What effects do evaporation and rain have on the salinity and density of seawater?
143717
evaporation would decrease the mass per unit volume of sea water..as the latent heat for vaporization will evaporate the water...there will lesser and lesser mass per unit volume, which will in turn decrease the density (m/V). Also due to evaporation the amount soluble water will get into vapor phase leaving behind the salts...so the salinity will increase..and yeah salinity is defined as the amount of dissolved salts in water...(normally in psu in oceanographic sense)...so more water gets evaporated, the dissolved salts get more compared to the dissolving solvent , which in this case the water...so the amount of salt increases relative to the water..
759317
The normal cycle is (very simplified): rain, transportation to sea, evaporation.\n\nThe main thing that mankind does to change this is after the rain has fallen and before it reaches the sea.  The main thing being irrigation which diverts water from the river into the surrounding land.  Obviously when water is soaked into the ground it cannot evaporate and so the 'residence time' in this part of the cycle is increased.\nBuilding damns and other structures (ie. cities) will also have similar effects by diverting the natural course of a river.\nWith global warming comes another problem.  Obviously the warmer something is the more energy it has.  This extra energy causes an unstable atmosphere leading to increased rainfall in some areas and less in others.  Rising sea temperature, which is also connected to global warming, will increase the rate of evaporation (which is why there are more hurricanes in the Atlantic).
723545
It saltier then fresh water so the difference in densities is less
470292
When sun shines on water, it warms it up and since heat is lighter, the water kinda floats up into the air. That's called evaporating. Then when it's high in the sky, many little water droplets come together and from clouds. When there's too many water droplets, the cloud becomes to watery and it rains. Then it starts all over again.
1020525
Salinity will decrease a bit, but it won't be very significant.  \n\nLower salinity fish might move out of their environments and colonize other parts of the oceans.
968670
Water in the sea can vary in salt concentration, temperature and in ion ratios. The first two create differences in the density of the water and therefore warm / less salty (light) water floats on cold/ salty (heavy) water.\n\nSince these currents do not mix easily, different ratio's of ions in seawater can maintain their difference. These differences are created by sources of ions (vulcanic activity which can create specific ions, incoming rivers) or by the fact that certain ion concentrations (HCO3-, HSOx-) are very temperature dependent. \n\nusefull info can be found on http://www.biosbcc.net/ocean/marinesci/02ocean/swcomposition.htm
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.
45495
While Mara gives a good description on the origin of salts in water (all water in general) it doesn't explain why the ocean is salty and streams, lakes etc are not.\n\nBascially the ocean has no outlet. Once water reaches the ocean, it stays there, along with all it's transported salts and minerals. \n\nThe Earth has weather though, and weather is driven in a large part by evaporation of water from the Earth's oceans. \n\nWhen you evaporate the water content, you fractionally reduce the volume of water, which therefore fractionally increases the concentration of salts and minerals. You should also know that some of these salts and minerals are removed from the oceans by precipitation into sediments on the ocean floors. So over the millions of years that the oceans have been around they have grown relatively saltier than the bodies of water that contribute to the oceans.\n\nThis process is exaggerated in trapped bodies of water that recieve a lot of heating. Take the Dead Sea for example - it's an enclosed body of water and since it does not have the vast volume of the world's oceans, the salt concentration process runs much faster. The Dead Sea is currently 6x saltier than the ocean. Salt lakes on any continent are another smaller example again - you'll find them in the USA and Australia to name but two examples.\n\nCommercial Salt production uses the same process, of evaporating water to leave behind salts.
539352
Salinity and the latitude is related because of the thermohaline circulation of the ocean waters. This means that the waters circulated around ocean and are driven by density (not temperature). The thermohaline circulation means that the are denser waters at high latitude due to high evaporation rates found in the tropics. Hope that helps
338742
Boiling point elevation, which means salinity increases the boiling point, and thus lowers the evaporation rates.
439952
You can find in "Chemical Engineer's Handbook", from Perry-Chilton, graphics for density of water + NaCl solution vs. %w/w of NaCl. The NaCl concentration is 3.5%
1138696
The salinity of specific regions of the oceans depends on the ratio of influx of sweet water and evaporation (or in cold regions, formation of ice, which also increases the salinity of the remaining water) and on the vertical and horizontal currents. The northern Atlantic is the most saline oceanic region, if I recall correctly - probably because of much evaporation in the subtropic zone and then the gulf stream carrying the saline water north.\n\nThe dissolved salts are mainly:\n\ncations: Na+, with K+, Mg2+ and Ca2+ as important additional components\n\nanions: HCO3-, Cl- as main components, SO4(2-) a distant third.\n\nTo get the salts, simply combine to neutral compounds.
637181
I dont know the exact calculation but this site might be able to help you.\n\nhttp://www.fseric.demon.co.uk/skills/salinity.htm
342985
Ocean currents can change the supply of scf level wind, and thier volume density, the fresher the water the more water vapor we would have.  Like with the effect of global warming yes, if there is too much fresh water entered into the oceans due to the melting of the sea ice at the poles, then the Thermohaline will indefinately stop, which would affect what are weather is like.  The waters in the tropics will become massively warmer and the water near the poles would be colder, and in order for the world to balance that out, it will create more hurricanes, to pick up the slack of lossing its main currents.
977415
Salt water does not have any specific effect on weather formation. But all sources of water whether it is river, lake, pond, sea or ocean; by evaporation affect humidity and therefore the weather conditions.
92893
You need to concentrate your answer in the following areas:\n\n1) The effect of oceanic circulation.\n2) The role of water vapour as a greenhouse gas.\n3) The role of water as ice and cloud in increasing albedo\n4) The role of water in oxygen production, and hence the effect of oxygen on climte.\n5) The effect of life on albedo.\n6) The role of oceans as heat sinks and atmospheric buffers.\n\n\nWater also has a lot of small scale effects on climate of course, but I'm assuming you really do mean global climate.\n\n\n\n>>>>> countries which are surroended by large bodies\n>>>>> of water have more amount of rainfall than those \n>>>>> countries who are surrounded by land.\n\nNot at all. Australia and the Galapagos islands for example are surrounded by large bodies of water and both are primarily desert. Likewise Antarctica is surrounded by large bodies of water and is the driest place in Earth.\n\nIn contrast Switzerland and Paraguay are both completely landlocked countries that recieve large amounts of rainfall.\n\nWhile it is very broadly true that rainfall decreases with distance from the coastline there is ismply no way to extend this to making comparisons between countries or regions. Many coastal regions are far drier than many central continental regions. Ther are just  too many factors at play to make generlistaions about the effects of oceans on rainfall.
519909
It's a combination of less sunlight & density currents.\n\nCold salty water is very dense. It sinks. This along w/ surface flow created by winds creates currents in the sea.\n\nCold water ends up on the bottom.\n\nThe amount of geothermal energy located on the ocean floor is negligible here. It only makes a difference on a local scale. The ocean floor is very deep and very large. Too much space for geothermal vents to heat.