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. Cmotaval

    Pressure of water exiting a hole in PVC

    I have a 1" PVC pipe that is 36" long, closed on one end and hooked up to a pump on the other. The pipe has 10 holes each measuring 1/32" in diameter and I have been trying to use Bernoullis equation to find the pressure of the water exiting those holes. I believe the volume of water that will...
  2. Delta2

    B What is the analogy for EM waves traveling in vacuum?

    So, is water for water waves, what is the vacuum for EM waves traveling in vacuum. I know the analogy can't be exactly perfect because water molecules oscillate in the presence of water waves, but in vacuum nothing seems to oscillate? Or the vacuum oscillates in some way? And no I am not trying...
  3. J

    Max linear speed of propeller tip in water

    Homework Statement:: project not homework Relevant Equations:: vectors Hi,I am trying to determine the maximum linear velocity of a propeller tip when subject to flowing water with velocity ##\vec V##. For simplicity, I will assume that rotational inertial is negligible. The drawing below...
  4. S

    I Does pressure affect the thermal breakdown of water?

    As per the title, I'm trying to research how the thermal breakdown (thermolysis) of water works. I gather that you need circa 3000°C to get it to break down, which is a lot, and I'm curious as to how pressure might affect this. I know that pressure affects the boiling point of water, and as...
  5. HelloCthulhu

    How does an electric field create velocity in a water bridge?

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  6. wnvl2

    Chemistry Using Pourbaix diagrams to calculate corrosion in water

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  7. Daniel Petka

    I When is a water surface not dispersive?

    For my project, I need water waves of all frequencies to move at the same speed. I read this article, but struggled to grasp some concepts. The key idea of the article is that a raindrop hitting a water surface basically creates a pulse containing all the frequencies, and since the water is very...
  8. person123

    I Shallow Water Wave Equation Simulation: Reverse Shoaling?

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  9. P

    How much ice to cool down this water?

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  10. CalvinandHobbes

    Engineering Electrical energy to empty reservoir with a siphon water pipe

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  11. A

    I Water has no shear force but it can be sheared?

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  12. A

    I What happens to the buoyant force at the surface of the water?

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  13. CalvinandHobbes

    Limitations on water siphoning

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  14. J

    I Is this water pumping device using the Rankine cycle?

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  15. N

    Why and How Ethanol + Water + Raw Material contain Essential Oil

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  16. aladinlamp

    I Viscous Drag of Water: Effects & Understanding

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  17. L

    I Surface tension and water (the smallest hole water will flow through)

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  18. Bernadette

    B Exploring Entropy with Svante Arrhenius' Salt Water Experiment

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  19. nik282000

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  20. W

    Heat Engine Efficiency: How Ice Water Affects Performance

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  21. B

    B What is my apparent weight in water?

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  22. Manshah

    Time to Empty a Tank with Water Flowing at 2h kg/s

    a tank is filled with water up to its brim a hole was made at the bottom of tank find time taken to empty tank if water flows at rate of 2h kg/s where h is height of liquid column and is equal to 20m radius is equal to h/2 [Moderator's note: moved from a technical forum.]
  23. S

    Cooling of a thick walled pipe transporting water

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  24. H

    How to calculate water pressure drop in cooling tower piping system?

    When calculating water pressure drop in chilled water pipisystem (closed circuit) we always use Hazen Williams equation as follow:- but in case of calculating water pressure drop in cooling tower piping system (open circuit), shall we modify something in Hazen Williams equation or shall we use...
  25. watersplit

    Neutralize chloramines in tap water

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  26. watersplit

    Can a Vortex Effectively Purify Water by Utilizing Gravity?

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  27. chwala

    Find the surface area of the water in the given prism

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  28. watersplit

    Is Distillation the Best Method for Purifying Water?

    Hi I want to to make 100% (or close to it) pure water and I guess distillation is the way. I know there are VOCs that can vaporize at different temperatures. And then we have the chloramines in our tap water. When water gets vaporized does the chloramines vaporize too? Can anyone provide some...
  29. P

    How much time does it take to warm up water?

    Water heater has the effect 2kW and is filled with 2kg water, with a heat capacity of 4,18Kj. The water needs to be warmed from 300K to 400K. How much time does it take for it to warm up? I've tried to solve this, but it seems that i need to know the heat capacity of the water heater, which i...
  30. Physics Slayer

    Boiling a glass of water in a bowl of water - tricky question?

    I think the water in the bowl of water will boil first because the glass won't conduct the heat instantaneously, and hence the water in the glass will boil after the water in the bowl. Is this correct? I am guessing this is a trick question and the water in both boil at the same time, but I...
  31. A

    A Calculating the heat loss of an open water tank (aquarium)

    Hi, I have been calculating a series of hypothesis for some aquariums/tanks situations, using heat transfer equations (conduction, convection, radiation, evaporation) Typically we have aquariums that run at higher temperatures than the surroundings in winter and lower temperature than the...
  32. BenDover

    Aluminum mystery -- Questions about elecrolysis in water

    Hello, human people's. I noticed a strange phenomenon while playing electrochemistry. - i used 2 strips of aluminum foil as electrodes in sodium sulfate solution, 1 for positive terminal and other for negative. Applied 5 volts, essentially zero current flew. - i used 1 strip aluminum for...
  33. L

