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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Why do crystals grow in preferred directions?

I want to know why snowflakes (and other crystals) grow symmetrically and I find the leading answer to the established question to be entirely unsatisfactory. When water freezes, you get ice. ...
12
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3answers
238 views

Crown shape in water waves?

Watching this slow motion video of waves caused by a droplet falling on water, I am puzzled by the first wave shape. The first wave rises with circular symmetry as I expected, but is not even in ...
12
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1answer
141 views

Why does water appear still near the shore

Often when there's a light wind I notice this behaviour on lakes that there appears to be a very distinct line between the water with waves and the calm water. I don't know how well it comes through ...
11
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4answers
36k views

Why does ice have a lower density than water?

Can someone explain me why is ice less dense than water? As I know, all solids are usually denser than the liquids (correct me if I am wrong).
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4answers
21k views

Why does adding solutes to pure water lower the the specific heat?

We found that water with salt, sugar, or baking soda dissolved in it cools faster than pure water. Water has a very high specific heat; how do these solutes lower it? We heated a beaker (300ml) of ...
11
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2answers
7k views

Is there a way to fill Tank 2 from Tank 1 through Gravity alone?

I am a newbie in water system design but I am currently faced with the exact situation below on my land, and I need to know whether gravity alone is sufficient in order to fill Tank 2 from Tank 1, as ...
11
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3answers
162 views

Why is the splash of water always vertical, no matter in which angle the gunfire hits the surface

When gunfire hits the surface of a pond, the water seems to always splash directly upwards, in 90° to the surface of the water, no matter at which angle the gun is fired. The angle is usually very ...
11
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1answer
3k views

Why does water flow out of an upside-down bottle? (Rayleigh Taylor Instability)

I am currently reading the excellent book An Indispensable Truth: How Fusion Power Can Save the Planet by Francis F. Chen and I came across this explanation. The Rayleigh–Taylor Instability ...
10
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1answer
445 views

Sandstone getting soaked with water

I have seen someone putting a sandstone in water. With only about 10% of the stone sitting in the water. One could see the stone getting soaked with water. So there must be a force, which lets the ...
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3answers
4k views

How fast does an ice cube melt in a microwave?

I have noticed that when I microwave an ice cube it appears to melt more slowly than I would expect. For example, an equal volume of water starting at 0 deg C would probably be at boiling point before ...
10
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2answers
8k 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 ...
10
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2answers
337 views

Can cannonballs go through water?

In the recent Spielberg/Jackson Tintin movie, there is a scene where Red Rackham and Captain Haddock's ships are fighting, and cannons are fired. The cannonball is shown at one point to go through a ...
10
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1answer
382 views

Phase transition water

The water-gas phase transition is said to be similar to the ferromagnetic-paramagnetic phase transition (same set of critical exponents = same universality class). In the former case the order ...
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4answers
2k views

A cup of water in ZERO gravity

What will happen if I try to pour a cup of water in zero gravity, into another empty cup? Will the water come out of the cup? The adhesive force between the water molecules and the interior of the cup ...
9
votes
5answers
13k 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 ...
9
votes
1answer
706 views

Why is ice more reflective than liquid water?

Why is ice more reflective (has higher albedo) than liquid water? They're both the same substance (water). Is something quantum mechanical involved?
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2answers
1k views

Why does the water in the toilet move around so much on stormy days?

On calm days, the water in the toilet looks completely still. But when it's rainy and windy out, the water looks like it moves and pulsates. Why is this?
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2answers
349 views

Water evaporation problem. Exercise from Feynman's lectures

I read lectures of Richard Feynman and try to solve problems and I have some trouble with a problem on water evaporation. A glass full of water is left standing on an average outdoor window in ...
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8answers
19k views

Why does hot oil explode when pouring water on it?

What is the reason that hot oil makes sound and explodes when water is poured on it?
8
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5answers
5k views

Why does water make a sound when it is disturbed?

When I disturb a body of water, what causes the familiar "water moving" sound?
8
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2answers
626 views

Why things get dry (meaning from water)? [duplicate]

When I leave wet clothes in the open air, they will get dry over time by themselves even at room temperature. I know that somehow the water becomes vaporized; it's not "disappearing". For that, it ...
8
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5answers
4k views

Are water waves (i.e. on the surface of the ocean) longitudinal or transverse?

I'm convinced that water waves for example: are a combination of longitudinal and transverse. Any references or proofs of this or otherwise?
8
votes
2answers
646 views

Why is the absolute zero a rational number in Celcius?

From the question "Why is the absolute zero -273.15ºC?" I understood that 1°C is the 100th part of the difference of melting and boiling temperature of water (this is my high school physics, ...
8
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3answers
11k views

Why does the water level equalize in a series of tubes?

