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

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0answers
21 views

Explanation of a match between shadows and wet floor at Niagara Falls

The question is about the cause of a wet-floor phenomenon. My vacation trip started at Niagara Falls (Canadian side, horseshoe fall on the upper left corner). It was around 10-11 AM, not too sunny yet....
0
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3answers
95 views

How much water did I actually drink? [on hold]

Water expands at temperatures over $5^\circ\mathrm C$ strictly monotonic. If you now drink $1~\mathrm{L}$ water ($5^\circ\mathrm C$) which will expand in your body on $37^\circ\mathrm C$, did you ...
1
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0answers
30 views

How much energy is released by decompressing water?

How much energy would be released if 2L of (relatively pure) water compressed to 1L at room temperature was suddenly decompressed to atmospheric pressure? Even a first-order approximation would be ...
-1
votes
0answers
13 views

Water Mist Problem? [on hold]

If a 150 USGPM 20 deg.C water in a 40 mm diameter with pressure of 25 bar need to be reduced to 2.5 bar through an orifice: will the water mist manifest?
1
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1answer
40 views

What is absorption rate of WiFi and Bluetooth RF in water? [closed]

Specifically, frequencies 5.75GHz and 2.4-2.485GHz. I want to place a hermetically sealed circuit at the bottom of a gold fish bowl, and want to know if the water will significantly attenuate WiFi or ...
2
votes
1answer
27 views

How does infrared light behave through water?

I have a project involving the detection of the presence of water in a cylindrical transparent plastic container (diameter=25cm) And I cannot put any device inside, so I was thinking of using and IR ...
1
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1answer
39 views

Water droplet lensing

Suppose I have a camera that is looking straight down at a single droplet of water resting on a flat surface. The droplet is small enough that surface tension forms it into a rounded shape. Inside ...
0
votes
2answers
75 views

Why does hot water freezes faster than normal water? [duplicate]

What is the reason behind hot water gets Freezes faster than normal water when we keep both the hot and normal water together in freezer ?
4
votes
1answer
29 views

Why do individual clouds not diffuse into a single less dense cloud?

On a partly cloudy day, many individual clouds can be observed in the sky. I would expect that the moisture in the clouds would want to diffuse out into the other less dense non-clouded areas. ...
2
votes
1answer
23 views

Bubbles in Hot Tub Jets

Ever since I was a child I have noticed a strange phenomenon in hot tub/jacuzzi jets, if you partially cover them, the water will still flow but the bubbles stop. No matter what hot tub I'm at, I can ...
3
votes
1answer
63 views

Is my thermometer faulty?

Today I decided to check my thermometer and measured the temperature of boiling tap water. The thermometer showed 98.5°C. The atmospheric pressure now is 742 mmHg. According to the Clausius–Clapeyron ...
1
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1answer
296 views

Is it possible to transfer water from a water bottle using condensation?

So currently I am travelling in a tropical country. I took my water bottle from the fridge and left it on the table, after a few hours it created a pool of water. Is this water from the outside air ...
0
votes
1answer
21 views

Ball under the water jet

What is the name of the physical principle that show that a ball under a water jet (for example in a bathtub) rotates but does not move? I am not able to find any video of this
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3answers
3k views

Why is ice made from boiled water clear?

A common trick to make clear water ice is to boil pure water prior to freezing it. Why does that work and what are the white inclusions in ice that was made from unboiled tap water?
5
votes
4answers
201 views

Does salt speed the transition of water from ice to vapor?

In a dry environment that is somewhat below the freezing point, water ice will, over time, sublimate to vapor. If you scatter salt across the ice, some of the ice will melt, and the melted water will ...
10
votes
1answer
1k views

Is there a temperature at which ice is denser than water?

