[__ Science __ ] What is Humidity?

[HeIsRisen2018]

And what is the point of using it exactly? I mean if it's seventy degrees outside and the weatherman announces that it feels like eighty, why not just call it eighty degrees temperature wise instead.

 

[Michael74]

Humidity is the amount of water in the air around you. It feels hotter when it is humid because humidity prevents you from cooling off efficiently when you sweat. The air isn't any warmer, but your body can overheat faster. People should be careful when it is both hot and humid.

 

[Bull of the Woods]

Warmer air is capable of holding more water vapor than cooler air.
So in general as the temperature of the air rises over the course of a day the RELATIVE humidity drops.
Your basement will feel more damp/humid because it is cooler than the upstairs (assuming there is no ac unit) and the same amount of available water vapor is closer to the capacity of the cooler basement air.

 

[HeIsRisen2018]

Humidity is the amount of water in the air around you. It feels hotter when it is humid because humidity prevents you from cooling off efficiently when you sweat. The air isn't any warmer, but your body can overheat faster. People should be careful when it is both hot and humid.

Ah,.. I think that I get it now. I'm just glad that I stay hydrated when it's really hot outside and always take my water bottle with me. That's why it also comes in handy to have a basket on my bike to put it in.

Warmer air is capable of holding more water vapor than cooler air.
So in general as the temperature of the air rises over the course of a day the RELATIVE humidity drops.
Your basement will feel more damp/humid because it is cooler than the upstairs (assuming there is no ac unit) and the same amount of available water vapor is closer to the capacity of the cooler basement air.

I see what you're saying, but I currently don't have a basement. I used to though back when I lived at my old house.

 

[WIP]

HeIsRisen2018 this now presents a challenge question for you. When it is raining, is it always 100% relative humidity?

The answer is no. Rain is condensed water in liquid form. Humidity is the amount of water vapor (gas) in the air. One measurement that gives you a more accurate picture of humidity is the dew point. When the air temperature reaches the dew point, the air is fully saturated with water vapor and cannot hold any more. Essentially, evaporation comes to a near standstill. When this happens, you'll feel very uncomfortable as the air feels extremely humid because it is.

 

[WIP]

Ah,.. I think that I get it now. I'm just glad that I stay hydrated when it's really hot outside and always take my water bottle with me. That's why it also comes in handy to have a basket on my bike to put it in.

Here's the problem. Our body regulates temperature by sweating. When the sweat evaporates, the process absorbs heat and this cools your body. When the relative humidity is very high water evaporation slows way down and can even come to a stand still if the air is fully saturated. In this condition, your body will sweat profusely but because the sweat will not evaporate, the sweating doesn't do anything but make you wet. This is when things can get dangerous.

 

[HeIsRisen2018]

HeIsRisen2018 this now presents a challenge question for you. When it is raining, is it always 100% relative humidity?

The answer is no. Rain is condensed water in liquid form. Humidity is the amount of water vapor (gas) in the air. One measurement that gives you a more accurate picture of humidity is the dew point. When the air temperature reaches the dew point, the air is fully saturated with water vapor and cannot hold any more. Essentially, evaporation comes to a near standstill. When this happens, you'll feel very uncomfortable as the air feels extremely humid because it is.

When you put it like that it makes a whole lot more sense to me now. It's sort of funny that you mentioned rain though considering the fact that it's raining right now lol.

 

[HeIsRisen2018]

Here's the problem. Our body regulates temperature by sweating. When the sweat evaporates, the process absorbs heat and this cools your body. When the relative humidity is very high water evaporation slows way down and can even come to a stand still if the air is fully saturated. In this condition, your body will sweat profusely but because the sweat will not evaporate, the sweating doesn't do anything but make you wet. This is when things can get dangerous.

How so if you're drinking enough water. I also noticed when I'm sweating I don't have to urinate as much even when I'm drinking a lot water. How is that so? (sorry, it's a kind of a gross question I know but I'm only just curious.)

 

[WIP]

How so if you're drinking enough water. I also noticed when I'm sweating I don't have to urinate as much even when I'm drinking a lot water. How is that so? (sorry, it's a kind of a gross question I know but I'm only just curious.)

If your body can't cool itself, it will overheat and you could suffer a heat stroke.

When you're sweating a lot, your body is losing fluids and so your bladder isn't filling up. I remember when I was working in the logging business. I'd sweat so much I rarely had to urinate.

 

[HeIsRisen2018]

If your body can't cool itself, it will overheat and you could suffer a heat stroke.

When you're sweating a lot, your body is losing fluids and so your bladder isn't filling up. I remember when I was working in the logging business. I'd sweat so much I rarely had to urinate.

