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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96 views

Is there an way water can burn or cause fire?

Water known as the fire extinguisher.What is the possibility watere being the fuel to fire. "Pure water"
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2answers
2k views

Do all liquids boil in a vacuum?

Water boils at positive temperatures when put into a vacuum. Is this the case with all liquids, e.g. mercury?
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3answers
3k views

Why are oxygen and hydrogen compressible, but water is barely compressible

What makes the two gases compressible, but does not apply to a liquid like water?
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3answers
11k views

Why does the water level equalize in a series of tubes?

Say I have a series of tubes (not the internet) looking like this, where w represents water: ...
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4answers
9k views

Why does a bottle shrink when you pour hot water in it?

I think the title says pretty much. Last night I poured hot water in a half full bottle of water and closed the cap. The bottle immediately shrunk. Why? My girlfriend suggested that the hot water has ...
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1answer
26 views

Water's Specific Heat Capacity as an Outlier

Can the specific heat capacity of water being ridiculously high as compared to other substances be explained at a molecular scale?
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0answers
46 views

Finding an equation for the cooling curve of water with respect to surrounding temperature

I would like to find a general equation that describes the cooling curve of water from 100 degrees Celsius to the surrounding temperature $T_s$ against time (say, in seconds). As far as I know and ...
2
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3answers
213 views

Does water absorb neutrons?

Water is used as a shielding material in nuclear reactors. What's its function as a shield? Does it absorb neutrons and is there a reaction between water and neutrons?
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1answer
35 views

Viscosity of Muddy Water

How do I calculate the viscosity of muddy water at 25 deg C and knowing the weight of undissolved solids either SiO2 or Al2SiO5 in H2O, grain size < 150 microns? Do I have enough information to get ...
0
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0answers
27 views

What are the physics principles behind “amphibious” camera lens windows?

Underwater camera housings have a window through which the lens looks. When the camera surfaces, a couple of things can happen, and I've seen both captured in the camera footage. In one case, water ...
4
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4answers
240 views

why water molecules in vapor contributes to the green house effect and water condensed in drops not?

I am a teacher planning a unit on climate change. I came across this statement: "Clouds are water vapor (green house gas) and water molecules will reflect heat into space… actually clouds are ...
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2answers
1k views

Why do some things crystallize? (And others don't, for that matter.)

Ice, for example, will form a crystal when frozen under certain circumstances. Why is this the case for ice? While on the subject of water crystallization, why do snowflakes usually form in base 6 ...
6
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3answers
1k views

Why is steam used to spin turbines?

The ideal gas law tells us that the relationship between Pressure (P), Volume (V), Temprature (T), and quantity/amount (n) is $$ PV = nRT $$ where R is the gas constant. Say your an engineer who ...
6
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4answers
58k views

Freezing point of water with respect to pressure.

I know when the pressure is reduced, the boiling point of water is reduced as well. But how does the pressure affect the freezing point of water ? In a low pressure environment is the freezing point ...
2
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1answer
80 views

Why is modelling water so difficult?

There are several models of water that have come into existence so far. Nevertheless, there is no one particular model which effectively gives all the properties of water correctly. A model like TIP3P ...
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2answers
62 views

Why does soaking something soften it up [duplicate]

Apologies if this is duplicate, I've dug around and can't find it. If you leave a sponge/cloth out to dry for a while it eventually becomes slightly stiff. Upon wetting again, however, it softens up ...
4
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2answers
5k views

Why are refrigerators 4 degrees and freezers -18 degrees?

I assume that the refrigerator's temperature of 4 degrees has something to do with the fact that water is densest at that temperature. Does that inhibit microbe growth? But what about the freezer, ...
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1answer
165 views

Why do hot tubs dehydrate you? [closed]

I was just sitting in a hot tub for a few hours with friends, and we all noticed we really wanted to drink some water. We felt dehydrated. I tried looking up why hot tubs dehydrate you and all I got ...
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2answers
86 views

Does water follow the path of least resistance

I am having hard time proving this either right or wrong. Let's take for example a river, does the water flowing down follow the least resistant path?
8
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3answers
8k views

Why did my frozen water bottle explode when I opened it after it defrosted a bit?

Last night I filled a 20 fl oz bottle (http://www.thenibble.com/reviews/main/beverages/soft-drinks/boylans-mash.asp) with lukewarm water from my tap. I filled the bottle pretty much to the brim, ...
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8answers
19k views

Why does hot oil explode when pouring water on it?

What is the reason that hot oil makes sound and explodes when water is poured on it?
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2answers
82 views

Is pure water electrically conductive? [closed]

I know that water with some ions dissolved is a good conductor. I wonder whether it is true for pure water?
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1answer
71 views

Paper Napkin Folded

Why folded napkins are better absorbing water than ordinary napkin. I think there must be related to cohesion of water element. Water are captivated between layers because they appeals each other or ...
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0answers
28 views

What do water stains make things appear dark? [duplicate]

If a piece of grey tarmac is damp after the rain, it appears darker. If I spill water on my carpet, the damp patch is darker than the rest of the carpet. Generally speaking, a lot of things appear ...
6
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1answer
12k views

Why does water sometimes form bubbles when I pour it into a glass?

Sometimes when I'm filling up a container with water from the tap, bubbles will form on the top of the water. They look a little like soap sud bubbles, but there's no soap suds present. I notice, ...
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3answers
4k views

How fast does an ice cube melt in a microwave?

