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ChatGPT5 in this demo: > For an airplane wing (airfoil), the top surface is curved and the bottom is flatter. When the wing moves forward: > * Air over the to
by kybernetikos 1y ago
ChatGPT5 in this demo:
> For an airplane wing (airfoil), the top surface is curved and the bottom is flatter. When the wing moves forward:
> * Air over the top has to travel farther in the same amount of time -> it moves faster -> pressure on the top decreases.
> * Air underneath moves slower -> pressure underneath is higher
> * The presure difference creates an upward force - lift
Isn't that explanation of why wings work completely wrong? There's nothing that forces the air to cover the top distance in the same time that it covers the bottom distance, and in fact it doesn't. https://www.cam.ac.uk/research/news/how-wings-really-work https://www.cam.ac.uk/research/news/how-wings-really-work
Very strange to use a mistake as your first demo, especially while talking about how it's phd level.
- mcs5280 1y agoSam will fix this in the next release he just needs you to give him more money
- rtkwe 1y agoIt's going to be really hard to root out it's all over the place because it's so commonly mentioned when teaching the Bernoulli Principal to kids.
- arcumaereum 1y agoYeah I'm surprised they used that example. The correct (and PhD-level) response would have been to refuse or redirect to a better explanation
- CamperBob2 1y agoI am, too. Between that example and the terrible bar charts, I'm very surprised there wasn't enough intellectual firepower around there to do better. In fact I'd classify it as downright strange.
- deleted 1y ago[deleted]
- AnimalMuppet 1y agoYes. But I strongly suspect that it's the most frequent answer in the training data...
- NelsonMinar 1y agoIIRC I was required to regurgitate this wrong answer to pass my FAA pilot exam.
- CPLX 1y agoYeah me too, so it's found in many authoritative places. And I might be wrong but my understanding is that it's not wrong per-se, it's just wildly incomplete. Which, is kind of like the same as wrong. But I believe the airfoil design does indeed have the effect described which does contribute to lift somewhat right? Or am I just a victim of the misconception.
- NelsonMinar 1y agoI've always wondered if the acrobatic exams require repeating the same wrong answer. Obviously planes can't fly upside down.
- carabiner 1y agoYeah, it's like asking a car driver (even a professional driver) to explain the Otto cycle. Enduser vs. engineer.
- gekoxyz 1y agoAnd your suspicion is right. The sad reality is that it's just a stochastic parrot, that can produce really good answers in certain occasions.
- hirvi74 1y agoThis honestly mirrors many of my interactions with credentialed professionals too. I am not claiming LLMs shouldn't be held to a higher standard, but we are already living in a society built on varying degrees of blind trust.
- tths 1y agoYeah, the explanation is just shallow enough to seem correct and deceive someone who doesn't grasp really well the subject. No clue how they let it pass, that without mentioning the subpar diagram it created, really didn't seem like something miles better than what previous models can do already.
- theappsecguy 1y agoThis is the headline for all LLM output past "hello world"
- traceroute66 1y agoHilarious how the team spent so much time promising GPT5 had fewer hallucinations and deceptions. Meanwhile the demo seems to suggest business as usual for AI hallucinations and deceptions.
- Vegenoid 1y ago> No clue how they let it pass It’s very common to see AI evangelists taking its output at face value, particularly when it’s about something that they are not an expert in. I thought we’d start seeing less of this as people get burned by it, but it seems that we’re actually just seeing more of it as LLMs get better at sounding correct. Their ability to sound correct continues to increase faster than their ability to be correct.
- stanmancan 1y ago> Yeah, the explanation is just shallow enough to seem correct and deceive someone who doesn't grasp really well the subject. This is the problem with AI in general. When I ask it about things I already understand, it’s clearly wrong quite often. When I ask it about something I don’t understand, I have no way to know if its response is right or wrong.
- peterdsharpe 1y agoYes, it is completely wrong. If this were a valid explanation, flat-plate airfoils could not generate lift. (They can.) Source: PhD on aircraft design
- ge96 1y agoWhat is the actual answer? I know the "skipping stone" idea is wrong too, thinking it's just angle of attack
- base698 1y agoWeight of the air deflecting downward. Plain ole Newtonian equal and opposite reaction.
- datadrivenangel 1y agoBut also pressure providing force. It's complicated.
- rtkwe 1y agoIt's both lower pressure above the wing (~20% of lift) and the reaction force from pushing air down (give or take the remaining 80% of lift). The main wrong thing is that the air travels faster because it has to travel farther causing the air to accelerate causing the lower pressure that's double plus wrong. It's a weird old misunderstanding that gets repeated over and over because it's a neat connection to attach to the Bernoulli Principal when it's being explained to children.
- boombapoom 1y agoa classic example of how LLM's mislead people. They don't know right from wrong, they know what they have been trained on. Even with reasoning capabilities
- rtkwe 1y ago
- 2StepsOutOfLine 1y agoDuring the demo they quickly shuffled off of, the air flow lines completely broke. It was just a few dots moving left to right, changing the angle of the surface showed no visual difference in airflow.
