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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7
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2answers
203 views

Why does warm water sink?

It is well known that water at 4C is denser than water at 0C. This is the usual explanation for why a body of water freezes from the surface (also it's because ice is even less dense, but that's ...
0
votes
1answer
42 views

How can condensation be aided?

I was wondering if certain factors of water vapor condensation can be aided? For example, being able to increase the saturation of water vapor via a certain method, or another example would be having ...
0
votes
1answer
38 views

How can we use conductivity measurements of water to find hydrogen ion concentration of water?

How can we use conductivity measurements of water to find the hydrogen ion ($\mathrm{H}^+$) concentration in water?
1
vote
1answer
39 views

Why does liquid flow along the mug [duplicate]

I have been wondering why situation described in the picture below happens Why does the water/milk or any liquid poured from the mug/bottle flow along the surface of the vessel instead of leaving it ...
3
votes
1answer
393 views

Lifting a wet object off a table

When there is a film of water in between an object and the tabletop it rests on, it is difficult to pull the object directly upward. However, when you slide the object, it comes off easily. What is ...
9
votes
4answers
6k views

Effect of water pressure on sinking objects

As I understand, water pressure increases as we go towards bottom of the ocean. So if an object* is thrown into water and it starts sinking with some speed, does the sinking object's acceleration ...
8
votes
2answers
657 views

Why things get dry (meaning from water)? [duplicate]

When I leave wet clothes in the open air, they will get dry over time by themselves even at room temperature. I know that somehow the water becomes vaporized; it's not "disappearing". For that, it ...
1
vote
1answer
38 views

Water + RF + Spark = Continuous Fire

Can anyone explain the physics of what is happening in the following video? https://youtu.be/p8xYUDiSGDk?t=37 Is this process Radiolysis? At what radio frequency & power level is h20 ...
1
vote
0answers
42 views

What is the maximum theoretical height upto which our oceans can rise? [closed]

The question is framed from a physics point of view so we will assume water is an indefinite resource. All I am interested in is if we go on adding water into our oceans then what is the maximum ...
1
vote
2answers
94 views

How does calblock (water softener) work?

This "calblock" device claims to prevent limescale accumulation on water heaters in a washing machine. It sits between the water faucet and the washing machine; the water passes through it. I cannot ...
3
votes
1answer
197 views

Sound waves creating bubbles in water

Sorry for the title, couldn't find a better one. A few years ago I read on a scientific magazine about a discovery, but I can't remember the name nor find anymore information on it. Basically they ...
1
vote
2answers
151 views

Heat Losses from water pan due to vaporisation before boiling

I'm studying heat transfer from an electric heater to a cooking pan (Stainless steel) filled with water; specifically, my problem is related to water vaporisation, as I've already found good models to ...
6
votes
3answers
8k views

What is the resonant frequency of liquid water?

I learned it's not 2.45 GHz. But what is it, then? In my failure to find the real value, I'm starting to wonder: does it even make sense talking about a resonant frequency of water molecules?
0
votes
2answers
32 views

Increasing water temperature without salt

I have been extremely curious on how to get water even hotter by couple more degrees when its boiling. Rather then adding salt .... I started to stirring it.. Same Concept works with cooling the ...
2
votes
3answers
215 views

Why does ice melts faster near the surface of water?

I had a few frozen bottles and while they were melting I saw this: in all of the bootles, the ice seems to get thiner near the surface. I have searched a bit and I've found this video that shows ...
2
votes
3answers
4k views

How does the boiling time depend on the amount of water?

For example we have 1 electric kettle with 1 litter of water and we have another (the same type) electric kettle with 2 litters of water. How much time each kettle will need to boil and why? How does ...
6
votes
1answer
12k views

Can a saltwater solution conduct electricity forever? [closed]

We know that very pure water does not conduct electricity, but salt water is a decent conductor. This is commonly explained by saying that "the ions carry the current through the solution", an ...
6
votes
1answer
1k views

Finding surface tension of water at certain temperature and pressure

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. ...
3
votes
2answers
74 views

Mirages under water?

In Polynesian shallow water, the temperature difference from short place to place is so high that one can see the same trouble refraction that exist in air above fire or metal sheet in summer. So I'm ...
5
votes
1answer
197 views

Why does a stream of water behave like this when aimed against a spoon or into a glass?

I noticed while doing everything except the dishes that water behaves quite strange. These two things might be two different phenomenon, but the water acts in a similar way in both cases. Spoon and ...
7
votes
2answers
553 views

Patterns in laminar flow of tap water

This is a simple experiment that anyone can do at home. Open your tap so that the water maintains a laminar flow, and the cross section of flow is considerably thin. Place your finger 3-4 cm below the ...
0
votes
2answers
61 views

How much energy could be obtained by freezing water?

I know with our current technology energy is required to freeze water. But if the theories are correct we should be able to freeze water by extracting energy correct? How much energy could be ...
1
vote
0answers
25 views

Waterproof Case Time Limits [closed]

A lot of cellphone cases are rated safe for one hour at two meter depth. I assume this is due to water molecule diffusion along case seams (like the zipped zipper in a ziplock bag), right? Is ...
11
votes
3answers
345 views

Why is the splash of water always vertical, no matter in which angle the gunfire hits the surface

When gunfire hits the surface of a pond, the water seems to always splash directly upwards, in 90° to the surface of the water, no matter at which angle the gun is fired. The angle is usually very ...
1
vote
0answers
90 views

standing waves on a cylindrical jet

as we know, there are some perturbations on a falling jet which are always present and according to their wave number and the radius of the jet, they can grow and decay over time. so, imagine a jet ...
1
vote
1answer
126 views

Can a hose filled with water go up if there is not a lot of pressure?

