Two Hydrogen atoms covalently bonded to one Oxygen atom. One of the more common compounds on the surface of the earth.
-1
votes
1answer
38 views
Producing Ice with water in vacuum [closed]
Do you think producing ice in large volumes is possible using this method? - say 500 kilograms a day?
How much vacuum should the pump's capacity be to make that happen at sea level?
Can it happen in ...
2
votes
2answers
70 views
Why is it faster (as in proportion to volume) to boil 4 cups of water than to boil 2 cups?
I did an experiment where I boiled two cups (500ml) of water in a kettle, and it took 1:30 minutes to reach around 98 C, average. However, when I boiled 4 cups of water, (1L) it only took me 2:30 ...
2
votes
4answers
118 views
Can a diver swim a short distance in great depths without being physically crushed by the pressure?
I recently saw "The Abyss".
Does it make sense that they do dives in these depths (700m) with soft suits?
Also - what is all the depressurization talk about? Why do divers need to depressurize long ...
1
vote
1answer
76 views
Does brown but transparent swimming pool water heat significantly faster than western style highly chlorinated pools?
Eastern European swimming pools are often brown tinted water. i was told it was the color of the chemical to keep the pools clean, but who knows. These pools did not smell unsanitary and may have even ...
2
votes
0answers
19 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 ...
0
votes
1answer
47 views
Absorption of Water
I was just watching the videos Chris Hadfield put on youtube from space, and was wondering why water doesn't get absorbed as well onto his toothbrush in space?
And what characteristic of ...
2
votes
0answers
41 views
Finding Surface Tension of water at certain Temperature and Pressure
So 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.
...
0
votes
1answer
49 views
Calculating the coefficient of thermal expansion in liquid
I am trying to write a matlab function that calculates the coefficient of thermal expansion of water from a given temperature. From what I understand the thermal expansion coefficient is calculated as ...
0
votes
0answers
23 views
Formula to calculate the density of satuared steam
I need to calculate (or look-up?) the density for saturated steam in a range of 8-12 bar. Is there a formula for this? It's ok if it's not perfectly exact.
-1
votes
0answers
102 views
When can a body of water glow in space?
How would superionic water be formed at the core of a giant water planet? The publication
Giant planets may host superionic water, E. Marris, Nature News, 22 March 2005,
states that water in ...
0
votes
0answers
52 views
Water evaporation
It is known that molecules at the surface are strongly attached to each other (more attraction less repulsion) than those within the bulk attraction and repulsion are balanced). This is the molecular ...
0
votes
1answer
57 views
Time constant of ice melt
I'm familiar with problems of "how much ice can you melt given some amount of energy", but I'm writing to get some clarification on the time constant of this event. This question might be somewhat ...
6
votes
4answers
240 views
Why is the water on the surface of the Earth?
What makes the water stay on the surface? Why the earth does not absorb the water in it?
0
votes
1answer
65 views
Does electrically heated water have an adverse effect on hair?
I know I should have asked this question on a different site. but this was the most suitable site available right now for my question. Perhaps after this proposed site goes on Beta, we can move it ...
3
votes
1answer
66 views
Does tapping at the side of a bottle prevent shaken soda from bubbling over?
Anecdotal evidence has it that a bottle of soda that was heavily shaken will not bubble over if tapped at the side multiple times.
Yet I wonder: Has the tapping really any effect? Or could it be that ...
3
votes
1answer
81 views
How to create visible reflections in shallow water?
Assumption: The only lights I have are candle, table lamp, and sunlight.
What would I need to create visible reflection of an object in the shallow water contained in a 5 liter bucket? Is it even ...
5
votes
2answers
214 views
What is the largest sphere of liquid water that could exist in space held together under it's own gravity? [duplicate]
What is the largest theoretical sphere of liquid water that could exist in space held together under it's own gravity? I've always wondered if a planet the size of earth could exist as a single volume ...
3
votes
1answer
90 views
Make water droplets charged?
