Thinking of Fluids Without External Forces

We are commonly accustomed to the fluid state. Let me consider the liquid state specifically.

Liquid State

But liquids are on one hand pushed in by the atmospheric pressure, and on the other, due to gravity. There is also the pressure of the container, and the pressure of intermolecular forces of attraction, which works against the repulsion.

In free space, they would simply boil, since the internal energy of the particles is higher than the outside energy (or heat), and the liquid is not as bound together as they are compressed by the external forces.

So it's as if liquids are only held in place because something keeps hitting them from the outside, in other words, due to external heat of gases (which itself is due to gravity and the amount of gas).

Gaseous State

In case of gases, if they have a pressure, they just spread out to infinity without the influence of gravity or a container.

In outer space

But in normal cases, a bottle will remain in ambient temperature and pressure due to heat radiating out if the external temperature isn't the same as internal temperature. While it's true there could be more air inside the container, the attractive forces between particles is higher as the kinetic energy is lowered.. (density doesn't change, because gas expands to fill the entire volume of the container). So the little energy left in space, if any, could motivate it to move outside the container.

At higher altitudes

In air, there's some pressure inside the container, and there's less particles per volume outside the bottle. But the pressure is the same. Given more volume, the pressure is likely to only decrease, so the air inside the bottle probably wouldn't move out. Instead, the air outside the bottle would probably enter the bottle first and increase the kinetic energy of individual molecules, and then the air inside the bottle would go out, because now there are more atoms with the increased kinetic energy, and hence the pressure increases (P = nRT/V, V and n are same, but T increased).

I find it interesting how air is 1000 times less dense than water (830 to be precise, but it's like \(\dfrac{\text{1.x} \: kg/m^3}{\text{1.y} \: g/cm^3}\)).

General Case of States of Matter

• High Energy, Low Attraction: Gases
• Medium Energy, Medium Attraction: Liquids
• Low Energy, High Attraction: Solids

It looks like Energy x Attraction remains close, maybe with some proportionality constant.
Instead of Energy x Forces, maybe we can look in terms of Momentum x Curvature / Charge too.
The units aren't clear, I haven't thought much about the details here, but the idea can be seen.

It's as if one always trades freedom for oneness.

But with freedom too, one can see the oneness, if you don't limit yourself to simply being closer to one another. Free particles can meet other particles much more easily than solids, where that's not possible.