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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2answers
217 views
What reflective media do laser shows use?
I am having a hard time in finding out what exact light media laser shows use. I am trying to build a laser show myself. I know that the laser light is reflected off these particles in such a way that ...
4
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3answers
1k views
Why does hot oil explode when pouring water on it?
I am puzzled to know, What is the reason of hot oil make sound and explode when we pouring water on it?
4
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5answers
546 views
What happens if you try to freeze water in an water tight container
If I have a container that is full of water and I attempt to freeze the water by freezing the container, what would happen if the container is strong enough to prevent the water expansion? Could the ...
4
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2answers
2k 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 ...
4
votes
2answers
73 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 ...
4
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2answers
420 views
Why does a slight drip of water protect pipes from freezing?
I've heard that turning on faucets to a slight drip will prevent pipes from freezing, but I've never understood why this is the case. Can anyone out there help me to understand? Thanks!
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 ...
4
votes
3answers
184 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 ...
4
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1answer
1k views
Why is there more steam after a pot of water *stops* boiling?
I have a pot of vigorously boiling water on a gas stove. There's some steam, but not alot. When I turn off the gas, the boiling immediately subsides, and a huge waft of steam comes out. This is ...
4
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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 ...
4
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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:
...
4
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2answers
2k views
Flow of liquid among branches
If water is flowing through big pipe is branched into 4 branches of small pipe. Lets say the flow is around 4 m/sec.
I have the following questions:
What will be the flow rate in each of the ...
4
votes
2answers
388 views
If you stop water from expanding, will its temperature stop rising?
Water expands when it heats up. If you heat water in a container that prevents it from expanding, will its temperature top out -- maybe around the boiling point?
And if not, will it still turn to ...
4
votes
1answer
266 views
How the bond angle of a water molecule is measured?
How the angle of a water molecule is measured?
The bond angle for water was first determined by vibrational and rotational analysis of its infrared absorption spectra. How is bond angle extracted?
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votes
1answer
737 views
How can I prevent drinking water from freezing in cold weather? [closed]
I'd like to keep a container of potable water in my car for when I get stuck, but in the winter it gets cold enough for bottled water to freeze.
I can't put salt in it, because then it won't be ...
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 ...
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 ...
4
votes
2answers
1k views
Why does earth look blue from outer space?
I know it's more than 70% water. But what has it got to do with earth's colour ?
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1answer
1k views
How cold does it need to be for spit to freeze before hitting the ground?
What is the dominant form of heat transfer between warm water and cold air?
If a $100 mg$ drop of water falls through $-40 C$ air, how quickly could it freeze?
Is it credible that in very cold ...
4
votes
1answer
164 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 ...
4
votes
3answers
244 views
Can anyone estimate what proportion of water remains after I flush a toilet?
Imagine I have a clean toilet with some amount of water in the bowl. When I flush the toilet much of that water will be displaced by the tank's water. I want to work out (or model really) what amount ...
4
votes
2answers
657 views
Is a given volume of sparkling water lighter or heavier than the same volume of still water?
I can see it two ways - if all the $CO_2$ has turned into bubbles I would imagine it is lighter. However dissolved $CO_2$ atoms are probably heaver than the $H_2O$ atoms they replace, or fit in ...
4
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1answer
221 views
How to estimate condensation from air?
How to estimate the amount of water condensing from air on a surface, given the air's temperature and relative humidity and how they change over time, the surface temperature, material's thermal ...
4
votes
0answers
131 views
How do I measure the temperature of a tiny water droplet?
How do I accurately (+/- 0.1 degrees Celsius or better) measure the temperature of a small (5 to 50 microliter) water droplet without noticeably affecting its temperature?
The mass of a thermistor or ...
3
votes
4answers
322 views
Withstanding charlatans: How to protect friends from buying “water structuring facilities”?
