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.

View More On Wikipedia.org
Recent contents Top users
  1. M

    MHB Rate of Water Rise in Cone-Shaped Vessel

    a vessel in the shape of a cone is standing on its apex. water flows in at a steady rate, of 1m^3 per minute. the vessel has a height of 2m and a diameter of 2m when the vessel is 1/8 full find the rate at which water is rising v=1/3 pi r^2 h however i can't differentiate this
  2. CivilSigma

    Programs Structural/Geotechnical or Water Resource Specialization (Civil Engineering)

    Hello, May I ask any civil engineers on this forum for their input of pros/cons of specializing in structural / water resources engineering? I am having a hard time choosing between the two because I really enjoy both subject. I enjoy both topics and I am afraid that if I choose one over the...
  3. R

    Why does a straw look bent in water?

    Homework Statement https://www.highlightskids.com/media/kids/highlightskids/images/thumbs/sciQuestions/sq1012_put-a-straw-in-a-glass-of-water_main.jpg Homework EquationsThe Attempt at a Solution From my understanding, this has to do with refraction. Here's my answer: ----- Light usually...
  4. P

    Is Ammonia absorption in water exothermic?

    A person working in a company that manufactures absorption refrigerator told me that when Ammonia dissolves in water, the water temperature rises. In short, Ammonia absorption is water is exothermic. If it's true, then what's the reason behind it? Is it due to the fact that the latent heat of...
  5. Thejas15101998

    What Causes the Sound of Water Unfilling From a Bottle?

    When we unfill a waterbottle, we here a periodic sound like- cloc.. cloc.. cloc..- How does this happen?
  6. J

    Is a hydronium (H3O+) less clear than a water pool (H2O)?

    Not that I know of any hydronium pools, I was just wondering if there would be a difference in clarity or not (as in, harder to observe the bottom)
  7. S

    Acoustics and Fluid Flow - COMSOL 4.2

    Hello everyone, First of all I am new here~ Second, I would like to "prove" on COMSOL that soundwaves (sound vibration) can alter/reshape the fluid flow Can someone tell me the physics i should use as well as all the other parameters to make it work? if someone is more experience can they...
  8. UMath1

    Can solids burn in water? Exploring the chemistry behind underwater combustion

    I was cooking oats in water yesterday and the oats at the bottom of the pot got scorched. How is this possible? Doesn't the water smother the oats from oxygen?
  9. R

    Polarisation (light on water surface)

    Homework Statement A student looks at the sunlight reflected off a puddle of water. She puts a polarising (Polaroid) filter in front of her eye. As she rotates the filter the puddle appears darker then lighter. Explain this observation Homework EquationsThe Attempt at a Solution Here's my...
  10. Delta Force

    Soviet Supercritical Water Reactors?

    The Soviet Union constructed at two AMB series supercritical water reactors at Beloyarsk in the late 1950s, AMB-100 (Beloyarsk 1) and AMB-200 (Beloyarsk 2). They apparently achieved a mid-30% conversion efficiency, on par with more modern nuclear power stations and much better than the...
  11. N

    Thermodynamics: vapor pressure water, given the gibbs energy

    Homework Statement Calculate the vapor pressure of water at 25°C, based on the Gibbs free energy when vaporising from liquid water to vapor (so at 1 atm and 25°C ). Homework EquationsThe Attempt at a Solution After integrating d g/d p= RT/p. I get my formula p = p0*exp (-delta gm(p0, T)/RT). I...
  12. T

    How Does Winkler's Method Calculate Dissolved Oxygen in Water?

    We were measuring the amount of O2 dissolved in water by Winkler's method. Here's a link to the procedure and reactions: http://file:///C:/Users/SANJUKTA/Desktop/Downloads/Capture.PNG http://dropcanvas.com/6su7m/1 (The same is attached to this post) We had to use this formula: c(O2)...
  13. S

    Water level accuracy for squaring a car frame

    I have a 1968 Mustang that I bought at auction from my grandfather's estate it is almost completely apart and I want to rebuild it for him has sadly he ran out of time, I have a reproduction manual from 1968 with frame dimensions in it and some of the dimensions car vertical to a datum line. I...
  14. C

    Penetration of falling object into sediment (after water)

    Hi All, Long time absentee from the forums hoping for some direction in my new research. I've been tasked to look into the stages of motion of objects (dropped from various heights), hitting a body of water (of various depths) and eventually hitting the seabed (of various sediment types). I am...
  15. baba bakjohikoplop

    How would a person under water see sunset and sunrise?

    A person completely under sea water tracks the sun. Compared to an observer above water, which of the following observation would be made by the underwater observer? Neither the time of sunrise or sunset nor the angular span of the horizon changessunrise is delayed, sunset is advanced but no...
  16. A

    Could water chemistry be altered to make swimmers faster?

    At swim practice last week I started thinking about how the composition of the water was affecting how fast my teammates and I were able to swim. The mechanical properties of the water--viscosity, density, surface tension, etc.-- are what determine how much force swimmers are able to generate by...
  17. K

    Weak bases react with water to produce strong base?

