What is Water: Definition and 999 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
  1. L

    Pressure, Density: Water & Oil in Glass Tube

  2. H

    B Some Questions About Drag (for ships in water and airplanes in air)

    I'm interested in the very basics of drag, both for ships in water and airplanes in air. Here's what I have so far : Flow of the medium can be laminar or turbulent. As the relative speed of the vessel increases, the more likely the flow is to be turbulent. Laminar drag increases linearly...
  3. B

    B Water surface under pressure

    Hi togehter, this may be an easy one for most, but I'm really struggling with imagining the process. Suppose we have a compressed air vessel that is half filled with water. The pressure in the vessel drops from 10 bar to atmospheric pressure within a few seconds. How does the water surface...
  4. gamecult

    Bernoulli equation for calculation of water flow

    Hello everyone; Please need some help to check if my calculation are correct (and if possible some explantation) Bernoulli's equation between point 1 and 3 is given by: P_1+1/2 ρv_1^2 + ρgh_1 = P_3+1/2 ρv_3^2 + ρgh_3 P_1 = P_(atm ) v_1= 0 m/s h_1= 0.875 m P_3 = P_(atm ) v_3= ? m/s h_3= 0...
  5. S

    Improving heat transfer in domestic hot water tank?

    A typical UK domestic hot water tank holds c. 200 litres of water. Hitherto the common method of heating it to say 60C has been by means of an internal coil of copper pipe through which is pumped hot water from a gas boiler at ~ 70C. Heat transfer on the outside of the coil is by natural...
  6. K

    Measuring the Speed of Sound in Water, Using Faraday's Law

    Hi! This project involves both mechanical and electrical elements, so I'm discussing it in this forum since I'm not sure which one it would fit better into. I'm working on an experiment in which I'm trying to measure the speed of sound through water. The approach is simple: I have a long...
  7. W

    I Neil DeGrasse Tyson on "sharing water" with historical figures

    Hello, I've heard versions of these statements (below) from other scientists, but I've never seen anyone break them down. Do molecules in air really move (diffuse?) their way around the entire globe, or are there localized "pockets" that really don't move that far from home? Intuitively, water...
  8. E

    Cooling Water in Hard Soil: Data and Questions

    Here’s the data is can supply. Water temperature entering ~51°C. desired water exit temperature ~38-40°C Water flow ~approx. 300L/min. Pipe Inside Dia.- 51mm Pipe Material- HDPE PN16 We would bury the pipe around 1 meter deep. Deeper is not feasible as the trenches would be hand dug in an area...
  9. kyphysics

    After Dissolving Salt in Boiling Water, How Do You Get it Back?

    in solid form (the salt that is)? I had to try to answer this question for my 14 y/o cousin and think I may have messed it up. Good thing she knows I suck at science and to ASK HER TEACHER next time! :smile: Anyways, it got me curious. . .I first thought of just reversing the process. Since...
  10. D

    Q regarding fixing old busted water line w/ no water in it for 2 yrs

    Water line on a certain property has been busted for 2 years and no water in line. I am calling plumber tomorrow to get fixed and am just curious before I do that if fact that there has been no water in line would pose any particular issue to plumber just coming out and fixing that one spot...
  11. PhysicsInterest

    The Miraculous Properties of Water

    What about water makes it such a great substance? I'm aware of properties like a high SHC providing aquatic habitats with stability, being a liquid at room temperature due to Hydrogen bonding and etc but what about water makes it so great why is it such a miracle substance, solely because of the...
  12. Pushoam

    Pressure inside a water drop

    Taking the shape of water drop to be spherical with radius R and ignoring the gravity, three forces acting on the surface of the water drop are 1) force ##F_o## in radially inwards direrction due to the outside pressure ##P_o## 2) force ## F_{in}## in radially outward direction due to the...
  13. J

    B Archimedes Principle - A Rock and Water Magic Trick

    I understand how to measure specific gravity of a rock. One weighs the rock then tares a beaker of water and then suspends the rock on a string to observe the “weight” gain of displaced water. My brain however could never get how, without adding a drop more water or adding the mass of the rock...
  14. C

    Finding how much heat released by evaporation of water

    For this, Dose anybody please know where they got the 120W from? Many thanks!
  15. M

    I At what level will the water settle in this system?

  16. bland

    How many ppm of O2 does H2O2 add to water?

    I'm starting with a litre of distilled water with a dissolved oxygen content of zero ppm, and I wish to raise the ppm of the dissolved O2 to 10ppm or 10mg/L using a 6% solution of H2O2. That is 10 extra molecules of oxygen in a litre! I've had no luck looking for through web based conversion...
  17. C

    Poiseuille equation for water flow rate

    For this problem, The mains water pressure at the council tubby (just before it enters a house) is of the order of 1.5 bar. Using Poiseuille equation, estimate the flow rate in a typical home at the kitchen tap. You will need to make reasonable estimates on several parameters, clearly state...
  18. P

    I Is it a fluke that the triple point of water is almost exactly 0°C ?

