Two Hydrogen atoms covalently bonded to one Oxygen atom. One of the more common compounds on the surface of the earth.
-1
votes
1answer
37 views
Producing Ice with water in vacuum [closed]
Do you think producing ice in large volumes is possible using this method? - say 500 kilograms a day?
How much vacuum should the pump's capacity be to make that happen at sea level?
Can it happen in ...
2
votes
2answers
70 views
Why is it faster (as in proportion to volume) to boil 4 cups of water than to boil 2 cups?
I did an experiment where I boiled two cups (500ml) of water in a kettle, and it took 1:30 minutes to reach around 98 C, average. However, when I boiled 4 cups of water, (1L) it only took me 2:30 ...
0
votes
1answer
46 views
Absorption of Water
I was just watching the videos Chris Hadfield put on youtube from space, and was wondering why water doesn't get absorbed as well onto his toothbrush in space?
And what characteristic of ...
2
votes
4answers
114 views
Can a diver swim a short distance in great depths without being physically crushed by the pressure?
I recently saw "The Abyss".
Does it make sense that they do dives in these depths (700m) with soft suits?
Also - what is all the depressurization talk about? Why do divers need to depressurize long ...
0
votes
2answers
91 views
Pascal's law: pressure of fluid at different locations
I know that's stupid question, but I'm really confused what my teachers says, so I need to check that theory.
Here are just two ordinary connected containers, which are full of water.
On grounds ...
1
vote
1answer
75 views
Does brown but transparent swimming pool water heat significantly faster than western style highly chlorinated pools?
Eastern European swimming pools are often brown tinted water. i was told it was the color of the chemical to keep the pools clean, but who knows. These pools did not smell unsanitary and may have even ...
2
votes
0answers
19 views
Can one get clear ice crystals from a dirty suspension?
Euteictic freeze crystallization is a method where an electrolytic solution is cooled and separated into a stream of (relativly) clean, pure ice and a salty brine. I know anectdotally of wine ...
0
votes
1answer
89 views
Limescale formation at room temperature?
There is a large metal container in form of a cube made of stainless steel. It is used for storing water in it for technical uses. The problem is that all joints at the bottom of the container have ...
-1
votes
0answers
102 views
When can a body of water glow in space?
How would superionic water be formed at the core of a giant water planet? The publication
Giant planets may host superionic water, E. Marris, Nature News, 22 March 2005,
states that water in ...
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 ...
2
votes
0answers
40 views
Finding Surface Tension of water at certain Temperature and Pressure
So the question is:
Using the Young-Laplace Equation (if applicable), find the surface tension (dynes/cm) for water at 20
degrees Celsius with 2.5 psi. Round to the nearest tenth.
...
8
votes
5answers
337 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 ...
6
votes
4answers
240 views
Why is the water on the surface of the Earth?
What makes the water stay on the surface? Why the earth does not absorb the water in it?
0
votes
1answer
48 views
Calculating the coefficient of thermal expansion in liquid
I am trying to write a matlab function that calculates the coefficient of thermal expansion of water from a given temperature. From what I understand the thermal expansion coefficient is calculated as ...
0
votes
0answers
23 views
Formula to calculate the density of satuared steam
I need to calculate (or look-up?) the density for saturated steam in a range of 8-12 bar. Is there a formula for this? It's ok if it's not perfectly exact.
0
votes
0answers
52 views
Water evaporation
It is known that molecules at the surface are strongly attached to each other (more attraction less repulsion) than those within the bulk attraction and repulsion are balanced). This is the molecular ...
0
votes
1answer
50 views
Time constant of ice melt
I'm familiar with problems of "how much ice can you melt given some amount of energy", but I'm writing to get some clarification on the time constant of this event. This question might be somewhat ...
0
votes
1answer
65 views
Does electrically heated water have an adverse effect on hair?
I know I should have asked this question on a different site. but this was the most suitable site available right now for my question. Perhaps after this proposed site goes on Beta, we can move it ...
3
votes
1answer
66 views
Does tapping at the side of a bottle prevent shaken soda from bubbling over?
Anecdotal evidence has it that a bottle of soda that was heavily shaken will not bubble over if tapped at the side multiple times.
Yet I wonder: Has the tapping really any effect? Or could it be that ...
3
votes
1answer
81 views
How to create visible reflections in shallow water?
Assumption: The only lights I have are candle, table lamp, and sunlight.
What would I need to create visible reflection of an object in the shallow water contained in a 5 liter bucket? Is it even ...
4
votes
3answers
1k views
Why does hot oil explode when pouring water on it?
I am puzzled to know, What is the reason of hot oil make sound and explode when we pouring water on it?
5
votes
2answers
214 views
What is the largest sphere of liquid water that could exist in space held together under it's own gravity? [duplicate]
What is the largest theoretical sphere of liquid water that could exist in space held together under it's own gravity? I've always wondered if a planet the size of earth could exist as a single volume ...
4
votes
0answers
131 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 ...
3
votes
1answer
90 views
Make water droplets charged?
