Force per unit area.

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8
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4answers
2k views

Water pressure in free fall

The increasing water pressure as you go deeper is generally explained in terms of the weight of the water column above the observation point pressing down. The question, then, is what would happen if ...
8
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5answers
8k views

Why will crushing a partially empty 2-liter bottle keep the soda more fizzy?

One of the curses of 2-liter bottles is that when carbonated beverages are stored in them for long periods (i.e. days between drinks) at least the last liter ends up being flat. However, if after ...
7
votes
5answers
985 views

What would ACTUALLY happen to a person jettisoned into space?

[insert obligatory statement of my lack of knowledge in physics] Alright, so we have all seen the movies where someone gets blasted out of the airlock on their starship, or their suit decompresses ...
5
votes
3answers
675 views

Why is Avogadro's hypothesis true?

Why is the number of molecules in a standard volume of gas at a standard temperature and pressure a constant, regardless of the molecule's composition or weight? Let's say I have a closed box full of ...
5
votes
3answers
307 views

Will an air-filled tire normally gravitate toward being nitrogen-filled just by refilling with air?

A big argument by the nitrogen-in-the-tire crowd is that: Nitrogen atoms are bigger and thus less likely to escape the tire, bringing stability to your tire pressure. If Earth's atmosphere is ...
45
votes
12answers
8k views

How long a straw could Superman use?

To suck water through a straw, you create a partial vacuum in your lungs. Water rises through the straw until the pressure in the straw at the water level equals atmospheric pressure. This ...
2
votes
4answers
2k views

Balloons and lifting gases

Hydrogen is the lightest element, so it's cable of lifting the most weight in out atmosphere (probably not the best terminology there, but you get the picture) Would hot hydrogen (in the same sense ...
11
votes
4answers
3k views

Why can't CO2 mix back with the liquid after a soda bottle has been shaken?

If you shake a soda bottle before opening it, and then open it, you get the fizz. That is the compressed CO2 releasing to the atmosphere which is at comparatively low pressure value. Two questions ...
10
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4answers
1k views

How does a steady wind flow generate sound?

When a wind blow through sharp edge, say, edge of a paper, you can see the vibration of the paper and hear the sound. For this type of oscillation, it should be a damped oscillation with external ...
0
votes
2answers
600 views

Would weighing scales show a negative weight if placed in a vacuum?

The weighing scales in my kitchen are currently showing 0 Kg. However, there is a column of air between the scales and the ceiling that is presumably exerting pressure on them. If I were to place ...
7
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3answers
4k 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: ...
3
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3answers
3k views

What is the relation of sound propagation to air pressure?

Hi there i am wondering, air is making sound propagate. So in vacuum there is no sound. but what is the relation of pressure to sound volume? is it linear? if i have a source of sound and lets say i ...
22
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4answers
2k views

Why can you “suck in” cooked spaghetti?

We all know that there is no "sucking", only pushing. So how are cooked spaghetti pushed into your mouth? The air pressure applies orthogonal on the spaghetti surface. Where does the component ...