Oh yeah, that's right, now I know what you're talking about. I remember hearing about both things before.

 

[Michael74]

In addition to drinking lots of water in the heat, electrolytes should be replaced too. People can sweat out things like sodium and potassium. That's why football players drink things like Gatorade during the game, instead of just water.

 

[Edward]

You got some fairly decent answers so far, though one of our fine posters did contradict himself in the same paragraphif you read close, lol. ;)

I could add a couple things. You want humidity in your home during the winter because the air will hold more heat and make it a more even temperature in the house. In summer time, you do not want humidity (but you knew that already, lol!) Air conditioners actually dehumidify the air. Unless something goes wrong and it doesn't. Nothing worse than cold and clammy!

 

[WIP]

You got some fairly decent answers so far, though one of our fine posters did contradict himself in the same paragraphif you read close, lol. ;)

I could add a couple things. You want humidity in your home during the winter because the air will hold more heat and make it a more even temperature in the house. In summer time, you do not want humidity (but you knew that already, lol!) Air conditioners actually dehumidify the air. Unless something goes wrong and it doesn't. Nothing worse than cold and clammy!

I'm not catching the contradiction, Edward. Where is it?

 

[Edward]

I'm not catching the contradiction, Edward. Where is it?

I didn't say it was you, lol. I'd have to think for a minute. I haven't had any coffee yet...I'll be back after coffee

 

[Edward]

I'm not catching the contradiction, Edward. Where is it?

I can't find it. Someone said yesterday that cooler air has a greater capacity to hold humidity than warmer air, then went on talking and later said something indicating that warm air holds more humidity. Maybe I just need more coffee still, lol.

 

[WIP]

Maybe you misread something or the post was edited. I don't recall anyone make that statement.

 

[Edward]

Maybe you misread something or the post was edited. I don't recall anyone make that statement.

I had decided that they must have edited it. I dont think I misread it, it kinda jumped out at me when I read it, lol.
But, it wouldn't be the first time if I misread it, lol.

 

[jasonc]

And what is the point of using it exactly? I mean if it's seventy degrees outside and the weatherman announces that it feels like eighty, why not just call it eighty degrees temperature wise instead.

Uhm ac is affected by it.water is what makes the room hot.remove it abd the temp drops,even freezes.

 

[WIP]

Uhm ac is affected by it.water is what makes the room hot.remove it abd the temp drops,even freezes.

Not necessarily. Can have very dry air and still be hot. What an air conditioner does is cool the air by evaporating the moisture out of it. The process of evaporation absorbs heat and that is what cools the air, not removing the water vapor. One reason you may feel cooler in the dry air is because evaporation of your body sweat is much more efficient and so your skin feels cooler.

I believe you've spent time in a desert before. The air in a desert is very dry and yet a desert climate is one of the hottest on the planet....during the day. At night it can cool considerably. With the lack of water vapor in the air, the atmosphere is unable to hold the daytime heat so it cools rapidly when the sun goes down. This is why it can be very beneficial to install a humidifier in our homes for winter heating. Moist air heats and retains the heat much better than dry air.

Prior to installing the whole house humidifier in our forced-air heating system, it was not uncommon for my wife to complain of being cold even when the room temperature was around 75 degrees. After installing the humidifier, she doesn't complain until the room temperature drops below about 68-70 degrees. Being able to reduce the temperature setpoint by 5-7 degrees 24/7 certainly offsets the cost of the humidifier.

 

[jasonc]

Not necessarily. Can have very dry air and still be hot. What an air conditioner does is cool the air by evaporating the moisture out of it. The process of evaporation absorbs heat and that is what cools the air, not removing the water vapor. One reason you may feel cooler in the dry air is because evaporation of your body sweat is much more efficient and so your skin feels cooler.

I believe you've spent time in a desert before. The air in a desert is very dry and yet a desert climate is one of the hottest on the planet....during the day. At night it can cool considerably. With the lack of water vapor in the air, the atmosphere is unable to hold the daytime heat so it cools rapidly when the sun goes down. This is why it can be very beneficial to install a humidifier in our homes for winter heating. Moist air heats and retains the heat much better than dry air.

Prior to installing the whole house humidifier in our forced-air heating system, it was not uncommon for my wife to complain of being cold even when the room temperature was around 75 degrees. After installing the humidifier, she doesn't complain until the room temperature drops below about 68-70 degrees. Being able to reduce the temperature setpoint by 5-7 degrees 24/7 certainly offsets the cost of the humidifier.

Humidity free air durst exist.you wouldn't like such an atmosphere, your body might break out in sores,it's common .I went through that.worse then a tan .chap stick didn't work ,cracked skin etc
Ac works better but you can have dry air in more moderate climates,Washington state is like that.