Two Hydrogen atoms covalently bonded to one Oxygen atom. One of the more common compounds on the surface of the earth.

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2answers
1k 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 ...
0
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3answers
2k 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
518 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
2answers
672 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
184 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
3k views

Air Regeneration in Closed Systems [closed]

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 ...
30
votes
4answers
111k 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
8k 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
492 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
14k 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
4k 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.
7
votes
5answers
2k 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
282 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 ...
15
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5answers
63k 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 ...
1
vote
0answers
1k views

Damping and stiffness constants of water

I'm working on a simulation of water drops falling into a pool. I'm specifically interested in the waves generated by the impact of the drops. In order to calculate the vertical motion of the waves, I ...
9
votes
2answers
1k views

Why does the water in the toilet move around so much on stormy days?

On calm days, the water in the toilet looks completely still. But when it's rainy and windy out, the water looks like it moves and pulsates. Why is this?
6
votes
1answer
933 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 ...
5
votes
2answers
241 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 ...
8
votes
1answer
2k 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
2answers
1k views

Tube under water and air pressure

If you take apart a syringe you are left with one piece that is a tube with a tiny hole in one end and the open end of a tube at the other. If you then submerge this underwater and cover the small ...
1
vote
1answer
480 views

Extracting water out of silica gel [closed]

From my preliminary research I've learned that desiccants are a good (best?) method to absorb water from air. Assuming I'm using silica gel (or kitchen salt, or rice) then what is the best way to ...
7
votes
1answer
389 views

How to simulate a crashing wave? [closed]

I'd like to create a very rough animation of a wave crashing on a beach. I'm guessing it would have to be a particle simulator, where you code in the forces between the particles and then integrate ...
2
votes
1answer
257 views

Auto-ionization of water

$HCl(g) + H_2O(l) -> H_3O^{+}(aq) + OH^{-}(aq)$ Assuming $HCl$ completely ionizes in water, if we prepare a $HCl$ solution, will the $[HCl]=[H_3O]$ ($HCl$ concentration = $H_3O$ concentration)? ...
8
votes
1answer
237 views

Evaporating water in -30ºC

I don't really know anything about physics even though I pretended studying it for years. How is this explained?: ...
26
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7answers
23k views

Why do tsunami waves begin with the water flowing away from shore?

A sign of a tsunami is that the water rushes away from the shore, then comes back to higher levels. It seems that waves should be both + and - polarized and that some tsunamis should go in the ...
8
votes
5answers
5k 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?
5
votes
4answers
307 views

When displacement isn't possible

Stop me if i'm wrong but displacement is, for example, when you enter a bathtub the water level rises around you. What happens when displacement isnt possible? I'll give an example. I have two ...
3
votes
4answers
410 views

Withstanding charlatans: How to protect friends from buying “water structuring facilities”?

In my country it is a big business now, to sell "water structuring facilities". Promoters telling that after passing through them the water obtaining fantastic abilities basing on the fact that "water ...
5
votes
5answers
14k views

Is it really possible for water to be held in a “cone shape” for a brief period of time?

I just saw this "trick" where a cup of water is turned over onto a table without spilling (using a piece of cardboard. After removing the cardboard from underneath the cup, the person then removes ...
4
votes
3answers
40k 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.
5
votes
1answer
194 views

Resonance modes of a cubic box of water which we shake

I don't know hydrodynamics, but I wonder how one would compute resonance modes of a cubic box of water which we shake. I believe the waves would directly depend on the height of water and the width ...
20
votes
3answers
7k views

Why is there more steam after a pot of water *stops* boiling?

I have a pot of vigorously boiling water on a gas stove. There's some steam, but not alot. When I turn off the gas, the boiling immediately subsides, and a huge waft of steam comes out. This is ...
21
votes
5answers
8k views

Eyes open under water

Yesterday I looked underwater with my eyes open (and no goggles) and I realized I can't see anything clearly. Everything looks very, very blurry. My guess is that the eye needs direct contact with air ...
5
votes
1answer
3k 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 ...
16
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4answers
5k views

Why are snowflakes symmetrical?

The title says it all. Why are snowflakes symmetrical in shape and not a mush of ice? Is it a property of water freezing or what? Does anyone care to explain it to me? I'm intrigued by this and ...
8
votes
3answers
5k views

Why does frozen water burst a pipe?

When water freezes in a pipe it can crack the pipe open. I assume this takes quite a lot of energy as when I try to crack a pipe it can be hard work! I think water freezing is a result of energy ...
6
votes
1answer
2k views

How can I prevent drinking water from freezing in cold weather? [closed]

I'd like to keep a container of potable water in my car for when I get stuck, but in the winter it gets cold enough for bottled water to freeze. I can't put salt in it, because then it won't be ...
7
votes
2answers
2k views

Why does a slight drip of water protect pipes from freezing?

I've heard that turning on faucets to a slight drip will prevent pipes from freezing, but I've never understood why this is the case. Can anyone out there help me to understand? Thanks!
4
votes
3answers
16k views

How does watering your plants help protect against freezing?

I've always heard that watering plants if the temperature goes a few degrees below freezing will help prevent them from freezing, but I've never quite understood the physics behind it. Can you guys ...
10
votes
2answers
8k views

How cold does it need to be for spit to freeze before hitting the ground?

What is the dominant form of heat transfer between warm water and cold air? If a $100 mg$ drop of water falls through $-40 C$ air, how quickly could it freeze? Is it credible that in very cold ...
12
votes
4answers
23k 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 ...
13
votes
5answers
7k 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?
12
votes
3answers
2k 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 ...
5
votes
1answer
706 views

How to estimate condensation from air?

How to estimate the amount of water condensing from air on a surface, given the air's temperature and relative humidity and how they change over time, the surface temperature, material's thermal ...
8
votes
3answers
12k views

Why does the water level equalize in a series of tubes?

Say I have a series of tubes (not the internet) looking like this, where w represents water: ...
8
votes
5answers
5k 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?
17
votes
4answers
4k views

Boiling water and salt

I would like to have a good understanding of what is happening when you add salt to boiling water. My understanding is that the boiling point will be higher, thus lengthening the process (obtaining ...
17
votes
3answers
929 views

How to show that the Coriolis effect is irrelevant for the whirl/vortex in the sink/bathtub?

There is a common myth that water flowing out from a sink should rotate in direction governed by on which hemisphere we are; this is shown false in many household experiments, but how to show it ...