Normally water molecules are electrically neutral.
But I have seen somewhere ideas about electric energy generators mentioning that water droplets might be used in some applications as they are ...
6
votes
2answers
148 views
Why water in the sink follow a curved path?
When you fill the sink with water and then allow the water to be drained, the water forms a vortex.. And then it starts to follow a curved path downwards by effects of gravity..
Why this phenomena ...
4
votes
3answers
113 views
Is it easier to pump water up or down?
I'm trying to gauge the strength of aquarium air pumps, for use in a vertical hydroponic farm. A curious question arose: is it easier to pump water upwards vertically, or is it easier to pump it ...
1
vote
2answers
153 views
Freezing point of water with respect to pressure.
I know when the pressure is reduced, the boiling point of water is reduced as well. But how does the pressure affect the freezing point of water ?
In a low pressure environment is the freezing point ...
0
votes
2answers
91 views
Pascal's law: pressure of fluid at different locations
I know that's stupid question, but I'm really confused what my teachers says, so I need to check that theory.
Here are just two ordinary connected containers, which are full of water.
On grounds ...
1
vote
1answer
86 views
A water balloon in vacuum: does it boil?
If I put water in a vacuum it will boil. But what if I put this water inside a balloon ?
I searched for answers and fount this video: http://www.youtube.com/watch?v=9q8F3ClUuV0
It seams that the ...
7
votes
1answer
109 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. ...
-2
votes
3answers
131 views
Water excitation with sine waves
I saw that video when they connected a water hose to a speaker emitting 24 hz sine wave, and its illusion on the shape of the follow going out of the hose (because the video capture rate is fixed at ...
1
vote
2answers
91 views
How long will a water drop exist until it evaporates based on ambient conditions?
How long will a water drop exist until it evaporates based on ambient conditions? I am looking for a simple equation or table that would tell me how long a water drop may exist until it evaporates ...
4
votes
2answers
106 views
Best shape to reduce the splash of a droplet?
Our coffee machine catches the last couple of droplets, after your cup is removed on a shape to reduce plash of the coffee droplets.
These shapes are placed inside the spill reservoir.
The shape ...
-1
votes
1answer
92 views
Sensible heat question (solving for temperature)
If $55 034.175 \rm{kJ }$ of heat are transferred to $150 \rm{kg}$ of ice at a temperature of $-12.15 ^\circ \rm{C}$, calculate the temperature of the resulting water.
Using $Q = mc(t_2-t_1)$ or ...
3
votes
3answers
265 views
How can my water cool down more quickly?
I have a cup and I can only pour hot water inside, I wanna know whether the heat will dissipate more quickly with more water or less water?
How about the occasion when my cup is well covered?
0
votes
1answer
650 views
Thermal expansion coefficient of water
I am working through the methods section of the following paper: Spatial-temporal variability in surface layer deepening and lateral advection in an embayment of Lake Victoria, East Africa
In the ...
3
votes
2answers
110 views
Pumping water from a closed column. Will the column get empty or just circualte?
As a picture is worth a thousand words, here is my problem:
It is a closed water column with a bit of air in the top section.
If I run the pump and make the water flow from IN to OUT,
Will the ...
40
votes
3answers
1k views
What causes insects to cast large shadows from where their feet are?
I recently stumbled upon this interesting image of a wasp, floating on water:
Assuming this isn't photoshopped, I have a couple of questions:
Why do you see its image like that (what's the ...
2
votes
2answers
102 views
How much better is salt water at letting through microwaves than pure water?
Radio Wave Attenuation
There are two general types of matter (substances) in the universe
that affect electromagnetic waves, conductors and insulators which
are called dielectrics by ...
1
vote
1answer
132 views
How fast does water fall in the middle of a very very thick waterfall?
Let me create a very artificial experimental set up. Take a bathtub the size of Delaware and suspend it a mile above the ground. Fill it with water (though I'm not sure to what depth - and it might ...