- on_the_train 1y agoIt's a misconception that almost everyone does though. I recently even saw it being being taught in a zeppelin museum!
- xeromal 1y agoWhy replace humans if make human mistakes
- metalliqaz 1y agoless overhead on benefits and pay raises
- sejje 1y agoLLMs are "ask the audience" Common misconceptions should be expected when you train a model to act like the average of all humans.
- antoni4040 1y agoOh my God, they were right, ChatGPT5 really is like talking to a bunch of PhD. You let it write an answer and THEN check the comments on Hacker News. Truly innovative.
- adolph 1y agoThe HN comments are "one of the most important methods of building knowledge – . . . the intersubjective verification of the interobjective." [0] https://jimruttshow.blubrry.net/the-jim-rutt-show-transcripts/transcript-of-ep-293-brendan-graham-dempsey-on-cosmic-teleology-and-emergence-vectors/ https://jimruttshow.blubrry.net/the-jim-rutt-show-transcript...
- addaon 1y ago> Isn't that explanation of why wings work completely wrong? This is an LLM. "Wrong" is not a concept that applies, as it requires understanding. The explanation is quite /probable/, as evidenced by the fact that they thought to use it as an example…
- agubelu 1y ago"Wrong" is a concept that clearly applies when something is objectively wrong. I asked ChatGPT for help with Wordle the other day, by asking for a 5-letter word that contained P, M, K and Y. It said: > Yes, the word skimp contains the letters P, M, K, and Y Would you say that wrong is not a concept that applies to this answer?
- syncmaster913n 1y agoI think the original commenter meant that the LLM can't be called wrong because the concept requires understanding. However, I think it would be fine to call the LLM's response incorrect.
- tshaddox 1y agoIt's an extremely famous example of a widespread misconception. I don't know anything about aeronautical engineering but I'm quite familiar with the "equal transit time fallacy."
- xboxnolifes 1y agoYeah, it's what I was taught in high school.
- Q6T46nT668w6i3m 1y ago[flagged]
- samfriedman 1y agoThe "demo" it made was pretty horrible too. I would have been impressed if it had simulated a NACA 4412 or something.
- timr 1y agoYour link literally says pressure differential is the reason, and that curvature matters: > “What actually causes lift is introducing a shape into the airflow, which curves the streamlines and introduces pressure changes – lower pressure on the upper surface and higher pressure on the lower surface,” clarified Babinsky, from the Department of Engineering. “This is why a flat surface like a sail is able to cause lift – here the distance on each side is the same but it is slightly curved when it is rigged and so it acts as an aerofoil. In other words, it’s the curvature that creates lift, not the distance.” So I'd characterize this answer as "correct, but incomplete" or "correct, but simplified". It's a case where a PhD in fluid dynamics might state the explanation one way to an expert audience, but another way to a room full of children.
- kybernetikos 1y agoPressure differential is absolutely one of the main components of lift (although I believe conservation of momentum is another - the coanda effect changes the direction of the airflows and there's 2nd law stuff happening on the bottom edge too), but the idea that the pressure differential is caused by the fact that "air over the top has to travel farther in the same amount of time" because the airfoil is curved is completely incorrect, as the video in my link shows.
- timr 1y agoIt's "completely incorrect" only if you're being pedantic. It's "partially correct" if you're talking casually to a group of regular people. It's "good enough" if you're talking to a classroom of children. Audience matters. The hilarious thing about this subthread is that it's already getting filled with hyper-technical but wrong alternative explanations by people eager to show that they know more than the robot.
- kybernetikos 1y ago"air over the top has to travel farther in the same amount of time" is just wrong, it doesn't have to, and in fact it doesn't. It's called the "equal transit-time fallacy" if you want to look it up, or follow the link I provided in my comment, or perhaps the NASA link someone else offered.
- carabiner 1y agoHoly shit that is wrong. That's what happens when you get software, ML engineers who think they know everything.
- 7734128 1y agoExtremely common misconception. NASA even has a website about how it's incorrect https://www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/airplane/wrong1.html https://www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/a...
- deleted 1y ago[deleted]
- adioe3 1y agoNobody explains it as well as Bartosz: https://ciechanow.ski/airfoil/ https://ciechanow.ski/airfoil/
- IanCal 1y agoAs a complete aside I’ve always hated that explanation where air moves up and over a bump, the lines get closer together and then the explanation is the pressure lowers at that point. Also the idea that the lines of air look the same before and after and yet somehow the wing should have moved up.
- 18172828286177 1y agoThe hallmark of an LLM response: plausible sounding, but if you dig deeper, incorrect
- hirvi74 1y agoDo you think a human response is much better? It would be foolish to blindly trust what comes out of the mouths of biological LLMs too -- regardless of credentials.
- deleted 1y ago[deleted]
- skydhash 1y agoAll science books and papers (pre-LLMs) were written by people. They got us to the moon and brought us the plane and the computer and many other things.