Say I have a series of tubes (not the internet) looking like this, where w represents water: ...
8
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1answer
2k views

Water in a vacuum sealed jar?

I recently purchased a Vacmaster VP215C chamber sealer, and have noticed that when I place a small container of water into the chamber, and pull a vacuum for just over 25 seconds, the water begins to ...
8
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2answers
468 views

Why does the gas cloud of an underwater gunshot pulse?

I have been watching some slow motion video and I was intrigued by the slow motion underwater gunshot. The first moments of the video go as expected. The gun fires and a cloud forms in front of the ...
8
votes
4answers
967 views

Hot water freezing faster than cold water

This question has puzzled me for a long time. There is already a question like this on Physics.SE. John's answer to the question seems quite satisfying. But when I googled the cause I found this and ...
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3answers
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Why did my frozen water bottle explode when I opened it after it defrosted a bit?

Last night I filled a 20 fl oz bottle (http://www.thenibble.com/reviews/main/beverages/soft-drinks/boylans-mash.asp) with lukewarm water from my tap. I filled the bottle pretty much to the brim, ...
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1answer
2k views

water flow in a sink

When one turns on the tap in the kitchen, a circle is observable in the water flowing in the sink. The circle is the boundary between laminar and turbulent flow of the water (maybe this is the wrong ...
8
votes
2answers
908 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 ...
8
votes
2answers
654 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 ...
8
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1answer
235 views

Evaporating water in -30ºC

I don't really know anything about physics even though I pretended studying it for years. How is this explained?: ...
8
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1answer
1k 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. ...
8
votes
5answers
873 views

What can wavy patterned sand tell about the Fluid that formed it?

Sand on the bottom of the ocean as well as sand on the low-tide beach often forms wavy patterns. Do the parameters of these wavy patterns have any relation to the water and waves that formed them? If ...
8
votes
3answers
1k 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.
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1answer
1k views

How to turn water opaque by pouring the smallest quantity of matter into it? [closed]

Consider a glass of water and a glass of coffee. Their contents differ by no more than a few grams of particles coming from the roasted and ground coffee, yet the former lets almost all visible light ...
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5answers
1k views

Zigzag flow of water along a vertical glass window

I've observed this behavior many times. When it rains, the rainwater will form vertical channels along a glass window. The flow of water is mostly confined within these vertical channels and the ...
7
votes
4answers
7k views

Eyes open under water

Yesterday I looked underwater with my eyes open (and no goggles) and I realized I can't see anything clearly. Everything looks very, very blurry. My guess is that the eye needs direct contact with air ...
7
votes
5answers
2k 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 ...
7
votes
2answers
2k views

Do all liquids boil in a vacuum?

Water boils at positive temperatures when put into a vacuum. Is this the case with all liquids, e.g. mercury?
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4answers
3k views

Sauna thermodynamics

Why does it get hotter (feel hotter) in a sauna when one pours water over the hot stones? Wikipedia says that the water condenses onto the skin, but the actual air humidity is so low that I doubt ...
7
votes
2answers
2k views

Does Uchimizu (watering streets in summer) help reduce temperature in an area?

It appears that in Japan, there is an old custom called Uchimizu. The name is a combination of words "road" and "water". The essence of it is moisturizing small parts of populated areas like ...
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5answers
2k views

Why the water remains on the surface of the Earth?

What makes the water stay on the surface? Why the earth does not absorb the water in it?
7
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2answers
2k 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!
7
votes
3answers
3k views

How does a canvas water bag cool water?

I was reading about this water bottle by Botl that behaves like a canvas water bags to keep water cool. I found out that this idea is an old idea and cars would drive with water bags in front as shown ...
7
votes
1answer
1k views

Why when I put a teabag into microwaved water does the water fizz? [duplicate]

When I am in a rush, I will heat up water in a cup in the microwave for tea. I usually put the cup on high for 2 mins. When I put the teabag in, the water starts to fizz almost like it is ...
7
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2answers
176 views

Flying eggshells

This question was asked on Judaism.StackExchange a few days ago, but I think it has a better chance of being answered here. Disregarding the grammatical discussion in the comments on that ...
7
votes
1answer
14k 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 ...
7
votes
4answers
4k views

Effect of water pressure on sinking objects

As I understand, water pressure increases as we go towards bottom of the ocean. So if an object* is thrown into water and it starts sinking with some speed, does the sinking object's acceleration ...
7
votes
1answer
239 views

Why water wont leak out in this case? (Picture provided)

just curious why the water in the aquarium tank would not leak out as shown in the picture provided below? The question is in the red circle. The water level in the aquarium tank is definitely higher ...