Why Is There Cold Wind? Investigating the Creation of Wind and Its Temperature"

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    Cold Wind
In summary, wind can feel hot or cold depending on various factors such as the temperature of the air and the presence of objects like clothes and hair. The kinetic theory of gases explains that wind is created by uneven heating of the Earth's atmosphere and the movement of air from areas of high pressure to areas of low pressure. Wind velocity does not directly affect temperature in this theory. Other factors such as humidity and evaporation can also contribute to the perception of wind's temperature.
  • #1
tony1grendel
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So awhile ago I was thinking about wind.

Sometimes wind is hot but when I think of wind I usually think of cold wind.
Wind seems to be fast moving particles and I know based on the kinetics theory of gases

[tex] KE = \frac{1}{2}mv^2 = \frac{3}{2}kT [/tex]

Maybe, I'm making a wrong assumption but to me this seems that if a particle of gas has a high KE and high v that it will have a high T

So why would there be cold wind. Shouldn't all high velocity wind be hot?

Through my investigation of this I have gotten some info on how wind is created.

From what I can gather

The sun heats the Earth unevenly
The atmosphere of the Earth that is getting heated
and the hot air rises because it becomes less dense

(here is where I get a little confused and maybe making wrong assumptions)

this causes less pressure in that area of the atmosphere
causing nearby particles of air to fill the uneven pressure (partial vacuum the rising hot air created?)

and so you have wind!

To me it seems if the gases filling the uneven pressure have a low T that it would seem plausible that we would have cold wind BUT wouldn't that air over time heat up because of it's increase in KE?

I know this looks like a wall of text now but this is my thought process
 
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Welcome to PF!

1. Bulk motion is not included in the temperature.
2. Can you calculate at what speed, the KE would make a noticeable difference if converted to heat?
 
  • #3
Also, the pressure of the atmosphere is not evenly distributed at anyone time. If a region of low pressure develops, a portion of the atmosphere from a region of higher relative pressure will move in. This movement will also create wind.
 
  • #4
Sometimes wind is hot but when I think of wind I usually think of cold wind.

Clothes and hair trap a layer of warm air next to your skin. Wind can remove this layer of warm air making it feel colder than it would otherwise.

More..

http://en.wikipedia.org/wiki/Wind_chill
 
  • #5
tony1grendel said:
Wind seems to be fast moving particles and I know based on the kinetics theory of gases

[tex] KE = \frac{1}{2}mv^2 = \frac{3}{2}kT [/tex]

Maybe, I'm making a wrong assumption but to me this seems that if a particle of gas has a high KE and high v that it will have a high T
You're right. You are making a wrong assumption. Velocity and energy are frame-dependent quantities -- change the frame of reference and you get different velocities, different kinetic energy. So in which frame are those velocities expressed? The answer is that it is a rest frame of the gas, a frame in which the total momentum is zero.

In other words, wind velocity doesn't come into play in determining temperature in the kinetic theory of gases.
 
  • #6
CWatters said:
Clothes and hair trap a layer of warm air next to your skin. Wind can remove this layer of warm air making it feel colder than it would otherwise.
There's also the effect of evaporation if a person is sweating, and the effect of relative humidity.

If the air temperature is around 100°F ~= 38°C or higher, the wind will make it fill hotter still.

http://www.zunis.org/at_least_theres_a_breeze.htm
 

1. Why is there cold wind?

The creation of wind is a result of differences in air pressure. As the sun heats the Earth's surface, the air near the surface becomes warmer and rises. This creates an area of low pressure. As the warm air rises, it leaves behind an area of low pressure, which is then filled by cooler air from other areas. This movement of air creates wind, which can feel cold due to the temperature of the cooler air.

2. How does wind affect temperature?

Wind can affect temperature in several ways. For example, when the wind is blowing, it can carry cooler air to a location, resulting in a decrease in temperature. Additionally, wind can make it feel colder than it actually is by increasing the rate of heat loss from our bodies through convection. On the other hand, wind can also bring warmer air to a location, resulting in an increase in temperature.

3. What factors contribute to the temperature of wind?

The temperature of wind is affected by several factors, including air pressure, air temperature, and humidity. As air moves from areas of high pressure to areas of low pressure, it can undergo compression or expansion, which can change its temperature. Additionally, wind can also carry air from different regions with varying temperatures, which can also impact its temperature.

4. Why does wind feel colder at higher altitudes?

Wind at higher altitudes can feel colder due to several factors. As you climb higher, the air becomes thinner, meaning there is less air to absorb and retain heat. This results in a decrease in air temperature. Additionally, wind at higher altitudes may also be affected by factors such as the presence of clouds, which can block the sun's heat and make it feel colder.

5. How does wind form and move?

Wind forms and moves due to differences in air pressure. As mentioned earlier, the sun's heat causes warm air to rise, creating an area of low pressure. This low pressure area is then filled by cooler air from other areas, resulting in the movement of air or wind. The speed and direction of wind can also be influenced by various factors such as the Earth's rotation, the topography of the land, and the presence of large bodies of water.

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