    Which of the following statements about weak acids and weak bases are false? (i) The strength of a weak acid decreases as itspKa decreases. (ii) Weak bases react with water to produce a small amount of a strong base. (iii) The strength of a base decreases as the strength of its conjugate acid...
  18. lippyka

    Man jumping into water: Conservation of Energy

    I'm sure most of you guys have heard of it, but I recently signed up for a service called "Gigwalk" and thought I'd share it with anyone who hasn't heard of it.Basically Gigwalk is a website where people post "gigs" that need to be completed. You can accept gigs in your area and get paid for...
  19. W

    Water level before and after metling of ice cube

    Homework Statement A big ice cube is placed in a small glass of water. The level of water in the glass is marked. When the ice cube melts completely,the overall water level will remain the same. Explain. Homework Equations Upthrust= weight of fluid displaced The Attempt at a Solution Since...
  20. hackhard

    Water Surface Touch Pad: Can My Project Work?

    an idea for my new project construction - a cubical bowl of tap water , 2 sheet electrodes for 1 pair (y-axis pair)of opposite face(square wave 10Hz 10vpp), 2 sheet electrodes for the other pair (x-axis pair)(similar square wave lags by half cycle ) left hand touches adc pin. right hand touches...
  21. F

    Optimizing Water Tank Volume and Pressure for a Wet Fire System on Upper Floors

    Hi, a water tank will be put in the third level floor or slab. What must be the volume if gravity tank will be used so the pressure would be strong at 2nd floor and ground? It will be primarily a wet fire system. The tank won't be used for any other water applications since the building already...
  22. F

    Question about water drop's critical radius

    Homework Statement Hi everybody. I am currently trinyg to solve the first exercice of the fifth chapter of R.R. Rogers book about cloud physics. "Show that the vapor pressure in equilibrium over a pure water drop of radius r decreases with T if r<2σ/LρL. Homework Equations...
  23. Z

    Gas Law applying to air vs water vapor

    Say we have a tire filled with air (equal to ambient air surrounding it in every way). pressure on the gauge is 0. Then, we pressurize it to 1 ATM (15psi). If we heat the tire , the air will be heated and expand based on gas law, or is there a factor that changes it based on the air's...
  24. hackhard

    Detect current direction in water

    a bowl is filled with tap water .electric current is made to flow due to electrodes attached to rim of bowl(opposite sides of bowl) i have 2 sense pins inserted into the water between the electrodes . how can i convert this analog signal(vd across sense pins) to a digital signal to detect...
  25. O

    Power drawn by a water pump to project water through nozzle

    Homework Statement [/B] This is problem 10.27 in the Exercises for the Feynman Lectures on Physics, or Problem C-2 in Chapter 10 of Leighton and Vogt's Exercises in Introductory Physics. Homework Equations Using ##v_f^2 = v_i^2 + 2 a S## for the water in the vertical direction, we can find...
  26. A

    Need an explanation -- Consider pure water separated from....

    Consider pure water separated from an aqueous starch solution by a semipermeable membrane, which allows water to pass freely but not starch. After some time has elapsed, the concentration of starch solution a. will have increased b. will have decreased c. will not have changed d. might have...
  27. J

    Upthrust Reaction - Water Injection @ 5bar -8msw Subsea

    Hello, I have a problem Basically, in theory -- a damaged 1220mm dia pipeline sub-sea (-8msw) with a 500mm hole in the 12oclock position 600mm. Pipeline resting on the seabed The goal of the problem is to flush the pipeline of its contents in both directions. The idea - have a containment...
  28. S

    How much water boils off when a hot horseshoe is dropped in

    Homework Statement A blacksmith drops a 0.7 kg horseshoe of iron at a temperature of 1200 ̊C into a bucket of 0.5 L of water at an initial temperature of 30 ̊C. How much of the water boils off? Assume the bucket absorbs none of the heat. Homework Equations I believe Q = mc delta(T) is what I'm...
  29. mktsgm

    Medical Does chilled water contains Deuterium?

    I have heard that chilled water contains hard water. ie in the H2O contains another isotope of Hydrogen with a neutron. Is it true? If so, how it might affect our health if we drink?
  30. MattNguyen

    Thermodynamics adding ice to water problem with latent heat

    Homework Statement Initially you have mW = 4.6 kg of water at TW = 74°C in an insulated container. You add ice at TI = -19°C to the container and the mix reaches a final, equilibrium temperature of Tf = 33°C. The specific heats of ice and water are cI = 2.10×103 J/(kg⋅°C) and cW = 4.19×103...
  31. Tomimo

    Making bubbles and trying to use Trompe

    Hi, I am trying to create a device that would "simply" make a bubble under the water. What I am aiming for is production of small bubble but continuously and under the water. When I say continuously, it doeant have to be for extended periods of time, could be just for ~2 hours but the longer...
  32. L

    Heat transfer between water tank and pipe system

    Hello All, I have a question for heat exchange calculation and hope someone can help. I would like to recover the "cooling energy" from a ice melting pool for air-conditioning for a small office. I plan to install three fan coil units with 800CFM for the office with closed loop water pipe to...
  33. mbewley59

    Sealing a wiring port to withstand water at 130+ psi?

