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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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 ...
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0answers
14 views
Water wave reflection angle in a circular container
In the picture shown below, the red line represents our water wave hitting the boundary of a container, whereas the green line represents the angle at which it is reflected.
I am curious whether the ...
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0answers
45 views
Moonlight reflection on ocean [duplicate]
I am trying to explain physically what is happening in the picture below:
My gut explanation is that we are observing the reflection of a cone of light emanating from the moon, it explains the form ...
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2answers
66 views
Density of ice < water?
In the situation of an ice cube placed in water and eventually melting, it is supposed that natural convection is the process in which heat transfer from water to ice occurs.
However, natural ...
6
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4answers
686 views
How does ice melt when immersed in water?
When an ice cube is immersed in water at a room temperature, how is the thermal energy from the water transferred to the ice cube?
Currently I have two answers:
Infrared radiation from the water ...
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0answers
24 views
Velocity of a leak in a cylindrical water tank that spins with constant angular velocity
We have a cylindrical water tank that spins over its axis of symmetry. Here's a diagram:
The objective is to find:
$1$ - The tangential and radial components of the velocity of the water as it ...
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1answer
38 views
Does light only mimic water waves, or also the properties of water?
Huygen's Principle compares diffraction to ripples in water. Do the similarities translate to surface tension? The hydrophobic effect?
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13 views
42kHz Mechanical Transducer Suggestion for Project [on hold]
I am having some difficulty obtaining a mechanical transducer for a project I am undertaking. Essentially I want to create a longitudinal standing wave in a cylindrical column of water with a ...
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2answers
45 views
Is there any reason to remove the air from a bottle of water before you freeze it?
When you put a sealed bottle of water in the freezer it explodes, (I get this part). I was told that filling it with 100% water (removing the air) first stops the bottle from exploding as this allows ...
14
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1answer
579 views
Does soap repel water?
Yesterday when I was taking my bath, I scratched my soap bar a bit and threw that bit on the shower floor. There was a little amount of water on the floor where that soap bit fell. To my surprise, I ...
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1answer
26 views
How does waterfall produces negative ions? Do rain do too?
I read that water molecule steal electron from oxygen molecule but the next sentences onward is talking about the benefit of negative ions for health, what is the cause of negative ion production in ...
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0answers
59 views
How long would it take for a cup of water to fully evaporate?
How long does it take for a cup of water to evaporate?
To answer this question, I'll assume some basic parameters, and that the water is blown on by a fan, to arrive at an estimate:
Water volume: $...
0
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1answer
80 views
Why microwave oven makes dried bread soft?
This is an old age trick: if you have some bread that became dried and you put it in the microwave few tens of seconds (10 to 30 for top results) you get a nice soft and warm loaf as if it just came ...
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0answers
29 views
Measure static pressure with measuring tubes of different diameter
Assume you have a horizontally placed cylindrical pipe with constant diameter. There is a flow of water, through this pipe. You want to measure the static pressure inside the tube, which should be the ...
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1answer
38 views
Water and Resonance
I want to confirm this, I’m not 100% sure on the subject and I’ve done a lot of research into this. Does water not only take the shape of the vessel it’s in but also the frequency and or resonance.
...
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1answer
48 views
Phase change in oceans
When ice cube melts in water the level of water doesn't change but when glaciers melts in oceans sea water level increases why?
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0answers
46 views
Do quantum effects play a role in the evaporation of water?
Imagine a thermodynamic system composed of a tumbler half-full of pure water, composed entirely of 1H and 16O. The system is isolated from extraneous influences by a perfect box impermeable to ...
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2answers
81 views
The maximum velocity of an object in water [closed]
Suppose we have the mass and volume of an object, like a sphere, with density less than water. We grab it under the water and leave it, so it will fly up to the surface. What will be the maximum ...
1
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1answer
39 views
Maximum density of water
The maximum density of water in its liquid form occurs at around 4°C (under normal pressure p = 1013,25 hPa). If the pressure is increased (or decreased) would the point of maximum density still be at ...
2
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1answer
48 views
Converting normal water into magnetic water [closed]
When I magnetize water by circular magnets of strength 0.8 T, how long will the magnetism be present in the water? I mean, how many days will it be in the water?
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0answers
19 views
Why sand in a water collects at center on rotating the water? [duplicate]
We commonly observe that on rotating dirty water, the dirt in water collects at the center. But why does it happens, and why does it not collect at edges due to centrifugal force. Does something ...
0
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1answer
48 views
Microwaves in other media
I saw a video on how microwaving grapes make plasma. He said that the refractive index of microwave is about 10 inside the grape. Now, we don't know the wavelength of the microwaves in the grape or ...
2
votes
2answers
96 views
Temperature change of water
Question:
If...
I have to identical vessels containing an equal volume of water.
I place them in a room with an ambient temperature of 20 C, at normal pressure, in a normal atmosphere.
I heat one ...
0
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1answer
40 views
Is light penetration through water affected by water pressure?
Does water pressure affect propagation of light through water?
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1answer
69 views
Is the triple point of water exactly 0.01 $\deg$C?
Is the triple point of water exactly $0.01 \deg$C, or is this an empirical value/is there some uncertainty to it? If so, how do we know it is exact, and why?
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2answers
38 views
What is role of nucleation centre in the formation of ice?
Water must be impure so that the impurities can act as nucleation centre for ice to form. What is role of nucleation centre? Why can not ice form with some nucleation centre?
About existing (and ...
