Two Hydrogen atoms covalently bonded to one Oxygen atom. One of the more common compounds on the surface of the earth.

learn more… | top users | synonyms

0
votes
0answers
8 views

hydrostatic pressure on a plane surface

I've been trying to calculate the amount of pressure on a wall of a rectangular structure, that is under sea watter. For example a dam. I can't come to see any example to be able to locate the ...
0
votes
0answers
26 views

An interesting question on the mass of a droplet of liquid experiencing the Leidenfrost Effect

Background and Inspiration: I have seen numerous demonstrations of the leidenfrost effect, both on the internet and in my mother's kitchen. But I started wondering about a general case after having a ...
0
votes
0answers
13 views

watter remaining liquid in low temperatures

On several occasions I have witnessed the following phenomenon and would like to understand the physics behind it: Water is placed in a very cold static location, in a cup or plastic bottle in a car ...
0
votes
2answers
88 views

Why does freshwater attenuate signals less than seawater?

One of the most interesting problem in underwater communication is how deep the device (i.e. submarine) could go to still be able to communicate with on-shore data centers. The attenuation in a ...
11
votes
3answers
13k views

Why does adding solutes to pure water lower the the specific heat?

We found that water with salt, sugar, or baking soda dissolved in it cools faster than pure water. Water has a very high specific heat; how do these solutes lower it? We heated a beaker (300ml) of ...
0
votes
0answers
63 views

In every glass of water there are water molecules that came through Hitler's urinary bladder? [on hold]

I was told that in every glass of water there are water molecules that came through Hitler's urinary bladder. How much it is true probabilistically?
6
votes
2answers
585 views

Is it possible to disprove water memory with an entropy argument?

Water memory was a controversial experiment claiming to provide an explanation supporting homeopathy. The results were largely dismissed as being tainted by experimental error. One possible mechanism ...
6
votes
2answers
698 views

Microwave oven + water: dielectric heating or ion drag?

When you place a water or food in a microwave oven, it heats. Which process commits more energy to that: dielectric heating, or ion drag i.e. resistive heating? AFAIK, in distilled water (which is a ...
0
votes
2answers
146 views

Dielectric constant of water

I need the dielectric constant of water from $10^{-2}$ Hz to $10^4$ Hz. As stupid as it may seem, I cannot find much info. I've googled for days. All I can find is close to GHz. And the only info ...
1
vote
3answers
43k views

Relation between water flow and pressure

Is there any equation that states the relation between pressure and water flow. I.e. Let's say that in 1 hour with 8mca (water collum meters) pressure I obtain 50m3. What if (giving the same ...
0
votes
1answer
2k views

Calculation of pressure from flow rate of water

Anybody kindly help me to find how to calculate pressure in bar from flow rate. I have a pipe and from that I am transferring water at a constant flow rate of 5ml/min. At this flow rate, with a 0.5 cm ...
2
votes
1answer
66 views

How to heat water at very high temepratures?

I am working on a project and recently came through a situation where I'll be working with water evaporation. On searching the internet I found that water heated at 350Celsius would generate almost ...
3
votes
2answers
191 views

Dynamic water pressure from flow and diameter

I've to test some fire hydrants and need to get the dynamic pressure. For that I know I can use a Pitot tube but... I don't have. After Googling a lot, I found two formulas allowing to compute the ...
2
votes
1answer
112 views

Fluid dynamics tsunami

I have been given a energy head (pressure) in meters for a given tsunami on land. If the tsunami hits a wall 1 meter by 1 meter, is it possible to calculate the height it will reach. I am thinking it ...
1
vote
1answer
46 views

Does water diffuse trough rubber of car tire of when liquid or only as gas

Does Water difuse trough rubber of car tire when its liquid or only when its a gas. Can also be that is diffuses but slower when liqiud. I want to know this for my argumentation that filling car tire ...
5
votes
1answer
430 views

Finding Surface Tension of water at certain Temperature and Pressure

The question is: Using the Young-Laplace Equation (if applicable), find the surface tension (dynes/cm) for water at 20 degrees Celsius with 2.5 psi. Round to the nearest tenth. ...
4
votes
1answer
126 views

Can ice freeze? [closed]

We know that ice is already the frozen (solid) form of water. The question is more like: Can this frozen form freeze further? Or can it become more solid? (for example, by exposing to colder ...
2
votes
1answer
938 views

How fast does water fall in the middle of a very very thick waterfall?

