This is what conspiracy theorists don’t get. The world’s scientists are not skeptical of your claims that water has secret spiritual memory because they hate you, they are skeptical because the claim you make, if it were true, would be so important and world-changing that they want to be absolutely sure of it before they endorse it.
The difference is that, to a scientist, “this would be amazing if it were true” is not a good reason to believe it anyway
The Elephant and Mice episode was so wild, because if I remember correctly, the elephant didn’t act afraid of the mouse, it acted afraid it would step on and harm the mouse; as if the elephant had a basic understanding and concern for the wellbeing of another creature conspicuously lacking in many human beasts
Yep. Elephants are wonderfully kind creatures. With my very limited understanding of elephant body language, it didn’t look like an ‘oh no, im scared’ it was more ‘oh hey little guy, didn’t see ya there. ill get outta your way.’
Just smart as hell. This video makes me wonder if elephants legit have a sense of humor:
https://www.youtube.com/watch?v=2VOvEFHDOaU
Animal behavior can be difficult to interpret (and even when descriptions come from experts, I often find myself asking “yeah, but how do we really know that?”), but this looks very close to being like someone who’s known for lighthearted pranks.
Oh my goooooood. This is so delightful, you can almost see the smirk. Thank you for sharing. <3
I WANT to believe this but I’ve seen too many elephant videos that turned out to be just elephants trained to do a quirky thing for tourists and there’s someone off camera subtly directing them.
New core memory unlocked, thanks!
Elephants are wonderfully kind creatures
So long as they’re not a bull in musth.
It’s amazing how intelligent and emotionally mature elephants are. It’s not wonder why people were willing to believe that “Elephants have a moon religion!” line for so long, it seems believable with how often elephants seem to act like chonky humans with a trunk instead of arms.
If we would, we would be all vegan.
This is why most skepticism based programs don’t work, and Mythbusters did.
They didn’t try to be smug about it, they didn’t belittle people who believed in the myths, they never brought religion and politics into it, and the biggest pitfall they avoided: They never pretended that the “science was settled” and that they “already knew everything”, they simply did the research and went where the data took them.
Too many skepticism based programs seem to think the scientific method is running into a church, yelling “FAKE!”, and then running outside to hurl insults at passersby.
Mythbusters didn’t do that, they skipped the dogma and went straight to the science.
Also, most of the myths weren’t “serious”- it wasn’t like they were debunking flat earth or something.
I hate that debunking flat earth is now seen as serious rather than a 5th grade science experiment.
True enough.
I mostly watch that one guy on YT for his dog…
it wasn’t like they were debunking flat earth or something
Though you could do that. And with equipment and a type of experiment that would make sense on their show. The experiment conducted at the very end of the documentary Behind the Curve is perfect. Great big lasers, a simple and easy-to-visualise pass condition. If they had wanted to, they absolutely could have done it.
Could’ve had an episode where they tried as many experiments as they could fit into a two-week production.
I mean, yes.
but their myths generally didn’t piss surprisingly large segments of the population off. it was more… the urban legends that gave them an excuse to blow stuff up, shoot stuff, or otherwise crash stuff; all in slow motion.
For anyone missing the show, there was a wonderful project called Streamlined Mythbusters where fans edited each episode down to remove the filler, pre and post ad recaps, etc. They usually also would reorder things so each individual myth was seld contained.
It’s wonderful, but some episodes legitimately got cut down to be 16 minutes long with no real content loss, which can be kind of jarring.
There is also Smyths, which is the same thing.
Unfortunately Mythbusters edits have a tendency to get pulled from the typical video sharing sites rather quickly. I wish someone would make a torrent of the entire series edited this way, and call it a day.
What, like the pinned post on the smyths reddit page?
Thank you so much for sharing this!!
Excellent; thanks. I cached the torrent to Real-Debrid, so if anyone reading this so happens to be using that service, you can download the torrent directly at 1Gbps by pasting the magnet link (the first one) in Torrents section of the website.
Oh god, I forgot, it was during the “REALITY TV!” boom where marketing and hype had more substance than the shows themselves, and if the show had substance… edit it like it is Reality TV…
I do not miss that.
Thanks for the Rec! I definitely miss the show. Adam’s YouTube channel sometimes scratches the itch, but not always.
You can find a torrent of all of them. I love putting Plex on shuffle when I’m doing chores around the house.
Remember kids: The difference between science and screwing around is writing things down.
