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Questions tagged [water]

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

179 questions with no upvoted or accepted answers
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8
votes
1answer
62 views

Time for which a drop stays in the leidenfrost point

Is there any way to find out the time required for a drop of given dimensions to vaporize after attaining Leidenfrost point?
8
votes
1answer
7k views

Melting ice: reversible or irreversible?

I am looking into whether the melting of ice (or any substance for that matter) at constant pressure and temperature is reversible or irreversible. Different sources say different things, and it may ...
6
votes
1answer
205 views

Chemistry of electrical conductivity of pure water

I understand the electrical conductivity of pure water is very low, but not zero, and is due to the slight number of H+ and OH- ions naturally present. I understand that they will move under the ...
5
votes
0answers
36 views

When does water decrease or increase friction?

Water often acts as a lubricant e.g. a wet floor or road, but sometimes the reverse happens e.g. putting on wet clothes. I understand that surface tension is involved e.g. microscope slides sticking ...
5
votes
0answers
62 views

Is it true that the bubbles do not touch each other in the boiling water while going up?

I heard once that the bubbles do not touch when the water is boiling. I want to know if that is actually happening, and I would be interested to hear why it is true or not.
5
votes
2answers
347 views

Glasses underwater

So I figured the refraction of the cornea is based on the index of air and the vitrous humor to make a perfect image. Underwater this is messed with because water has the same index as the eye. Hence ...
4
votes
1answer
65 views

Why and how are wave sets (groups) created?

At a coasts wave normally arrive in groups (sets) and we wondered why this is the case. Some internet research did reveal some clues but no convincing answer. I want to know why waves gather in ...
4
votes
1answer
502 views

Under water light reflection of air in a cup vs water in a cup

The last time I was on vacation I was drinking on the swimming pool, and after I was finished with the drinks I started playing with the 2 plastic cups I had, and noticed that the air produces a ...
4
votes
0answers
1k views

Why water heat capacity has minimum at body temperature?

Water heat capacity has the following plot: One can see it has minimum near 40 degrees of Celsius, i.e. close to human body and other warm blooded animals have. Is this just coincidence? UPDATE ...
4
votes
0answers
98 views

What is the deepest cause of the such high specific heat capacity of water?

Yes, I know about the hydrogen bridges. But I think, it isn't the deepest cause. Anyway, they are only second-order bindings, although quite strong. I think, somehow should have the water a ...
4
votes
1answer
517 views

Fluid dynamics tsunami

I have been given a energy head (pressure) in meters for a given tsunami on land. If the tsunami hits a wall 1 meter by 1 meter, is it possible to calculate the height it will reach. I am thinking it ...
3
votes
0answers
72 views

Using convolution to simulate acoustic dispersion in shallow water

Background I'm a marine biologist who's trying to wrap my head around shallow water propagation. I'm interested in how acoustic dispersion (as described by Pekeris' waveguide) alters how sounds ...
3
votes
0answers
403 views

Can water drip from a capillary tube top? Perpetual motion?

In a normal capillary tube (ex: tube A), where the water doesn't travel as high as the tube's height, h, the meniscus formed is "normal" (concave, as seen in tube A). From previous posts, I ...
3
votes
1answer
123 views

Why does a salt water solution have a higher coefficient of thermal expansion (i.e. expands more) than distilled water?

I have found several different sources of data which show that a solution with a higher concentration of salt has a higher coefficient of volumetric thermal expansion than a lower concentration salt ...
3
votes
0answers
42 views

Water vapour behaviour during hypersonic expansion

I have a question about the behaviour of air with a small mass fraction of water vapour at extremely low pressures and temperatures. I am currently running experiments in a large vacuum facility that ...
3
votes
0answers
128 views

How does air going through silica gel change its humidity

Assume that the properties(temperature,humidity,velocity and so on) of the incoming air flow stay constant. The air flow goes through a silica gel plate. Humidity of the air will decrease, but how to ...
3
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0answers
139 views

Detect ions in water using impedance spectroscopy

I would like to check the presence of Na, Ca or other ions dissolved in water using impedance spectroscopy. I was thinking that because the ions have different masses they will have different ...
3
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0answers
727 views

Suction from flowing water

My memory from physics says yes but I want to check. Our pool is dirty and our vacuum is broken. If I were to stick the vacuum hose into the pool drain, would the flow of water going into the drain ...
3
votes
0answers
867 views

How would water drain out of a sealed pipe?