2
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2answers
75 views
Temperature of items from a freezer [duplicate]
I've read that all items in a freezer are at the temperature at which the freezer are set to (obviously items have to be in the freezer long enough). So, if I put normal tap water in a freezer which ...
0
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2answers
100 views
Which one is better to boil water, using high heat or less heat?
Consider that I have a water boiling kettle as below. Assume that it is made of metal, not plastic (but plastic probably also will do). Assuming I can adjust the power it uses to boil the water with ...
8
votes
3answers
480 views
Why does sound behave differently in water than in air?
I noticed in some experiments at home that sound does not behave the same in water than in air. Is there a good scientific explanation to this?
I noticed that the sound sounded distorted in water but ...
0
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0answers
11 views
Why is water attracted by static electricity and not repelled? [duplicate]
As most of you will certainly know, when a statically charged object is put close to a stream of water, the stream of water bends towards the charged object.
Gathering information online, it seems ...
23
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4answers
2k views
Why do ice crystals form from the top to the bottom of a bottle filled with supercooled water?
If I bang a bottle filled with supercooled water against a hard surface, the ice crystals form from the top to the bottom:$\hspace{50px}$$\hspace{75px}$–source.
YouTube has videos showing this ...
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1answer
39 views
Is it possible to drain all oceans' water to space? [duplicate]
Assuming:
That I have an ideal straw (a very long pipe) from the ocean to space;
That the straw (pipe) is ideal (will not break);
That i can pump all the air from the pipe creating vacuum inside the ...
3
votes
1answer
37 views
Sound emitted by droplets hitting a liquid surface
when a liquid jet (e.g. water) hits a water surface sound may be produced if, due to Plateau Rayleigh instability, the water jet has formed into droplets.
But what exactly causes the sound? Is it the ...
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2answers
144 views
Is it possible to have a planet entirely made out of liquid water?
Earth is mostly covered in oceans, but they only go a few kilometres deep. It's obviously not possible to have a planet the size of the earth to be made entirely out of water, because of the kind of ...
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1answer
39 views
How can one the find normal force of a block resting on a pool floor underwater?
There is the force of gravity on the block, the atmosphere, the water pressure o top of the block, but how about between the block and the floor? Would we calculate water pressure pushing up from the ...
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2answers
53 views
Why does air get trapped below water pouring into a glass?
The drinking-water-tap at my workplace has a low pressure continuous stream of water. When I pour water into a glass which has at least about (depth) 5cm of water in it, surprisingly large air bubbles ...
1
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1answer
50 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 ...
2
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3answers
58 views
water pipes break when temperature goes down, how to estimate the energy involved?
Normally low temperature is associated with lower energy state and high temperature with higher energy state.
There is an apparent paradox when a water pipe breaks due to low temperature: when ...
0
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0answers
18 views
Is there any equation to calculate water vapor condensation?
Basically, I can to calculate the mass of water accumulated on a surface at a given time if the surface is exposed to Room temperature keeping its temperature let say -25 C.
Any help will be ...
0
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1answer
29 views
Charge density of sea water
If sea water contains salt ions and some H+ and OH- ions, what are the charge density of a certain volume of sea water? And is there a way to calculate?
2
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1answer
46 views
How do salt crystals evaporate in water?
Salt dissolves in water but when water has evaporated it is still there. What has happened
to the salt in the water and why is it still there when water has evaporated?
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1answer
39 views
Water / Air flow via thermal difference
This is a simple water/air flow thought experiment I had that I'd like to understand better... The basic idea is that you have a closed loop of water or air standing vertically. One side is heated to ...
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3answers
50 views
What am I doing wrong in electrolysis of water?
I am trying to two 1.5V battery in series to electrolysis a small bowl of tap water oversaturated with salt. But I can't see any bubble on the part submerged (circled on the photo). Could you guys ...
1
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1answer
23 views
Will water spill out of filled capillary tube, if raised from water?
if to raise a filled capillary tube from the level of water, will the inside will spill out? or will it keep stuck inside?
imagine a capillary tube put in water, the water rises inside the capillary ...
18
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4answers
2k views
Why are we able to see air bubbles under water?
Title is self explanatory.
I'm assuming both water and air are transparent.
So, if they are true, how can I clearly distinguish an air bubble under water?
82
votes
4answers
6k views
Why doesn't water actually perfectly wet glass?
According to many high school textbook sources, water perfectly wets glass. That is, the adhesion between water and glass is so strong that it is energetically favorable for a drop of water on glass ...
66
votes
3answers
6k views
Why does a lot of water vapour come suddenly after the heat source of boiling water is removed? [duplicate]
I have noticed this several times. When I am boiling water, a few seconds before its boiling point, vapours are formed as usual. But if I turn the gas off before boiling, the moment it turns off, I ...
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4answers
72 views
When is it more efficient to blow air over a wet laundry in order to dry it - when it's wetter or when it's drier?
If I want to speed the drying of laundry and allocate for it one hour of fanning - should I use it just after I hang it to dry or several hours later?
When we want to cool hot tea it's better to add ...
5
votes
1answer
51 views
Why does salt ions is not exist at vapor when the water is boiled and evaporated?
I would like to understand when the water is boiled only pure vapor is produced and ions do not exist with vapor. Why?
Can't the ions stick to water vapor?
And
Are Na+ and Cl- have boiling points? ...
2
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5answers
90 views
In thermal spas the temperature of steam is about $50^{\circ}C$, but feels way hotter. Why?
So when you're in hot water and start to move or something the steam feels really hot even though I read its temperature is about 50 degrees Celsius in thermal spas. So why does it feel that warm?