I have noticed that when I microwave an ice cube it appears to melt more slowly than I would expect. For example, an equal volume of water starting at 0 deg C would probably be at boiling point before ...
71
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8answers
21k views

Why does hot water clean better than cold water?

I had a left over coffee cup this morning, and I tried to wash it out. I realized I always instinctively use hot water to clean things, as it seems to work better. A Google search showed that other ...
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1answer
42 views

How long can water hold elevated pressure and energy after opening pressure cooker lid?

I noticed today that the water warmed up in pressure cooker (1.5 ATM) dissolves sugar much faster and much more than water cooked in 1 ATM. I am interested in how long can water hold the high ...
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2answers
2k views

Pump pressure required to fill water tower

I have a water pump at a distance of x meters from a water tower located h meters above the pump through a pipe with diameter d. I am not concerned with the exact value just want to make sure my pump ...
2
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2answers
82 views

Is it possible to mix a drink with a non-standard phase of ice?

Would it be possible to safely cool and drink a glass of water with anything else than the Ih form of ice? Here and here you can see that some alternative forms of ice have a higher density than ...
6
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2answers
805 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 ...
2
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1answer
72 views

Why does water remain as a “hemispherical bubble” when it falls on a page?

Today while drinking water, a drop of it accidentally felt on a page of my book, and I was thinking that, "Oh my god! The water will spread instantly, making the part of page wet". But, I observed, ...
2
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1answer
75 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 ...
12
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3answers
237 views

Crown shape in water waves?

Watching this slow motion video of waves caused by a droplet falling on water, I am puzzled by the first wave shape. The first wave rises with circular symmetry as I expected, but is not even in ...
1
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1answer
72 views

Why does water boil differently in a microwave than over a flame?

Over a flame, small bubbles will start to form on the bottom of the pot, and as the average temperature rises, the bubbles will become larger until they start rise to the top. As it gets even hotter, ...
63
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7answers
11k views

When I boil a kettle, what stops all the water from turning (exploding!) in to steam in one go once it reaches 100°C?

While making a cup of tea in the office kitchen, a colleague asked me this question and neither of us could answer with any certainty. We're guessing it has something to do with the pressure of the ...
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2answers
79 views

movement of water in plants

Books say that water moves from places with a high water potential to places with a low water potential. The movement of water in plants are explained because water potential is lowest in leaves and ...
2
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0answers
54 views

Suction from flowing water

My memory from physics says yes but I want to check. Our pool is dirty and our vacuum is broken. If I were to stick the vacuum hose into the pool drain, would the flow of water going into the drain ...
9
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2answers
348 views

Water evaporation problem. Exercise from Feynman's lectures

I read lectures of Richard Feynman and try to solve problems and I have some trouble with a problem on water evaporation. A glass full of water is left standing on an average outdoor window in ...
3
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1answer
123 views

Calculation of long-range forces in Molecular Dynamics - Ewald summation

I am trying to write a code to calculate the potential and forces, for the same using ewald summation.For this purpose, the formula for potential and force I have used is : $$ U = U^{(r)} + U^{(k)} ...
0
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1answer
71 views

How does a water-steam mixture behave?

Namely, if I mix a flow of steam that has density $\rho_s$, velocity $v_s$, and pressure $P_s$ with a flow of water that has pressure $P_w$, velocity $v_w$, and density $\rho_w$, how can I find the ...
0
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1answer
574 views

Why is there steam in a hot shower even though the water is not boiling? [duplicate]

When I take a hot shower, there is normally a fair amount of steam. However, I don't think the water coming out of the shower-head is actually boiling (unless I am mistaken). Why is there water ...
4
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3answers
1k views

Why is boiling not just a surface phenomenon?

The boiling point of a liquid is defined as The temperature at which the vapor pressure of the liquid is equal to the external atmospheric pressure. That being the case, why, in a pot of boiling ...
0
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3answers
27 views

Breathe Air from a source without any pressure compensation?

I just thought about what I'd do if I was on a sinking ship and of course breathing was the first thing that came into my consideration. Now imagine the ship's front going up and the room you are in ...
3
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2answers
2k views

Why can't I evaporate water without wind, just heat? (not boiling,evaporating!) Or can I?

So here is the thing, I searched all over the internet for this but all the sources say that I need wind because the process of evaporation goes as follow: Water particles at the top layer with ...
2
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1answer
77 views

Why is it that not the entire surface of Earth is covered by water? [closed]

Isn't it a coincidence that our planet is mostly but not completely covered by water? Is there a reason why less water or more water is not compatible with intelligent life? Also, isn't it a ...
0
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3answers
219 views

Does ice made out of salt water melt slower than ice made of pure water?

I'm trying to make this whole bunch of ice bottles to cool down my little aquarium. What I want in the ice bottles is that, fter freezing the whole bottle full water into ice, I need the ice to melt ...
3
votes
1answer
178 views

Why does water get significantly colder while falling through the air?

I think we've all experienced this effect. You turn on the shower and the stream of water at the shower head is a fair bit hotter than the water towards the bottom of the stream. Alternatively, if you ...
11
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4answers
36k views

Why does ice have a lower density than water?

Can someone explain me why is ice less dense than water? As I know, all solids are usually denser than the liquids (correct me if I am wrong).
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1answer
97 views

Can capilliary action move liquid against gravity?

I was wondering if it was at all possible to very slowly suck up water from a cup with a rope, and then deposit the water into another cup on a 3cm thick book or similar object. Here is an example ...