# Questions tagged [water]

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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### Water moving up in a pot of soil

Assume I have a pot of dry soil. Now I add water to the bottom of the pot. What happens is that water will move up the soil. No more dry soil in the pot. I am not sure what precisely is going on here,...
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### Tracking down a citation for the dynamic viscosity of sea-water

I inherited some computer code that estimates the dynamic viscosity of sea-water from the water's temperature. The formula in the code uses is \mu = 2.414 \cdot 10^{-5} \cdot 10^{\frac{248.8}{T+133}...
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### When boiling water, why does the water level decrease?

When boiling water, the level of water decreases and will disappear after a while. I guess this has something to do with the condensation of water vapour into the visible white "steam" or "cloud". ...
107 views

### dVolume/dt= inflow-outflow and ∇⋅𝑣=0

First, I had to say I am very confused about fluid mechanics. Here is one question about continuity question. For the incompressible flow, and density is constant, we have the continuity equation ∇⋅ �...
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### Pressure of air in a cup

If I have a 1.0m long cylindrical cup, and fill it up to $h$ = 0.5m with water, then the 0.5m of air above it will be at atmospheric pressure. But if I now place a perfect seal on the cylinder, and ...
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### Fluidity: Convex or level

So I'm debunking a flat Earth article here and I came across a false proof stating that "If the Earth was round, fluids such as water would have a convex surface that matches the roundness of the ...
23 views

### How much air does it take to lift the seeds? [closed]

I have a vessel with seed and water in side. The is a total of 6100 Lbs. and water is 523.6 Gals. the bulk density of the seed is 178 Lbs/CuFt. The water seed mix is expected to be 8' above the ...
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### Size hole needed to make my water vortex work properly [closed]

Im making a water vortex for the front of my home. I've got an old plastic 6 gal water jug that im going to cut down to hold approximately 5 gallons. The water pump I have can pump up to 55 gal/hr. I ...
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### What if we throw many buckets of water into the Sun?

What will happen if we throw many buckets of water into the sun and keep repeating the process? Will it get cooler or hotter?
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### At what pressure will water boil at room temperature and why?

Is there a specific pressure that is needed to boil water at room temperature? If there is, what is it? Why does water boil at a low pressure at all?
275 views

### Moving an object underwater water - the effect of density

I have $2$ designs both moving an object through water. The standard design (design $1$) has the object with a density greater than water and so will sit on the floor of the chamber the object is ...
146 views

### Why is inverting a cup with water in it an example of the Rayleigh-Taylor instability?

Sorry if this is considered a duplicate, but I have further questions that are based on an old post. I was told that air pressure is strong enough to hold up water. Is this true? The vapour pressure ...
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### When we mix water with H$_2$SiF$_6$ and boil them, how much of the H$_2$SiF$_6$ evaporates?

If water evaporates also at temperatures much lower then its boiling point, and so do, I believe, other liquids, how much H$_2$SiF$_6$ (boiling temp. 108 C) is to be found in the steam over boiling ...
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### Supercritical Water

I was trying to find out what would happen to Supercritical Water (3200psi/374C) if the pressure was suddenly reduced to 1 atm (14.7 psi). [EDIT: My actual plan is to reduce it to 2000psi]. My guess ...
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### What is causing the repeated creation and destruction of bubbles in boiling starchy water?

A while ago I was cooking rice, and I noticed a recurring pattern of creation and destruction of bubbles. It seemed like the bubble-layer would increase in height, until it 'popped', and the layer ...
955 views

### How fast can water from a lake be frozen?

Warning: this question contains spoilers for the first episode of 2018 TV series Lost in Space by Netflix. On the series, the Robinsons spaceship, Jupiter, falls on a planet, and it’s submerged in ...
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### What is the enviroment in which water will come out of an ice fishing hole?

I have watched some videos on YouTube of people cutting holes in ice and water not just finding equilibrium in the hole, but water actually coming out of the hole along with many fish. There has to be ...
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### Where does the energy of the expansion of frozen water come from?

As you cool a system, you are removing energy, yet as water transitions to a solid, it expands, exerting sufficient force to rip through metal, for example in residential copper water pipes that ...
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### Human body water storage effects on weather patterns

There are 7.614 billion humans and counting. On average a human being consists of 60% water. With that water being locked away from natural circulation for an average of 80 years. Are there any ...
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### Why can't we stand on fluid surface if newton's third law is applicable [duplicate]

I try to stand on water surface but I just drown. A book resting on the table because of the W(gravitational Force) and normal force of the table acting on the book oppositely in equal magnitude ...
162 views

### Can water boil at 100% absolute humidity?

The definition of absolute humidity is the amount of water that can exist in solution with air as a gas. My question is, in a closed vessel that contains a flask and a burner or heat source below it ...
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### Is it easier to lift an object in air rather than in vacuum?

I was reading about why lifting an object in water is easier then in air. The explanation goes on the line that the water which was above the object will fall downward and sideways, taking the place ...
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### Could H2O have a 4th phase rather than 3? [closed]

I just finished a book which is hard to argue: "The Fourth Phase of Water" by Dr. Gerald H Pollack. He states there's a negative layer of H2O (which is termed the 'Exclusion Zone') which develops all ...
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### Why does a near UV laser show as a green path in tap water?

i am using a 405nm laser and shining through a glass with regular tap water, also i noticed that it shows as an almost white path in the thick glass bottom, what causes this?
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### How would a fixed triple point of water cell respond if the pressure was raised with additional (liquid) water?

