What is Water: Definition and 1000 Discussions

Water is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a solvent). It is vital for all known forms of life, even though it provides no calories or organic nutrients. Its chemical formula is H2O, meaning that each of its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. Two hydrogen atoms are attached to one oxygen atom at an angle of 104.45°."Water" is the name of the liquid state of H2O at standard conditions for temperature and pressure. It forms precipitation in the form of rain and aerosols in the form of fog. Clouds consist of suspended droplets of water and ice, its solid state. When finely divided, crystalline ice may precipitate in the form of snow. The gaseous state of water is steam or water vapor.
Water covers 71% of the Earth's surface, mostly in seas and oceans. Small portions of water occur as groundwater (1.7%), in the glaciers and the ice caps of Antarctica and Greenland (1.7%), and in the air as vapor, clouds (consisting of ice and liquid water suspended in air), and precipitation (0.001%). Water moves continually through the water cycle of evaporation, transpiration (evapotranspiration), condensation, precipitation, and runoff, usually reaching the sea.
Water plays an important role in the world economy. Approximately 70% of the freshwater used by humans goes to agriculture. Fishing in salt and fresh water bodies is a major source of food for many parts of the world. Much of the long-distance trade of commodities (such as oil, natural gas, and manufactured products) is transported by boats through seas, rivers, lakes, and canals. Large quantities of water, ice, and steam are used for cooling and heating, in industry and homes. Water is an excellent solvent for a wide variety of substances both mineral and organic; as such it is widely used in industrial processes, and in cooking and washing. Water, ice and snow are also central to many sports and other forms of entertainment, such as swimming, pleasure boating, boat racing, surfing, sport fishing, diving, ice skating and skiing.

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  1. bubble-flow

    Where are the pressure nodes on a standing acoustic wave in water?

    I have calculated the wave length of a 36 kHz acoustic wave in 20 °C water to be around 41.16mm. Suppose I have a transducer that produces a 36 kHz acoustic wave and a small water container with a length of 41.6 mm. How will the standing acoustic wave look like, which is produced by the...
  2. S

    Question about water container with hole at the bottom

    (a) $$V=\int_{0}^{x} A~dx$$ $$=\int_{0}^{x} f(u) dx , \text{u is dummy variable}$$ Is this the answer? Or there is something else I can do to continue the working? (b) $$\frac{dV}{dt}=\frac{d}{dt} \int_{0}^{x} f(u) dx=f(x).\frac{dx}{dt}$$ Is this correct? (c) $$\text{time}=\frac{\text{rate...
  3. D

    Water Pressure and Different Pipe Sizes

    Started an irrigation project. There are 4 points in this irrigation system; A, B, C and D. The main water line to the house is 1" diameter pipe. (Point A) The distance from Point A to Point B is approximately 30 feet. Here at Point B the pipe size is reduced down to 3/4" pipe. The distance...
  4. Rafael Aiguzhinov

    What Objects Can Survive the Deepest Water?

    I wonder, what object can be drown to the deepest water ? I mean, the object where gravity is a lot more bigger than force of Archimedes
  5. K

    Could packaging leach under hot water?

    I like cup noodles that come with convenient packets of seasoning or sauce. From time to time I forget to take away all packets before pouring hot boiling water into it. In most cases those packets are printed with color and are made of kind of plastic or tin or something with metallic color, I...
  6. K

    Iron block dropped into a container of water sitting on a scale

    Does the scale change during the block sinks? I am so confused... Is there any difference on change of scale with the applying of drag force?
  7. J

    Fish Reflection: Analyzing Light's Interactions with Water

    So first I looked at where the image of the fish appeared to be when it went through the water surface. since we can assume the water is flat, R is infinity, so n1/p=-n2/q. plugging in the values (n1=1.29, n2=1, p=3.5) I get q=-0.3686. So the image of the fish appears at 0.369 above the...
  8. Richard DiMaria

    The sound that rushing water makes

    What actually caused the sound made by rushing water, for example in rapids. Is it molecules bumping against each other? Or something else?
  9. M

    How much salt/other product add to water so a medium acorn floats?