Normally ice would float on water because its density is less compared to that of water as a liquid. But is it possible that its density will increase due to a very low temperature or is ice in any ...
-1
votes
0answers
30 views

Hexagonal shape of snow flakes [duplicate]

As we know snowflakes has hexagonal shape. My question is why is that? and Is there any mathematical model which can explain that particular geometric shape of the snowflakes?
1
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2answers
59 views

Force of water hitting a wall [closed]

If you had a 8" pipe with 500psi stream of water exiting it and hitting a wall at 90 degrees 8 feet away, what would the force of the water on the wall be? Thank you all. Non-mathematician.
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0answers
56 views

How was microscope-level zoom created by a lens and a water droplet?

It was a rainy night. My glasses were speckled with fresh water droplets. I looked at a distant street light and I was surprised to see cells - a single cell was zoomed in to the level where I could ...
-1
votes
1answer
36 views

Water Boiling Time Calculator

Is there a way to calculate out how quickly a body of water will boil? My primary concern is to measure in relationship to different temperatures. For example, heat at 100 degrees Fahrenheit versus ...
4
votes
2answers
115 views

Why is it easier to get sunburnt in the water? [duplicate]

I went today to the swimming pool and I remembered that when I was younger my mom used to tell me to be careful because you get sunburnt much more easily in the water than in the ground. I never gave ...
4
votes
4answers
817 views

Would water, given enough heat, instantly vaporize?

(Please excuse the wrong usage of words, I'm not a trained physicist. Please point out any misuse.) So far, my understanding of water evaporating is the following: Water always evaporates, whatever ...
0
votes
0answers
41 views

what is the mathematical expression of the water drop curve on the surface?

As a part of a high-school research about water drops on surfaces, I've been trying for a long time to find some theory that gives the expression of the curve, without any success. In fact, the ...
0
votes
6answers
103 views

Can I recirculate water from an open reservoir to the bottom of a bigger, closed one, without a pump?

A fountain head pumps water out of the main tank into a 'pond' reservoir. Can the water recirculate back into the main tank without the help of another pump? I'm sorry if this a dumb question. I'm ...
0
votes
1answer
64 views

How does the levitating water illusion work?

After watching a movie in which levitating water was used as an illusion, I was curious to discover how it works. Unfortunately I cannot find any great explanations of the science behind the effect, ...
1
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1answer
48 views

global warming due to CO2 vs water

What is the physical reason for CO2 being a vital greenhouse gas when it is present at only approx 0.03% of atmospheric composition compared to water vapour, which is present at at least 100 times ...
0
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2answers
131 views

If a water molecule is neutral how do water molecules attract one another by electric force & form water?

This no sense to me! (im new to physics) and my textbook didnt explain this well!
81
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6answers
10k views

Why is oil a better lubricant than water?

How come mineral oil is a better lubricant than water, even though water has a lower viscosity? When two surfaces slide over each other with a gap filled with a fluid, the different layers of the ...
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2answers
95 views

Why is water not considered a proper liquid in terms of thermometers?

We were just discussing about why liquids in general are used in glass thermometers. I was wondering why water isn't considered a proper liquid. Is it because of the way is expands differently to ...
0
votes
1answer
47 views

Calculate how much air will cool from an amount of ice? [closed]

So, there are $3kg$ of ice at $-18$ degrees Celsius and $50kg$ of air at $30$ degrees Celsius. I need to calculate how much the air will cool by the time the ice reaches its temperature. I thought I ...
0
votes
1answer
38 views

find the density of water only by its pressure?

Is it possible to find the density or specific volume of water, by only knowing its pressure? Or we need to know its temperature as well? I can't find any relevant table, so can you advise me please? ...
0
votes
1answer
46 views

what causes water to be white in a river?

I know it is because of turbulance, causing air to enter the water. But neither air nor water are White, why does the combination of the two make White.
9
votes
1answer
88 views

Measuring tides in a swimming pool

The tidal range of a perfectly fluid inertialess ocean on the Earth (taking into account lunar tides only) is approximately half a metre: this is the range between "high" and "low" points of an ...
4
votes
1answer
48 views

Which way the water evaporate faster?

