Problems with Densities and Elements

[Yffriium]

As this is my first post, I want to mention that I love this game. I'm just under 100 hours, and I've never experienced a dull moment. However, there are some things I've noticed that don't make much sense to me.

For example, the densities of gases. In the game, these five gases would be arranged from heaviest to lightest as: carbon dioxide, chlorine, natural gas, oxygen/polluted oxygen. In the real world, though, chlorine gas is denser than carbon dioxide, and on top of that, natural gas is mostly made of methane, which is less dense than oxygen. Why would Klei change how these compounds arrange themselves? As for elements, my gripe is much smaller. The gas and liquid element sensors are called "element" sensors when they should be called "compound sensors" or something that more accurately reflects the things that it sorts, as methane is a compound and polluted water is a mixture. It may seem trivial, but it certainly feels wrong to label it with a false title.

Let me know what you think; maybe there's a great reason for all of this.

[nakomaru]

There are a lot of simplifications made for the sake of gameplay and performance. The issue you seem to be having is that ONI uses ONI physics rather than ordinary physics. Instead of density, pressure, gravity, the ideal gas law, mixtures, etc, we have single tile physics and sorting by molar mass and phase.

Sorting and swapping by molar mass and phase is straightforward, and also easy for the player to predict, once learned.

[angrybovine]

I assume that the Devs are treating chlorine as Cl instead of Cl2.  Either a mistake or a deliberate balance decision to make CO2 the heaviest gas.

[badgamer123]

would really love a mod for this,no way water float above petroleum.

[KittenIsAGeek]

On 11/10/2019 at 9:40 PM, Yffriium said:

However, there are some things I've noticed that don't make much sense to me.

For example, the densities of gases. In the game, these five gases would be arranged from heaviest to lightest as: carbon dioxide, chlorine, natural gas, oxygen/polluted oxygen. In the real world, though, chlorine gas is denser than carbon dioxide, and on top of that, natural gas is mostly made of methane, which is less dense than oxygen. Why would Klei change how these compounds arrange themselves? As for elements, my gripe is much smaller. The gas and liquid element sensors are called "element" sensors when they should be called "compound sensors" or something that more accurately reflects the things that it sorts, as methane is a compound and polluted water is a mixture. It may seem trivial, but it certainly feels wrong to label it with a false title.

Part of the confusion stems from ONI using terms in a different way than you are familiar.  In Physics, an element is a single atomic unit, such as hydrogen or oxygen.  By the definition of physics, water is a compound because it contains 3 elements: Two hydrogen, one oxygen.  However, in computer programming, an element is defined as a single item or unit.  For example, an array is made up of a number of identical units called "elements."  Since ONI was designed by programmers, their definition of "element" has been used.  So in ONI, "Water" is an element, because it is a single thing that can occupy a location.

As for the "density" stuff, again ONI wasn't designed to imitate physics.  So density really doesn't exist in ONI.  The weights of various "elements" are based on their real world densities, but only loosely.  Instead, they are adjusted based on what works better for the game.  In the real world, a mixture of CO2, Oxygen, and Hydrogen would be relatively evenly distributed in most of the area, with slightly more CO2 being present at the bottom and slightly more hydrogen being present at the top.  In the real world, temperature affects gasses much more than their base molecular weights.  This is why you're more likely to survive a fire by crawling out and keeping your head close to the ground.  The much colder air has settled to the bottom, while the hot smoke (chock full of CO2 and containing very little O2) fills the rest of the room.

However, in ONI, only one particular thing (element) can occupy any given tile at any given moment.  So they had to "weight" the items such that they would sort themselves out instead of all trying to occupy the same space.

 

On 11/11/2019 at 9:26 PM, badgamer123 said:

would really love a mod for this,no way water float above petroleum.

In the real world, you are correct.  However, in ONI, its a decision based on game play.  In the real world, oil floats on water.  Crude sinks.  Crude contains a lot of extra junk that gets removed while processing it into things like gasoline or oil lubricants.  In ONI, changing from crude oil to petroleum doesn't result in the loss of any of this extra junk.  It isn't until you boil the petroleum into sour gas, then condense the gas that the "extra weight" falls out (in the form of sulfur).  So I can see them sitting around discussing how the elements should sort themselves out and someone saying, "Well, see, the crude is heavy 'cause its got stuff in it.  Petrol doesn't lose anything, so it shouldn't be much lighter."  And others at the table responding, "Sure, we can go with that."

 

However, I will point out that I have, on a number of occasions, pushed petroleum out of the way with a much smaller amount of water.  I can consistently push 500g of petroleum off of a tile using only 27g of water.  Which really confuses things because in ONI, the petroleum should be heavier than the water.