Two Hydrogen atoms covalently bonded to one Oxygen atom. One of the more common compounds on the surface of the earth.
2
votes
2answers
617 views
How the pipes of water don't freeze in -40 celsius?
Does anyone have a good answer how comes that the water in the pipes in our houses doesn't freeze even if it is -40 celsius for a whole week? of course assuming we don't make the water to fluid in it
9
votes
3answers
1k views
Thermodynamics of supercooled water
Now that it's been freezing outside for the last few days, I experimented a bit with supercooling. I've left a bottle of clean water outside for a few hours, and behold, when I shook the bottle, the ...
3
votes
1answer
698 views
Cooking pasta: why does adding a lid lead to overflow?
When cooking pasta, some organic foam usually forms on the surface of the boiling water and the situation can be kept under control by adjusting the heat (and/or adding some oil).
Covering the pot ...
0
votes
1answer
303 views
Temperature change effected by electric heater [closed]
A 40-gallon electric water heater has a 10kW heating element. What will the water temperature be after 15 min of heating if the start temp is 50F degrees.
There must be an equation. I can't find it ...
2
votes
1answer
99 views
Clouds in closed hydrosphere
Is possible estimate the needed size of an geodesic dome (like in the Eden project) for creating an real hydrosphere - especially clouds (and rain)?
With other words, under what circumstances can ...
1
vote
2answers
658 views
How thin a filter to filter particles out of salt water to make salt for human consumption?
I have gathered some salt in the Death Valley and for the fun of it I would like to clean it and make it edible. The process I plan to follow is simple:
1) Dissolve the salt in water
2) Boil water ...
0
votes
0answers
80 views
If cars could run on water intead of gasoline, are we going to empty the oceans sooner or later? [closed]
Imagine that car engines producing a lot of energy from a very small
quantity of water are of very widespread use.
Does this pose a risk of running out of water on planet Earth ?
7
votes
1answer
74 views
Polar ice deposits on the Moon - dispersed in permafrost loose rubble, or also massive/layered?
Water has been discovered on the Moon with remote sensing methods. Read the press release Diviner results indicate presence of widespread ice on the Moon on the "Diviner" infrared instrument on the ...
1
vote
0answers
631 views
Easy to obtain liquid with freezing point a couple of degrees above 0 Celsius [closed]
Please advice me a liquid whose freezing point is 2-5 Celsius.
I know that the solution of salt in water can have freezing point of about -3 Celsius. I would like to know if similar liquid but with ...
0
votes
0answers
1k views
How to determine size of a Heat Exchanger?
I am designing a Tube heat-exchanger, similar to this:
My process requires water (at room temperature, 18C ~ 22C) that is being pumped out of a small tank (300 Liters) to be heated in a ...
7
votes
1answer
53 views
How plausible is a subsurface ocean on Pluto?
According to this article on physorg.com, it's likely that Pluto has a subsurface ocean of liquid water. It suggests that the ocean would be about 165 km deep, under an equally deep crust of solid ...
2
votes
3answers
962 views
Does stirring water in a bucket in whirlpool keeps it warm?
I did an experiment when I was a teenager. I want to prove/see what really went on in that experiment.
When taking a bath, take a warm water in bucket and start taking a bath. You will notice that ...
2
votes
1answer
671 views
Where are the ice rings in X-ray crystallography located?
I threw this image of one of my protein crystal's diffraction pattern (not the greatest) on a poster, and was wondering where (what reciprocal dimension) the ice rings are located as it might be a ...
11
votes
2answers
690 views
Why doesn't water come out of tap/faucet at high pressure when I turn it on?
(tap=faucet)
When I turn a tap on full and then put my thumb over the spout covering, say, 90% of it, then the water spurts out. If I turn it on to, say 10%, then the water dribbles out.
What's the ...
4
votes
2answers
700 views
Is a given volume of sparkling water lighter or heavier than the same volume of still water?
I can see it two ways - if all the $CO_2$ has turned into bubbles I would imagine it is lighter. However dissolved $CO_2$ atoms are probably heaver than the $H_2O$ atoms they replace, or fit in ...
