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Questions tagged [evaporation]

The process of a liquid changing to a gaseous state

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Is evaporation a kind of phase transition?

When liquid is heat up to a critical temperature $T_{c}$, it starts boiling and converting to gas. In statistical mechanics, we learn that it is a phase transition. We studied all the properties near ...
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Evaporating tungsten wire

Consider an incandescent bulb having a thin filament of tungsten that is heated to high temperature by passing an electric current. The hot filament emits black-body radiation. The filament is ...
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Why does water start to evaporate after I turned off the stove (see details)?

I observe this every day. I heat water by first pouring it in a pan (made of aluminium, not that I think this detail is important). I put the pan on top of a flame, originating from natural gas. After ...
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What happens when a black hole evaporates?

I have read other articles here on the subject and I think my question is different.. When a singularity evaporates enough to reach just above the limit of mass required to make the singularity, what ...
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Evaporation cooling dynamics

I have a liquid (say, water) and a gas (say, air) at the same temperature. How will the temperature of either evolve over time? What's the steady-state of relative temperature of liquid and gas with ...
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Cooling effect caused by evaporation

Evaporation is said to cause cooling effect because it absorbs energy from surroundings to change its phase from that of a liquid to gas. I am in doubt as to why would the surroundings be ready to ...
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Do different liquids have different distributions of kinetic energy of their particles, and does this influence their vapor pressure significantly?

This is a bit of a cross-over between a physics and a chemistry question. When we say a liquid has temperature $T$ we make a statement about the mean kinetic energy of a particle in that liquid. That ...
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Exact mode of evaporation

I am having a doubt regarding what is the exact mechanism of cooling during evaporation. At one place it is said that as surface water molecules evaporate it takes heat from surroundings and hence ...
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Condensed water freezes and other water condenses around it

So I was on a plane and tiny crystals of ice formed on the window glass. This window is formed by a few screens of glass (maybe or maybe not) with vacuum inside. I think the frost was due to some ...
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Does water boil faster in a shallow wide pan or a deep pot

I make my own Maple syrup and have to boil away lots water from the sap to make syrup. I have a propane burner and a wide roasting pan and a deep stew pot, both hold about the same amount of sap. My ...
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How long would it take for a cup of water to fully evaporate?

How long does it take for a cup of water to evaporate? To answer this question, I'll assume some basic parameters, and that the water is blown on by a fan, to arrive at an estimate: Water volume: $...
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Should I walk or run to my towel when naked and wet? [closed]

This morning when I got out of the shower, I realised I had left my towel in the bedroom. Naked and wet I ran as fast as I could to get the towel. On my way back I didn't run, but rather walked, and ...
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Cause of change of tea volume during cooling

At work I often drink tea, and i usually fill my cup to the brim with boiling water. When I let it cool though, until it's ready to drink, the liquids surface has sunken by about a fingers width. To ...
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If I leave a glass of water out, why do only the surface molecules vaporize?

If I leave a glass of water out on the counter, some of the water turns into vapor. I've read that this is because the water molecules crash into each other like billiard balls and eventually some of ...
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Does water need oxygen to evaporate?

For example, if you had a thick piece of glass and it had a kind of reservoir inside with half water and half space allowing the water to move but not escape from the inside of the glass, and then you ...
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can we create an artificial cloud by evaporating ground water?

I need a clarity about whether an artificial cloud can be made by human or not,if it is so, then it will be useful for many.
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On the evaporation of fluids

Q. In which portion (1,2,3) there will be maximum concentration of evaporated water droplets? Or there will be uniform distribution of droplets? Background: Today, I noticed something really strange ...
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How do salt crystals evaporate in water?

Salt dissolves in water but when water has evaporated it is still there. What has happened to the salt in the water and why is it still there when water has evaporated?
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Why did the liquid disappear from some unopened aluminum cans? My experience (read below) has not been answered [duplicate]

I’m posting my question because I read this original post. The post was from 2016, so I’m reposting in hopes that someone can answer. Here’s the original post: (Also, do not flag as duplicate. If you ...
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Water vapor pressure in oxygen bubble

Suppose we have a source of O$_2$ bubble formation in water at specific nucleation sites, how can we estimate the water vapor pressure inside the O$_2$ bubbles? I know that: (1): $p_\mathrm{O_2}+p_\...
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Relative humidity, definition and its dependence on state variables

Relative humidity ($RH$) is defined by the following equation: $$ RH = \frac{p_{vap}}{p_{sat}} $$ Where $p_{vap}$ is the vapour pressure and $p_{sat}$ is the saturation vapour pressure. VAPOUR ...
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Why does salt ions is not exist at vapor when the water is boiled and evaporated?

I would like to understand when the water is boiled only pure vapor is produced and ions do not exist with vapor. Why? Can't the ions stick to water vapor? And Are Na+ and Cl- have boiling points? ...
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Rate of direct (non-thermal) photon-induced evaporation of water?

I have read a long time ago of early experiments in the evaporation rate of surface water, and a discovery that in addition to the Sun's impact on the temperature of the water, it was believed that ...
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Evaporation rate of water with forced convection

A steel pot (diameter 200 mm) is fully filled with water (2 kg of water) and the water is maintained at a constant temperature of 40°C by supplying heat from an electrical tabletop burner. Assume ...
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Why do we sweat on a hot and humid day but the clothes are able to dry?

I know that on a humid day,water vapour content is high in air and as a result evaporation of sweat is lesser and hence we feel hotter. What I am not able to get is, if water vapour content is high,...
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Can we enhance evaporation rate with a vacuum pump?

