Two Hydrogen atoms covalently bonded to one Oxygen atom. One of the more common compounds on the surface of the earth.
Questions tagged [water]
1959 questions
217
votes
1 answer
Strange ice found in my garden
This morning I found a really strange ice formation in my garden. I can't figure out how it appeared, because there was nothing above. The night was particularly cold (Belgium).
To give an idea, it has the size of a common mouse (5 cm of Height and…
snoob dogg
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203
votes
3 answers
Surviving under water in air bubble
An incredible news story today is about a man who survived for two days at the bottom of the sea (~30 m deep) in a capsized boat, in an air bubble that formed in a corner of the boat. He was eventually rescued by divers who came to retrieve dead…
Maxim Umansky
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146
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7 answers
Why doesn't water boil in the oven?
I put a pot of water in the oven at $\mathrm{500^\circ F}$ ($\mathrm{260^\circ C}$ , $\mathrm{533 K}$). Over time most of the water evaporated away but it never boiled. Why doesn't it boil?
Hovercouch
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109
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6 answers
Why is oil a better lubricant than water?
How come mineral oil is a better lubricant than water, even though water has a lower viscosity?
When two surfaces slide over each other with a gap filled with a fluid, the different layers of the fluid are dragged at different speeds. The very top…
DK2AX
- 4,860
100
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8 answers
Why does hot water clean better than cold water?
I had a left over coffee cup this morning, and I tried to wash it out. I realized I always instinctively use hot water to clean things, as it seems to work better.
A Google search showed that other people get similar results, but this Yahoo answer…
user-2147482637
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88
votes
4 answers
Why does rainwater form moving waves on the ground? Is there a name for this effect?
A while ago it was raining and I noticed that, on sloped pavement, water was flowing in very regular consistent periodic waves, as you see below.
However, I realized I had no idea why this should be happening. There was nothing uphill actually…
user541686
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86
votes
5 answers
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 to spread out and coat the entire surface.…
knzhou
- 107,105
81
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6 answers
Why does water stop boiling immediately after turning off the heat?
When I am heating water on a gas stove, it begins to boil after some time and bubbles of air can be seen escaping out.
However, as soon as I increase the amount of heat in the stove, the rate of escape of air bubbles increases immediately, and as…
Mrigank Pawagi
- 1,131
79
votes
1 answer
Why does soaking a fabric make it more transparent?
It's a well-known fact that when one soaks a thin piece of fabric, it will often become more transparent than it was before.
What is the reason behind this? I can't put glass behind the fabric and increase its transparency.
(Also, just in case this…
Isky Mathews
- 1,965
78
votes
9 answers
Why does ice melting not change the water level in a container?
I have read the explanation for this in several textbooks, but I am struggling to understand it via Archimedes' principle. If someone can clarify with a diagram or something so I can understand or a clear equation explanation that would be great.
stackseverywhere
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76
votes
4 answers
How does water evaporate if it doesn't boil?
When the sun is out after a rain, I can see what appears to be steam rising off a wooden bridge nearby. I'm pretty sure this is water turning into a gas.
However, I thought water had to reach 100 degrees C to be able to turn into a gas.
Is there an…
Malcolm Crum
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75
votes
5 answers
Why is water clear?
Water appears transparent to visible light, yet most other objects are opaque. Why is that? Is there an explanation why water appears transparent?
Is water transparent at all wavelengths, or are the visible wavelengths somehow special? If it is…
D.W.
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72
votes
7 answers
When I boil a kettle, what stops all the water from turning (exploding!) in to steam in one go once it reaches 100°C?
While making a cup of tea in the office kitchen, a colleague asked me this question and neither of us could answer with any certainty. We're guessing it has something to do with the pressure of the column of water, or temperature differences between…
Mark Hatton
- 809
71
votes
3 answers
Why does water falling slowly from a tap bend inwards?
This is something anyone could easily verify. When we open a tap slowly, water bends inwards (towards the axis) while maintaining its laminar flow. After a certain height below the opening, the flow becomes turbulent. I've approximately illustrated…
Vishnu
- 5,336
71
votes
3 answers
Why does a lot of water vapour come suddenly after the heat source of boiling water is removed?
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 see a lot of vapours being formed all of a sudden…
Abha Vishwakarma
- 741