This might be more a general knowledge-type question or physics basics (or maybe not even physics) if so, I apologize and never took a physics class (my school never offered it), so I am not really ...
0
votes
1answer
252 views

What wavelength of light is the least absorbed by water?

As I understand it, an infrared laser range finder will not work underwater because the infrared rays are heavily absorbed by water. What wavelength (optical, ultraviolet, microwave, etc.) of light ...
1
vote
1answer
53 views

Difference of water pressure

We know that $P = \rho gh$, so is it true that water pressure at 2nd floor will be higher than water pressure at 9th floor of a 12 story building?
2
votes
0answers
33 views

How fast does water have to be moving for it to gain a lot of heat? [duplicate]

A random question popped into my head a few minutes ago: objects, when moving fast enough, start to get resistance from the air. Since there is friction between the air and the object [water], there ...
0
votes
3answers
186 views

Why is alcohol less dense than water?

Ethyl alcohol (ethanol) is less dense than water, and it's boiling point is lower. But this molecule is more complex and bigger than the simple H2O. How can a substance with a higher molecular size ...
24
votes
2answers
3k views

When a drop of water falls into water, where do the splashes come from?

When a drop of water falls into a reservoir of water from a high enough altitude, water droplets will splash (image credit): My question: Does the water in those droplets come from the original ...
0
votes
1answer
79 views

Are particles that locally evaporate off water's surface at T = 100?

Water molecules can evaporate off a surface without needing to boil (How does water evaporate if it doesn't boil?). This is because surface particles are sometimes energetic enough to overcome ...
3
votes
0answers
46 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 ...
3
votes
2answers
134 views

Why water boiling time depends linearly on water volume?

I thought that the function will follow the Square-cube Law since we heat water at the surface (which is x^2) while we heat the volume (which is x^3) as it happens in animals according to Bergmann's ...
0
votes
0answers
32 views

Superheating Water Demonstration with a Vacuum

There are many Youtube videos which place a cup of water into a vacuum chamber and cause boiling around 0.020 atm, but I can't find any which show a vacuum-only "superheating" effect (to be clear, I ...
3
votes
1answer
725 views

Why does sound not travel between media?

So imagine you're at the beach; you go into the water and the moment you enter the water you stop hearing anything from the outside world. The same happens vice-versa: your friend shouts at you from ...
1
vote
1answer
87 views

What makes bathroom soap bars to crack during winter season?

Is there some relation between winter season and cracking of bathroom soaps? I noticed that , cracking happens only during winter season.I also learned earlier from physics stack that, During winter ...
0
votes
2answers
75 views

Why is water such a poor electromagnetic conductor? [closed]

1.-Why does salt water not conduct any form of non-visible light? 2.-Why does it conduct red light so much worse than other colours? (Why does it absorb red so much and not blue, for example). It's ...
2
votes
4answers
614 views

Better explanation of why an object floats: density? or buoyancy in equilibrium with object's weight?

Across StackExchange, you see two explanations for why an object floats: The buoyant force, equal to weight of displaced water, is in equilibrium with the object's weight. The density of the object ...
-1
votes
2answers
458 views

How long will it take to fill a bath tub with oil compared to water?

As everyone knows, the oil is more viscous than water. But, I've been wondering how long it will take to fill a bath tub compared to water. It is quite obvious that oil will take longer. But, how much ...
3
votes
3answers
3k views

Why is ice less dense than water?

The answers to this question explain that ice is less dense than water because it has a "crystal structure", but they dont explain what exactly that is and why this happens, also I saw this answer ...
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 ...
21
votes
3answers
25k views

Why does water pouring from a glass sometimes travel down the side of the glass?

If you have a glass of water, say, three quarters full and you pour it at an angle of say, $45^{\circ}$ with respect to the the table, the water comes out of the glass and goes directly down towards ...
2
votes
2answers
140 views

How does a rising bubble take a dome-like shape?

Since I have swam on the swim team for most of my life, I am very familiar with bubbles. I know a raindrop falling through the sky gets its shape because it is the most aerodynamic shape, but how come ...
0
votes
1answer
36 views

Hydrostatic pressure in a vase at different depths

I am building a water level sensing device on the base of Arduino. The sensor is the eTape by Milontech. The resistance changes almost linearly with depth as the sensor is immersed in liquid (...
9
votes
1answer
1k 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. ...
1
vote
0answers
11 views

Capillary bridge force function given volume and distance

Given two surfaces and a fluidic glue with sufficient adhesion, what is the force provided by the capillary bridge provided the cohesive properties of the glue, volume, and distance between the ...
1
vote
1answer
357 views

If I mix 1 unit of water at at 30C° with 1 unit of water at 60C°, is the resulting water at 45C°? [closed]

I'm curious how temperatures work when mixing water. I'm not very good at physics but I'm always learning. Let's say I've 1 gallon of water at 30C° and 1 gallon of water at 60C°, and I mix them ...
6
votes
4answers
3k views

Force of an impact on water

Today, at the Brazilian news, I heard that a men fell from a cruise into the sea, from a height of 50m, and decided to see if he could have survived. I took his weight for being 80kg. I did $V^2=V0^...
0
votes
0answers
54 views

Entropy changes of water

I have a few questions regarding entropy and water. Suppose you cool down water so that it freezes at $273.15K$. How is entropy positive in this case? I have a feeling it may have to do with the ...