Normally water molecules are electrically neutral.
But I have seen somewhere ideas about electric energy generators mentioning that water droplets might be used in some applications as they are ...
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 ...
8
votes
2answers
393 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 ...
6
votes
2answers
148 views
Why water in the sink follow a curved path?
When you fill the sink with water and then allow the water to be drained, the water forms a vortex.. And then it starts to follow a curved path downwards by effects of gravity..
Why this phenomena ...
4
votes
3answers
113 views
Is it easier to pump water up or down?
I'm trying to gauge the strength of aquarium air pumps, for use in a vertical hydroponic farm. A curious question arose: is it easier to pump water upwards vertically, or is it easier to pump it ...
1
vote
2answers
151 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 ...
1
vote
2answers
89 views
How long will a water drop exist until it evaporates based on ambient conditions?
How long will a water drop exist until it evaporates based on ambient conditions? I am looking for a simple equation or table that would tell me how long a water drop may exist until it evaporates ...
1
vote
1answer
85 views
A water balloon in vacuum: does it boil?
If I put water in a vacuum it will boil. But what if I put this water inside a balloon ?
I searched for answers and fount this video: http://www.youtube.com/watch?v=9q8F3ClUuV0
It seams that the ...
-2
votes
3answers
130 views
Water excitation with sine waves
I saw that video when they connected a water hose to a speaker emitting 24 hz sine wave, and its illusion on the shape of the follow going out of the hose (because the video capture rate is fixed at ...
1
vote
1answer
225 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 ...
7
votes
1answer
109 views
What determines bubble locations in boiling water?
Something a little different to our usual fare. I was boiling a pan of water for cookery the other day, and got to wondering what caused the location of the bubble streams from the bottom of the pan. ...
0
votes
1answer
645 views
Thermal expansion coefficient of water
I am working through the methods section of the following paper: Spatial-temporal variability in surface layer deepening and lateral advection in an embayment of Lake Victoria, East Africa
In the ...
-1
votes
1answer
91 views
Sensible heat question (solving for temperature)
If $55 034.175 \rm{kJ }$ of heat are transferred to $150 \rm{kg}$ of ice at a temperature of $-12.15 ^\circ \rm{C}$, calculate the temperature of the resulting water.
Using $Q = mc(t_2-t_1)$ or ...
4
votes
2answers
106 views
Best shape to reduce the splash of a droplet?
Our coffee machine catches the last couple of droplets, after your cup is removed on a shape to reduce plash of the coffee droplets.
These shapes are placed inside the spill reservoir.
The shape ...
11
votes
3answers
897 views
A water drop in vacuum
Let's imagine the following situation:
At an initial moment $t=0$, a large water drop with diameter for example $D=10\ \text{cm}$ is placed in deep space (Say an astronaut is experimenting). Let's ...
3
votes
3answers
262 views
How can my water cool down more quickly?
I have a cup and I can only pour hot water inside, I wanna know whether the heat will dissipate more quickly with more water or less water?
How about the occasion when my cup is well covered?
2
votes
3answers
3k views
Explanation for different boiling points of water on different altitudes
I understand water boils at different temperatures depending on altitude.
I am seeking to get an illustrative explanation for this, including a diagram if possible.
10
votes
4answers
13k 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 ...
8
votes
4answers
1k views
Are water waves (i.e. on the surface of the ocean) longitudinal or transverse?
I'm convinced that water waves for example:
are a combination of longitudinal and transverse. Any references or proofs of this or otherwise?
3
votes
2answers
109 views
Pumping water from a closed column. Will the column get empty or just circualte?
As a picture is worth a thousand words, here is my problem:
It is a closed water column with a bit of air in the top section.
If I run the pump and make the water flow from IN to OUT,
Will the ...
40
votes
3answers
1k views
What causes insects to cast large shadows from where their feet are?
I recently stumbled upon this interesting image of a wasp, floating on water:
Assuming this isn't photoshopped, I have a couple of questions:
Why do you see its image like that (what's the ...
2
votes
2answers
101 views
How much better is salt water at letting through microwaves than pure water?
Radio Wave Attenuation
There are two general types of matter (substances) in the universe
that affect electromagnetic waves, conductors and insulators which
are called dielectrics by ...
1
vote
1answer
131 views
How fast does water fall in the middle of a very very thick waterfall?
Let me create a very artificial experimental set up. Take a bathtub the size of Delaware and suspend it a mile above the ground. Fill it with water (though I'm not sure to what depth - and it might ...
2
votes
2answers
131 views
Changes in Water Bonding Angle
I heard something recently in a casual discussion, but have yet to be able to confirm it: is there any evidence that the bonding angle for a water molecule, currently defined as 104.5, has been either ...
7
votes
1answer
49 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
4answers
877 views
Which is more efficient, heating water in microwave or electric stove?
So our propane tank in the kitchen ran out again today.
Which is more energy efficient, boiling water in a microwave on an electric stove? All things being equal i.e. starting temperature and mass ...
7
votes
5answers
317 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 ...
