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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1k views

Why water is not superfluid?

My question is in the title. I do not really understand why water is not a superfluid. Maybe I make a mistake but the fact that water is not suprfluid comes from the fact that the elementary ...
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1answer
1k views

What makes water-droplet/dew stick to spider's web and what keeps them there?

How water-droplet/dew stick to spider's web? What keeps them there?
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1answer
13k views

What makes water boil?

Basically how boiling takes place? Also like to know... What makes boiling point alter at various altitudes? Why bubbles rise through boiling water?
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3answers
8k views

273 + degree Celsius = Kelvin. Why 273?

Temperature conversion: 273 + degree Celsius = Kelvin Actually why is that 273? How does one come up with this? My teacher mentioned Gann's law (not sure if this is the one) but I couldn't find ...
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 ...
3
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1answer
774 views

Pascal law with two connected cylinders filled with water, and 50kg stones at both their ends

If I have two connected cylinders filled with water, and 50kg stones at both their ends (pressing both ends of the water) how much weight do I need to add on one side so that one of the stones reach ...
5
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1answer
405 views

How do I measure the temperature of a tiny water droplet?

How do I accurately (+/- 0.1 degrees Celsius or better) measure the temperature of a small (5 to 50 microliter) water droplet without noticeably affecting its temperature? The mass of a thermistor or ...
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0answers
82 views

What phenomenon is responsible for the evolution pattern of waves created by waterfalls?

I have been fascinated lately by the pattern of the waves created by a waterfall in my town. Specifically, the pattern shows a gradual decrease in the density of the waves as they travel away from ...
4
votes
3answers
338 views

Water Jet Cutter and Laser

I watched a video of "Glass cutting" which uses a Water Jet Cutter. It was said that Cutting glass simply by machines would eventually crack it... So, They're using grains of sand (by placing a sand ...
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2answers
19k views

Why does earth look blue from outer space?

I know it's more than 70% water. But what has it got to do with earth's colour ?
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2answers
1k views

Why does it take until the middle of summer before lakes have warm water, but desert sand heats up in hours?

My sister asked me this question and I keep thinking that water would conduct heat much faster than sand. Hence the energy transfer of heat across the lake does not allow it to heat up soon. Sand on ...
2
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2answers
342 views

The physics behind The Great Flood [closed]

The book of Genesis floats (pardon the pun) some interesting numbers when discussing the Great Flood. For example, it rained for 40 days and 40 nights, and at the end of that time, the entire planet ...
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3answers
513 views

Water, can it break through temperature?

If water is heaten up to ridicilously high temperatures, is it possible for the atoms in the molecules to lose their bonds? And if it is possible, isn't this some kind of chain-reaction? Like you ...
1
vote
2answers
141 views

How to find out the compress happen when some force act on water/oil/air?

I need to do some calculation to find out whether my design works. I may use oil/water/air in my pneumatic cylinder (or you can call it hydraulic cylinder). Assume I have just a cylinder and I put oil ...
2
votes
2answers
522 views

Fluid Dynamics - Water Bottle Drink Mix: Air or No Air?

If you take an ordinary sized plastic water bottle full of water and pour a packet of powdered (or liquid) drink mix into it, Will shaking the bottle with the cap screwed on to dissolve the mix into ...
7
votes
1answer
16k views

How fast would someone have to run to run over water?

I was thinking about Flash, the superhero, or the little boy in the Incredibles. There is one Yahoo answer that doesn't answer a lot. Especially, I don't think surface tension would help a lot for a ...
3
votes
1answer
4k views

Calculating time to heat cold water in bowl of hot water

How would I calculate the time it takes to heat a given volume of water to a given temperature with a given temperature T1 when it is submerged in a volume of water with a temperature T2 Estimation ...
5
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1answer
571 views

Distinctive properties of liquids

The molecules are closely arranged in solids, loosely arranged in liquids and are free to move in gases... But, Why are liquids (especially water) exhibiting these distinctive properties such as ...
3
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2answers
1k views

Does a fluid's temperature affect the way light passes through it?

For example, if I were to supercool water would it's refractive index still be 1.33 or would it be 1.31, the same as water-based ice even though it's still in liquid form?
2
votes
2answers
440 views

Why water will stay on a piece of toilet paper?

I think everyone has tried to blow air (breath) on toilet papers. The papers will get wet. I believe the holes diameters on a toilet paper should be much larger than diameters of water molecules. (The ...
0
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0answers
416 views

Reduction in velocity in pipe

I have two pipes divided from main pipe. If I add one more pipe, what would be the amount of velocity in each pipes. I know the velocity of main pipe, then diameter and radius of each pipe. Edit: 1) ...
8
votes
5answers
1k 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 ...
19
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5answers
1k 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 ...
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vote
1answer
426 views

Why does the water-pressure of my shower fall if I hold the shower head high?

I live in a very old house - build 1902 - in the 4th floor in the city of Karlsruhe (Germany). I have a shower and the gas-heater for the water is in it: If I hold the shower head over some height ...
0
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1answer
102 views

how to stop water reaching up inside an under water structure (see video)

in this video at arround 0:47 they deliver the 'dry pots' to the under water lab, bellow the water and they seem to swim up into an opening where it is completly dry.. how is this dry, surly the water ...
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2answers
14k views

Flow of liquid among branches

If water is flowing through big pipe is branched into 4 branches of small pipe. Lets say the flow is around 4 m/sec. I have the following questions: What will be the flow rate in each of the ...
2
votes
1answer
139 views

Is my electric kettle collecting old water during the week?

