# Questions tagged [humidity]

The tag has no usage guidance.

172 questions
Filter by
Sorted by
Tagged with
56 views

### How long does it take to saturate the water vapor pressure in a small enclosed space?

I am trying to create an as much humid as possible small enclosed space (like a zip bag). If I leave more than required amount of water in the zip bag, how long does it roughly take to reach the ...
• 101
14 views

### Dewpoint of a particular place

can dewpoint of a certain room change if I decrease the temperature or increase it? And what factors does RH,Dewpoint and Saturated cloud pressure depends on?
1 vote
62 views

### For hot air at 150 °C have a density of 0.61 kg / m³, how to calculate the density for 160 °C? [closed]

I am working on a project draft and in an existing device, hot air up to 160 °C is generated for drying processes. I have found old documents where densities of air are reported at three different ...
1 vote
87 views

### Steam from a cup of coffee

I observed that, in winter there is more visible steam from a cup of coffee than in summer. Is there any phenomenon taking place here.
48 views

### How do I calculate the Relative Humidity from number density and pressure? [closed]

From some measurements I have determined and calculated the temperature and number density of water molecules in (m^-3) at a pressure of X Pa. How do I get the RH value out of those variables?
• 23
1 vote
56 views

### Why there is water produced on the phone if we keep our phone in our pocket for a longer time?

one day I kept my phone in my pant pocket, I haven't opened it for a long time. My phone is covered with a plastic case. So why the phone is getting wet when I observed it after some time even though ...
• 27
49 views

### Is stoßlüften - quick exchange of air through windows actually more efficient than slow exchange through a wall ventilation fan?

In German areas with near air-tight homes, it is recommended that full house ventilation is performed by stoßlüften - opening windows fully to exchange as much air as possible in shortest amount of ...
• 21
1 vote
240 views

### Is water capacity of air affected by air pressure?

Air can hold water in proportion to partial pressure of water vapor. This is affected by temperature. But is the water capacity of air also affected by ambient pressure? I did find some answers that ...
• 11
155 views

### Does relative humidity rise faster in cooler or warmer air?

A bit of background: I live in an old house in Austria and have been following the changes of temperature and relative humidity in our basement (which has two small but permanently open windows). The ...
• 101
114 views

### How does athmospheric pressure influence dewpoint?

I have a sensor that measures temperature, relative humidity and air pressure. All the formulas I could find for both absolute humidity and the dew-point only use the temperature and humidity values, ...
324 views

### How much electricity can be directly generated from air humidity?

There have been some recent papers on harvesting electrical energy from air humidity using nanoengineered materials: "Power generation from ambient humidity using protein nanowires" in ...
• 11.7k
94 views

### Can water in a small container increase the humidity of the surrounding area? [closed]

I have been instructed to keep a liquid drug in a cool and dry place (away from humidity), at temperature not exceeding $25^\circ$ C, but also to avoid freezing it, as it may crystallize. On a very ...
• 101
1 vote
16 views

### Effects of altitude on constant relative humidity maintained by aqueous glycerin solutions

ASTM D5032-19 describes how to generate and maintain a constant humidity by means of aquesous glycerine solutions. The procedure allows for the relative humidity to be calculated from the mass of the ...
77 views

### Why does relative humidity appear limited for temperatures above 80°F?

I recently compiled ten years of NOAA local climatological data. I noticed that the maximum relative humidity dropped linearly from 100% at about 80°F to 20% at about 110°F. Nothing obvious comes to ...
18 views

### Oil humidification

I would like to investigate how to increase relative humidity of transformer oil experimentally. Firstly, to find out at which rH value saturation occurs and secondly, how long this takes. So far, ...
• 1,507
210 views

### What would happen if I put a wet/dry bulb hygrometer in supersaturated air (RH > 100%)? Would the wet bulb read hotter than the dry?

Answers to Why is there a maximum humidity? address the thermodynamics of water vapor in air, and the Earth Science SE question How is relative humidity determined from a wet and dry bulb readings? ...
• 6,273
4k views

### 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" - ...
• 6,936
1 vote
40 views

### Question regarding converting analog sensor value into mA [closed]

I'm doing a project with an absolute humidity sensor. When I bought an absolute humidity sensor and implemented it into a machine, I expected the output value to be representative of absolute humidity,...
104 views

### What can cause this condensation pattern in a window's glass?

What can cause a condensation pattern like this one: in a kitchen's window? Found early in the morning. Adjacent windows had an homogeneous condensation "pattern" all over the surface. ...
120 views

### Do bubbles of humid air condense when bubbled up through water?

I'm working with an ultrasonic humidifier that bubbles the humid air produced through water. I'm wondering if the humid bubbles condense into the surrounding water. Does this happen?
• 111
40 views

### Water equilibrium when relative humidity is high

Suppose a puddle has water and another component whose composition is known. The water in it would be in equilibrium with the water vapour following Raoult and Dalton's law (also here): P_T y=P^0_{...
306 views

### What are the most important physics of hair dryers? [closed]

I can think of at least three distinct mechanisms by which a hair dryer could remove moisture from hair, but I do not know which, if any, of them dominates. Mechanically remove the water. This ...
• 1,950
87 views

### What mechanism allows dehumidifiers to remove more humidity than air conditioning? [closed]

So an air conditioner has a condenser and evaporator on different sides of the window, and produces a lot of condensation as a byproduct. A dehumidifier pulls air onto cold coils, separating water out,...
• 101
1k views

### Will the relative humidity in a closed container reach 100 % on heating the liquid within it?

If we heat a partially filled closed container with liquid in it, will the relative humidity ever reach 100% (assuming that the vessel is strong enough to hold infinite amount of pressure). I have ...
• 148
129 views

