Two Hydrogen atoms covalently bonded to one Oxygen atom. One of the more common compounds on the surface of the earth.
0
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1answer
109 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 ...
2
votes
1answer
264 views
At what temperature does water become a liquid on Mars? On the asteroids? And in a vacuum?
I know that I can just read off the phase diagram for water (for the surface atmospheric pressure on each object). But could there possibly be some nuances that someone might miss just from viewing ...
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?
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
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 ...
3
votes
2answers
306 views
Why water is not superfluid?
My question is in the title. I do not really understand why water is not a superfluid. Maybe I make a mistake but the fact that water is not suprfluid comes from the fact that the elementary ...
2
votes
2answers
228 views
Will the siphoning effect help a system pump water upwards if the water's entry and exit points are at the same height?
I am looking to pump water from a pool up to a roof for solar heating (black plastic tubing) and then back into the pool with the original source water. Does the gravitational force of the water ...
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 ...
3
votes
4answers
264 views
Water to ice expansion in $1\textrm{mm}^3$ pit - pressure on the pit walls?
[EDITED] by mistake, the subject was regarding 1m^3 instead of 1mm^3. There should be a significant difference between the two...
A 1x1x1mm pit filled with water is frozen at a slow rate (1K/minute). ...
1
vote
2answers
60 views
How to detect ice in thermostat
I think of making precise thermostat based on ice-water phase transition.
The idea is to keep 50% ice content, and monitor that instead of temperature.
I am thinking of monitoring dielectric ...
14
votes
1answer
318 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 ...
4
votes
2answers
72 views
Is there a good explanation for the observation of Martian canals?
Martian "canals" have been observed by independent observers after their first description. Now, they are attributed to "optical illusion", but I think that this is not a good choice of word, because ...
6
votes
1answer
672 views
How fast would someone have to run to run over water?
I was thinking about Flash, the superhero, or the little boy in the Incredibles.
There is one Yahoo answer that doesn't answer a lot. Especially, I don't think surface tension would help a lot for a ...
10
votes
1answer
212 views
Could there be a body of water the size of a planet?
My friend and I were reading the news of the discovery of a black hole spewing huge amounts of water vapor into space, and it got us thinking: could there be a blob of liquid water in space the size ...
4
votes
3answers
183 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
95 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 ...
5
votes
3answers
496 views
Is a water world possible, and for how long could it be stable?
I have several questions regarding this topic.
First, could a water world be stable for thousands of years with most of its surface remaining covered in water. What would it take for this to be ...
13
votes
3answers
328 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 ...
3
votes
4answers
179 views
Water Jet Cutter and Laser
I watched a video of "Glass cutting" which uses a Water Jet Cutter. It was said that Cutting glass simply by machines would eventually crack it... So, They're using grains of sand (by placing a sand ...
3
votes
2answers
3k views
Can pockets of air exist underwater?
If yes, why don't they fill up with water, and can you breathe the air there? Like, it's not exactly atmosphere there, but an underwater cave with higher ceiling.
P.S. Possible that it has a ...
1
vote
1answer
124 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 ...
8
votes
2answers
918 views
273 + degree Celsius = Kelvin. Why 273?
Temperature conversion:
273 + degree Celsius = Kelvin
Actually why is that 273? How does one come up with this?
My teacher mentioned Gann's law (not sure if this is the one) but I couldn't find ...
0
votes
1answer
81 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 ...
13
votes
1answer
245 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 ...
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.
23
votes
2answers
2k views
Before a once-warm lake starts to freeze, must its temperature be 4°C throughout at some point?
This is a problem I just started puzzling over, and I felt this would be a good forum to check my reasoning. So here are the relevant observations followed by my question:
Water achieves its maximum ...
4
votes
1answer
163 views
Can you measure the speed of water coming out of a hose by its arc?
Water comes out of a horizontally stationed hose and creates an arc as it heads towards the ground. Can I determine the speed the water was traveling in when it exited the hose by the measuring the ...
1
vote
2answers
635 views
How thin a filter to filter particles out of salt water to make salt for human consumption?
I have gathered some salt in the Death Valley and for the fun of it I would like to clean it and make it edible. The process I plan to follow is simple:
1) Dissolve the salt in water
2) Boil water ...
1
vote
1answer
215 views
Pump pressure required to fill water tower
I have a water pump at a distance of x meters from a water tower located h meters above the pump through a pipe with diameter d. I am not concerned with the exact value just want to make sure my pump ...
0
votes
2answers
137 views
Why laundry dry up also in cold/frost?
Why laundry dry up also in cold/frost? When you have frost, water in the clothes should freeze, but if clothes are dry, then it should be possible that steam in the clothes does not have time to ...