Remember kids: publishing negative results is hard.
But super important and not done enough! Disproving something can save humanity such time.
There’s a bit more to it than that
Yes. Being exploited by greedy publishers and a failing academia system, while barely making a living for example.
It doesn’t matter how you run because ALLIGATORS WON’T CHASE YOU.
I used to live in Florida on the edge of a big lake where my landlord had carved out a lagoon that mama gators used to hatch their broods, so there would often be between 50 and 100 little alligators chilling out in my backyard sunning themselves. For fun I would try to sneak up on one of them and poke it on the head just to watch it and all the others scatter into the lagoon. Everybody I told about this thought I was absolutely batshit crazy, but I knew that at the time there had been something like 5 alligator attacks on humans in Florida since the 1940s, always on little children playing in water (I was obviously a little child mentally but physically I was a 200-pound adult man). So I knew I wasn’t risking life or limb doing this. For the record, my sneaking up technique was to stand stock still and only move a step or two towards the gator whenever the wind blew; it seems that the gators just took me for a swaying branch and ignored me.
What made me stop doing this was one day I happened to look down at what I thought was a big log and realized that it was actually the mama gator, about 12’ long from tip to tail and probably 2’ in diameter at her midsection. I was fairly confident that she wouldn’t attack me on land either - but not that confident.
So, we meet at last, Florida Man!
No way! I left and I still have all my teeth.
but not that confident.
That’s how you bust myths!
Being excited about being wrong because either way it’s information
This literally is the basis of science that I think a lot of people misunderstand. Science doesn’t prove anything conclusively. What scientists try to do is disprove the leading theory and when they can’t, it adds to the pile of evidence that increases the likelyhood of the leading theory being correct. Even things that we’re very, very, very sure are correct are still like 99.99999999999…% confirmed.
A good example that’s often used to show how it’s more important to try to disprove a theory rather than trying to prove it is the existence of black swans. It was long thought that all swans were white and every time someone saw a white swan, that idea was reinforced. But when someone actually went out of their way to go looking for a black swan, they found a bunch of them!
I feel it is my pedantic duty to inform you that 99.9… is equal to 100.
Only if you’re rounding. 99.9 is still 1/10 of a digit separated from 100, but it’s not equal to 100 for good reason.
But the “…” matters.
It only signifies that the post-decimal nines are repeating infinitely. It still doesn’t make 99.99999…=100 unless you intentionally round the value for some nondescript reason, and even then, rounding off isn’t changing the value, only the perceived value for mathematical simplicity, not objective accuracy.
“.9…” is repeating, but rational. So it’s actually “1” . Let’s do the math.
.9… / 3 = .3…
.3… = 1/3
1/3 x 3 = 3/3
.9… = 3/3
3/3 = 1
.9… = 1
Still not convinced? We’ll use algebra instead of fractions.
0.9… = x
10x = 9.9…
10x - 0.9… = 9
9x = 9
x = 1
So why is it represented as 99.999… Instead of just 100? It’s because you’re forgetting the fact that fractions and decimals are infinite depending on the magnification. 99.9999… literally goes on forever. That means that no matter how close it gets to 100, it will never be equivalent to 100.
It’s like how you can know infinitely nothing and still think you know everything. 👀🫠
It’s because we can write numbers in many ways. 9900/99 is 100 just as surely as 99.99… is.
Love how you fight this to the death in a thread where people are discussing how a scientific mindset is so important.
Sometimes they called stuff busted because they couldn’t personally do it though, even though the myth involved elite athletics. I was pretty stoked when they brought in an actual ninja to test if ninjas can grab arrows out of the air. The guy actually did catch some arrows, which was quite amazing.
Yeah… There are many pitfalls to doing a Skepticism based program, sadly one of the few Mythbusters DIDN’T avoid was “Well I can’t personally do it, so it’s impossible for everyone!”
“Could the DOOM marine actually carry all those weapons while running around?” - Adam and Jamie couldn’t manage it, but they brought in someone who could.
I thought you were joking till I clicked the link.
Ha! That was fun.
Man i should rewatch the whole thing. I only watched few of the earlier seasons, totally missed this one.
Which was ridiculous considering they’re a couple of science nerds with no physical aptitude at all. LOL. They nailed the science stuff though.