Let me create a very artificial experimental set up. Take a bathtub the size of Delaware and suspend it a mile above the ground. Fill it with water (though I'm not sure to what depth - and it might ...
1
vote
0answers
22 views

Will a longitudinal wave propagate “forever” in a tube?

I understand that the wave will lose energy due to "friction" between the, lets say, water molecules, but in my mind at least the biggest loss of energy in a wave is normally the dispersion of it. ...
1
vote
3answers
82 views

Why does a metal boat float?

I was in class learning about density and stuff. Our teacher told us that things that are denser than water sink in water, and less dense things float. Then, our teacher asked us why metal boats ...
0
votes
3answers
75 views

What could be added to tap water to reduce air bubble formation on a submerged object?

Submerge your hand in a bucket of water. Some air bubbles appear immediately and others add to the surface of the hand over time. Is there anything that could be added to the water to reduce the ...
8
votes
5answers
697 views

Zigzag flow of water along a vertical glass window

I've observed this behavior many times. When it rains, the rainwater will form vertical channels along a glass window. The flow of water is mostly confined within these vertical channels and the ...
1
vote
3answers
116 views

Why doesn't water start to boil in soils?

Consider the following two scenarios: I take a vessel filled with some water and evacuate the air, the water will (or rather can) start to boil; if the pressure in the vessel is << atmospheric ...
3
votes
1answer
119 views

Force field for Calcium ions, potassium ions and water in molecular dynamics

I want to adapt my existing MD simulation so that it can handle these three species. For the interactions of the ions I thought that I would use the coulomb potential, but I don't know what sort of ...
2
votes
1answer
52 views

Why does ice melts faster near the surface of water?

I had a few frozen bottles and while they were melting I saw this: in all of the bootles, the ice seems to get thiner near the surface. I have searched a bit and I've found this video that shows ...
1
vote
3answers
108 views

Why do cold drinks get sweaty?

I drink a lot of iced tea and live in a very humid part of the country. My drink accumulates so much water, I had to purchase coasters to collect all the water dripping from the sides. Where does ...
3
votes
2answers
3k views

Time required for water to freeze

recently I was wondering if there is any specific formula in order to calculate how long it takes for certain liquids to freeze (especially water). I know this depends on: the volume of the liquid, ...
1
vote
1answer
153 views

Does the termination point(level) influence water flow from a pipe

I get water to my home from a nearby Tank A at a certain height above ground level. I have a 1" pipe through which I get this water to my home.. I leave this water into my well by connecting a 1" tube ...
4
votes
0answers
108 views

Calculation of water bulk modulus using equation of state

I simply want to calculate the bulk modulus of water at 50C and increasing pressures. I think I am correctly calculating the new specific volume from the original conditions at (25C and 1atm) to 50C ...
4
votes
3answers
87 views

Can liquid contain information?

Is there any principle in physics that would allow liquid to contain some kind of information - could we, for example, in theory, use a glass of water to save information? For example digital photo ...
8
votes
4answers
645 views

Hot water freezing faster than cold water

This question has puzzled me for a long time. There is already a question like this on Physics.SE. John's answer to the question seems quite satisfying. But when I googled the cause I found this and ...
4
votes
1answer
45 views

Is the IoR of water exactly $4/3$?