2
votes
2answers
132 views
Changes in Water Bonding Angle
I heard something recently in a casual discussion, but have yet to be able to confirm it: is there any evidence that the bonding angle for a water molecule, currently defined as 104.5, has been either ...
0
votes
1answer
113 views
Temperature Vs. Volume of Water
Here and here it states that water is at its highest density around $4^\circ$ Celsius. I know very little physics and a Google search has left me without an answer. I am teaching an ODE class in the ...
1
vote
1answer
99 views
Does increasing the density of a solution decrease the rate of temperature change?
I did an experiment to compare whether salt water (5% concentration of salt) or fresh water of the same volume took longer to heat up to a certain temperature. We found that salt water took longer to ...
0
votes
1answer
36 views
Depends river stream on river level?
If we have referral particle in the middle of the river, will it's velocity increse with higher river level?
4
votes
1answer
75 views
Ways to create controlled small bubbles in water within plastic tubing
What is a practical way in an engineering or physics laboratory to create bubbles of a specified size in water within plastic tubing? The tubing is a few mm inner diameter. We'd like to make bubbles ...
2
votes
0answers
43 views
How does a snowflake “know” to form symmetrically? [duplicate]
Possible Duplicate:
Why are snowflakes symmetrical?
Under ideal situations, a snowflake forms into near perfect hexagonal symmetry. How? For instance, when a water molecule moves towards ...
14
votes
1answer
326 views
Is there some way to narrow down the Leidenfrost point for water?
Cooks sometimes use the Leidenfrost effect to estimate the temperature of a frying pan by flicking a few drops of water onto the heated pan. I had no idea, before looking into this, that this could be ...
2
votes
3answers
113 views
Why is there more steam when water is subject to less fire?
When I cook things, such as scallop and salmon, I found that the food may be more tender if I wait till the water boils (at 100 C) and immediately turn the fire lower so that the water is not bubbling ...
4
votes
3answers
186 views
How can I keep a smaller water reservoir's water level at half available when being fed from a larger reservoir? [closed]
I'm trying to create my own ultrasonic humidifier. I ordered the misting part which works great but it only functions correctly in shallow water. So I'd like to feed from a large water reservoir to a ...
6
votes
1answer
98 views
How to model the form of a surface water wave?
Normal surface water waves, as generated by wind, do not have sine form but wave peak is higher and shorter than wave trough with different wave steepness. What parameters characterize such a surface ...
13
votes
3answers
330 views
Why don't I feel pressure on my body when swimming under water?
If I put a couple of lead bricks on my foot, there would be a definite sensation of a heavy, perhaps even painful, force. Calculating the pressure for $20 kg$ of lead over a $100 cm^2$ area of my ...
1
vote
1answer
128 views
How to find out the maximum radius of a hole that can keep water stay in a container by water viscosity?
Assume I have a inverse cone which holds 200ml water. I am going to cut the tip of the cone to create a small hole. How to calculate the maximum radius of the hole that the water will still stay in ...
0
votes
1answer
82 views
Measure maximum volume of liquid of a water tap
I need to know the consumption of a water tap in Liters.
I'm able to know the cross-sectional area of the pipe and how long the tap is open. With these data, how can I know the consumption/volume of ...
1
vote
0answers
54 views
Why do power lines buzz more when it is low-humidity outside?
I have observed that the power lines buzz louder when there is less moisture in the air.
Why is this?
If it will help the lines are located on the foot hills of a nearby mountain.
13
votes
1answer
246 views
Why is boiling water the second time more quiet than boiling it the first time?
First of all: This is a different question than Why is boiling water loud, then quiet?, although the answers might be similar.
When I wake up, I boil some water for a cup of tea. It happens quite ...
0
votes
1answer
89 views
Limescale formation at room temperature?
There is a large metal container in form of a cube made of stainless steel. It is used for storing water in it for technical uses. The problem is that all joints at the bottom of the container have ...