I liked the one where they tested it you could stop a sword by slapping your palms together to stop the swing like in ninja movies They actually built a machine with rubber hands to simulate it. Long and short of it … No you can’t
But maybe… JK. The strength required to do that would be inhuman.
Yeah, one that I always think of is the see-saw one where a sky diver’s parachute failed so he aimed for a see-saw with a girl sitting on one end which resulted in the girl launched shot upwards and then landing safely on top of a building.
Their first test used basically a metal plank on a fulcrum and the forces did more to bend the plank than they did to launch the girl and she didn’t get high enough.
Their second attempt used a see-saw that was built using suspension bridge tech to essentially make it instructable, resulting in fatal forces from the launch. At this point, they called it busted.
But I see two unrealistic extremes where reality would exist somewhere in the middle where see-saws are designed to not break easily but not to the point of being indestructible and there might be a sweet spot where the forces are high enough to launch girl several stories up but not high enough that she dies from the forces.
Also, for the bull in a china shop one, I’m guessing that saying resulted from a bull ending up inside a china shop during a running of the bulls event, where stress would be high and there wouldn’t be an easy and obvious path out on the other side, plus maybe a shopkeeper suddenly trying to get it out in a panic. I think that would get the expected result, especially after a few shelves have broken and each step makes more broken sounds.
If you want to accelerate a person to “fly high into the air” speed over a distance of a see saw’s arc is going to kill the person. There is no sweet spot
Ive told people this many times, we need to create more room for failure. From school, to jobs, to building businesses, to loans, to health.
If we can try something because if we fail we can try something else, we would find a hell of a lot more to care about in this world.
And the most important thing we would care more about is ourselves
I cannot agree enough with this statement and especially love your closing. We definitely don’t tend to be able to take enough time to really care for ourselves and try and fail at new things.
Oh thank you very much
Mandatory Dwarf Fortress in every school.
Okay thats it im tired of people commenting about this Dwarf fortress. How much of my soul does it cost? Whats that in hours needed?
First, read Boatmurdered. Then realise it’s worth whatever the cost is
If you’re the type of gamer that gets sucked into Rimworld, then Dwarf Fortress will very likely consume you.
Yes. Be ready for the most fun you’ll ever experience in a game.
Science and academia, too. There’s way too few papers being published about failed experimemts. “I thought A, so I did B in order to achieve C, but it didn’t work out because of D.” is a very useful result.
Oh is it better to separate school from science and academia. Thank you, noted
I wish more people in general would be OK with being wrong. Noone ever learned something new without knowing they’d been wrong
The last comments in the image are exactly right.
It bothers me when I screw up and someone says “I fixed that for you” without explaining how I screwed things up, or how they fixed it.
If I’m wrong, I get it. I’m not always right, nobody can be right 100% of the time, IMO, that’s impossible. But when I’m wrong, let me learn so I can avoid being wrong in the same way twice.
IMO, schools have failed us, they teach us what we should know but don’t encourage us to always be curious and always be learning. It’s okay to make mistakes, and it’s okay to be wrong. What’s not okay is never learning from your mistakes, and being so stubborn that when you are wrong, you double down on being wrong instead of seeking more information so you can be correct next time.
Being wrong is always condemned. You get low grades, you fail and get held back in some cases… It’s been rare that any teacher I’ve ever had would review anything from a test after its over. A very small number went back and said “a lot of people had trouble with x question from the test, here’s the answer and this is why it’s the correct answer”. IMO, that should be way more common… Review the test after its over and let the class know that low marks are not the end, they’re a wonderful beginning to learning. If you know what you don’t know and you have even the smallest amount of ability and willingness to improve, with the addition of opportunities to learn that, then you will always succeed.
Be successful. Get a bunch of shit wrong.
I’m glad you addressed the aversion to being wrong because I think that’s part of the core of what’s causing so many problems in America today (and maybe other places, but I can only speak to my own familiarity).
I feel like as a society we have created an environment where we demonstrate and reinforce to children from like kindergarten onward that the worst thing you can possibly do is be wrong. Someone who is always right is seen as smart, capable…in short, a winner.
Conversely, if you’re ever wrong, that completely and permanently undoes your entire argument/position and not only that, but you’re branded as unreliable/untrustworthy, uninformed, stupid, dishonest, or naive.
We expect perfection in correctness, and while being right is the expectation, being wrong is a permanent black mark that is treated as a more serious negative than being right is considered as a positive. Nobody just assumes that if you’re right about one thing that you’ll be right about all things, but if you get something wrong, there’s a very real shift toward double-checking or verifying anything else that comes after.