    I have a lot of acorns in my pebbles. I'm looking for a way to sort these out quickly. I was thinking of the possibility that something floats on water and another material does not. If I use plain water, most of these acorns will sink too. So my questions is how much salt or other product...
  10. BillTre

    Missing Water on Mars: Hydrated Crust Minerals May Explain

    The solar wind driven removal of water from Mars can only explain a portion of the water thought to have once existed there. This process, indicated by the D/H ratio of normal hydrogen to its heavier form (deuterium) of Martian hydrogen, can only a count for the lower estimates of Martian...
  11. DaveC426913

    How deep under water could this new dino breathe?

    https://www.sciencealert.com/scientists-finally-know-how-this-ancient-reptile-lived-with-such-an-absurdly-long-neck?fbclid=IwAR3Ibk7KyqKHrnkoKa-7C0kPvWKGVG1hjWnRgFfkTS54wJiZ9W5E2BYCFHY I didn't infer from the text that the dino's neck rose vertically from the bottom to the surface - it may well...
  12. reddwarf4ever

    Correct bore sizing for a shower hose for a pumped water supply

    Please don’t laugh, this may sound a trivial question, but it is important. I have seen so many conflicting opinions, even from manufacturers. Some say, just use the biggest bore possible, others say use a small bore 8mm for a fully pumped system & a large bore 11mm for a gravity system. There...
  13. Rzbs

    Coriolis effect and water experiment

    Is the Uganda water experiment (that shows corilios effect on water drain) a scientific experiment or not? I searched but I couldn't find a final answer to this question. There are two opposite opinions, which one is correct? Or this argument is an open issue yet? Thanks for your replies...
  14. P

    Rate of heat flux from from hot gas in a pipe to water outside

    I have solved the first 2 parts. For the 3rd part, I have obtained the equation: T(x) - T0 = (T1 - T0)e^(-Φx/fc), where f = fm in the question. How do I obtain that expression for H? Thank you!
  15. T

    Does Throwing an Object Overboard Affect Pond Water Level?

    I was asked this question: Assume you're sitting in a boat (you and the boat, together, are a mass M) which also contains a heavy object (of mass m). The boat (inc. you and the heavy object) is floating in a pond (a fixed body of water, rather than open sea). If you throw the object overboard...
  16. M

    Condenser calculations - uncertainty

    A water cooled plate condenser, condensing refrigerant. Heat exchanger (condenser with plates) characteristics: Description symbol value value (converted) number of plates np 28 number of channels nc 27 number of water channels nwc 14 number of flowing channels for refrigerant...
  17. G

    Question about chlorine + water

    2.5% active chlorine + water is very volatile and spreads around the house oxidizing metals and other objects ?? here we use a product called sanitary water
  18. J

    Calorimetry - finding the final temperature of a system of ice and water

    So all of the ice melts and I am guessing it then warms some so Q=mL+mc(change in T) for the water that cools down Q=mc(change in T) Q_cold = -Q_hot so -mc(Tf - Ti) = mL+mc(Tf - Ti) My issue is that I have 2 unknowns. I don't know the specific heat capacity of water and I don't know the...
  19. Jack of some trades

    Does Watt's Law apply to flowing water in a pipe?

    Is the heat generated by flowing water in a pipe proportional to the product of the rate of flow and the pressure drop across the section of pipe in question, analogous to an electrical circuit? If so, what units would you plug into get an answer in watts?
  20. L

    Uncertainty of Speed of Sound in water, using Mackenzie's Equation

    I need to calculate the overall uncertainty of the value I have obtained for the speed of sound in water, using Mackenzies equation... I am not sure in what way to combine the above uncertainties. Any help would be greatly appreciated! Lloyd
  21. I

    Chemistry Water and Le Chatelier's Principle

    I think that adding water here shifts the reaction to the left in favour of reactants (since the amount of product is increased). This will also decrease the concentration of [Co(H2O)6]2+, Cl-, and CoCl42− too (dilution), but I'm not sure how much that would affect the direction that the...
  22. E