2
votes
1answer
232 views
Why does blowing on someone who is wet feel colder than on someone who is dry?
The title says it all. If I'm standing in the wind and I'm wet, I feel much
colder than when I'm dry. This is true no matter how warm or cold the water.
Why is this?
3
votes
0answers
332 views
How to turn water opaque by pouring the smallest quantity of matter into it?
Consider a glass of water and a glass of coffee. Their contents differ by no more than a few grams of particles coming from the roasted and ground coffee, yet the former lets almost all visible light ...
1
vote
1answer
507 views
How does liquid convert to gas on getting thermal heat energy?
Say for example, when we heat, water converts to steam gas. How does it happen? What happens underneath giving rise to breaking of bond between molecules in liquid state and spreading them in gas ...
4
votes
2answers
397 views
If you stop water from expanding, will its temperature stop rising?
Water expands when it heats up. If you heat water in a container that prevents it from expanding, will its temperature top out -- maybe around the boiling point?
And if not, will it still turn to ...
3
votes
2answers
255 views
Will the water added to an ice piece freeze?
Water, at room temperature is poured into a hole made of a block of melting ice(kept at room temperature).I was wondering if the water will ever freeze?
Thank you.
2
votes
2answers
213 views
Water and superconductors
If you have seen my previous questions then this may make better sense. If you put an insanely powerful superconducter on the outside layer of a ROV that is underwater, would it form an outer layer ...
3
votes
1answer
263 views
Tear drop shape
i heard that a tear drop shap is the most aerodynamic shape possible or the best is this true? If this isn't true what is since i need to make a fast ROV? Also since i need to have a propeller to ...
2
votes
3answers
198 views
can Superconductivity be used to repel water?
Can water be repeled with the force from superconductivity gathering current on the surface cuased by Faraday law of induction? I'm trying to make a ROV that can run underwater that uses ...
1
vote
1answer
150 views
Surface Tension of a Liquid - When a liquid body is acclerating
As far as I understand it (which admittedly isn't very far), surface tension forces are made up by the tension-attractive forces of molecules at the liquid-gas/vacuum interface, such as those between ...
8
votes
5answers
344 views
What can wavy patterned sand tell about the Fluid that formed it?
Sand on the bottom of the ocean as well as sand on the low-tide beach often forms wavy patterns. Do the parameters of these wavy patterns have any relation to the water and waves that formed them? If ...
3
votes
4answers
411 views
Could hydrogen liberated from water provide lifting energy which exceeds the energy it took to liberate it from water
I was thinking about Hydrogen balloons and that large ones which are used for weather balloons which sometimes go up to 100,000 ft (approx 30km). Then I was wondering, how much potential energy has ...
2
votes
1answer
396 views
Can sound be used to purify/filter water?
I remember reading about all chicken at a poultry farm being violently sick/dying for apparently no reason. It turned out the culprit was machinery at a nearby factory that emitted sound at a ...
2
votes
1answer
3k views
Best way to solve P-V-T Question
Typically in an exam or problem set we have a problem that's like this:
Determine the specified property at the indicated state of water. Locate the state on a sketch of the T-v and P-v diagram.
p= 3 ...
10
votes
1answer
219 views
Could there be a body of water the size of a planet?
My friend and I were reading the news of the discovery of a black hole spewing huge amounts of water vapor into space, and it got us thinking: could there be a blob of liquid water in space the size ...
5
votes
3answers
543 views
Is a water world possible, and for how long could it be stable?
I have several questions regarding this topic.
First, could a water world be stable for thousands of years with most of its surface remaining covered in water. What would it take for this to be ...
3
votes
2answers
4k views
Can pockets of air exist underwater?
If yes, why don't they fill up with water, and can you breathe the air there? Like, it's not exactly atmosphere there, but an underwater cave with higher ceiling.
P.S. Possible that it has a ...
2
votes
1answer
871 views
Simple formula for liquid heat transfer
I'm trying to do a simple simulation of a solar panel coupled through some piping to a boiler, with the aid of a pump. My input constants could be something like: volume of liquid inside the panel, ...
5
votes
2answers
1k views
ice 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 ...
