Questions tagged [humidity]
176 questions
30
votes
4 answers
Why does humidity cause a feeling of hotness?
Imagine there are two rooms kept at the same temperature but with different humidity levels. A person is asked to stay in each room for 5 minutes. At the end of experiment if we ask them which room was hotter, they will point to the room with the…
tollin jose
- 1,293
22
votes
5 answers
Does humidity make cold air feel colder?
I sometimes hear stories where people compare their feelings in winter in different places in the world.
It goes like
in city X the temperature was the same as in city Y, but the humidity made me feel much colder...
or
oh well, -20°C would be…
user27542
- 876
18
votes
1 answer
Why does pepper not stick to the glass with print inside my pepper shaker?
So I have this pepper shaker made of glass with a print on it:
One fine dinner, it ran out of pepper, so I opened the lid to fill it up and noticed a peculiar thing – small particles of pepper dust were stuck to the inside glass walls but only in…
kamilazdybal
- 273
17
votes
7 answers
How does humidity affect the path of a bullet?
Background
Last night, I was reading the FM 23-10 (The U.S. army official field manual for sniper training), and I've noticed that they're potentially teaching snipers incorrect information.
Generally speaking, when we say "impact goes up" it means…
Adi
- 1,628
17
votes
7 answers
Why is there a maximum humidity?
Recently I've been browsing humidifiers for my room. Everyone "knows" that humidity is measured in percentages, and 100% humidity is the maximum humidity that the air "can hold" - that's how people seem to explain it.
But, why should there be a…
spinachflakes
- 7,318
10
votes
2 answers
Why does desiccant cool down air?
I put a lot of desiccant inside a large airtight container and left it for a while, then I opened it and put my hand inside, I can feel the air is much cooler, why is that?
Sujal Singh
- 227
9
votes
2 answers
What determines the shape of the 100% relative humidity curve
Figure 1. Source: Wikipedia Commons.
The Wikipedia article on relative humidity states:
A useful rule of thumb is that the maximum absolute humidity doubles for every 20 °F or 10 °C increase in temperature.
A coarse thumb, perhaps, but it gives…
Transistor
- 222
9
votes
1 answer
How to calculate the volume of water in a certain amount of air, given the relative humidity?
If, according to the weather forecast, the current humidity is 90%, how can I calculate the volume of water that could be extracted from a certain volume of that air?
Amr Bekhit
- 227
8
votes
1 answer
Why is sound attenuation greater in dry air than humid air?
I have just learned the surprising fact that the attenuation coefficient of sound in air depends strongly on relative humidity: at any given frequency, it can be several times larger in very dry air (10-20% RH) than in very humid air. The internet…
Ben51
- 10,037
8
votes
3 answers
Inside vs outside humidity
I have a practical problem that I want to reduce the humidity inside our house. I know the inside and outside temperature (degrees C) and the relative humidity (both inside and outside). How do I know if opening the window will make it less humid…
psiphi75
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7
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Preventing fog inside snow goggles
I understand that goggles fog up because of a rapid temperature change. In other words, goggles that have been sitting on a table outside (i.e., are very cold), when you put them on your face which emits warm air, can start to fog. Dangerous for…
james
- 249
7
votes
4 answers
How to relate speed of sound with relative humidity?
I am exploring the idea of measuring the humidity of a space using sound waves, however I am having trouble finding a mathematical relationship between the speed of sound and the humidity level.
$c_{air} = 331.3 \sqrt{1 + \frac{T}{273.15}}$ but…
Michael
- 800
6
votes
2 answers
Why do fireproof safes "capture and hold in moisture"?
From The Best Fireproof Document Safe | Reviews by Wirecutter:
Humidity can be an issue with these safes, as they tend to capture and hold in moisture, which can damage their contents.
Someone commented:
Is this really as good as it gets? Is the…
Kenny Evitt
- 197
6
votes
2 answers
Does fog clean the air of fine dust
When fog forms, the air is usually saturated with moisture. Thus, small droplets form and creates fog. Suspended fine dust can serve as condensation nuclei during the formation of fog.
So my question is: when fog forms overnight over a city, is the…
Dohn Joe
- 598
5
votes
1 answer
Why can I see my breath after I pop my ears?
I have this weird but reproducible thing that I can see my breath for less than a second even in hot/humid weather. The key to do that is to pop my ears - I have to do that often, it's like I'm on a flight, not sure why my ear is that way... Anyway…