I have an electric kettle at work. On Monday, it's empty and I pour in about 1.5 liters of water. I usually end up drinking about 1 liter per day and refilling 1 liter each morning. At the end of the ...
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1answer
641 views

How would this rapid depressurization of water really behave?

An in-development game(Starbound) recently released a demo of their water physics. At about 39 seconds into the video, a volume of water in a container is released when the cap on the container is ...
11
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1answer
4k views

Why does water flow out of an upside-down bottle? (Rayleigh Taylor Instability)

I am currently reading the excellent book An Indispensable Truth: How Fusion Power Can Save the Planet by Francis F. Chen and I came across this explanation. The Rayleigh–Taylor Instability ...
2
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2answers
6k views

Why I will feel colder when I get out from a swimming pool? [duplicate]

A friend of mine told me that because water heat capacity is higher. He also mentioned that it was similar to alcohol on skin effect. Assume that there are 3 situations. 1. I did not get wet 2. I got ...
3
votes
1answer
675 views

Cause of sea ice freezing during an upwell event

One of the Episodes of BBC's documentary Frozen Planet describes an upwell phenomenon in the Antarctic Ocean. I am trying to understand the cause of seawater freezing when this upwell occurs. Liquid ...
10
votes
2answers
346 views

Can cannonballs go through water?

In the recent Spielberg/Jackson Tintin movie, there is a scene where Red Rackham and Captain Haddock's ships are fighting, and cannons are fired. The cannonball is shown at one point to go through a ...
8
votes
3answers
10k 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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2answers
80 views

How to detect ice in thermostat

I think of making precise thermostat based on ice-water phase transition. The idea is to keep 50% ice content, and monitor that instead of temperature. I am thinking of monitoring dielectric ...
3
votes
4answers
941 views

Water to ice expansion in $1\textrm{mm}^3$ pit - pressure on the pit walls?

[EDITED] by mistake, the subject was regarding 1m^3 instead of 1mm^3. There should be a significant difference between the two... A 1x1x1mm pit filled with water is frozen at a slow rate (1K/minute). ...
2
votes
2answers
2k views

How much water must flow trough canal to maintain a constant water deep?

In order to maintain a constant water deep in canal, how much water must flow trought the pipe ? As shown on picture, canal have a rectangular shape. I don't know if canal length have an influence. ...
4
votes
3answers
496 views

Can anyone estimate what proportion of water remains after I flush a toilet?

Imagine I have a clean toilet with some amount of water in the bowl. When I flush the toilet much of that water will be displaced by the tank's water. I want to work out (or model really) what amount ...
2
votes
2answers
2k views

Why droplets of water under oil explode when heated

In experiment, cold skillet with droplets of water was filled with layer of oil and heated. The droplets started exploding. Why water can not leave skillet less violently, like steady chain of steam ...
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1answer
3k views

Anomalous Expansion Of Water

How can the Anomalous Expansion of Water from 4$^\circ$C to 0$^\circ$C be explained with reference to subatomic particles?
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1answer
784 views

Does the Relative density of water change based on the state it is in

Will Relative density of water change based on the state it is in? Ie solid, liquid, gas. What causes this change(if any) in Rd?
20
votes
3answers
24k views

Why does water pouring from a glass sometimes travel down the side of the glass?

If you have a glass of water, say, three quarters full and you pour it at an angle of say, $45^{\circ}$ with respect to the the table, the water comes out of the glass and goes directly down towards ...
2
votes
4answers
2k views

What happens to water level when ice XII melts?

There exists this famous idea that if all floating icebergs melt, water level will stay the same (because the water replaced by ice is the volume of the melted ice). Now, Is this always so, if you ...
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vote
3answers
79k 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 ...
35
votes
2answers
12k views

Why is boiling water loud, then quiet?

Water in my electric kettle makes the most noise sixty to ninety seconds before the water comes to a full boil. I have been fooled many times by the noisy kettle, only to discover that the water was ...
3
votes
1answer
564 views

Boiling when I plunge my french press?

Occasionally when I make coffee in my french press I experience something odd. It happens pretty infrequently but certainly enough to be curious about. I have the grounds ready in the carafe. The ...
34
votes
2answers
10k views

Before a once-warm lake starts to freeze, must its temperature be 4°C throughout at some point?

This is a problem I just started puzzling over, and I felt this would be a good forum to check my reasoning. So here are the relevant observations followed by my question: Water achieves its maximum ...
2
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1answer
477 views

How much water is destroyed in photosynthesis, relative to the world's supply?

Water is involved in the photosynthesis. How much water are we talking about compared with the total amount on water on Earth? Is it enough to have an effect on the average age of water molecules?
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2answers
14k views

Water Electrolysis Calculations

From Wikipedia (http://en.wikipedia.org/wiki/Water_electrolysis#Efficiency): The electrolysis of water requires a minimum of 237.13 kJ of electrical energy input to dissociate each mole. Each ...
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2answers
6k views

How does the process of freezing water remove salt?

How does freezing water to make ice remove whatever salts were in the water to begin with?
2
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1answer
807 views

Calculating temperature of water in the freezer

Assuming water volume ($V$), initial water temperature ($T_0$) and environment temperature ($T_e$) are known, what is the easiest way to calculate temperature of water in given time ($T$)? For the ...