# Tagged Questions

The process of a liquid changing to a gaseous state

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### Methods to solve a vapor pressure equilibrium question with water on the moon? [on hold]

"Imagine a tall column of water on the Moon, maintained at a temperature of 50°C and left to the open vacuum at the top. Up to what depth will the water continue to boil? The Moon's radius is 0.273 ...
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### Acer saccharum (Sugar Maple) Sap & Freezing

This may or may not be the appropriate scientific discipline to ask this question of, but I'll give it a shot. I'll happily invite chemists to chime in as well. It's time to tap sugar maples in the ...
250 views

### Conditions for heat exchange and evaporation

I wonder if there is any law for heat exchange. I have learnt that heat exchange between systems occurs when the temperature of the systems differ , but in case of evaporation, the process creates a ...
154 views

### Calculating Evaporation Rate for Milk

So, I am kind of physics dumb. I have found the equation for water evaporation from a pool and I have been attempting to make work and make sense for creating a spreadsheet that will help me predict ...
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### Understanding the relation between pressure, ideal gas and, volume

I was given the following formula which is used for ideal gasses: $$pV = nRT$$ where: p:pressure V: volume n: number of moles R: gasconstant T: temperature now when speaking about vaporpressure ...
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### How can condensation be aided?

I was wondering if certain factors of water vapor condensation can be aided? For example, being able to increase the saturation of water vapor via a certain method, or another example would be having ...
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### Boilling a liquid in a closed container, less heat required?

If you boil a liquid with latent heat $L$ in a container of infinite volume (i.e. open to the universe) the heat required is: $$Q=Lm$$ Where $m$ is the mass of the liquid boiled. If however you boil ...
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### What temperature is an evaporating cup of water at “room temperature”?

If I put 100 g of water in a cylindrical cup and I know it takes 2 weeks (lets say 1.2 × 106 seconds) at some RH/temp to completely evaporate in my room with a constant temperature, can I ...
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### Heat Losses from water pan due to vaporisation before boiling

I'm studying heat transfer from an electric heater to a cooking pan (Stainless steel) filled with water; specifically, my problem is related to water vaporisation, as I've already found good models to ...
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### Are particles that locally evaporate off water's surface at T = 100?

Water molecules can evaporate off a surface without needing to boil (How does water evaporate if it doesn't boil?). This is because surface particles are sometimes energetic enough to overcome ...
22 views

### Superheating Water Demonstration with a Vacuum

There are many Youtube videos which place a cup of water into a vacuum chamber and cause boiling around 0.020 atm, but I can't find any which show a vacuum-only "superheating" effect (to be clear, I ...
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### Pressure inside tank while discharging water

I have two tanks, one initially fully filled with water (large tank) and the other one (smaller) is empty and has low pressure (say 0.5 bar) and the two tanks are connected from the bottom with pipe ...
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### Bottle cap burst phenomenon [closed]

There is a trick you can do with a simple plastic water bottle: After putting the cap on as tight as you can, you twist the body of the bottle a few times so that it compresses the air in the bottle. ...
1k views

### Why does a water drop on a hot plate at 150°C evaporate faster than on a plate at 200°C?

I recently read that: A drop of water landing on a hot plate at 150°C (300°F) evaporates in a few seconds. A drop of water landing on a hot plate at 200°C (400°F) survives a whole minute. How ...
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### Can there be net condensation into a pool of water?

I'm curious about the equilibrium of evaporation and condensation. Given that the surface area of a dehumidifier's evaporation coil at 4C is proportional to the rate of condensation, how would the ...
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### Why doesn't water turn into liquid after boiling it? [duplicate]

Water's boiling point is 100 degree Celsius. So water shouldn't remain vapour under 100 degree Celsius. But water remains vapour even in the environment temperature. Why does that happen?
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### Water evaporation

It is known that molecules at the surface are more strongly attached to each other (more attraction less repulsion) than those within the bulk (attraction and repulsion are balanced). This is the ...
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### Water evaporation problem. Exercise from Feynman's lectures

I read lectures of Richard Feynman and try to solve problems and I have some trouble with a problem on water evaporation. A glass full of water is left standing on an average outdoor window in ...
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### Why is there steam in a hot shower even though the water is not boiling? [duplicate]

When I take a hot shower, there is normally a fair amount of steam. However, I don't think the water coming out of the shower-head is actually boiling (unless I am mistaken). Why is there water ...
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### Can evaporation occur in an air-tight container?

As the title states, can evaporation occur in an air-tight container? Could the liquid water turn into gas and just stay inside the container until it's opened? Would there be a limit to how much ...
2k views

### Why can't I evaporate water without wind, just heat? (not boiling,evaporating!) Or can I?

So here is the thing, I searched all over the internet for this but all the sources say that I need wind because the process of evaporation goes as follow: Water particles at the top layer with ...
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### What is the equation that determines evaporation rate for water?

So I'm guessing it has to do with temperature of surface water, temperature of surrounding, surface area, humidity,... I always wondered if there was an equation to describe evaporation, never learned ...
1k views

### How much does lighting of room effect evaporation?

Suppose there is a wet floor under normal conditions, how much can we alter the rate of evaporation of the wet floor by trying out different types of lights ex. Incandascnet, cfl, fluorescent etc ? I ...
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### When drying paint brushes washed with water, which way is the best to orient them?