May be a basic question, but I'm a technician, not a physicist (or physics student.) I came across triple point cells in some research on practical thermometer calibration, and I'm having a hard time ...
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### Wood vs static Water

First of all: I'am not a physicist or anything close to it. I jhust enjoy to think about certain thinks in a different way and to ask for a much more detailed "how". So here is what keeps me from ...
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### Force of Body Impact Upon Water

So in 2014 I fell from 70 feet and landed flat on my back on slowly moving water (.5ft/sec) on the Willamette River. I weighed aproximately 190 pounds at the time. I was curious if someone would help ...
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### Calculating the rate of pressure increase in a water-filled boiler

I'm trying to think about how fast the rate of pressure will increase in an idealized boiler filled with water starting at 100°C, standard pressure, and supplied with 1000W of power. I'm assuming a ...
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### Why does water splash up?

I’ve noticed occasionally whenever I start to put down a glass of water quickly it splashed up, even without it making contact with the desk. And another example is when I have the faucet running ...
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### What happens when you put water under intense pressure?

Pretend you have an indestructible tube that cannot leak, inside which is water. Imagine that in each side of the tube, you have very powerful pistons What would happen if you compress the water ...
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### Final temperature of ice and water [closed]

My answer doesn't seem likely but I can't see where I've gone wrong: Q: Ice of mass 0.125kg at -5 degrees is added to water of mass 0.25kg at 8 degrees. Calculate the final temperature of the water ...
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### Condensation of water

So I was wondering why does condensation occur at the molecular level. I can understand evaporation as the external atmospheric pressure being less than the vapor pressure ( energy of the water ...
1k views

### Refraction: Swimming goggles, short-sightedness, and underwater vision

I have thought of this question due to personal experience. I am short-sighted, and over the last three years my short-sightedness has worsened. Taking a lifeguard certificate again now that I did ...
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### Can I suck water out of a full bottle?

If i have a bottle full of water (there's no air in the bottle) with a straw in it and the bottle is sealed completely without any opening except the straw, will i be able to suck water out of the the ...
1k views

### Is water really $H_2O$? On a comment concerning the quantum mechanical description of water made by Hilary Putnam [closed]

I wanted to pose a question here (also posted to r/physics a bit earlier) and was hoping the you all might be able to help. I was re-reading a book by the philosopher Hilary Putnam titled Naturalism, ...
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### Water pressure depth vacuum?

Recently I saw an article describing Static Fluid Pressure which says "The pressure exerted by a static fluid depends only upon the depth of the fluid, the density of the fluid, and the acceleration ...
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### Airplane trails

Some airplanes leave a trail through some regions of sky. This post explains why it is so, but it seems not enough. The trail is said to be made mostly of water which, on a specific altitude, ...
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### Do sound waves in the ocean reflect off the surface at 90 deg incidence?

Let's say you have a sound source, in the ocean, at a frequency around 50 kHz. It's a point source, so the sound waves emanate in all directions. Some will go straight up. Do these straight up sound ...
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### Do water waves moving from deep water to shallow water always have higher amplitude?

I've seen many images like the following one that the height (amplitude) increases as the water becomes shallower. However, I also found some images showing that the amplitude remains unchanged. So ...
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### Strange ice found in my garden

This morning I found a really strange ice formation in my garden. I can't figure out how it appeared, because there was nothing above. The night was particularly cold (Belgium). To give an idea, it ...
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### Ice floating on water [duplicate]

Why is the hydrogen bond different from other bonds that allows ice to float in water rather tan sink. I don't want the math. I want the reason that bond is different than the rest. Why, not how.
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### Whose electric energy consumption 'copper' or 'aluminium' element in Water heater will be greater?

Considering water of 20 litres 25 degree celsius of temperature needs to be raised. Using the heat equation q=mcpdt considering cp of water to be 4.2 kJ/kgk we get q=2100 kJ which equals 2100000 J. It ...
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### Theoretical vs Experimental flow rate of fluid coming out of a water bottle with a hole in it

Say there is a water bottle that is filled with 300 mL of water and has a circular hole with a radius of 2 mm. In this bottle, the water sits 7.8cm above the top of the hole (which has been drilled 1....
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### What is the difference between vapour and steam?

What is the difference between vapour and steam? These two terms seemingly are similar but have different meanings. trying to define these two gets us a similar definition which is not actually true I ...
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### Why can I touch hot things longer with water on hands?

So I have done a couple of personal experiments with water on my hands. One day I was taking bread (rolls to be exact) out of the oven with my bare hands and burned my hands when my hands were dry. ...
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### Does air have to be oversaturated in order to make resublimation possible?

I am writing a pre-scientific work about the chemtrail conspiracy theory. A part of that is the exact process of contrail formation. There is one more puzzle piece missing. Hopefully the answer to ...
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### Determining friction force while stirring water

So I researched a bit on this, and found a video which showed an experiment in which he boiled the water, just by pouring it into a high-speed blender and stirring it. Can someone tell me how can I ...
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### 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 ...
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### How realistic is it to dry clothes in freezing weather?

There are stories about clothes freezing and drying in cold weather. The typical reason given for that is that the water is undergoing sublimation (ice -> vapor). The phase diagram for water is In ...
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### Dependency of $\mathrm{H_2O}$ surface tension on vapour pressure

How is does the surface tension between: liquid water, and humid air depend on $\mathrm{H_2O}$ partial pressure in the air, and temperature? Edit: I assume that temperature and humidity will both ...