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. 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...
  2. G

    Heating a steel spring then quenching in water

    Hi group, I heated a steel spring until red hot then plunged in water quenching it. My understanding is that quenching so quickly would have an effect of the grain size such that I would expect it to be much more brittle as with small grain there is much less plastic deformation possible (as...
  3. kyphysics

    Do You Call a Plumber if Washing Machine is Dripping Water in Tub?

    Two questions: 1.) If you have a washing machine that is dripping water into the tub (no leaks outside that I can see), would that typically be a problem that plumbers are called for or some other sort of repair/handyman/technician? 2.) Anyone know what's up with mine? IT WAS WORKING FINE...
  4. C

    The importance of water for life

    Hi PF, I'm teaching a college level introductory course about planet Earth and we are briefly discussing the importance of water for life. This is not covered in our textbook but I thought it was important to cover. I found some good resources...
  5. A

    Understanding MAL of Cadmium in Soft Water

    What does ‘MAL (is it Maltol) of cadmium’ in soft water mean?
  6. Dario56

    I How Does Surface Tension Balance Small Objects on Water Surface?

    When small object such as needle is put on the surface of water it displaces small amount of water which creates a depression under the object. Such depression increases surface area of the water because of which surface tension tends to decrease it. Explanation why surface tension balances the...
  7. S

    Help understanding refraction in water

    I recently had some trouble understanding refraction but after I finally understood where I went wrong (thanks to the people on this forum) I went back to my old lecture notes because I thought that what I recently learned didn't fit right with something that had previously been presented in my...
  8. B

    Cooling tower -- hot and cold water tanks

    Hi In some projects, I saw that hot and cold water tanks have been used for open circuit cooling towers. What is the need to use these tanks?
  9. X

    I How does the Lota Bowl water experiment work?

    Hello! Can anyone help me understand why this experience works this way? If we plug the hole on the left side, the water does not affect the cup that has the hole on the bottom. However, if we let go of this hole on the left side, the water will start to pour into the cup again. Is the law...
  10. L

    Which diagram of water molecules is correct?

    I've seen both types of diagrams when drawing covalent dot and cross diagrams. And some students that I teach said that the electrons should be on the circles. But I do know that this is actually showing the electron overlap and electron field and in reality electrons are not in circular orbits...
  11. K

    B Cheapest equipment to boil water at 60℃

    Water (any liquid) in a closed container boils when the vapor pressure of water (a property that depends on its temperature) equals the surrounding pressure. The vapor pressure of water at 60℃ is about ##1.99\times10^{4}## which is roughly 150 mm Hg.This principle is so simple, and yet, it is...
  12. RawPotatoes

    I Issue calculating water pressure due to the constriction of water flow

    For an experiment where I must be able to control the pressure i attached to a syringe a 'chamber'. The inner diameter of the syringe is 19.3 mm and i will fill water to 17 cm of the syringe bottom (i call this P1), the spout has a inner diameter of 2 mm and a length of 2 mm (i call this P2) and...
  13. N

    Chemistry Help with this interpolation (change in entropy while heating water)

    Hello, everyone :). I try to resolve this common problem. But, when i got in the interpolation of state 2, the values not make the sense. I have 25 psia and 75 F, but, in the superheated water table, there are not values with 25 psia (only 20 psia and 40 psia). And, the temperature values...
  14. Pim_Verwoerd

    Engineering Pressure after a water turbine

    For an engineering project we have to make an energy storage system. We thought of something like a hydro dam. We were having a discussion about the pressure after the turbine in the hydro dam. The water immediately flows into the atmosphere ( so it falls down into a lake ). Can we then safely...
  15. C

    I Why does a drip of water into water make a noise?

    What is the 'gloop' noise; what actually makes the energy noise (from gravitational/kinetic into ... what transformation?), how is that transformed energy then coupled into a propagating wave in air? Further, whatever 'that' is, is it the same for an ocean wave, just godzilions of little drops...
  16. BillTre

    How surface water flows in the US

    Found this map website. Click on the map somewhere, and it will figure out the path surface water, from that point, would take, as it flows to the sea (or where-ever). It also makes a 3D fly over if you click the path. It doesn't show drainage basins, which would have been nice, but there...
  17. R

    Force of pressurized water exiting a hose or pipe?

