Two Hydrogen atoms covalently bonded to one Oxygen atom. One of the more common compounds on the surface of the earth.
75
votes
2answers
28k views
Surviving under water in air bubble
An incredible news story today is about a man who survived for two days at the bottom of the sea (~30 m deep) in a capsized boat, in an air bubble that formed in a corner of the boat. He was ...
1
vote
1answer
41 views
1/2 freeze a water bottle
Is it possible to quick freeze half of an unopened bottle of water or soda by putting half of the bottle in a subfreezing solution liquid nitrogen or other solution without freezing the whole bottle?
-1
votes
0answers
32 views
Calculating Apparent Depth at any angle: am I doing it right?
just wanted to check my understanding was right as scientific & mathematical equation notation is all a bit new to me - familiar as I am with equations in a programming context. I need to be able ...
2
votes
1answer
71 views
Reflections in a glass of water
I've noticed that if you take a full glass of water and look from above, through the water, you can't see through the glass sides - instead, you see a reflection. I tried with a laser pointer and the ...
1
vote
2answers
134 views
How long will a water drop exist until it evaporates based on ambient conditions? [closed]
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 ...
3
votes
1answer
37 views
Dissolving oxygen into water
I was wondering how one would actually calculate how much oxygen would dissolve into water given the necessary initial conditions, and what those initial conditions would need to be. I assume they ...
1
vote
2answers
37 views
Water pressure on slanted wall
Water pressure is simply $pgh/2$ for a vertical wall parallel to the depth of the water at exactly the half the water's depth. Suppose the wall is tapered (angled) slightly at around 2 degrees from ...
1
vote
0answers
49 views
How do you calculate the absorption spectrum of water? [migrated]
If you look online you can find various graphs of the absorption spectrum of water. The graph below for examples comes from this blog post.
As far as I can tell these graphs come from empirical ...
0
votes
1answer
103 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 ...
-5
votes
1answer
38 views
How we can measure floating water in Grams [closed]
I have a glass of water (500 ml) i will drop that water over a marble surface(Or anything else through which we can count) and some water outside the surface. Now i want to calculate that how much ...
2
votes
1answer
40 views
How to homegrow large, momocrystalline water ice crystals
This is a follow up to this question:Can one get clear ice crystals from a dirty suspension?.
How could one grow a large - meaning visible with the naked eye - water ice crstal with common household ...
0
votes
1answer
80 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 ...
2
votes
0answers
17 views
How to detect harmful gas occurence in carboy bottle [migrated]
To fill with drinkable water, I have lots of empty 19lt carboy bottles. Since they came from different people and companies, I have to check their healthiness to decide wheter they can be sterilise ...
0
votes
1answer
66 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 ...
-1
votes
1answer
47 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
86 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
50 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
159 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
112 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
98 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
36 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 ...
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 ...
3
votes
0answers
54 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
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 ...
6
votes
4answers
253 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
0answers
48 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
62 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
70 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
75 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
86 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
226 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
132 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
104 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
405 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 ...
7
votes
2answers
159 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
127 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
263 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
1answer
98 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
144 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
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 ...
8
votes
1answer
133 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
784 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
102 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
113 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
918 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
324 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
4k 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
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 ...