First, consider having water at 100C and 1atm and a heat source. If more heat added to water, we have more evaporation rate according to the following formula: $$Q_{in}=m_{vapor}*h_{fg}$$ THEN ...
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Water at 0 atmospheric pressure

Suppose I put a bucket of water on the surface of the Earth. Then somehow the atmosphere disappears. My question is: Would the water fly out of the bucket, or would it be still there? My reasoning ...
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Amount of steam generated using gas burner and Induction cooker

I did an experiment by boiling water using two different heat sources. At first, I boiled water using a gas stove, then I repeated by using an induction cooker. I noticed that the amount of steam (...
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Effect of pressure when drying wet clothes in a windy environment

When we hang wet clothes outside, they dry faster if it is windy. The wind causes forced convection and removes the air saturated with vapor, and the rate of evaporation does not decrease much in ...
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Why perspiration drops are seen in shopping bag?

Why perspiration drops are seen in shopping bag? When i put hot bread in shopping bag after sometime i saw perspiration drops in the shopping bag.
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Will having two water pans in my smoker make any difference?

I have a backyard smoker, and I use a tray of water in it as thermal mass to help keep the temperature stable. I don't think the size of the tray is going to matter, but it's roughly 40cm x 30cm x ...
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Potential Energy of Particles

I read the following statement in my textbook While a liquid is boiling, the energy supplied to the liquid goes to breaking the bonds between neighbouring molecules. Can anyone explain the process ...
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Once a black hole is formed, is there anything other than Hawking radiation which shortens its life?

Hawking radiation is supposed to very slowly evaporate a black hole (terms and conditions apply :] ). Apart from Hawking radiation, is there any mechanism or effect that can make a black hole cease ...
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What happens at the molecular level during evaporation?

During boiling the liquid gets its energy from the heat source so it can break the force between molecules and turn into gas while evaporation happens at the top of the liquid at any temperature. ...
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Does the presence of a flame affect the flow rate of gas out of a lighter or torch?

If I were to set a propane torch's valve to a fixed open position, would it run out of gas faster lit or unlit? Does the flame produce any kind of pressure change that affects the flow rate through ...
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Evaporation amount of water for a Storm [closed]

How much water from the ocean is evaporated for a storm over water? I am trying to figure out what conditions will cause the most evaporation or how to calculate the amount of water evaporated for a ...
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Can a substance have zero vapour pressure above absolute zero?

According to this Reddit thread, the answer is no, vapor pressure can't be zero when temperature is above absolute zero. I suspect the answer might actually be yes according to a precise definition I ...
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Will water in a vacuum evaporate continously?

Will a vacuum chamber that is maintained at 0.1 Atmospheres with an open water container inside ever reach 100% humidity of the remaining air, so that no more water evaporates or will water ...
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Simple question about molecules leaving a liquid at a temperature below the boiling point

My textbook asks the question why a liquid cools down when partial evaporation occurs just below the surface at a temperature below the boiling point. The answer is of course that only those ...
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Temperature Proxy (Climate)

At the bottom of the wikipedia article on climate proxies there is this formula: $$ \delta \, {\rm ^{18}O} = \frac{\frac{\left[\rm{^{18}O}\right]}{\left[\rm{^{16}O}\right]}}{\frac{\left[\rm{^{18}O}\...
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Calculating gas pressure following water transformation to vapor (in contact with boiling oil)

When water falls into a pot of boiling oil, it turns into vapor, and in an enclosed space this will create a higher gas pressure. Is there a way to figure out how high of a gas pressure there will be ...
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What type of heat is efficient to evaporate water?

I found that there are several type of heating element in a hair dryer, but basically I mainly classify them into two ways of heat transfer: Radiation and Conduction. The conventional hair dryer uses ...
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Why does evaporation cause cooling?

I am aware that the evaporation process causes cooling in the remaining liquid, but why? If anyone can give me the maths and or equations to prove / show this I would be most appreciative.
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Do solids do something analogous to liquids evaporating below their boiling point?

I'm probably not entirely right, but evaporation differs from boiling in that it is surface rather than bulk phenomenon driven by a pressure gradient rather than temperature. If a volume of liquid is ...
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Why do really cold objects evaporate really quick? [closed]

So I saw a video of LNG (liquid natural gas) and when it got in contact with water, which was room temp the LNG evaporated instantly...why? Ice takes a while to evaporate like a sec even when hot ...
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Rate of evaporation/mass loss of liquid in a bowl

Say a hemispherical bowl filled with a liquid was left in a room. I was wondering how we could model the rate of mass loss of liquid as it evaporates. Will it be a quadratic relationship with time? ...
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Does the saturated vapor pressure depend on the external pressure or just only temperature?

So far I understand that the saturated vapor pressure is the pressure exerted by a substance in liquid (or solid) vapor equilibrium, and that this pressure depends on the temperature of the system. ...
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Evaporation inside a container

This is for my engineering design project and our group needs to make a storage where humidity inside should be maintained above a certain range. So as a simple prototype, we simply added a bit of ...
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Can a droplet of formalin evaporate in midair while falling? [closed]

I am designing an evaporator for use in an enclosed environment. Due to the hazardous nature of formaldehyde, I want my evaporator to be wick-free. The environment in which the evaporator will be ...
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Interesting thought experiment on evaporation and pressure

Little background: the enthalpy of vaporization equals energy required to change state, plus the work done against ambient pressure. Say I made a balloon with Gore tex.(Gore tex is a fabric that ...