    Well known examples of the force produced by pressurized water exiting a pipe: JetLev Water Propeled jet Pack. Hovering Car. I need to calculate the maximum for the thrust produced when the hose or pipe is bent rearward. Since this is similar to the case of a water bottle rocket, the guess...
  18. E

    B The Mysterious Water Bottle: Uncovering the Physics Behind It

    Today, I filled a bottle with water and I created a small hole beneath the bottle on the side. I realized that if I open the cock of the bottle, the water flowed out of the hole but if I close it, the water stopped flowing. WHY?
  19. SilverSoldier

    Approximations in Chemical Equilibrium (add a weak acid HA into pure water)

    Suppose we add a weak acid HA into pure water, so that upon addition its initial concentration is c. The following equilibria should establish in the system. $$\text{HA}+\text{H}_2\text{O}\rightleftharpoons\text{H}_3\text{O}^++\text{A}^-$$...
  20. R

    I Minimize supported weight of a water pipe

    I’m trying to calculate the weight I have to support at one end of a pipe with flowing water. So suppose you had a water pipe that extended from the ground upwards some distance away both horizontally and vertically, i.e., at an angle. Normally, you don’t have to worry about this issue because...
  21. K

    Why do we need drinking water?

    I was taught that we need 8 cups of water every day to keep healthy, but why can't we have other drinks instead of distilled water? Many drinks today contain a lot of water, what is the logic when there is something else it is not considered to be as good as simple water?
  22. J

    B Discover the Reason Why Light Moves Slower in Water | Fermilab Video Explanation

    I watched a Fermilab video on light propagation in water: . He says (~) at time 7:50: "The oscillating electric field of the light make electrons in the glass move. These set up a second oscillating electric field that combines with the first to make a single oscillating field. That is the wave...
  23. person123

    I Water Waves Over Obstacles: Higher Frequencies Grow, Not Decay

    In general, it seems that higher frequencies of a wave dissipate more than lower frequencies. For sound waves, it explains why you can hear lower pitches from farther away. For a vibrating string or plate, the higher frequencies also dissipate first, with the fundamental fading last. For water...
  24. L

    Inlet Water Temp vs Feeder Water Temp in a BWR

    How can the inlet water temp be higher than the one of the feeder water that is in the reactor tank of a BWR?
  25. Istiak

    How much of the wooden timber was submerged in water?

    >Mass of a timber is $20 \ g$. And, density of that timber is $0.27 \ g/cc$. That timber was bind to a metallic materials and, it was released to $0.970 \ g/cc$ water. How much the wood was submerged in water? I was trying to solve the problem following way. $$F=Ah\rho g$$ $$=V\rho g$$ $$=V \...
  26. Ebi Rogha

    I Mass of Water Increasing with Heating

    Suppose we heat up a sealed container of water (no vapour escape), will it mass increase according to E=m.c^2 ?
  27. S

    Question about direction of movement of water molecule

    When the boat moves to the left, water molecules below it also move to the left. Is it correct to say the reason is because of Newton's 3rd law? Water molecules provide friction force to the boat so force on boat by water molecules is to the right. By Newton's 3rd law, there will be force on...
  28. MattGeo

    I Exploring the Physics of a Straw & Water: A Detailed Analysis

    For quite a long time I had just gone by the traditional explanation that when you place a straw vertically into water without fully submerging it and then you withdraw the straw from the water, the water column stays inside because the pressure from the atmosphere acting on the bottom of the...
  29. xpell

    Calculating Energy Released by Sodium Reacting with Water

    Hi! After watching a couple videos about the explosive reaction of sodium in freshwater and seawater, I felt curious and wanted to calculate how much energy is released. However, my Chemistry is super rusty and I think that my result is way too high (equivalent to almost 2 g of TNT per gram of...
  30. Einstein44

    Calculating the volume of a bottle of water using disk method

    .
  31. S

    Diesel Injector and Water Tube Boiler Back-Pressure

    Diesel injector: How much pressure relative to the maximum combustion chamber pressure during the sharpest phase of detonation does an injector need to be able to overcome to inject its full charge? How much overlap is typical between injection and detonation? Water-tube boiler: Are the water...
  32. E

    Engineering Thermodynamics homework help, water cooled air cooler

    I'm not looking for someone to tell me the answer, just help steer me in the right direction. I feel like I need to find the air density or air velocity at entry to proceed, but I'm unsure any help and guidance is greatly apricated!
  33. russ_watters

    Plumbing Water Softener Troubleshooting/Repair

    I have an older Morton System Saver water softener, model MSS20B. It's similar to THIS (pdf manual), but the buttons are different (it's 15 years old). It is currently flashing "VAC" (vacation mode) and "RCHG" (recharge mode) and is hissing like it's doing a recharge. At this point it has...
  34. marcelo

    How Much Calcium Carbonate to Add for Optimal pH in a Fish Tank?

