Earth's atmosphere is a layer of gases that surround it, permitting life and protecting life by absorbing ultraviolet solar radiation, warming the surface by retaining the heat and mitigating the temperature difference between day and night.
Questions tagged [air]
749 questions
119
votes
4 answers
Why do clouds have well-defined boundaries?
Why do cumulus clouds have well defined boundaries? In other words, what are the physical mechanisms that hold a cloud together, as an entity separate from other clouds, that prevent it from spreading, etc.
Naively, one could expect the atmospheric…
Roger V.
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104
votes
12 answers
Why is filling a balloon from your mouth much harder initially?
Why is it that when you first fill up a balloon, it's hard to get air through, but after inflating it a bit, it becomes much easier to further inflate the balloon?
yuritsuki
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84
votes
1 answer
Why do chimneys have these spiral "wings"?
While walking around I noticed something very peculiar. Many chimneys had spiral "wings", while others didn't. I came up with two possibilities:
The wind circles around the chimney upwards which pushes whatever gases being released even higher into…
Adi
- 1,628
66
votes
6 answers
Why is jumping into water from high altitude fatal?
If I jump from an airplane straight positioned upright into the ocean, why is it the same as jumping straight on the ground?
Water is a liquid as opposed to the ground, so I would expect that by plunging straight in the water, I would enter it…
Conrad C
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62
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3 answers
How can a butterfly dodge the windshield of a fast moving car?
While driving, an unlucky butterfly was about to hit my windshield. But instead of splattering, it sort of glided smoothly upwards across the surface of my windshield. The butterfly was clearly not skillfully dodging the car because the required…
AlphaLife
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56
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4 answers
On a hot day, when it's cooler outside than in; is it better to put a fan in an open window pointing inwards or outwards?
If it's really hot inside, but cooler outside; what is the best way to place a single fan to try and cool a room down?
I always assumed it would be better pointing inwards (and this thread suggests the same).
However; today I had a thought - if the…
Danny Tuppeny
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54
votes
3 answers
Will helium in the tires of a bike make it lighter?
I know that helium balloons float because it is less dense than air. I'm not expecting my bike to float, although that would be pretty cool. I just wanna know if replacing normal air with helium in the tires will produce a noticeable effect on its…
masterwarrior123
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Why does the air we blow/exhale out from our mouths change from hot to cold depending on the size of the opening we make with our mouth?
Why does the air we blow/exhale out from our mouths change from hot to cold depending on the size of the opening we make with our mouth?
It's not just a subtle difference, but significant in my opinion. I'm inclined to discredit the notion that it's…
John
- 581
45
votes
11 answers
Why does moving air feel colder?
If temperature is just the average kinetic energy of particles, why would moving air feel colder rather than warmer?
BOUNCE
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44
votes
10 answers
Why can't we see gases?
I am not sure what causes gas molecules to be invisible.This question may look silly but I really want to know the story behind it.
Praveen Kadambari
- 1,663
43
votes
6 answers
How much air needs to be displaced to generate an audible sound?
I'm reading a book where in one scene a wizard/alchemist teleports a scroll after reading.
He folded the parchment carefully and muttered a single cantrip. The note vanished with a small plop of displaced air, joining the others in a safe…
npst
- 543
41
votes
5 answers
Why do heavier objects fall faster in air?
We all know that in an idealised world all objects accelerate at the same rate when dropped regardless of their mass. We also know that in reality (or more accurately, in air) a lead feather falls much faster than a duck's feather with exactly the…
Simd
- 1,151
40
votes
4 answers
Is this cheap "air conditioner" able to cool a room?
My parents bought this "air conditioner", but I am very skeptical that this can cool a room, or even cool anything.
I doubt that it even has a cooling element, I suspect that it is just a fan + humidifier.
But even if this device had a cooling…
SinOfficial
- 503
36
votes
7 answers
Is it possible to "cook" pasta at room temperature with low enough pressure?
It is known fact, that boiling point of water decreases by decreasing of pressure. So there is a pressure at which water boils at room temperature.
Would it be possible to cook e.g. pasta at room temperature in vacuum chamber with low enough…
Viliam
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36
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3 answers
If aerographite is lighter than air, why doesn't it float?
Air is 6 times denser than aerographite but looking at pictures or videos presenting the material, I see it resting on tables rather than raising to the ceiling.
Also, since the material is made of carbon nanotubes, I assume there are empty spaces…
Youcha
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