In my country it is a big business now, to sell "water structuring facilities". Promoters telling that after passing through them the water obtaining fantastic abilities basing on the fact that "water ...
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 ...
3
votes
2answers
805 views
How does the process of freezing water remove salt?
How does freezing water to make ice remove whatever salts were in the water to begin with?
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
4answers
1k views
Why the shape of rainbow is semicircular after rain why not the whole atmosphere is colorful?
I have a very simple question.
Everyone must have seen the rainbow after rain. According to the theory the rainbow is created due to the passing of sunlight from small drops of water in the ...
3
votes
1answer
159 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 ...
3
votes
2answers
249 views
Will the water added to an ice piece freeze?
Water, at room temperature is poured into a hole made of a block of melting ice(kept at room temperature).I was wondering if the water will ever freeze?
Thank you.
3
votes
1answer
65 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
3answers
255 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?
3
votes
4answers
400 views
Could hydrogen liberated from water provide lifting energy which exceeds the energy it took to liberate it from water
I was thinking about Hydrogen balloons and that large ones which are used for weather balloons which sometimes go up to 100,000 ft (approx 30km). Then I was wondering, how much potential energy has ...
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 ...
3
votes
2answers
149 views
Does a fluid's temperature affect the way light passes through it?
For example, if I were to supercool water would it's refractive index still be 1.33 or would it be 1.31, the same as water-based ice even though it's still in liquid form?
3
votes
1answer
166 views
Boiling when I plunge my french press?
Occasionally when I make coffee in my french press I experience something odd. It happens pretty infrequently but certainly enough to be curious about. I have the grounds ready in the carafe. The ...
3
votes
5answers
3k views
How to measure resistance of DI water
It is known that good DI water have resistance ~20 MΩ·cm
But how can I measure that? Using good vanilla ohmmeter (with 2000 MΩ range) showed crazy results (too low, not much dependent from distance ...
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 ...
3
votes
2answers
201 views
Why does it take until the middle of summer before lakes have warm water, but desert sand heats up in hours?
My sister asked me this question and I keep thinking that water would conduct heat much faster than sand. Hence the energy transfer of heat across the lake does not allow it to heat up soon. Sand on ...
3
votes
1answer
88 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 ...
3
votes
2answers
109 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 ...
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 ...
3
votes
1answer
177 views
Why is there a hiss sound when water falls on a hot surface?
Why is there a hiss sound when water falls on a hot surface? I have searched a lot, asked my teachers but none of them seem to give me the logical answer to it.
3
votes
1answer
222 views
Pascal law with two connected cylinders filled with water, and 50kg stones at both their ends
If I have two connected cylinders filled with water, and 50kg stones at both their ends (pressing both ends of the water) how much weight do I need to add on one side so that one of the stones reach ...
3
votes
1answer
428 views
Calculating time to heat cold water in bowl of hot water
How would I calculate the time it takes to heat a given volume of water to a given temperature with a given temperature T1 when it is submerged in a volume of water with a temperature T2
Estimation ...
3
votes
2answers
125 views
why water molecules in vapor contributes to the green house effect and water condensed in drops not?
I am a teacher planning a unit on climate change. I came across this statement: "Clouds are water vapor (green house gas) and water molecules will reflect heat into space… actually clouds are ...
3
votes
1answer
104 views
Experiment to find structure of water
Who first determined the structure of water (two hydrogen atoms stuck to an oxygen atom at approx 105 degrees), and, more importantly, how was this done?
3
votes
1answer
251 views
Tear drop shape
i heard that a tear drop shap is the most aerodynamic shape possible or the best is this true? If this isn't true what is since i need to make a fast ROV? Also since i need to have a propeller to ...
3
votes
1answer
186 views
Cause of sea ice freezing during an upwell event
One of the Episodes of BBC's documentary Frozen Planet describes an upwell phenomenon in the Antarctic Ocean. I am trying to understand the cause of seawater freezing when this upwell occurs.
Liquid ...