We even tease friends, family, and children for mispronouncing words or singing incorrect lyrics. Basically, being incorrect is so stigmatized that we reinforce to everyone, children and adults alike, that it’s better to not even try…not even make an attempt or join into a conversation…than to risk being wrong. When someone is wrong we use words like “admit” like it’s a crime, or admit defeat…and that just creates an environment where nobody is ever encouraged to speak up about anything for fear of (gasp!) being wrong.
And now we’re coming full circle on this at the highest levels, with our leaders being blatantly and objectively wrong…and absolutely dead set on avoiding having to admit that at all costs, setting a precedent that has oozed into even casual discourse among regular people. It seems like it used to be that being wrong was bad enough, but to dig in and refuse to admit it was even worse…lately it seems that admitting you were wrong is now even worse than doubling down on it…so now we have a situation where we can’t even agree on basic facts because one or more sides will be wrong but would rather insist on their position than just acknowledge they were incorrect.
You’re hitting on every point I could make.
My advice to anyone reading, and wanting to be okay in being wrong, the first step is admitting you don’t know something. Even if it’s something you should know. For example if you’re considered to be an “expert” or at least very knowledgeable about something and someone asks you about that specific thing, but it’s not something you know, avoid making things up, or trying to derive an answer from what you do know. Explain that you’re not sure what the right answer is, but you’ll figure it out, then do some research to figure it out. Don’t go off the cuff and start informing people of what you presume it is based on what you know, without knowing for sure.
The next step is when someone contradicts what you believe to be true, hear them out, then do whatever lookups and research you need to figure out if they’re right, or you’re right. Don’t immediately tell them they’re wrong, just listen, then find the truth and go from there.
The other thing I do, is I stay away from absolute statements as much as I can. Instead of saying that this thing I know is absolute and true, I preface it with qualifying statements like “I believe…” Eg, “I believe you need to use that switch over there to do the thing” rather than “use that switch to do the thing”. If you’re wrong then it was qualified as an uncertainty which can make a correction sting that much less.
Finally, always pursue the truth above all else. The point shouldn’t be whether you are right or wrong, the point is getting and giving true information to/from others. When getting seemingly true information from someone, trust but verify anything you’re told before passing that information along, whenever possible.
Always be learning, always be seeking the truth, always verify the statements of others. After a while, you’ll find that you’re right far more often than when you’re wrong… Having that kind of track record will help in your ability to handle the times that you’re found to be wrong and you’ll have a much easier time with it.
The whole thing is a process, so don’t beat yourself up over it. You will falter and catch yourself doing things wrong and making assumptions and providing information you later determine to be wrong. It will happen. Learn the correct information and move forward. When you lose, don’t lose the lesson.
There’s a ton more that I could say on the matter, but I think that’s the core points.
For me, I got a huge wake-up call while working at a large software provider doing end user support. I went to the escalation team and asked them about a problem, and they asked me about some of the details, when I provided them, they questioned “did you verify this? Or did you just take the customers word for it?”… I didn’t verify the information. They sent me back to verify the situation before they would engage on the matter, and IIRC, it ended up being one of the assumptions that the end user, or I made, which wasn’t configured correctly, that caused the problem. I managed to avoid needing escalation. From then on, “trust but verify” was a constant mantra. I’ve been growing and learning ever since.
More great points, I agree.
Also…it might just be me, but I find that I subconsciously have more respect for a person, both as a person and as a reliable source of information, if they present things with qualification, as you suggest. To me, it’s a sign of humility and an indication of an appreciation for the complexity of any given subject if someone is knowledgeable enough to both field questions and demonstrate proficiency while also being careful to qualify and delineate between what’s fact, what’s generally accepted, what’s their understanding, and what’s their opinion or guess.
I listened to a podcast last year about TOP GUN instructors and the grueling process they go through to become subject matter experts in their specific subject, and one of the things that stuck out to me was that they’re less worried about being right all the time and more worried about three qualities: being knowledgeable, approachable, and humble…with the understanding that with those three qualities, you’re going to eventually get to the point where you’re almost always right, with the added benefit that you’ve trained yourself to remove ego from the equation, so you’re less likely to fall prey to the trap of clinging to bad information/belief/assumption just because you want to look correct.
I only had time to read a few paragraphs, but yeah. That’s a good one.