The index of refraction of water is commonly cited as $n \approx 1.33$, to varying numbers of decimal places. I've never seen a decimal expansion for this value with any digit other than $3$ past the ...
0
votes
1answer
2k views

Mixing Water at Different Temperature

If I have cup of water at room temperature (say, $25^\circ$C). What would be the resultant temperature if I pour another cup of same amount of water at $100^\circ$C to it? Is it simply ...
1
vote
1answer
47 views

Equilibrium between two water tanks

I've been reading about hydrostatic theory, however I couldn't find a similar case/exercise about my basic problem. I have two water tanks (same size) filled with different water heights, and ...
5
votes
0answers
87 views

What would happen to a submarine coated in water repellent

I saw the article about laser-etched hydrophobic metal, and it got me thinking, how would a submarine function differently if coated as such? Would it move faster, sink completely, be unable to move ...
1
vote
1answer
36 views

Why does the surface structure of a metal make it hydrophobic?

I was just reading this article from phys.org describing water-repellant surfaces. However the article doesn't go into enough details of explaining why a particular structure repels the water. Can ...
2
votes
1answer
54 views

Can an electric field align water molecules?

Water is a polar molecule, which means it has an uneven charge distribution. How much of an electric field strength would it take to align all, or most, of the molecules at room temperature?
1
vote
1answer
138 views

Can a liquid boil in a closed container?

The title says it all. When one fills a container (with water for example) and closes it so no air can escape from it, then heats the container continuously, can the liquid boil or completely ...
16
votes
4answers
978 views

What is the status of Mpemba effect investigations?

There is this puzzling thing that is called Mpemba effect: paradoxically, warm (35°C) water freezes faster than cold (5°C) water. As a physisist, I've been asked about it several times already. And I ...
1
vote
1answer
55 views

Compute pipe restriction from water flow and static pressure

How can I determine if residential water pipes have a restriction given, for example, flow rate and static pressure? Details: (1) You hook up a static pressure gage to a faucet which is in the ...
12
votes
2answers
130 views

Why do crystals grow in preferred directions?

I want to know why snowflakes (and other crystals) grow symmetrically and I find the leading answer to the established question to be entirely unsatisfactory. When water freezes, you get ice. ...
24
votes
7answers
13k views

Why do tsunami waves begin with the water flowing away from shore?

A sign of a tsunami is that the water rushes away from the shore, then comes back to higher levels. It seems that waves should be both + and - polarized and that some tsunamis should go in the ...
2
votes
2answers
686 views

How much better is salt water at letting through microwaves than pure water?

Radio Wave Attenuation There are two general types of matter (substances) in the universe that affect electromagnetic waves, conductors and insulators which are called dielectrics by ...
1
vote
0answers
32 views

I need to remove water from a system [closed]

I work in an industry and I need to remove water from a system. The scenario: There is a washer and a blower on a conveyor belt. The item being washed is plastic (not sure what type) and can't be ...
0
votes
0answers
31 views

How can we describe or model the spread of ice during the freezing of the surface of a still lake?

Premise: I live in a place where it is unquestionably wintertime in every aspect of the phrase. I was driving down the street and I drove by a lake. There was a recent and sudden temperature drop ...
0
votes
0answers
17 views

Heating water with low and high gas heat

Similar type question is asked before but i'm looking for other aspect of it. I observed that if water is heated with low gas heat, it takes long time but it retains it high temperature for long time ...
0
votes
2answers
4k views

Is water considered a substance with low friction or high friction?

Like, for example, rubber is a substance with high friction, as an object with neither high or low friction would easily stop on it, and wouldn't skid. Ice is considered an object with low friction, ...
3
votes
2answers
563 views

What air pressure is needed on mars, to have fluid water?

The atmospheric pressure on the Martian surface averages 600 pascals (0.087 psi), about 0.6% of Earth's mean sea level pressure. There is a lot of frozen ice on mars, but it can't melt, because of ...
0
votes
0answers
33 views

How much does grabbing a piece of a plane free falling change your survivial?

Just for context let's saying you are falling from a plane in free fall position at 56m/s(200 km/h or 120 mph) and you grab onto a wing which slows you down to 25m/s. You weigh 70kg. so ...
5
votes
6answers
12k views

Is it really possible for water to be held in a “cone shape” for a brief period of time?

I just saw this "trick" where a cup of water is turned over onto a table without spilling (using a piece of cardboard. After removing the cardboard from underneath the cup, the person then removes ...