While hiking through the Grand Canyon, I started wondering. Say we have a pipe for the purpose of transporting water across a canyon, with the bottom submerged in a pool of water. Like the blue line ...
3
votes
0answers
2k 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 ...
3
votes
1answer
290 views

Can heavy water be isolated with water centrifuges?

If a container of pure water is rotated fast enough at high rpm, would $\mathrm{D_2 O}$ separation be feasible? Another way to ask is: it practically and physically possible with current technology ...
3
votes
3answers
617 views

Is evaporative cooling more efficient with dry or moist air?

I live in India, and in the summer season, the temperature can reach up to $45 \sideset{^\circ}{}{\mathrm{C}} .$ We use Split 1.5 Ton AC in our small office. The idea is to put an evaporative cooler ...
2
votes
0answers
45 views

Can water be made more violet?

Water is intrinsically blue because of molecular vibrations. The topic is covered here: Only sea water appears blue in color, why this is not happening in river water? And here, which I post ...
2
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0answers
49 views

Why perspiration drops are seen in shopping bag?

Why perspiration drops are seen in shopping bag? When i put hot bread in shopping bag after sometime i saw perspiration drops in the shopping bag.
2
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0answers
102 views

Forces acting upon body on impact with water

I am investigating the water-entry of a steel ball-bearing at different speeds. Ideally, I would like to model (to an extent) the forces experienced by the ball bearing as it transitions from air to ...
2
votes
0answers
69 views

Why aren't canal locks nearly impossible to open?

So I've just been watching a TV program where two people open a canal lock, and it occurred to me: aren't you pushing against the entire pressure of the river when you push the lock doors open? Why is ...
2
votes
0answers
650 views

Tap water conductivity differences between AC and DC

Direct current is often used in electrolysis and because of the alternating nature of AC, it's not great for electrolysis. Tap water, however, conducts AC really well. But why is that? Why does ...
2
votes
2answers
88 views

Why water clouds don't fall when there is strong wind and no updraft?

I see clouds traveling at speed where is no updraft, keeping the same altitude, in windy conditions...why they don't fall? Also I experienced clouds hovering in valleys and stationary clouds above ...
2
votes
2answers
86 views

Demonstrating that water density is at its maximum at 4 degree

I want to demonstrate to the students this fact in class. I checked the density of water as a function of temperature. The variation is minute, on the scale of one in ten thousand, from 0 degree to 4 ...
2
votes
1answer
63 views

Does rate of heating of water change with altitude?

I was recently on a trip at 5,000 feet with a bunch of people I don't know well, all of whom swore that water "takes longer to boil" at higher altitudes. I'm pretty sure they were confusing boiling ...
2
votes
0answers
707 views

How was microscope-level zoom created by a lens and a water droplet?

It was a rainy night. My glasses were speckled with fresh water droplets. I looked at a distant street light and I was surprised to see cells - a single cell was zoomed in to the level where I could ...
2
votes
0answers
93 views

How fast should 6 liters flow out of the sink through a 6cm pipe?

I had 6 liters in the sink when I pulled the plug. It took the water about 30 seconds to get through a pipe which has about 5cm in diameter. I think the pipe might be blocked a bit, causing it to have ...
2
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0answers
448 views

Best frequency for underwater transmission

What is the best frequency for a high data rate of underwater transmission? I have read that the threshold of hearing underwater is around 170 to 180 db. Can this be useful in calculating the best ...
2
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0answers
56 views

What is the spheroidal temperature of water?