-Hello everyone, Yesterday I was preparing some tomato sauce and, in order to remove some water from the sauce, I put it in a pot on the burner and waited until it started to evaporate. When I sow a ...
1
vote
3answers
92 views

Pressure Drop in Water Fountains

In first grade, my class made a list of things that our school could improve on. One of the things on the list was to increase the water pressure in the drinking fountains because it was very poor and ...
0
votes
1answer
67 views

How cold does this ice have to be to freeze this water bottle solid?

We are at sea level in a room that is 21 celsius. We have 1 liter of sterile water with a temperature of 21 celsius in a normal plastic bottle. We have a 20 liter bucket of ice cubes, consisting of ...
3
votes
1answer
52 views

How could water pour out from upside-down bottle, unless its pressure is smaller than atmosphere pressure?

Just a simple question : when we remove a stopper of an upside-down bottle, water flows out. But the pressure caused by the mass of water's column is usually smaller than atmosphere pressure unless we ...
1
vote
1answer
38 views

The colour of clouds

Clouds can be a variation of grays, from white to some dark gray, almost black. They are clearly grayscale, so it means they reflect all colours uniformly, but some clouds are whiter than others, so ...
0
votes
2answers
104 views

What is the nature of equilibrium between water and air in a sealed container that is heated above 100C?

In the case of a single substance (water), looking at the phase diagram is enough to conclude what happens upon heating: (source: WolframAlpha) But what if I have water and air (or some other gas) ...
1
vote
1answer
29 views

The thickness of a puddled sheet of water

If I pour water of different amounts into a puddle on a level surface, it appears by eye that both puddles have the same height. The water seems to retain itself into a puddle by surface tension. I ...
3
votes
0answers
39 views

Chemistry of water under pressure [closed]

What is the structure of water under extreme pressure, like the bottom of the ocean on a moon like Europa.
4
votes
1answer
35 views

Will water cool faster in an earthen pot if wetted externally?

If we put water in an earthen pot then water is being absorbed and it reaches the surface of the pot and then water evaporates and makes inside water cool. So is it right that if we wet the earthen ...
1
vote
1answer
17 views

Lengthening in-flight evaporation time of water droplet in air

How one can increase the in-flight evaporation time of sprayed water droplets in air without changing the thermodynamic conditions of the ambient air ( i.e. RH, T ). For instance mixing water with ...
3
votes
1answer
67 views

Why is it easier to remove stains with water?

And I don't mean stain removers, but literally tap water. See here's the thing, you can't remove a stain without some sort of friction, and water reduces friction. Yet if I say, spill some coffee and ...
1
vote
4answers
51 views

How can removing energy from a system do work? (ice)

Water freezing into ice expands, damaging roads, breaking rocks, etc. To my understanding, this is doing work (in a physics sense) by removing energy from the system. How is this possible?
0
votes
0answers
35 views

How can I get the exit temperature of water entered 100 degree in a pipe surrounded by 30 degree water?

Assume any value for: Length of the pipe The material of the pipe Velocity Heat transfer coefficient. I tried considering it as parallel flow heat exchanger but the water in this example isn't ...
2
votes
0answers
57 views

How fast should 6 liters flow out of the sink through a 6cm pipe?

I had 6 liters in the sink when I pulled the plug. It took the water about 30 seconds to get through a pipe which has about 5cm in diameter. I think the pipe might be blocked a bit, causing it to have ...
0
votes
0answers
19 views

Role of heat flux on bubble size

This is sort of related to this question, in that the question was spawned from the same question on Worldbuilding. Say you have a relatively shallow open pool of water (a pot or pan). When the ...
0
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0answers
27 views

Water in pot with a heat source beneath it to boil it, does the water move?

I mean if there is there heat transfer by convection in the water? since convection requires motion. if it moves, then how can i determine the velocity of the water?
7
votes
2answers
278 views

Does the size of bubbles in water brought to a boil ever vary as a function of the amount of water?

Some discussion surrounding this answer on Worldbuilding got me curious. When water is brought towards a boil, bubbles are formed. Anyone who has ever cooked anything whatsoever knows about this. ...