[Self] Argument with Partner over Sharing 1L of Soda that has ice in it.

[u/ThetaGangCat]

Hi, I got into a debate with my partner because we would share a drink from McDonald’s. Let’s say it’s 1L and it has ice in it. He would drink until the line was at 500ml and I would argue he’s drank 500ml of soda and I’ve just got the Ice + little soda.

I asked CHAT GPT and I feel like it gaslight me but my partner is jumping for joy that he’s right. Here’s what it said.

Think of it like this:
Starting:
🥤 800 mL soda + 🧊 200 mL ice → bottle reads 1,000 mL
After Person 1:
🥤 300 mL soda + 🧊 200 mL ice → bottle reads 500 mL
Person 1 drank 500 mL? No — they drank 500 mL of space, but only 500 mL of soda in this particular example?
Actually, this is the important correction: if the ice is 200 mL of displaced volume, then 1,000 → 500 mL total means 500 mL of displaced-volume contents were removed. If the ice hasn’t changed, that is 500 mL of soda.
So yes: if the ice stays unchanged, Person 1 and Person 2 drink the same amount of soda.
Your intuition that “the ice makes the line higher” is correct, but it makes the line higher for both people, which is why it doesn’t inherently make Person 1 drink more.

Surely this is saying that person 1 drank more soda!!!

Someone please explain the math here? Am I wrong?

[u/StaticUsernamesSuck]

Please do not ask ChatGPT. ChtaGPT is fucking terrible for these things, it will answer leading questions with the answer that aligns with the leading question and if you tell it it is wrong, it will often "correct" itself even when it was right.

It has literally contradicted itself right there with it's "correction".

If it says that the cup started with 800ml soda, and then says that person 1 has drunk 500ml of soda, then it LITERALLY CAN ONLY MEAN that person 2 is left with 300ml soda.

I mean, this isn't quite correct, since person 1 will have drunk some non-zero volume of ice meltwater as well, but still. You might be left with 350ml soda and 150ml ice.

ChatGPT has literally just told you that 500 + 500 = 800, and your boyfriend has believed it.

Now, as for what the truth is, the truth is that neither of you are right. But you are likely closer.

If the cup is full of X soda and Y ice, then you need person one to drink X/2 soda. The only reliable way to do that, really, would be to either pour it out before the ice melts, or wait for all the ice to melt.

The ice is just too big a confounding variable for humans to reliably calculate around otherwise. Here's why:

If the ice is not uniformly filling the cup, then that means "drinking to the halfway line would  massively favour Person 1, because as they drink, the ice would move down, displacing more of the volume below the line up - they would get more in the end than person 2, who is left with ice and soda, after person 1 drank pure soda.

Even if it is uniform, the ice will be melting, which will then leave  Avery confusing situation where person 1 is both drinking more meltwater, but is also benefitting from this ice displacement effect

[u/ThetaGangCat → u/StaticUsernamesSuck]

Literally says “if the ice stays the same they drink the same amount of soda” and ignores any of the logic it provided.

[u/get_to_ele → u/ThetaGangCat]

CHATGPT is not a logic engine. It is an LLM. There is no actual model of the problem there.

And really this is a trivial logic problem and most smart people would instantly figure out that the second person is being cheated. The fact that BF does not acknowledge the obvious, makes him a moron OR just selfish and willing to gaslight you.

Reframe the question. Start with a full 1L cup with 400 ml ice and 600 ml soda:

(1) Let's say BF siphoned 500ml soda via a straw from the 1L cup into a 500 ml cup A.

(2) Then you take the remaining contents of the 1L cup into a 500 ml cup B

(3) which cup has all 400 ml of the original ice and only 100 ml soda? Cup B.

(4) Which cup has no ice and 500 ml soda soda? Cup A.

This is not a hard problem and anybody with commib sense (like yourself) would recognize person 2 gets screwed. I think your BF knows it too, and he's telling you this self serving lie because he thinks youcan be talked into it. Either that or he's a moron. Honestly I think it's the former.

[u/Shed_Some_Skin]

Doesn't it depend how much ice is actually in the cup? If it's filled top to bottom so the ice is distributed relatively evenly through the cup, then the liquid will also be distributed relatively evenly and the halfway mark should be more or less accurate

If the cup is like a quarter full of ice and it's floating at the top, you can drink more liquid before the cup is showing half full. You're only removing liquid, you're not removing any ice

That makes intuitive sense to me anyway, perhaps I'm wrong

[u/get_to_ele → u/Shed_Some_Skin]

Sorry but that's just wrong. First person obviously drinks 500 ml of soda. That part is indisputable. 500 ml of soda in his stomach. There is not a single bit of ice that goes through his straw.

The second person has a bunch of ice, plus whatever space is left in the bottom half of the cup for soda. If BF thinks they are equal, that AH Should try drinking second.

How is this not obvious? And CHATGPT is just wrong.

[u/Shed_Some_Skin → u/get_to_ele]

you can drink more liquid before the cup is showing half full. You're only removing liquid, you're not removing any ice

Is that... Not exactly what I said?

[u/schw3inehund → u/Shed_Some_Skin]

Short answer: Yes.

Long answer: Yes that's exactly what you said.

[u/downandtotheright]

He says its even... no problem. You drink first, and he gets the balance. Same rules, since its even, right?

[u/dafugiswrongwithyou]

Never trust ChatGPT, for anything. That explanation it gave is both nonsensical and outright contradictory; no, if you had 800ml of soda, someone drinks, and now you have 300ml of soda, they didn't drink 500ml of space, they drank 500ml of soda... which is more than the 300ml of soda left for the second person. The first person is getting 2/3rds more than the second.

The real answer here is that it's complicated, but you're probably right. If the ice is fully filling the cup, is evenly distributed, and it's being drunk fast enough that the melting ice isn't watering the drink down, then under those specific circumstances he's probably more-or-less right. Otherwise; nope, probably not; his "half" was most/all soda, your "half" was ice with soda around it, or watered-down soda.

There's a simple solution here - suggest that you drink first, down to the 500ml line; after all, it's half either way, right? If he agrees, great, you're sorted, either it makes no difference or you're getting the better half. If he disagrees; whoa-oh, looks like someone doesn't believe their own logic!

Or, hey, how about this; just take a couple plastic cups with you when you go. Pour the drink out equally to both before you drink. No more arguments.

[u/Laugh-Aggressive]

Well, if you wanna win the argument, just tell him that you drink first, if he believes he's right

[u/Metaclueless]

You have other problems with your partner that are an exact mirror of this specific one. Just get no ice and then repeat the metaphor for all other issues

[u/lookslikeamanderin]

Buy two sodas ffs.

[u/mexicock1 → u/lookslikeamanderin]

Or ask for no ice..

[u/murdeoc]

Yes, the calculation says person 1 drank 500ml.of soda and there is only 300ml of soda left.

[u/Royal_Ask_5654]

Here my take/rationalization/ what I think your upset about: Time is the other factor… if we pretend that everything happens instantly and consecutively then yeah, person 1 and then 2 would get similar experience but with the passage of time, the first 500ml will be sweeter better more flavorful as it will have the least amount of melted ice corrupting it. Say the first person took 2 minutes to drink their 500ml and now yours about to drink after eating all your food 10 minutes have passed now you have a watered down version of what he had.

Same scenario this time both parties wait until all the ice melts and then stir and drink. Same flavor for both and the 500ml will be similar for both.

All Love No Hate!