I understand that when a hot plate reaches a certain temperature water will no longer wet the surface, but will form perfect spheres on the surface of the plate. The temperature at which this happens ...
2
votes
0answers
237 views

Bond Angle in a water molecule

I recently started up reaching up on the Feynman lectures on Physics and in Vol I,Chap 1-2,Feynman states that the bond angle between the hydrogen and oxygen atom is 105° 3′. I know that the bond ...
2
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0answers
739 views

Heat Transfer, Water in a pot

I have a question I've been pondering for a while. How can I determine the temperature in a pot filled with water? I know these things: I have a known mass of water, of mass $m_w$ I have a pot of ...
2
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0answers
698 views

Calculating PSI generated by water entraining air as it flows down a pipe

This is the concept used in a trompe. Basically, the idea is that if we allow water to flow down a pipe and if that pipe has inclined air intake orifices near the top where the water enters, then the ...
2
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0answers
120 views

Could water physically makeup the core of a planet or otherwise large celestial mass?

Knowing very little about the nature of water, wondering how it might behave at the centre of a planet or centre of an another massive gravitational body. Could water take such pressures or might it ...
2
votes
0answers
117 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 ...
1
vote
0answers
12 views

Thickness and refractive index of silica gel layer between fused silica and water interface

I learned that when fused silica contact with water, a layer of silica gel will be formed. However, I cannot find any reference about the thickness and the refractive index of the silica gel. Can ...
1
vote
0answers
17 views

Temperature dependency on $D_2O$ stratification

The original problem is the research of low energy consuming process to take away D2O from drinking water. Reading the Q&As on this post, particularly the answer provided by @DjohnM, I would like ...
1
vote
1answer
38 views

Why isn't the water moving when it is undergoing electrolysis

I understand that in electrolysis of water, the water around cathod is splited in the way of 4H2O + 4e => 2 Hydrogen + 4 OH- . And the hydroxide will move to the anode due to electric field in the ...
1
vote
0answers
51 views

Density of water after absorption

I was wondering if I could assume a water density ~1.0 g/cm3 after it was absorbed by the skin, or other medium. I am particularly thinking on a molecular level, if the nanostructure and size of ...
1
vote
0answers
32 views

How is reverse osmosis even possible for desalination?

I don't understand how reverse osmosis for desalination is possible for existing RO membranes of pore size 10 angstroms (A) if the radius of a sodium atom is 3.14 A, chloride is 3.7 A and maximum ...
1
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0answers
20 views

Underwater acoustics: particle motion

The properties of an acoustic wave field depend on the mechanical properties of the supporting medium, including the density, and the bulk modulus. With increasing density, the propagation speed of ...
1
vote
1answer
61 views

Laminar Flow From Outdoor Faucet

I ran across a video recently that really caught my attention. It's been circling the internet over the past couple weeks, but I'm trying to figure out what's going on. Basically, it's a video of an ...
1
vote
1answer
60 views

How did Mars lose all its surface water?

A lot of geological evidence suggests that Mars once had quite a bit of surface water. I assume it wasn't whisked away into space, so where did it all go? What processes caused the water to go there? ...
1
vote
4answers
158 views

Can someone explain why there is water in this vacuum chamber?

I work at a water treatment plant that uses a vacuum system to pull the water into the filters and backwash the filters. In the middle of the vacuum system there is the vacuum chamber. What I don't ...
1
vote
1answer
179 views

Why is water inside a vacuum chamber not boiling?

I have a vacuum that shows a max vacuum gauge reading of 23"Hg when connected to a chamber. When placing room temperature water inside vacuum, the water doesn't boil. I have seen this chart before ...
1
vote
2answers
153 views

Is it possible to create circulation of water in bypass pipe without water pump?

There is a pipe of 32mm in diameter. Water flows from left to right. There are two branches in that pipe. To one of them connected input of water heat exchanger, to another - output of water heat ...