1
vote
0answers
53 views
Determining Water Level
Given a cylinder of a constant shape and size, how can the water level be calculated using the inside surface of the container?
For instance, could the inside lining of the container be a pressure ...
1
vote
1answer
95 views
boundary limit conditions in 3D water surface simulation
As is discused on this post, taking some assumptions, the water surface can be simulated by a discrete aproximation of a grid of heights using this formula
Where:
HT is the new height grid
HT-1 ...
4
votes
4answers
428 views
How far can water rise above the edge of a glass?
When you fill a glass with water, water forms a concave meniscus with constant contact angle $\theta$ (typically $\theta=20^\circ$ for tap water):
Once you reach the top of the glass, the water-air ...
10
votes
5answers
7k views
jumping into water
Two questions:
Assuming you dive head first or fall straight with your legs first, what is the maximal height you can jump into water from and not get hurt?
In other words, an H meter fall into ...
5
votes
1answer
150 views
Distinctive properties of liquids
The molecules are closely arranged in solids, loosely arranged in liquids and are free to move in gases... But, Why are liquids (especially water) exhibiting these distinctive properties such as ...
2
votes
1answer
74 views
DIfference in Pitch Caused by Water Temperature?
I have recently been intrigued by the following question: What is the difference between the pitch of the noise of dripping water between hot and cold water? For example, would cold water create a ...
2
votes
1answer
72 views
Can small clouds reflect enough light to hurt your eyes/blind you?
I looked out my window a minute ago and immediately noticed a very bright spot where a cloud and a jet/plane trail met. The spot was so bright that I thought the sun was behind it because it left that ...
3
votes
1answer
107 views
How would one calculate the amount of water contained in a cloud?
So I was looking out the sky one day and I wondered how I would go about calculating how much water was contained in a cloud. I figured the following simple outline
1) We need to roughly know how big ...
6
votes
3answers
2k views
Why does frozen water burst a pipe?
When water freezes in a pipe it can crack the pipe open. I assume this takes quite a lot of energy as when I try to crack a pipe it can be hard work!
I think water freezing is a result of energy ...
5
votes
1answer
54 views
Fresco in his “Future By Design” introduces drawing of underwater vessel and its front system of generating air bubbles. Is idea energy efficient?
I recently saw Fresco's Future By Design and noticed something miniature to investigate.
My notice regards about one of his illustration he describes in the documentary. Here is the link on youtube, ...
6
votes
1answer
331 views
Microwave oven + water: dielectric heating or ion drag?
When you place a water or food in a microwave oven, it heats.
Which process commits more energy to that: dielectric heating, or ion drag i.e. resistive heating?
AFAIK, in distilled water (which is a ...
1
vote
2answers
156 views
How does blow-drying a mirror keep it from steaming up again?
After a hot shower, the mirror in my bathroom steams up. When I try to clear it with a towel, it immediately refogs. Yet once I use my hair-dryer, it will clear the fog and the mirror will stay clear.
...
0
votes
1answer
122 views
What is the ion drag mechanism in dielectric heating?
While reading about dielectric heating on Wikipedia, I read about the ion drag mechanism but there wasn't enough information about.
I know there is another Phys.SE question talking about the ion drag ...
4
votes
1answer
126 views
What would jumping into a pool and feeling cold be called? Conduction, or convection?
This was another question from my son's workbook. It said:
...
3
votes
1answer
158 views
Does $\lambda\nu = c$ hold for all the waves in the universe?
Are all waves in the universe the same as electromagnetic waves?
Basically, my question arises from an equation I found in my chemistry textbook:
$$\lambda \nu ~=~ c.$$
This states that the ...
12
votes
4answers
2k views
Why are snowflakes symmetrical?
The title says it all. Why are snowflakes symmetrical in shape and not a mush of ice?
Is it a property of water freezing or what? Does anyone care to explain it to me? I'm intrigued by this and ...
0
votes
1answer
49 views
Action on Lard Oil
If water is mixed with lard oil and heated (creating some super-critical liquid with water), how does this affect the volatility of the mixture in comparison with its purity..?
So, My question is: ...
0
votes
1answer
430 views
Is water considered a substance with low friction or high friction?
Like, for example, rubber is a substance with high friction, as an object with neither high or low friction would easily stop on it, and wouldn't skid. Ice is considered an object with low friction, ...
0
votes
1answer
78 views
The Ultimate Hand Dryer
I have come across many hand dryers that attempt to dry your hands really fast after you wash them. Here are two of them:
XLERATOR
http://www.exceldryer.com/
Dyson Airblade
...
