and anyone interested in the principles of thermodynamics and fluid dynamics, particularly in relation to human perception of temperature and humidity.

kartikwat
Messages
49
Reaction score
0
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.
 
Physics news on Phys.org
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.
 

Similar threads

High School Fan is pushing in the front and sucking from the back
  • · Replies 32 ·
2
Replies
32
Views
1K
High School The Physics of blowing a puff of air
  • · Replies 3 ·
Replies
3
Views
2K
High School Help understanding the physics of airflow
  • · Replies 3 ·
Replies
3
Views
2K
High School Moist air - does it rise or drop?
  • · Replies 42 ·
2
Replies
42
Views
12K
High School How to estimate the heating power of warm air entering a room?
  • · Replies 8 ·
Replies
8
Views
3K
How to determine air velocity in open ended tube?
  • · Replies 9 ·
Replies
9
Views
2K
Improving Air Flow on a 50ft Houseboat in the Desert SW
  • · Replies 33 ·
2
Replies
33
Views
4K
High School Are wind farms stealing the cooling capacity of the wind?
  • · Replies 4 ·
Replies
4
Views
3K
Undergrad Centrifugal separation into hot & cold air streams?
  • · Replies 1 ·
Replies
1
Views
2K
High School Does the Bernouli Effect Work On Cars?
  • · Replies 8 ·
Replies
8
Views
3K