    Evacuation of a liquid-vapor water mixture

    suppose i have liquid and vapor water inside a vessel at say 3000kPa, then i suddenly open the valve, as the water (liquid) flows out the vessel (control volume) is water inside the cv evaporating at the same rate liquid flows out? so the volume of water inside the cv remains constant?
  23. M

    Force on an object that is stationary in flowing water

    Hello there, I was wondering, and i can't seem to really find the answer to my question, i found something that looks like it, but I am not sure if i understand correctly, that why I am turning to PF.com 1) What is the basic formula of the force on a object in flowing water when we assume that...
  24. J

    Finding the normal force of a block under water, under pressure

    So since the block is at the bottom there's no pressure pushing it up. To calculate the mass and force of gravity, I multiplied the density of the block by its height and cross sectional area and got 564 kg. Multiplying this by 9.8 I got the force of gravity of 5527.2 N. Now to find the force...
  25. Cheesycheese213

    Electrolysis of Water -- Rate of Reaction?

    I'm so sorry if this is a bad question! I am doing an experiment measuring the rate of gas production (hydrogen) of the electrolysis of water, and I got myself a bit confused about whether I have been taking the correct measurements? I had originally thought that, since the "concentration" of...
  26. ayans2495

    What is the Relationship Between Work and Temperature Change in Melting Ice?

  27. ayans2495

    Calculating initial temperature of iron block submerged into water

  28. S

    Why does a stationary wave form at a free end of a water tank?

    This is the set up to produce stationary wave. The oscillator on the left will produce wave on water surface then this wave will travel to right, reflected at the tank and the incoming and reflected wave will superpose to form stationary wave. My teacher said when the water wave hits the tank...
  29. S

    Calculate energy required to heat water using a steam coil

    I'm trying to complete this past exam paper Q. Water volume = 200hl = 20000L 1L=10^-3 m^3 20000L = 200 m^3 Density of water at 15 deg C = 999 kg m^3 Density = Mass/Volume 999 kg m^3 = Mass/(200 m^3) Mass of water = (200)(999) = 199800 kg Heat required to to heat 199800 kg water: Q =m C dT =...
  30. S

    Bernoulli Equation — Discharging water from a partially-filled sealed tank

    Hi there, I'm doing a past exam paper Q and i'd like some help. Assumptions are: The velocity in the tank is negligible and the hydrostatic head is 4m. Pressure in the vessel: Gauge pressure 1 bar g = 10^5 Pa 0.2 bar g = 20,000 Pa Hydrostatic Pressure: (4)(9.81)(978) = 38,376.72 Pa Absolute...
  31. M

    Chemistry Adding sugar to water; water level doesn't go back to the original volume

    What are we missing in this experiment? Thanks
  32. C

    Fire protection -- Water in a cylinder pressurized with Nitrogen

    I wondered if anyone could help, I work in the fire protection industry. We currently have a project using a pressurised cylinder. The cylinder hold 200 lites of water plus 40 litres of nitrogen gas as a propellant at 10.0 bar. I’m trying to work out once the 200 litre water volume has been...
  33. S

    Acceleration of U-pipe containing water

    I am thinking of using ΣF = m.a to find the acceleration but I don't know what causes the resultant force to the right. I thought it will be the difference in pressure on the left and right leg of the U-pipe (picture on the right), which is ΔP = ρ.g.h but the force (ΔP . A) won't be directed to...
  34. KrisOhn

    Boiling Water using Heat vs. Vacuum

    If you bring a pot of water to boil, you will notice that the bubbles form on the bottom surface of the pot. This seems to make sense intuitively as this is the hottest surface, so this would be where the boiling action starts. When I was in school during a thermo lab we pulled a vacuum in a...
  35. Cheesycheese213

    Concentration of electrolyte for the electrolysis of water?

    I'm doing an experiment with the electrolysis of water, and I'm hoping to vary the electrolyte concentration (Epsom salt/MgSO4) to see changes in the rate of gas production. I was planning to just do intervals from no salt to maximum solubility, but was wondering whether there might be any...
  36. C

    Hydrostatic Problem: Hinged water gate at the bottom of a reservoir

    My son and I are having a problem with part c that suggests our answer for part a and b are wrong.. Part a). If we've understood the teaching notes correctly the force on the gate acting through its centroid perpendicular to the gate and is given by F = ρgAd where ρ is the density of water...
  37. T

    Under floor water heating - result of overflow

    Several apartments have under floor heating (water) with a common boiler room and a central pump. There is no pump in the apartments. Each pipe run on each apartment's manifold has its own flow-indicator. The owner of one apartment is worried that if the neighbor turns off its heating, then more...
  38. kyphysics

    Spilled 1/3 bottle water onto table and laptop keyboard area....