    Seems a crazy coincidence that the tiple point of water is also virtually the same temperature at which water freezes/melts. Or is it that the triple point of water was always going to be at the temperature that water freezes/melts (so those two neccessarily co-exist) and then above water there...
  19. T

    B Water swirl in the sink

    I have a trivial question. What causes the direction in which the water in the spout turns? They say it's according to the Earth's hemisphere, but I don't really believe it and I'm looking for other reasons. Finally, even this reason would have to have some explanation.
  20. J

    Calculating Wave Amplitude & Wavelength in Water Pools

    How would we model/calculate the circular waves in a pool of water (wavelength and amplitude) from a mass falling into it from a given height, and from a fountain of water falling into it continuously? Is there is a way to describe the initial configuration of the wave based on the stimulus...
  21. C

    Calculating Radius & Water Depth of a Spherical Bowl

    The water level in a spherical bowl has a diameter of 30 cm. If the horizontal diameter of the bowl is 10 cm below the water level, calculate the radius of the bowl and the depth of the water in the bowl. I managed to draw a diagram below: In my drawing, I am seeing the sphere ABCD as the...
  22. P

    Why do you feel heavier in water?

    I am searching for the common explanation why people believe it is so. Google and other places are suggesting that it related to gravity. However. the gravity (buoyancy) reduces our weight. The question: do we really heavier in water? If it is not the case, what makes us think that we are...
  23. archeryemily9085

    B Filling a bathtub (Hot water to cold water exchange)

    Hey there, I honestly don’t know if this is the right place for this, but I figured I would ask. lets say you are going to take a bath, but someone just took a shower and you know your hot water heater will be running low on the goods. Just for arguments sake, let’s say you have just enough...
  24. C

    Why Water Won't Flow From Faucet with 2000 Pa Pressure?

    Picture below can someone please explain me why will the water come out of faucet with the pressure of 2000 Pa? I was expecting the answer to be "water will not come out thrugh the faucet because the pressure from the barrel is not strong enough to overcome the height of the pipe" since...
  25. S P

    As much steam as possible from engine exhaust gas + warm water?

    Hi all, The idea is to generate as much as possible water steam from heat of internal combustion engine exhaust gas. The so called steam generation device is a simple sloped engine exhaust pipe where water from engine cooling and hot gas is fed at the top and all the mix is exiting at the...
  26. C

    How does soap water membrane thickness affect surface tension?

    1.If the thickness of soap water surface decrease, whereas the concentration remain the same, how will the surface tension change? 2. If the membrane of soap water start to evaporate, its thickness become thinner and it’s concentration increase, How will the surface tension change? Thank you!
  27. abdulbadii

    Oil emulsification by way of the put-off water

    How is the correct work to be done on white mineral oil emulsified as O/W but most of the water is to be deferred / put off later by indefinite amount of time? At the time water is added/mixed that mixture just become exactly the same as the emulsification mixture being done at once
  28. T

    How much air pressure is needed to push water up a column?

    Hello, I was creating a device to move water up a tube using air pressure, but I am not certain how much pressure I would need. I attempted to create it using 5 gallon buckets, however I was unable to apply the needed pressure needed to the airtight container. The image below is what I have...
  29. haha0p1

    Finding the weight of an object submerged in water

    I have solved the question in the following way: The downward force is equal to the upward force. the upward force is equal to the weight of water displaced. If we find the weight of the water displaced then we will know the upward force. And since upward force is equal to downward force, we...
  30. lxhull

    Specific Heat Capacity of a metal bar placed into water

    Previously solved thermal energy gained by water as Eth= 0.15(4180)(17.6) = 11035.2 J Not sure if its relevant
  31. C

    Calculating pressure of air pocket in a pressurized water column

    Looking for some guidance in calculating pressure of air pocket in pressurized water column. Example: 2" vertical pipe, capped, with 2" of air and 40 psi water applied.
  32. NODARman

    Work calculation for lifting a Tetrahedron-shaped object from the water

    Hi, I'm calculating the work done by regular tetrahedron during taking from the water by crane (USING INTEGRALS). I don't know how bad is that solved so if anyone checks my work and gives me some advice or hints I would be very glad. Everything is written in the PDF file. There were given...
  33. G

    Fluid mechanics: water jet impacting an inclined plane

    I was looking at an example of fluid mechanics and I don't understand this. Statement figures: CONTINUITY EQUATION $$\left. \dfrac{dm}{dt}\right]_{MC}=(\dot{m}_2+\dot{m}_3)-\dot{m}_1=0$$ $$\dot{m}_1=\dot{m}_2+\dot{m}_3$$ $$\rho c_1A_1=\rho c_2A_2+\rho c_3A_3$$ $$\rho c_1 h1=\rho c_2...
  34. C

    Do you need to account for the water heating up to the boiling point?