    Hey everyone- I'm designing an ROV thruster which, for starters, will operate down to a depth of 300 feet. My problem is that I can't find any information regarding an electrical port which can pass through the hull out into the pressurized atmosphere without leaking. This will be a 12v system...
  34. mfb

    B Huge amounts of water ice found on Mars

    NASA report. ~10,000 cubic kilometers, more than even the most enthusiastic colony concepts could use in the whole 21st century, and even if we don't take recycling into account at all. The ground has 50-85% water ice, buried under a 1 to 10 meter surface layer of regolith - it should be easy...
  35. neil63

    Recycled acidic water evaporation / condensation

    I would like to recycle a source of used water at work. The water is contaminated with an acid solution and other chemicals used in a powdercoating process. My question is -- if I were to evaporate the water and then turn it back to condensate, would the water be pure? or would the acid and...
  36. A

    Ksp and Q precipitate, Why does volume of water matter

    Homework Statement Homework EquationsThe Attempt at a Solution [/B] So here's my question again, why do you need to include 40L of water in the total volume? It's not like AgCl is going to dissolve in water right? AgCl has low solubility in water. I mean if it was like NaCl then you should...
  37. S

    Purify Water in a Rolling Barrel

    Hello - I am hoping for a bit of helping on a high school science project. I am looking for suggestions on how to force water through a tube or a screen within a barrel full of water as it rolls. I had a concept for using a UV light system to purify the water, but that option fell apart so I...
  38. T

    What Is the Entropy Change When Ice Melts in Hot Water?

    A closed, well-insulated container is filled with 454 g of water at 94.4 °C. To the hot water, 200 g of water ice at exactly 0 °C is added. The mixture reaches an equilibrium temperature of 41.1 °C. Assume the molar heat capacity is constant and all the processes are at constant pressure. The...
  39. Grayman

    Carbonated Water Freezing and boiling points

    Is there a way to calculate the freezing and boiling point of water that has different levels of CO2 in it?
  40. nfcfox

    Frequency of a mass bobbing up and down in water

    Homework Statement This was a test question I had today but basically, initially the mass is at rest as the buoyant force opposes the force of gravity. Then we push it down X meters and let it go. This can be described by SHM. We are also given the density of water, a cross sectional area of...
  41. HorseRidingTic

    Calculate the area of water suspended at 500m to produce 23TWh

    Calculate the area of water, suspended at 500m, needed to produce 23TWh of energy I've done a calculation but the answer seems far too small If I needed to store the UK's supply of energy for three months i.e. 23TWh of energy in a reverse pump hydro storage at an elevation of 500m using P=mgh...
  42. Ali Durrani

    What amount of amperage do i need for electrolysis of water?

    ok i want to make 1g/sec of hydrogen out of an unlimited supply of water, i know the electrolysis won't start below 1.48 volts, let suppose i am supplying 2 volts of DC current, i need to find out the total wattage for electrolysis, for this i need the amount of current required to produce 1...
  43. I

    The force with which a stream of water pushes an object

    Hello! I'm having trouble finding out how to calculate the force with which a river can push an object, well an propeller to be more exact. I would like to know what do I need to find about the river, like speed and cubic metres, and how do I use this information to calculate the force with...
  44. Adrianus

    What heat capacity is needed to evaporate water in oil

    Homework Statement In an industrial fryer is f.e. 400 kW. Heating capacity installed. The fryer may contain as much as 1.450 ltr of oil. I can fry 2.000 kg of chicken nuggets per hour in that. These products loose 7% of moisture/water in this process. That water can only escape from oil in gas...
  45. Misha Kuznetsov

    Voltage applied to urchin-like iron spheres in salt water?

    Hello, if I had salt water and put microscopic spheres with iron spikes in (a lot of them, say 1,000). Then if a high static charge was applied to the water (say 500,000 volts), what would happen? My intuition tells me that the electric field would concentrate on the tips of the spikes, making...
  46. F

    Water and its interesting 3 phases....

    Hello Forum, I am reviewing water and its 3 phases (solid, liquid and gas). a) At the triple point, water can be in the three phases simultaneously. Does that mean that for a certain amount of water, say 30grams, we would find, approximately, 10 grams of liquid water, 10 grams of ice and 10...
  47. L

    I Do electrons really behave like waves?

    If we say electron behaves as wave, does this mean if we were able to see an electron, we would see it moving up and down?
  48. Galbi

    Water evaporation by negative pressure and 0% of RH

    Greetings! I'm trying to evaporate water in some samples. I'm trying 3 methods. Baking samples with 100°C, normal air pressure, and normal RH. Put the samples in 0% RH, 23°C, and normal air pressure. Put the samples in container of -15 psi air pressure, 23°C, and normal RH. The total amounts...
  49. micromass

    Another Water Riddle: What Will Happen & Why?

    What will happen? And why?
  50. B

    Why sound produced by rapids varies in pitch based on height

    The other day I was at a river listening to some rapids. The sound produced by the rapids appeared to vary in pitch depending on how high up I was (squatting down to the ground and standing up produced about a fifth in the variation of the pitch); and I can't think why it should be? Many Thanks
Back
Top