Two Hydrogen atoms covalently bonded to one Oxygen atom. One of the more common compounds on the surface of the earth.
3
votes
4answers
264 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). ...
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 ...
3
votes
0answers
319 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 ...
2
votes
4answers
116 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 ...
2
votes
4answers
739 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 ...
2
votes
1answer
955 views
Do my noodles cook quicker when the water is boiling or when it is just about to boil?
I was just cooking some noodles and staring at the pot waiting for them to cook made me wonder... Will my food cook quicker when the water is boiling and bubbling, or when it is at a temperature where ...
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 ...
2
votes
3answers
113 views
Why is there more steam when water is subject to less fire?
When I cook things, such as scallop and salmon, I found that the food may be more tender if I wait till the water boils (at 100 C) and immediately turn the fire lower so that the water is not bubbling ...
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 ...
2
votes
1answer
267 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
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 ...
2
votes
1answer
193 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?
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.
2
votes
2answers
328 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 ...
2
votes
1answer
706 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, ...
2
votes
2answers
604 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
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 ...
2
votes
1answer
384 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
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 ...
2
votes
2answers
228 views
Will the siphoning effect help a system pump water upwards if the water's entry and exit points are at the same height?
I am looking to pump water from a pool up to a roof for solar heating (black plastic tubing) and then back into the pool with the original source water. Does the gravitational force of the water ...
2
votes
1answer
102 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 ...
2
votes
2answers
1k views
Why I will feel colder when I get out from a swimming pool?
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 ...
2
votes
1answer
223 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?
2
votes
1answer
74 views
DIfference in Pitch Caused by Water Temperature?
I have recently been intrigued by the following question: What is the difference between the pitch of the noise of dripping water between hot and cold water? For example, would cold water create a ...
2
votes
4answers
878 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 ...
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 ...
2
votes
1answer
620 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 ...
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
1answer
840 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, ...
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 ...
2
votes
1answer
72 views
Can small clouds reflect enough light to hurt your eyes/blind you?
I looked out my window a minute ago and immediately noticed a very bright spot where a cloud and a jet/plane trail met. The spot was so bright that I thought the sun was behind it because it left that ...
2
votes
2answers
285 views
Riddle: can you swim faster upstream than downstream (with respect to the water)?
A friend of mine posed a riddle to me:
A man swims upstream in a river, which is flowing at an unknown rate. He is wearing swimming goggles. At a certain point he loses his goggles. 10 minutes later ...
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 ...
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.
...
2
votes
2answers
616 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 ...
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
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 ...
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 ...
2
votes
0answers
41 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.
...
2
votes
0answers
43 views
How does a snowflake “know” to form symmetrically? [duplicate]
Possible Duplicate:
Why are snowflakes symmetrical?
Under ideal situations, a snowflake forms into near perfect hexagonal symmetry. How? For instance, when a water molecule moves towards ...
2
votes
1answer
412 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.
...
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 ...
1
vote
2answers
156 views
How does blow-drying a mirror keep it from steaming up again?
After a hot shower, the mirror in my bathroom steams up. When I try to clear it with a towel, it immediately refogs. Yet once I use my hair-dryer, it will clear the fog and the mirror will stay clear.
...
1
vote
3answers
132 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
152 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
86 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 ...
1
vote
2answers
155 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 ...
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 ...
1
vote
3answers
8k 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 ...
1
vote
2answers
131 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 ...