    High School Physics Lab: Take 200mL of water (Room temp) and place it in a microwave on high for 60 seconds. Calculate the Energy transferred to the water by the microwave. Pretty easy: Step 1: Heat of Temp Change : Q= mC∆T where m=200mL Step 2: Add Heat due to phase change: Q=mL where m=...
  35. A

    Energy absorbed by water illuminated by an LED source

    Good morning, I was wondering if I am thinking correctly. I am trying to establishing some step by step to calculate the amount of energy is being absorbed by a water body when a LED pendant is shining right above. Being the parameter that I want to calculate, the energy absorbed by the...
  36. H

    Why am I blowing a laptop powerpack with dc water pump?

    Hi, I have a water pump rated 12v dc 2.3A. I tried using Microsoft Surface powerpack rated at 15v dc 2.5A to power it. Pump just started pulsing. I removed the water pump and checked the voltage coming out the powerpack and it was fluctuating between 0 and 15v. Thought I had a dud powerpack so...
  37. Strato Incendus

    Wall thickness of ring habitats for radiation shielding

    This is a topic that will be relevant for anyone who plans to use "realistic" artificial gravity (of the centrifugal kind, rather than the "acceleration-based" kind) in their stories - be it on spaceships or space stations: How much of the ring walls has to be dedicated to radiation shielding...
  38. M

    Buoyant force acting on an inverted glass in water

    My answer : According to the question, the glass and the air inside it entered the water. Let's assume that the net force becomes zero at a moment, that is, the sum of the weight force and F is equal to the buoyancy force. By going down in the water, the gas volume decreases, so the buoyancy...
  39. A

    Does water electrolysis work efficiently under high pressure?

    One of the stages in hydrogen production after electrolysis is to run the hydrogen through a compressor and that can take a lot of energy. Would it be possible to run an electrolysis setup inside an already high pressure hydrogen tank so that the hydrogen being separated during the electrolysis...
  40. C

    Bernoulli’s Equation for plugging finger into dike under water

    For this part (b) of this problem , The solution is, However, why are they allowed to assume for the Bernoulli's equation for the water outside the hole, that the water is stationary (i.e v_1 = 0)? It also appears that they assume that the pressure inside the Holland is 1 atm, which is only...
  41. P

    Vapor pressure -- How does water still boil at 100°C in an open pot?

    Vapor pressure is the pressure of the vapor when it is in equilibrium with its liquid. This only happens when the container where the liquid is present is closed. Indeed, when the container is open, this liquid-vapour equilibrium is never reached, because the partial pressure of the vapor (at a...
  42. I

    Physics of Water in the Closed System of the Great Pyramid

    Hello, I am working on a theory for a Great Pyramid power plant and I need some help understanding if my current hypothesis is even possible and how to calculate how much water will fill the upper structure. I believe the water system to work as follows: An aqueduct delivers a steady flow of...
  43. epenguin

    B Disk with holes falling on water

    Just yesterday evening I saw a video of a few minutes where metal disks with holes in them were let fall into a basin of water.The water went up in twisted columns and made the most astounding and beautiful patterns. I thought I would show it to other people who might be interested - but I have...
  44. Z

    Strong Inequality Hydrodynamics: Flat Cylinder in Water

  45. P

    Energy/Power Question for pumping water out of a well

    Im guessing you start off with P=E/t but I'm unsure of what I need to sub in, in order to solve for v. P = 1000W h = 20m v=?
  46. mastermechanic

    I Vertical acceleration of the water bubbles in a kettle?

    Question is simple, as we all know water boils at the bottom surface and it forms tiny bubbles. These bubbles grow up and rise in the water until they detach. What is the acceleration of these bubbles compared to gravitational acceleration? - Is it constant velocity? - Is it approximately...
  47. A

    Reusing Isopropyl Alcohol bottle for Drinking Water?

    Hello, I’m an electronics hobbyist, and fairly regularly buy isopropyl alcohol for cleaning with that, and to clean a vaporiser as well. I recently found my electronics store started carrying 5 litre bottles. They are strong, and the screw top thread, in particular, is substantial, so I thought...
  48. D

    Dissolving Particles in Oil (but Water resistant)

    Hello Everybody, I have a superoleophobic surfaces which shows high contact angle for Water, Oil, Hexadecane... I am looking for a kind of particles which are attached to the surface and once I touch them with a droplet of oil are dissolving in that oil droplet. If I then remove the droplet...
  49. A

    Air wedge interference pattern after being filled with water

    An air wedge is illuminated with light and an interference pattern is produced. What will happen to the interference pattern when the air wedge is filled with water? The answer given at the back of the book is that the fringe spacing of the interference pattern will increase, however my...
  50. Induana

    B Hydrostatic pressure in a bottle of water on ISS

    Hello, I am new in physics but I really like it so far. I have a question about hydrostatic pressure. I know that hydrostatic pressure equals (height)x(density)x(g). Am I right if I say that hydrostatic pressure in a bottle of water on ISS (state of weightlessness) will be zero ? Thank you for...