how does water evaporate?
147077
That's a very interesting question (and boiling as mentioned by other posters is only part of the story).  Let's take evaportaion of water from a bath towel in a shower room as an example.  When you "dry" yourself with a fresh towel it gets wettter while you get dryer.  But the towel can not make you totally dry.  It easily removes the beads of water and excess layers of water but leaves you with a final surface film of water that can not be removed by the towel.  This water film must evaporate.\n\nIn the towel itself, water molecules (H2O) absorb energy from the air by collision with numerous air molecules.  Some of the molecules gain enough energy to vibrate and separate from the rest of the water and enter the air to join any present water vapor.  At this point, water molecules can leave and re-enter the towel's moisture and the net gain or loss of water will depend on the relative humidity in the room.  At 100% relative humidity the towel will theoretically never "dry" unless condensation is being removed somewhere from the room.  At zero relative humidity, the towel dries very quilckly because there are a lot of molecules trying to escape but few trying to return.  High temperature, especially at low humidity, can speed up the process by supplying more energy to the water molecules in the towel.\n\nIf the towel is folded, moisture will evaporate from one fold and re-enter another fold slowing up the enttire process.  The more you expose surface area the faster the towel will dry (and the less time there will be for bacteria to grow!).\n\nIn a glass jar of canned tomatoes, water molecules are constantly evaporating from the liquid surface and re-entering it at the same rate without any net change.  The jar is under a partial vacuum because air was excluded and the trapped vapor is saturated with moisture to the same extent air would be saturated with moisture at the same temperature because the exchange of water molecules occurs due to its own energy levels (perhaps supplied by collisions with air molecules) but not influenced by any interference by the air molecules.\n\nWhen water (or sweat or gasoline, etc.) evaporates from your skin, it feels cool because it is taking energy from your skin to evaporate, taking the latent heat of vaporization which is significant.
737067
Evaporation.\n\nSalt water + heat source + vessel. Apply heat source to vessel containing salt water. Evaporate water. Harvest salt.
827629
Evaporation=matter or the quantity of matter evaporated or passed off in vapor.\nCondensation=the act or process of reducing a gas or vapor to a liquid or solid form.
677096
its called phase change of water, but it is given a common name known as evaporation
273633
precipitation and evaporation
994448
It takes energy to evaporate.  When a liquid reaches the evaporation point, an amount of the liquid starts to turn to a gas, to complete this transformation in state, it absorbs energy from the surrounding liquid which cools it.\n\nYour Air Conditioner works on the same principle.  In your attic is a coil where high pressure refridgerant is suddenly exposed to a low pressure zone inside the coil of your air conditioner.  When it meets this low pressure zone, it evaporates from a liquid to a gas.  Again, to make this state change, it absorbs energy from anything around it, in this case the air flowing over the coils provides that energy.\n\nThe gas then is pushed through the system out to your outside unit where the excess heat it absorbed is vented off and the gas is compressed back into a liquid.
579734
Water always evaporates. Higher temperatures will increase the evaporation rate, but water always evaporates. It has no relation with the boiling point; evaporation is a different phenomenon.\n\nExtracted from wikipedia:\n"It is a misconception that at 1 atm, water vapor only exists at 100 °C. Water molecules are in a constant state of evaporation and condensation flux near the surface of liquid water. "
951858
Evaporites (IPA: /iˈvapərʌɪt/) are water-soluble, mineral sediments that result from the evaporation of bodies of surficial water.\n\nEvaporites are formed by evaporation of restricted bodies of water at the Earth's surface.\n\nAlthough all water bodies on the surface and in aquifers contain dissolved salts, in order to form minerals from these salts, the water must evaporate into the atmosphere in order to precipitate the minerals.\n\nIn order for this to happen the water body must enter a restricted environment where water input into this environment remains below the net rate of evaporation. This is usually an arid environment with a small basin fed by a limited input of water.\n\n--> http://en.wikipedia.org/wiki/Evaporite#Evaporitic_formations\n\nSedimentary rocks are laid down in layers called beds or strata. Each new layer is laid down horizontally over older ones. There are usually some gaps in the sequence called unconformities. These represent periods in which no new sediments were being laid down, or when earlier sedimentary layers were raised above sea level and eroded away.\n\n--> http://en.wikipedia.org/wiki/Sedimentary_rocks
245118
Evaporation is the process whereby atoms or molecules in a liquid state (or solid state if the substance sublimes) gain sufficient energy to enter the gaseous state. \n\nOR\nEvaporation : \nThe conversion of a liquid (eg water) into a vapor (a gaseous state) usually through the application of heat energy; the opposite of condensation.  \n\n\nExpansion : the act of increasing (something) in size or volume or quantity or scope
307745
Water boils at 100 deg Centigrade but it is not necessary for it to reach that temperature to evaporate. Try spilling a little water on a plate and see how it eventually dries. What happens is that the groups of free molecules of water (H2O) escape into the atmosphere due to their movement. These are still small pieces of 'water' and can float until they attach to other matter, usually dust, and cause precipitation (rain). Naturally because the collections of molecules are so small they will rise into the atmosphere on thermals as being less dense than the surrounding air and eventually, when they reach optimum height depending on temperature and mass they form clouds. Water vapour as a gas is NOT steam. When water boils and becomes a gas it is colourless and cannot be seen. Look at the spout of a boiling kettle and you will see a small area between the spout and the steam that is true gaseous water. Once the gas hits normal air temperature it forms steam which is a collection of water droplets as the gas turns back into water. Steam, therefore, is not gaseous water but water itself. Evaporation from the sea is exactly the same principle but on a larger scale. Most liquids evaporate eventually, i.e. dry up, under normal conditions of temperature and pressure (See Boyle's Law). When evaporation from the sea takes place the water does not take solubles with it such as salt which is why rain derived from sea evaporation is not salty.
1079581
Because the earthern pot has pores in it . By which some water droplets comes out & evapourate. During evapouration some heat is absorbed from the pot .\nHence the pot cools down & the water also.
960864
add water, salt will dissolve pepper wont\n\nput through filter paper, so the pepper collects in that\n\nheat the salt solution so the water evaporates off
164163
Evaporation is vaporization of a liquid below its boiling point.
474034
It decreases, as everyone said. The reason may be given like this: water at a given temperature is just a bunch of molecules wildly moving around. The temperature tells you just how fast. Evaporation (water drying up) happens because some of the fastest molecules escape into the surrounding air. Now, evaporation happens faster at higher altitude: that is because there is less air, the air molecules are less bunched together. This means a water molecule escaping into air is less likely to be bounced right back into the water. \n\nNow boiling occurs when evaporation is so violent that the water cannot hold itself together any more. Again, it will happen more easily in thin air, that is, at high altitudes.
622178
Some things that will affect evapotranspiration are ambient temperature, exposure to sunlight, and relative humidity.  These things affect the rate at which water will evaporate or how plants will transpire.
222634
Tap water evaporates as it sits around.  The additives become more concentrated as the water evaporates but they don't dissipate.  Eventually they "precipitate" as salts and end up as solids in the container.
547960
The water is in the form of a vapor or gas, like steam.  When the vapor becomes concentrated enough to form droplets, it turns to rain.