I’ll try to return to this and finish this reading.
It make me really sad when I learned that James and Adam were not friend.
James said their relationship doesn’t really extend beyond the show.
That’s fine and I think its pretty much the perfect example of a solid professional relationship (no need to be buddies or “like a family”) and what greatness can be achieved when you work with same endgame in mind. They may have disagreed plenty but only because they wanted to achieve the best outcomes possible.
While they are not friends, if you follow Adam on youtube, you’ll realize there is a huge amount of mutual respect between the two, even to this day.
You mean Jamie?
No, he means James. James Franklin Hyneman.
Who goes by Jamie, and always has?
Yes, he does always go by Jamie. Cordlesslamp technically wasn’t wrong though, and I think Adam even called Jamie by his full name a couple times for comedic effect.
Yeah, but the “for comedic effect” is key here. Unless you’re going for comedy or confusion, you shouldn’t refer to someone by a name they don’t use.
Yeah, I’m sorry English is my second language, sometimes I’m confused how names are spelled.
Interesting, what’s your first language?
“Failure is always an option.”
My favorite is the fan mounted to the boat blowing the sail causing the boat to move. I mean there are a shitload more experiments in fun episodes that are far better and more entertaining, but this one is my favorite because it flies in the face of logic. It shouldn’t work. My brain rejects the possibility. But physics and fluid flow work otherwise and I found it pointlessly infuriating only because I’d been unassailable in my confidence that it couldn’t possibly work. Yet there it is with a perfectly logical explanation. I still find it irritating even if I accept the reality of it. (Episode 165 if anyone’s wondering)
That said, I still follow Adam on various platforms. That enthusiasm and joy of discovery is all still there, along with some maturity and some life observations. Literally the only celebrity figure I follow.
My favorite is planes on a treadmill.
Mostly because fans still argue about it and it’s hit the point they had to ban PoaT comments.
Which is insane as it’s not that difficult to understand. When a plane is on the ground, its gear/wheels will roll at ground speed, but the wings provide lift at airspeed.
If the ground is being moved under the plane (as on a treadmill,) the wheels will just roll faster.
Sure they’re not zero friction and some of that needs to be overcome; but this is something encountered on a daily basis all across the world- or rather, the opposite.
If the wind is coming from ahead, its airspeed is increased and the plane needs a lower ground speed to get into the air where if the wind is coming from behind, then they need more.
(This is why carriers set course into the wind when launching jets,)
At no point is ground speed and airspeed necessarily the same (i suppose you could have a calm day, but most days, the wind is blowing at least some.)
Which is insane as it’s not that difficult to understand
I found it hard to understand because neither they nor any of the other sources I’ve seen explaining this even attempted to answer what I thought was an incredibly obvious question: at what point does this become true? A stationary aeroplane on a treadmill will obviously move with the treadmill. I assume an aeroplane moving at like 1 km/h still gets pulled backward by the treadmill. At what point does the transition occur, and what does that transition process look like? Why can’t a treadmill prevent the plane from taking off by pulling it backwards by never letting it start getting forward motion? Where does the lift come from?
I can understand how a treadmill doesn’t stop a plane that’s already moving, but how does it get lift if it is prevented from accelerating from 0 to 1 km/h of ground speed (relative to the real ground—relative to the ground it experiences, it is moving forward at the same speed as the treadmill is moving backward), since until it starts getting lift, airspeed and ground speed are surely effectively equal (wind being too small of a factor)?
A stationary aeroplane on a treadmill will obviously move with the treadmill. I assume an aeroplane moving at like 1 km/h still gets pulled backward by the treadmill.
so, every wheel or ball or any other kind of rolling-thing has rolling resistance, which is how we sum up the total drag on the system. A steel ball bearing on a steel plate will have a significantly lower rolling resistance than, say, a steel cube on that same plate. Tires have some- but not a lot- of rolling resistance.
You can see that in a car, just put it into neutral and watch as you slow down, even on flat ground. Plane wheels also have rolling resistance. it’s just the way our world works. But it’s generally ignored because it’s hard to model perfectly and in any case pretty negligible relative to the amount of acceleration being put out by modern aircraft engines.
A treadmill will only push an aircraft or whatever else along, with an acceleration that is equal to, or lower, than the rolling resistance. If you try to accelerate the plane faster, it’ll ‘slip’, and the plane will remain largely stationary- like the dishes in the tablecloth trick (if you want to try that at home… make sure the tablecloth doesn’t have a hem, heh.)