### Convert specific humidity to relative humidity but without having all variables available?

I was wondering if there is a way to obtain relative humidity from specific. My constraint is that I am not trying to solve a problem by hand. I am downloading data for a specific region, in order to ...
• 1
14 views

### From specific to relative humidity?

I was wondering if there is a way to obtain relative humidity from specific. My constraint is that I am not trying to solve a problem by hand. I am downloading data for a specific region, in order to ...
• 1
149 views

### Air temperature drop by water mist cooling [closed]

if we have a volume of air (1m3/1'200g) at a certain temp (25°c) and let water evaporate into it, what is the max achievable air temp drop? how much water has evaporated (i guess i can calculate the ...
• 1
180 views

### Variation of Relative Humidity (RH) in closed room vs outside

I have an insulated garage room with the doors closed, and I am interested to monitor the Temperature + Relative Humidity (RH) inside the room, compared with outside. I have taken some readings ...
• 121
528 views

### How much humidity value underwater?

Stumbled upon this question this morning. Yet couldn't find the answer on google If humidity is defined as ratio of water (vapor) content in air, what value will it show if we put the sensor ...
• 11
2k views

### Does water evaporate more quickly from ocean if air is cold or hot?

If a colder air mass blows over warmer ocean water, does evaporation of water happen quicker than earlier when the air was warmer?
• 51
68 views

### Is it better to line dry inside or outside a house? [closed]

On a winter night (so no radiation from the sun), my house is 10°C warmer than outside. Both temperatures are above freezing. I measured the humidity and found out it to be the same both outside and ...
• 121
78 views

### Mystifying Relative Humidity - That can't be accurate?

While humidifying a room in my home, measuring the Temperature and Relative Humidity (T&RH respectively) every 8 hours, I noticed that RH rises and falls with T when it should be the inverse. I ...
• 101
30 views

### Temperature-Humidity-Wind (THW) index for hot and cold weather [duplicate]

Does anyone know the formula (or the algorithm, even a fortran code) to calculate the Temperature-Humidity-Wind (THW) index not from the heat index but in general? (someone published a (too simple?) ...
1 vote
58 views

### If I maintain air temperature in a room, but allow humidity to vary, will room objects remain at the same temperature?

Let's say I have a room with a HVAC system and I'm trying to keep objects in the room at a constant body temperature. My HVAC system maintains a constant air temperature, but the relative humidity in ...
• 155
1 vote
155 views

### Why i feel cool when near a lot of trees although it absorb heat from environment still it make environment humid ALSO? [duplicate]

Why I feel cool in a region with lot of trees inspite of humidity by transporation? Today I went for a walk and entered a region with lot of trees, It feel a sudden chill, a cool feeling (...
321 views

### What actually we mean when we say "reaching 100% relative humidity and no further evaporation"?

What do we mean by reaching 100% relative humidity? Is that we reach the utmost vapor pressure at that particular temperature of liquid? Or something else. If I have 2 half filled water bottle, in one ...
115 views

### Why I feel cool in a region with lot of trees inspite of humidity by transporation?

Today I went for a walk and entered a region with lot of trees, It feel a sudden chill, a cool feeling (comparatively) Why, Although trees perform transpiration that cause moisture so we should feel ...
3k views

### Mollier diagram and reading the relative humidity when knowing the dry- and wet bulb temperatures

I had a thought error when reading Mollier diagrams and thankfully we have the internet to assist, but even after finding the correct sources showing the answers, I can't get out of my thought-loop to ...
2k views

### How is it possible to calculate the water content of air in liters ( from relative humidity and temperature )?

My home has 150 m3 air. I would like to calculate, that how much liters of water this air contains, if the temperature is 25 C° and the relative humidity is 60%. I would like to calculate it for 26 C° ...
• 297
264 views

### How they work: dehumidifier vs air conditioner [closed]

From what I understand both dehumidifiers and air conditioners do the same thing. They blow air onto cooled pipes. This means that dehumidifiers must cool the air and air conditioners must dehumidify ...
• 31
1 vote
3k views

### How do we cool exactly as sweat evaporates from our skins?

We all know that when our sweat evaporates to the air we feel colder, but since this process is a latent heat transfer our body temperature will not change, then if our body temperature is constant ...
332 views

### What is the effect of atmospheric pressure on the vapour pressure of water?

This question relates to a planned test simulating cold, humid air flowing inside a cold pipe at altitude and measuring the ice that is formed inside the pipe. I have a value from: https://courses....
77 views

### What is the RH of blown air effect?

From xto 2 is a dehumidification process to an air inside an air conditioner. This process will sure give you air with low moisture content which will let you feel dry air. But also this air holds a ...
43 views

### Air Conditioners Proccess

When using cooling with dehumidification process sometimes the relative humidity increases, my question is that won't the blown air effect your skin by humidity due to this increase in relative ...
1k views

### Relative humidity at different temperatures misconception

People in hot arid deserts often look at the weather report and find out the RH is 20%. Then they say it's 20% in a warm tropical country, so we're in just as humid a place as that! Doesn't a RH of 20%...
• 340
34 views

### How to maintain moisture on a substrate?

I know that different materials absorb water differently and dry differently. The simplest example is when washing clothes and putting them in the dryer they take different amounts of time to ...
82 views

### How exactly does air accommodate water vapor?

I would like to have clarity on how air accommodates water. When water vaporises, does the water molecules just squeeze into the space between already existing molecules of nitrogen and oxygen? From ...
• 941
2k views

### What does 'saturated' air actually mean?

I'm having some problem in getting an insight on what 'saturation with vapor' actually means. The question is asked in the context of atmospheric air becoming saturated with water vapor and beginning ...
• 941