After washing my paint brushes with soap and water and rinsing them, in order to avoid damage to the bristles and the ferrules and the wooden handle, is it best to hang them bristles down and let ...
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### What's the surface area of a liquid? How does evaporation increase if the surface area of a liquid is increased?

Wikipedia says that a substance that has a larger surface area will evaporate faster, as there are more surface molecules that are able to escape. I think the rate of evaporation should decrease as ...
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### Is water steam in air a case of liquid in gas solution?

Thinking of this question, I thought that the phenomenon of water evaporation into the air is totally analogous to the solid (say, salt) that is dissolved into a liquid (water). Indeed, in this ...
2k views

### Calculating rate of vaporization of water

Let there be a cylindrical vessel with diameter D that only has liquid water and water vapor as the picture below shows (The water vapor is the grey portion and the liquid water is the blue portion). ...
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### If you charge water will the evaporation rate change?

If you take away electrons or add electrons to a body of water will the evaporation rate be changed? (Even if it's brief or the effect is small)
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### Does wrapping a wet paper towel around a glass bottle really speed up the cooling process?

There are claims like this one that you can improve the cooling speed of beverages when you put them wrapped in a wet paper towel inside the refrigerator/freezer. I've just tried it by myself and ...
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### Confusion understanding relative humidity levels

I have difficulty in understanding how can the relative humidity of a mixture of air and water can be 100%. I understand that places like where i live have high relative humidity, so the place is more ...
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### Where are real limits of evaporative cooling?

There are many projects focused on utilising evaporative cooling for food preservation or computer cooling purposes. I have other thing in mind, however and that's cooling beer. Once you're outside, ...
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### How long does a black hole last after it becomes white hole?

According to Stephen Hawking's theory of black holes, once a sufficient mass has been lost through evaporation, the escape velocity $3 \times 10^8$ meters per second so light is able to escape from ...
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### Can I always assume that a vapour pressure over a liquid is ideal?

Can I assume that the vapour of a subject over its liquid is ideal-ish? I'm thinking that if the vapour pressure is low the subject in question wont interact with itself, but it doesn't necessarily ...
206 views

### If water evaporates at below 100 degrees then why not stone?

I have asked this question recently: Why does evaporation take place? and I got a satisfactory answer, that temperature is macroscopic and is the average temperature of the object. That said, why ...
205 views

### Evaporate water using compressed air [closed]

I want to evaporate water by forming air bubbles which are formed by flow of compresses air through perforations. What is the energy (in KWh) input to compress 1 cubic meter volume of atmospheric ...
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### How can i turn home gas from liquid to gas [closed]

I hope i am not too off topic, couldn't find a more suitable stack-exchange forum for this, if there is a better one, please point me to it, Well my question is the following, I am working on a ...
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### Vacuum Systems, Vapor Pressure, and Machine Damage

When operating a vacuum pump, after we have pumped it to its (almost) limit, and want to pump it back down, we normally Turn off the Turbomolecular Pump first Turn off the rotary vane pump next ...
9k views

### Does placing a lid on a pot affect the rate of boiling?

On the subject of cooking, someone once told me "If you have too much water in your pot after cooking a dish, just turn up the heat and let it boil without a lid for a few minutes". Now I've thought ...
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### How to heat water at very high temepratures?

I am working on a project and recently came through a situation where I'll be working with water evaporation. On searching the internet I found that water heated at 350Celsius would generate almost ...
6k views

### How to calculate the evaporative cooling rate needed to protect a house from forest fire

Recently in our area there has been a large forest fire and I've been looking into home defense from such things. I am not a physicist - but can do some basic math. I was wondering how I could ...
144 views

### Why doesn't water start to boil in soils?

Consider the following two scenarios: I take a vessel filled with some water and evacuate the air, the water will (or rather can) start to boil; if the pressure in the vessel is << atmospheric ...
17k views

### Thermodynamics: Are pressure and temperature enough to calculate enthalpy?

From the chart above, it looks like it is possible to calculate enthalpy from just pressure and temperature. After a few hours of Googling my question, I'm not able to find anything helpful. My ...
119 views

### Bowl of water to humidify

I kept a bowl of water in my room last night, thinking I need to improve the humidity as I had a sore throat. On waking up, I find that the bowl is still filled with water. Why didn't the water ...
44 views

### Pressure and Phase Experiment Questions

Consider the experiment where a test tube filled with water is inverted in a beaker of water . (The following figures are not to scale of actual apparatus.) At time t=0, the instantaneous snapshot is ...
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### I need to remove water from a system [closed]

I work in an industry and I need to remove water from a system. The scenario: There is a washer and a blower on a conveyor belt. The item being washed is plastic (not sure what type) and can't be ...
1k views

### Reducing the evaporation of water at room temperature

Water drops kept on different surface evaporate after a few minutes. How can I reduce the rate of evaporation of these drops? Can I add some additives which suppress evaporation?
467 views

### Temperature to make oceans evaporate [closed]

The Boiling point of the water is 100 C after that water evaporates. If we are to heat the water of all the oceans combined, what should the temperature be set at, so that all the water gets ...
144 views

### Smell the Coffee [closed]

Do non-water particles of coffee evaporate or leave the surface of hot coffee over time? Are they some sort of carbon-based molecules? Are they carried into the air by the evaporating water molecules? ...