But, keep in mind you’re thinking about the plane relative to either the ground, or the treadmill’s belt.
the plane’s wings and it’s engines are ‘thinking’ about the plane relative to the air it’s moving through. It’s the airspeed that generates the lift, and the engine isn’t coupled to the wheels, they’re just rolling along doing their thing. (aircraft engines work by taking a volume of air and accelerating it. newton’s equal-and-opposite does the rest.)
Oh wow thank you. This is genuinely excellent and immensely helpful. I think this bit:
A treadmill will only push an aircraft or whatever else along, with an acceleration that is equal to, or lower, than the rolling resistance. If you try to accelerate the plane faster, it’ll ‘slip’
As well as this video that I found where a pilot explains how under specific but unrealistic conditions you could construct a treadmill that does indeed prevent an aeroplane from taking off,
Really helped solidify my understanding of the problem. So you end up with a situation where the wheels are going to be slipping, just like the slippage created when your hand pushes a toy car on a treadmill.
Thanks!
So, another way to think about it is with Kites.
The air flows around it the same way it would any other kind of aircraft, though they have effectively zero ground speed.
They do differ in that, being tethered, they’re pulled through the air, with the wind providing the energy to stay up.
But they’re still moving through the air, and the airfoils are inducing drag to convert some of that energy into lift.
In both cases, the important speed is relative to the air, not the ground and not the treadmill. The wheels might impart some drag while they’re on the ground, but they’re never going to impart enough to overpower the engines- 747s typically take off at about 75% of their rated take off power, which means a longer take off roll, but less wear and tear.
but how does it get lift if it is prevented from accelerating from 0 to 1 km/h of ground speed
That’s the thing - it is not prevented from accelerating. The wheels are functionally frictionless. That’s why planes have brakes. The plane pushes on the air to move, & the treadmill could accelerate backwards until the plane’s tires explode.
The key insight is that the force a plane uses to move is independent of the ground, because planes push on the air, not the ground.
Imagine you put a ball on a treadmill and turn it on, what happens? The ball starts to spin and move with the treadmill. Now take your hand and push the ball backwards against the motion of the treadmill, and the ball easily moves in that direction. The force your hand put on the ball is exactly what planes do, since they push on something other than the ground (the treadmill) they have no problem moving, no matter how fast the treadmill is moving.
The tricky bit is that the air within a few millimeters of the treadmill will move with the treadmill. The air slightly above that will be slightly disturbed and also move a bit in the direction of the treadmill. If you had an extremely long and extremely wide treadmill (say the length and width of a runway) it’s possible that the air at the height of the propeller would be moving along with the treadmill, rather than staying still, or moving with prevailing winds.
But, even in that case, the plane could still take off. All the plane needs to do is move the body of the plane through the air at enough speed to allow the wings to start generating lift. If the air at propeller-height is moving with a treadmill that is moving at take-off speed, the plane might take off with zero forward speed relative to the non-treadmill ground. But, as long as you’re not somehow preventing the propeller from moving the plane through the air, the plane will always be able to take off.
There are videos of planes taking off by themselves in high wind, and videos of VSTOL (very short take-off and landing) planes taking off and landing using only a few metres of runway.
at what point does this become true?
It’s always true.
A stationary aeroplane on a treadmill will obviously move with the treadmill
What do you mean? The plane has its parking brakes on and moves with the treadmill surface? If you don’t have parking brakes engaged and start up a treadmill under a plane, the plane’s wheels will spin and the plane will stay pretty much in one place. Because the wheels are free to spin, initially that’s all that will happen. The inertia of the plane will keep it in place while the wheels spin. Over time, the plane will start to drift in the direction the treadmill is moving, but it will never move as fast as the treadmill because there’s also friction from the air, and that’s going to be a much bigger factor.
I assume an aeroplane moving at like 1 km/h still gets pulled backward by the treadmill.