    I was reaching for some crackers across the table. My arm tipped over a full opened bottled water that splashed about 1/3 of its contents out of it. Of that 1/3, about 50% got on the table and the other 50% splashed across my laptop's keyboard area. I immediately reached for towels to soak...
  39. richengle

    How does water flow from a faucet?

    water flow from a faucet will neck down its radius as it flows to the bottom of the sink. It is asserted that this is due to the fact that gravity increases the velocity of the fluid. This is shown at . I am trying to simulate this, and am not having much luck. shows this for a flat...
  40. seeker11

    Steam Speed from a Heat Ruptured 120 Gallon Water Tank?

    PROBLEM: A 120 gallon tank (26" diameter, 60" height) containing 40 Gallons of water is heated up until the tank ruptures from overpressure at 125 PSI (maximum tank rating). How to calculate the initial escaped steam velocity at the ruptured tank, assuming the gash is 2 feet long in the...
  41. supak111

    Resonant frequency of a pipe submerged under water

    How do I calculate a resonate frequency of a length of pipe submerged totally under water? Do I just take speed of sound in water which is 1,481m/s at room temp, and decided it by length of pipe in meters multiplied by 4? so at 20 celsius water and 20cm pipe it would just be: 1481 / (.2 x...
  42. G

    Calculating Heat Gained by Supercooled Water

    My argument is that heat lost by lump of mass converted to ice will be gained by remaining water. But how do I find heat gained ?
  43. H

    Boiling Tap Water for Drinking: Benefits & Risks

    Recently I have been boiling tap water, for about 30 minutes, everyday for drinking water. The reason I do it is because I don't like the taste of chlorimines and chlorine and this is the only way I know to get rid of them without also losing minerals. It works great, and in fact, the water...
  44. guywithdoubts

    Water bending with comb: but where do the electrons go?

    I suppose the stream isn't being charged!
  45. Johnnyallen

    Water pressure affects air pressure

    In the movie The Abyss an oil rig crew works and lives at the bottom of the ocean in a deep sea structure. There is a compartment where there is an opening in the floor allowing the crew to lower a submersible craft without going through any kind of air locks etc. We all should know from high...
  46. kmot

    Fluid mechanics - Linearized shallow water equations

    Hi, In a text describing solution to linearized shallow water equations, I am not able to move forward. It's a 1 dimensional shallow water setup. There is a steady state (velocity) and (height of free surface). On top of this steady state there are u' and h' as disturbances. The goal is to...
  47. Y

    Can someone tell me which formula to use here? (time to boil water)

    An amount of water at a temperature of 20 °C is passed through a water boiler in 1.5 min to brought to boiling point. The kettle is broken and does not jump off. The time between the moment when the water reaches boiling point and the moment when all the water is evaporated, is equal to: a) 7,5...
  48. S

    Do equations for groundwater flow refer to water density?

    As I understand Darcy's law, it computes the flux of water through an area. The same value of flux can be the realized by different combinations of a density of water in the soil and the velocity of that water. So. as far as I can see, Darcy's law is ambiguous about which combination of...
  49. danielhaish

    Does ice melt faster in water because helps to change the phase

    so according to this https://en.wikipedia.org/wiki/Nucleation nucleation start faster when there is a round matter that already in the phase that the other matter is going to ,so in case of ice melting in water because it would have more Nucleation points, edit: i mafe alittle experience and it...
  50. J

    Water analogy in Particle Physics

    There is something unusual about water. Without atmosphere, water can't exist. It's as if water is part of atmosphere. In vacuum, liquid water can't exist. What other things like water where it needs other aspects like atmosphere to exist? And what is the analogy of water in particle physics...
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