    Position of the image of an object placed in water

    I tried using the formula for the refraction of a spherical lens ##\frac{n_1}{p}+\frac{n_2}{q}=\frac{n_2-n_1}{R}## consider each slab as a spherical lens with curvature ##R=\infty## and by doing that I get ##\frac{1.33}{10}+\frac{1.5}{q}=0\Leftrightarrow q\approx -11.3 cm##. Since the piece of...
  34. sophiecentaur

    Plumbing Finding a leak in a Central Heating system (water)

    It has to be going somewhere! The boiler pressure drops by about 0.5Bar every few weeks. I've looked at the radiators for signs of small leaks but I haven't been inside the boiler as yet because I only recently terminated a maintenance contract with British Gas. BG were not interested in a leak...
  35. bluesteels

    Quick question about the heat Q transferred between water and skin

    My work Q= 0.025 * 4190 * (34-100) = -6910 but on chegg but did they do Q= 0.025 * 4190 * (100-34) = 6910. I thought the initial is 100C and final is 34 because it goes from 100 to 34
  36. W

    Thermal Physics Problem -- Dropping a hot mass of iron into 20C water

    Hi, The solution for this question is thermal energy lost= thermal energy gained 0.200x450x(300-T)=1.0x4200x(T-20) T=26 degrees celcius. However, I am struggling to grasp why (300-T) is used. I have always known a change in something to be final - initial. Therefore change in T= Final-...
  37. P

    B How Does Ambient Temperature Affect Aquarium Water Temperature?

    Hello, I am in the process of trying to figure out the conditions required to heat an aquarium using the surrounding air. The first step is to figure out how to calculate the room temperature required to keep the aquarium at a desired temperature. I was drawn to this forum when I ran across...
  38. bluesteels

    Confusion about whether to use the specific heat of water or ice

    My thought process of how i do the ice melting part: (note I just ignore the copper/lead part cause I already know how to do that part) Q_ice + Q_melt + Q_liquid so, it 0.018(2100)T+0.16(4190)T+0.018(334*10^3) but on chegg they didn't use 2100 but they just use 4190 instead and I am confused...
  39. F

    How To Convert Kvs-Value For Water To Kvs For Gas?

    Hello, for an instrument I have given the Kvs-Value for water and I want to convert it to gas. Can someone help or explain the calculation? Of course I have the formulas for liquid and for gas KVs-calculation. How do I convert it? Thanks for the help Falko
  40. S

    I Why does light travel slower in water?

    I always thought it was from individual water molecules absorbing and reabsorbing light, but this explanation in a video from Fermilab is very strange to me . What is this "new wave" he speaks of; wouldn't it be light too? If so, then this light is now slower than the speed of light, which...
  41. E

    Theoretical reaction rate for water electrolysis

    So I'm designing a proces where carbondioxide is converted into methane using the Sabatier reaction. For this reaction hydrogen is required which I'm planning on producing using the electrolysis of water. But I'm having a problem where I need the speed of this reaction to determine the size of...
  42. T

    Mars - Igneous Rock, Exposed to Water, and with Organic Material

    A good candidate for the sample retrieval mission. https://www.nasa.gov/feature/jpl/nasa-s-perseverance-mars-rover-makes-surprising-discoveries
  43. W

    I The reflection of the sunset on the water is redder--Why?

    I presume that some kind of absorption occurs when the sunset is reflected on the water, but can anyone describe this in more detail?
  44. S

    I Water Tank Overflow Air Piston concept/question

    I am trying to determine the minimum piston weight/force that would be required to push the air from the air tank into the top of the supply tank, filling up the supply tank and purging the discarded water thru the outlet supply pipe. We can assume no friction loss and sufficient air in the air...
  45. D

    I A New Idea for the Origin of Earth's Water

    I will begin with the concept that the Moon was originally a rocky terrestrial planet that orbited at roughly one AU from the Sun and lost the majority of its lighter volatiles including water during the T-Tauri phase of the Sun's transition into a Main-Sequence yellow dwarf star. A similar...
  46. maistral

    A Shallow water equations evaluation

    Summary:: A little confusion on the momentum equation (I think). According to Wikipedia (I know, I just need basic resources for now), the conservative SWEs are : If I use product rules, I am supposed to get: For context, note that ρ is a constant and can be taken out (thus canceled out)...
  47. S

    MHB Calculating Total Area Under a Trapezoidal Curve for Water Tank Fill Time

  48. kyphysics

    Can You Add Water to a High Efficiency Washer (There is So Little)?

    I used a HE (high efficiency) washer for the first time today at a relative's house (they're gone on vacation, so no one "warned" me). I washed a "medium" load of clothes ("medium" for a traditional/regular washer) and to my utter shock, the water level was only about 1/5 or 1/4 (at most) of...
  49. A

    Supercritical Water Reactor: Density & Temperature Impact

    Hi, I'm working on an MCNPX design for the Supercritical Light Water Reactor, and I want to know how does the density of the water -which plays the role of the coolant and moderator- change with temperature? I think the pressure is fixed at 25MPa, but the temperature of the water may vary, Does...
  50. S

    Is electrolyte chemical consumed during alkaline water electrolysis?

    In alkaline water electrolysis you add Potassium hydroxide, or Sodium hydroxide to the water you want to turn into hydrogen and oksygen. But is the Potassium hydroxide, or Sodium hydroxide consumed during electrolysis and needs to be replaced? Or do you just have to keep adding water as it is...
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