Moving at 1 km/h relative to what? The surface of the treadmill or the “world frame”? A plane on a moving treadmill will be pulled by the treadmill – there will be friction in the wheels, but it will also feel a force from the air. As soon as the pilot fires up the engine, the force from the engine will be much higher than any tiny amount of friction in the wheels from the treadmill.
but how does it get lift if it is prevented from accelerating from 0 to 1 km/h of ground speed
It isn’t prevented from accelerating from 0 to 1 km/h of ground speed. The wheels are spinning furiously, but they’re relatively frictionless. If the pilot didn’t start up the propeller, the plane would start to move in the direction the treadmill is pulling, but would never quite reach the speed of the treadmill due to air resistance. But, as soon as the pilot fires up the propeller, it works basically as normal. A little bit of the air will be moving backwards due to the treadmill, but most of the air will still be relatively stationary, so it’s easy to move the plane through the air quicker and quicker until it reaches take-off speed.
The point it occurs at is when the plane uses the air to propel itself.
Plane on a treadmill is really interesting because if you understand how planes work its so obvious what will happen you don’t need to test it. Planes move on the ground by running their engines, which push against the air, the wheels provide zero motive force. It’s also why planes need tugs to move away from the gate, you can’t run the engines in reverse. Planes are not cars, but people tend to assume the thing they don’t understand works like the thing they do understand, and refuse to believe their hasty assumption is wrong even when told directly their hasty assumption is wrong.
You actually can run the engines in reverse. They have thrust reversers. There’s very good reasons that they do not reverse the plane from the stand using the engines, but it is possible.
my criticism of PoaT actually has to do with the scale model they used to prove it.
scale aircraft have ridiculous power-to-weight ratios
but that’s just me being a stickler.
Plane on a treadmill always seems so obvious to me. Planes don’t have power connected to their wheels. Put a plane on a dynamometer and crank the engine up as fast as it will go, and the wheels will still not spin. At the same time, water planes use pontoons and are still able to take off just fine.
The question I have is, can a plane take off with a tailwind that matches the speed that the propeller is pushing out.
I think the confusion is that the conveyor belt is running at a fixed speed, which is the aircraft’s takeoff speed. That just dictates how fast the wheels spin, but since the plane generates thrust with its propeller, the wheels just end up having to spin at double takeoff speed. Since they’re relatively frictionless, that’s easy.
The more confusing myth is the one where the speed of the conveyor belt is variable, and it always moves at the same speed as the wheels. So, at the beginning the conveyor belt isn’t moving, but as soon as the plane starts to move, and its wheels start to spin, the conveyor belt movies in the opposite direction. In that case, the plane can’t take off. That’s basically like attaching an anchor to the plane’s frame, so no matter how fast the propeller spins, the airplane can’t move.
Except it’s not like attaching an anchor. The plane isn’t physically attached.
The wheels will just roll double whatever the current ground speed is. If the plane has enough thrust to take off with the treadmill moving an inverse of its take off speed, then it has enough force to start rolling, too.
At most, the force applied by the treadmill would be sufficient over enough time to lengthen the take off roll, but given enough space to do so, the plane will take off.
To keep the plane from rolling forward; the treadmill would have to be able to apply an equal force as the engines, it can’t do that through the wheels- the wheels can only apply a force equal to their rolling resistance and friction in its mechanics.
If the conveyor moves at the same speed as the wheels, it is exactly like attaching an anchor. That isn’t the myth they were testing, but it’s a more interesting myth.
it can’t do that through the wheels- the wheels can only apply a force equal to their rolling resistance and friction in its mechanics.
It can do that if it can spin the wheels fast enough. Picture the ultra-light airplane from the episode with big, bouncy wheels and a relatively weak propeller. If the treadmill was moving 1000 km/h backwards, that little propeller could never match the force due to rolling resistance from the wheels.
Just to clarify; you understand that because the engines are pushing on the plane itself and not the wheels, by the time the wheels start moving, the plane is already moving relative to ground and air alike.
Which, said another way, this thought problem appears confusing because it’s being considered from otherwise irrelevant reference frames.
An anchor sufficient to keep the plane from rolling forward is different because the force it is apply is significantly greater.
Sure, you can deflate the tires and increase the rate of spin on the wheels. But at that point, you might as well ask “can we creat a scenario where planes can’t take off”
To which the answer is definitely “Yes”,
And as a side note, if we assume the wheels are indestructible, which I’d argue is only fair, then even if what you’re saying is true and we ramp up the drag induced by the wheels sufficient to counter the engines… then the wind generated by the rolling treadmill would be producing a sufficient headwind for the plane to take off. (Remember, the air resistance of the treadmill’s belt moving will accelerate the air some.)
But again, the wheels have almost zero drag to begin with, the speed at which the roll is independent of both the actual groundspeed and the airspeed of the airplane.