    Considering a fish breeder decided to breed small fishes which needs a pH between 6,0 to 7,0 to stay alive. He needs to adjust the water's pH that is 5,0 to a value of 6.5, having available only calcium carbonate. The mass in mg added to 5L of water is about: A)2,5 B)5,5 C)6,5 D)7,5 E)9,5
  35. river928323

    Maintaining Component Temperature with Water Bath

    Using water bath to maintain temperature of the component
  36. D

    I Maximum hole diameter to prevent water leakage

    I have a empty bottle and immersed it into the water, where the pressure inside the bottle is equal to air pressure. If I want to make a hole on the bottle, how big is the hole to prevent the water leak into the bottle at different depth? what kind of parameter is involve in this phenomena? can...
  37. bob012345

    Is Wastewater Recycling the Solution to Extreme Drought?

    Due to the extreme drought, what is the minimum amount of water required to wash a small car such as a Corolla and how would you do it?
  38. DaveC426913

    Floating a cruise ship in a bucket of water

    OK. I'm sure we're all in agreement that it is theoretically possible to float a cruise ship "in" a bucket of water, right? If not, maybe we need to sort that out first. A couple of practical provisos to start: Allow some leeway on what constitutes a Cruise Ship for our purposes. I submit that...
  39. N

    I Volume of water consumed by vacuum

    I'm trying to do the math for a backyard thermodynamic pump experiment, and getting stuck. Suppose an empty 3.79 liter container was airlocked by a vertical 25 cm long empty tube whose end sits at the top of an unlimited supply of water in a basin. The tube protrudes through the container such...
  40. Nauticale

    Force from Water Entering a Pressurized Tank with No Relief Valve

    Hello all, I am trying to understand how a force at the opposite wall from water entering a pressurized air (atmospheric pressure) tank, and for this discussion it is rigid, with no relief valve to displace the compressed air can be deduced. I have created a simple illustration and believe this...
  41. C

    I Can a hose spray higher than the water tower?

    As our family drove along the highway, one of my 3 college boys started commenting about the water towers we were seeing. We started a deep discussion about how water towers work and that led to a fascinating discussion about water supply in skyscrapers that are clearly taller than your average...
  42. I

    Chemistry Why does evaporating water cause some water to be cooled and form ice?

    Answer: I know that when water evaporates, it absorbs heat, that's why the process is endothermic. I don't understand why the water would be cooled and some ice would form, when the water is supposed to evaporate. What causes some water to be separately cooled instead of evaporated? Thanks.
  43. coolul007

    Barrier to Flood Water: Is it Effective?

    This has been bothering me for a year. I saw a news report outlining the potential of a flood coming down a street. The street was lined with plastic barricades filled with water to keep the flood waters from getting to the buildings on the street. It seemed to me that since the specific gravity...
  44. The Baron

    What Happens to the Wavelength of Light as it Passes Through Water?

    I have a question, say a wave of light is emitted, and it passes through water, changing it's wave length to 380nm inside the water, once it comes out of the water, to vacuum will the wavelength remain at 380nm or will it change?
  45. C

    Ejection speed and travel distance of a ball in a pressurized water pipe

    Diameter of metallic ball : 3.000 inches SG of ball is : 2 ID of pipe is : 4.05 inches ID of seat : 2.885 inches Pressure behind ball when released from seat #1 is 1100 psi Fluid in pipe is Seawater (above and below the ball) Fluid flow rate after ball is released is 800 litres pr minute The...
  46. brotherbobby

    Force of water against a dam gate

    Question : I start by putting the image of the problem from the book. The water surface is given to run along the (top) edge of the bridge. Attempt : The crux of this problem lies in the fact that the pressure of water against the gate will vary along its depth ##h## as ##\rho gh##. This makes...
  47. K

    Can you move water vertically without a pump?

    Hi I would like to design a water fountain/waterfall and want to know if i can pump water upward without using a pump. Perhaps using gravity and pressure. My planned size would be between 1 foot to 10 feet.Thanks
  48. P

    Does the colour of a container affect how fast water in it cools?

    Containers are painted with the 7 colours of the rainbow; each colour corresponds to a different wavelength. Pour boiling water into each container. Which container would cool the fastest? Does the result change depending on whether the exterior or the interior or both are painted? The material...
  49. D

    Cooling things in water vs air

    Hi everyone After I've cooked beans in a pressure cooker, I put the cooker (with beans inside) into a sink full of water to help it cool down. After a while, the water heats up. At this point, would the cooker cool faster if I left it in the sink or if I took it out again? I'm guessing it...
  50. 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...
Back
Top