Well this is very interesting. I pasted your prompt into a new chat just now and I got the correct answer:
> One cubic foot of nails and one cubic foot of feathers both have the same volume, but nails are denser than feathers. Therefore, one cubic foot of nails will be heavier than one cubic foot of feathers.
Are you using the free version at chat.openai.com?
However, I did initially misspell the prompt to say "heaver", and with the misspelling it had answered correctly. Once I corrected it to "heavier", it then came up with the wrong answer.
Looking at it with fresh eyes, it's possible that my methodology was flawed. While I only ever intended to showcase the first response, I did also try regenerating the responses a few times. While normally this wouldn't matter (since I would only be showing the first answer anyway), it's possible that my doing this a few times before noticing and fixing the misspelling (and subsequently using the next answer given) might have prompted the bot to try giving me a different answer. (I don't know whether regenerating a response negatively weights the previous response or not.)
I apologise for not mentioning this! In my defense, I was tired.
As a follow-up, I tried again in a new thread and it still got it wrong in almost the exact same way:
> One cubic foot of nails and one cubic foot of feathers weigh the same amount, which is approximately 100 pounds. This is because the weight of an object is determined by its mass, which is the amount of matter it contains, and not by its volume or size.
> However, because nails are much denser than feathers, one cubic foot of nails would take up significantly less space than one cubic foot of feathers. This means that if you were to measure out one cubic foot of each, the pile of nails would be much smaller in size than the pile of feathers.
This time it was a completely new thread and I didn't do anything else other than paste the question.
Well this is very interesting. I pasted your prompt into a new chat just now and I got the correct answer:
> One cubic foot of nails and one cubic foot of feathers both have the same volume, but nails are denser than feathers. Therefore, one cubic foot of nails will be heavier than one cubic foot of feathers.
Are you using the free version at chat.openai.com?
Does it say Feb 13 version at the bottom?