2
votes
1answer
277 views
At what temperature does water become a liquid on Mars? On the asteroids? And in a vacuum?
I know that I can just read off the phase diagram for water (for the surface atmospheric pressure on each object). But could there possibly be some nuances that someone might miss just from viewing ...
2
votes
2answers
630 views
How to calculate concentration of vapor at the surface of a water drop
I'm reading a paper that examines the evaporation rates of water. In the final formula, it has the following constant:
$c_s - c_\infty $ where $c_s$ is the concentration of the vapor at the sphere ...
-3
votes
1answer
180 views
What makes sound when a huge wave is coming in an ocean? [closed]
normally at ocean beaches the waves are normal but they make lot of that a person standing at far can even listen that sound
What makes that sound what going to happen a
0
votes
3answers
401 views
What makes waves at beaches to come with high velocity and frequency at nights?
When we are in beach we can see waves coming when the sun light goes of the waves amplitude will increase what is the reason
Some people said me that for moon light the frequency and velocity of ...
2
votes
1answer
393 views
Water droplet evaporation due to humidity and temperature
I am conducting an experiment that requires comparison to models for a water droplet's change in size due to evaporation. I've found plenty of papers, but they all seem to require measurement of the ...
2
votes
2answers
360 views
the form of a kettle
What is the best form for a kettle, that is, to have the water boil the fastest? I am particularly interested in the following case: for one given kettle (whose volume is constant) containing ...
4
votes
2answers
76 views
Is there a good explanation for the observation of Martian canals?
Martian "canals" have been observed by independent observers after their first description. Now, they are attributed to "optical illusion", but I think that this is not a good choice of word, because ...
2
votes
3answers
196 views
Air Regeneration in Closed Systems
I wonder what's the way to regenerate O2 in air without using consumable chemicals (where one can use electricity through electrolisis or using UV lamps)?
We can dissolve water into O2 & H2, but ...
10
votes
4answers
14k views
How does water evaporate if it doesn't boil?
When the sun is out after a rain, I can see what appears to be steam rising off a wooden bridge nearby. I'm pretty sure this is water turning into a gas.
However, I thought water had to reach 100 ...
0
votes
2answers
751 views
Why does an object when filled with water sink, but without water inside float (in a body of water)?
Why does an object sink when filled with water, even if the same object would float without water inside?
For example, put an empty glass cup into water, and it floats.
But if you put a plastic ...
0
votes
1answer
373 views
Uses and interpretation of the 'Bowen Ratio' ($B_o=SH/LE$)
The Bowen Ratio is the ratio of sensible heat flux to latent heat flux, so presumably it gives some information about the relative importance of these processes. But it is not clear how this ...
3
votes
5answers
3k views
How to measure resistance of DI water
It is known that good DI water have resistance ~20 MΩ·cm
But how can I measure that? Using good vanilla ohmmeter (with 2000 MΩ range) showed crazy results (too low, not much dependent from distance ...
1
vote
3answers
587 views
Maxiumum weight a buoy can float [closed]
I have a buoy that can hold 2943.02 cubic millimeters of non-pressurized air, I need and equation to work out the maximum weight that the buoy can float.
4
votes
5answers
570 views
What happens if you try to freeze water in an water tight container
If I have a container that is full of water and I attempt to freeze the water by freezing the container, what would happen if the container is strong enough to prevent the water expansion? Could the ...
1
vote
1answer
227 views
Why is it that the splash pattern for every drop is never the same?
This was just a random thought that crossed my mind, and I'm sure there is a simple physics explanation. Say we have a leaky faucet 20 feet above the ground that lets out the exact same amount of ...
0
votes
0answers
141 views
Why is it that when I mix tea with hot water there appear to be far less floaters on the surface than if you mix with regular temperature water? [closed]
I've got loose tea that I pour to the bottom of a glass, then apply water, stir and drink. I've noticed that when the water in the water boiler has gone cold a larger portion of the tea remains ...
10
votes
5answers
8k views
jumping into water
Two questions:
Assuming you dive head first or fall straight with your legs first, what is the maximal height you can jump into water from and not get hurt?
In other words, an H meter fall into ...
