Two Hydrogen atoms covalently bonded to one Oxygen atom. One of the more common compounds on the surface of the earth.
10
votes
4answers
5k 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 ...
3
votes
2answers
814 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?
0
votes
1answer
2k 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 ...
5
votes
2answers
219 views
What reflective media do laser shows use?
I am having a hard time in finding out what exact light media laser shows use. I am trying to build a laser show myself. I know that the laser light is reflected off these particles in such a way that ...
2
votes
1answer
558 views
static flow of water
The title, I don't know whether it's correct or not, but I came across a video in youtube, http://youtu.be/_PkgQQqpH2M.
The author of video used the title and hence I used the same..
The video ...
6
votes
3answers
2k views
Why does a bullet bounce off water?
It is known that bullets can ricochet off a body of water. Is surface tension responsible for this or is this the same behavior we see when an asteroid ricochets off the atmosphere? I don't think ...
0
votes
2answers
710 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 ...
3
votes
2answers
127 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 ...
7
votes
1answer
743 views
water flow in a sink
When one turns on the tap in the kitchen, a circle is observable in the water flowing in the sink. The circle is the boundary between laminar and turbulent flow of the water (maybe this is the wrong ...
1
vote
1answer
225 views
How to model water flow with and without friction against other objects?
I am interested in modeling water flow including boundary flow (with friction) against other objects in the path of the water flow.
I'm not a physicist but I am interested to learn the relevant ...
5
votes
1answer
222 views
Water flushed down, water pumped up (in buildings)
I live in a tall building (20 floors) on a mountain. Because the water pressure from the water company is not enough, there is a water pump at the last floor which is activated each time someone is ...
3
votes
1answer
105 views
Experiment to find structure of water
Who first determined the structure of water (two hydrogen atoms stuck to an oxygen atom at approx 105 degrees), and, more importantly, how was this done?
6
votes
1answer
364 views
What is highest water pressure at which electrolysis can be performed?
What is highest water pressure at which electrolysis can be performed to derive hydrogen and oxygen? Does the dielectric constant of water, which which lowers as pressure increases, have an effect on ...
1
vote
1answer
45 views
How do I determine when this object is about to get covered in dew? I can measure the environment parameters
There is a large disk of glass sitting outside, it is pretty thick and wide. Via different sensors hooked up to a controller, I can measure the air temperature, glass temperature (on the surface), and ...
1
vote
1answer
678 views
How much disolved oxygen is removed by boiling water?
Apologies if this is a chemistry question
I've read that drinking water contains dissolved oxygen to the tune of $10\:\rm{ppm}$.
I've also read that raising the temperature of water will remove some ...
5
votes
4answers
627 views
Sauna thermodynamics
Why does it get hotter (feel hotter) in a sauna when one pours water over the hot stones?
Wikipedia says that the water condenses onto the skin, but the actual air humidity is so low that I doubt ...
11
votes
2answers
664 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 ...
0
votes
1answer
1k views
Is sea water more conductive than pure water because “electrical current is transported by the ions in solution”?
Apparently, electrical charge is transported by the ions dissolved in water, is this true?
2
votes
1answer
243 views
Calculating spacecraft water leak flow rate
A large container of heated water is floating in space. How can I calculate leak rate if a small puncture is opened?
I'm assuming the water is kept at 298K and in the liquid state inside the chamber.
...
0
votes
1answer
71 views
The force of a phase transition
At standard temperature and pressure, I fill a bottle to capacity with $N$ liters of water, then place a weight of mass $M$ kg on its opening to serve as a lid. What values of $N$ and $T$, where $T$ ...
2
votes
2answers
605 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
7
votes
1answer
71 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 ...
3
votes
1answer
631 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
277 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 ...
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 ?
1
vote
0answers
608 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 ...
2
votes
3answers
913 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 ...
7
votes
3answers
2k views
Waves in water always circular
I have had a question since childhood. Why do we always get circular waves (ripples) in water even when we throw irregularly shaped object in it?
6
votes
5answers
2k views
Why does water make a sound when it is disturbed?
When I disturb a body of water, what causes the familiar "water moving" sound?
4
votes
2answers
662 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
621 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 ...
4
votes
5answers
549 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 ...
2
votes
2answers
617 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 ...
1
vote
1answer
498 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 ...
0
votes
3answers
385 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 ...
4
votes
2answers
390 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 ...
2
votes
2answers
207 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 ...
2
votes
3answers
197 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 ...
3
votes
2answers
249 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.
3
votes
1answer
251 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 ...
3
votes
4answers
401 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
2k 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 ...
2
votes
2answers
350 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 ...
2
votes
1answer
842 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
988 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
386 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 ...
-3
votes
1answer
176 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
2
votes
3answers
192 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 ...
