Granny's gone and done it again

Can someone explain dew point to me like I'm stupid?

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MOTC
Roadrunner
5/31/1311:55 AM
I don't know why I'm having such a hard time getting my head around this idea. I know it has to do with the saturation of moisture in the air, and therefore the evaporation of sweat and your body's ability to cool itself. What I don't understand is the way in which it is measured by temperature. If the dew point is 66 degrees, does that mean that is the temperature at which the air can no longer hold moisture? if that is the case, then wouldn't a dew point of 46 degrees be worse because the air is saturated at a lower point? Obviously thats not true so I'm missing an important element of this. Help?

Imagine cooling a volume of air. Dew point is the temperature at which the first droplets of water appear. Here is another way to think about it. You are probably familiar with condensation on the outside of a glass of ice water. Imagine, instead of ice water, a series of water glasses at different temperatures. Dew point is the warmest temperature that would still produce condensation on the outside of the glass.

This effect occurs because warmer air can hold more moisture. For example air at 100F can hold 0.043 lbs of water per pound of air, while air at 50F can only hold 0.0077 lbs of water per pound of air. Suppose the air temperature was 100F and there was 0.0077 lbs of water per pound of air in the air. The dew point would be 50F because once the air was cooled to 50F it would be saturated and water would begin condensing.

In the above example, if there was more than 0.0077 lbs water/lb air then the dew point would be higher. Higher dew point represents higher humidity.

You may be wondering what this has to do with evaporation of sweat. For evaporation to occur there must be a difference in humidity. This is known as a driving force. The larger the driving force the faster the evaporation will occur. (same thing applies to cooling, e.g., an object will cool faster in the freezer than the refrigerator). Faster evaporation means more cooling.

I hope this helps.

It did not.
hmm.png
I can understand he mechanics, just not how it relates to me, why I want to know.
idunno.gif
 
Quote:
MOTC
Roadrunner
5/31/1311:55 AM
I don't know why I'm having such a hard time getting my head around this idea. I know it has to do with the saturation of moisture in the air, and therefore the evaporation of sweat and your body's ability to cool itself. What I don't understand is the way in which it is measured by temperature. If the dew point is 66 degrees, does that mean that is the temperature at which the air can no longer hold moisture? if that is the case, then wouldn't a dew point of 46 degrees be worse because the air is saturated at a lower point? Obviously thats not true so I'm missing an important element of this. Help?

Imagine cooling a volume of air. Dew point is the temperature at which the first droplets of water appear. Here is another way to think about it. You are probably familiar with condensation on the outside of a glass of ice water. Imagine, instead of ice water, a series of water glasses at different temperatures. Dew point is the warmest temperature that would still produce condensation on the outside of the glass.

This effect occurs because warmer air can hold more moisture. For example air at 100F can hold 0.043 lbs of water per pound of air, while air at 50F can only hold 0.0077 lbs of water per pound of air. Suppose the air temperature was 100F and there was 0.0077 lbs of water per pound of air in the air. The dew point would be 50F because once the air was cooled to 50F it would be saturated and water would begin condensing.

In the above example, if there was more than 0.0077 lbs water/lb air then the dew point would be higher. Higher dew point represents higher humidity.

You may be wondering what this has to do with evaporation of sweat. For evaporation to occur there must be a difference in humidity. This is known as a driving force. The larger the driving force the faster the evaporation will occur. (same thing applies to cooling, e.g., an object will cool faster in the freezer than the refrigerator). Faster evaporation means more cooling.

I hope this helps.

It did not.
hmm.png
I can understand he mechanics, just not how it relates to me, why I want to know.
idunno.gif


LOL those were 2 posts that I combined NONE of it is in my words or understanding really,. Other then I know sweating helps cool a person's body off faster. or and here I am assuming in cold weather would chill a person down quicker for hypothermia to set in.
 

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