- hirvi74 1y agoMany other things like war, animal cruelty, child abuse, wealth disparity, etc.. Hell, we are speed-running the destruction of the environment of the one and only planet we have. Humans are quite clever, though I fear we might be even more arrogant. Regardless, my claim was not to argue that LLMs are more capable than people. My point was that I think there is a bit of a selection bias going on. Perhaps conjecture on my part, but I am inclined to believe that people are more keen to notice and make a big fuss over inaccuracies in LLMs, but are less likely to do so when humans are inaccurate. Think about the everyday world we live in: how many human programmed bugs make it past reviews, tests, QA, and into production? How many doctors give the wrong diagnosis or make a mistake that harms or kills someone? How many lawyers give poor legal advice to clients? Fallible humans expecting infallible results from their fallible creations is quite the expectation.
- skydhash 1y ago> Fallible humans expecting infallible results from their fallible creations is quite the expectation. We built tools to accomplish things we cannot do well or at all. So we do expect quite a lot from them, even though we know they're not perfect. We have writings and books to help our memory and knowledge transfer. We have cars and planes to transport us faster than legs ever could... Any apparatus that doesn't help us do something better is aptly called a toy. A toy car can be faster than any human, but it's still a toy.
- croes 1y agoIt’s a common misconception, I doubt they know themselves and GPT 5 doesn’t tell them otherwise because it’s the mist common in explanation in the training data. A quite good example of AI limits
- ttoinou 1y agoIts not fully wrong but its a typical example of how simplified scientific explanations have spread everywhere without personal verification of each person involved in the chinese whisper
- dbagr 1y agoSee also about this misconception: https://www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/airplane/wrong1.html https://www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/a...
- low_tech_punk 1y agoThat was debunked by Veritasium 13 years ago: https://www.youtube.com/watch?v=aFO4PBolwFg https://www.youtube.com/watch?v=aFO4PBolwFg
- tim333 1y agoFrom Wikipedia >In fact, theory predicts – and experiments confirm – that the air traverses the top surface of a body experiencing lift in a shorter time than it traverses the bottom surface; the explanation based on equal transit time is false. So the effect is greater than equal time transit. I've seen the GPT5 explanation in GCSE level textbooks but I thought it was supposed to be PhD level;)
- karel-3d 1y agoyeah that's a great thing to use as LLM demo because it sounds plausible yet it's completely misleading and wrong.
- avs733 1y agoIts a particular type of mistake that is really interesting and telling. It is a misconception - and a common socially disseminated simplifcation. In students, these don't come from a lack of knowledge but rather from places where knowledge is structured incorrectly. Often because the phenomenon are difficult to observe or mislead when observed. Another example is heat and temperature. Heat is not temperature, but it is easy to observe them always being the same in your day to day life and so you bring that belief into a college thermodynamics course where you are learning that heat and temperature are different for the first time. It is a commonsense observation of the world that is only incorrect in technical circles These are places where common lay discussions use language in ways that is wrong, or makes simplifcations that are reasonable but technically incorrect. They are especially common when something is so 'obvious' that experts don't explain it, the most frequent version of the concepts being explained These, in my testing, show up a lot in LLMs - technical things are wrong when the most language of the most common explanations simplifies or obfuscates the precise truth. Often, it pretty much matches the level of knowledge of a college freshman/sophmore or slightly below, which is sort of the level of discussion of more technical topics on the internet.
- ricardobayes 1y agoTo me, it's weird to call it "PhD-level". That, to me, means to be able to take in existing information on a certain very niche area and able to "push the boundary". I might be wrong but to date I've never seen any LLM invent "new science", that makes PhD, really PhD. It also seems very confusing to me that many sources mention "stone age" and "PhD-level" in the same article. Which one is it? People seem to overcomplicate what LLM's are capable of, but at their core they are just really good word parsers.
- chamomeal 1y agoAgree on the weirdness of “PhD-level knowledge”. Most of the phd’s I know are studying things that I guarantee GPT-5 doesn’t know about… because they’re researching novel stuff. Also, LLMs don’t have much consistency with how well they’re able to apply the knowledge that they supposedly have. Hence the “lots of almost correct code” stereotype that’s been going around. I was using the fancy new Claude model yesterday to debug some fast-check tests (quickcheck-inspired typescript lib). Claude could absolutely not wrap its head around the shrinking behavior, which rendered it useless for debugging
- ethan_smith 1y agoYou're right - this is the "equal transit time" fallacy; lift is primarily generated by the wing deflecting air downward (Newton's Third Law) and the pressure distribution resulting from airflow curvature around the wing.
- hollowturtle 1y agoIt's wrong because it's a theory that you can still find on the internet and among experienced amateur pilots too! I went to a little aviation school and they teached exactly that
- ryandv 1y agoYou mean it's not ready for vibe physics?
- tlarkworthy 1y agoThey did not ask how wings work. They asked for the bernoulli effect, that's a different question.