If it has the thrust to over come friction at take off speeds, and at standing, then it has enough power to get to take off velocity eventually.
On the other hand, this entire conversation assumes the thrust to weight ratio is less than 1. If it’s more than one, well they just…. Go straight up.
Just to clarify; you understand that because the engines are pushing on the plane itself and not the wheels, by the time the wheels start moving, the plane is already moving relative to ground and air alike.
The wheels are attached to the plane so they move at the same time as the plane. But, I get what you’re trying to say, that the wheels are effectively being dragged by the plane, they’re not powering the movement. But, what you need to think about is that if you oppose that dragging by moving the conveyor belt in the opposite direction you can prevent the plane from moving at all. Yes, the wheels are merely dragging and there isn’t a lot of friction there, but friction increases with speed. And, if you move the conveyor belt fast enough, you can stop the plane from moving relative to the ground, which can stop it from moving relative to the air, which can prevent it from taking off.
An anchor sufficient to keep the plane from rolling forward is different because the force it is apply is significantly greater.
No, by definition it’s the same. The conveyor moves with however much speed is necessary to stop the forward motion of the plane. The conveyor would eventually go so fast that it generated enough force to stop the plane from moving, so it’s indistinguishable from an anchor.
Sure, you can deflate the tires and increase the rate of spin on the wheels.
You don’t need to deflate the tires, you merely need to increase the speed at which the conveyor moves to match the speed of the wheels.
if we assume the wheels are indestructible, which I’d argue is only fair, then even if what you’re saying is true and we ramp up the drag induced by the wheels sufficient to counter the engines… then the wind generated by the rolling treadmill would be producing a sufficient headwind for the plane to take off
That seems like an unfair assumption because you’re assuming that the conveyor belt has second-order effects on the air (i.e. generating a “wind” over the wings of the plane), while ignoring the second-order effects the conveyor would have on the wheels (massive heat from friction leading to failure).
On the other hand, this entire conversation assumes the thrust to weight ratio is less than 1. If it’s more than one, well they just…. Go straight up.
I mean, the discussion is of a plane, not a helicopter or a rocket. Even jet fighters with a thrust-to-weight ratio of more than 1 typically have engines that only have that ratio once they’re at high speed, not from a standing start. That’s why even fighter jets on carriers need a catapult-assisted takeoff. A VTOL aircraft like a Harrier wouldn’t need that, but then its takeoff speed is zero, and the myth isn’t very interesting when the conveyor belt doesn’t move.
The wheels are attached to the plane so they move at the same time as the plane. But, I get what you’re trying to say, that the wheels are effectively being dragged by the plane, they’re not powering the movement.
no. I’m saying that by the time the wheel is rolling, the plane’s is already moving forward, the engines have already overcome the drag in the wheels. the treadmill is locked to the wheels, not the plane. The plane would continue accelerating even as the wheels reported weird rates of turning.
As for the (very brief) time delay, that’s a function of the plane’s gear’s suspension that is quite well sprung.
the rate of roll on the tire is, effectively, decoupled from the airspeed (and groundspeed) of the plane. which makes this:
No, by definition it’s the same. The conveyor moves with however much speed is necessary to stop the forward motion of the plane.
… entirely different. an affixed anchor does not allow the free motion that a wheel would.
You don’t need to deflate the tires, you merely need to increase the speed at which the conveyor moves to match the speed of the wheels.
And one of a few things happen. Either the plane has enough engine thrust to overcome the acceleration induced by the wheels, and therefore takes off, or it does not.
In the case that it does not, the wheels would continue spinning in increasing RPM until the plane begins moving backwards. because, again, the airspeed of the airplane is not dependent on the wheel’s RPM. Assuming the airplane doesn’t crash from suddenly becoming incredibly difficult to control… eventually it would take off anyhow. because the airflow over the wings would still generate lift. (though they would become horribly inefficient.) and therefore take off.
this is of course ignoring the whole “can a pilot actually control that and manage a take off like that” thing. If you don’t want to grant godlike piloting skills, we could then just make the treadmill irrelevant and leave the brakes on.
I’m saying that by the time the wheel is rolling, the plane’s is already moving forward
The wheels are attached to the plane, so they move at the same time. There’s going to be slight flex due to rubber and metal not being insanely stiff, but essentially as soon as the plane starts moving forward through the air, the wheels start rolling forward along the ground. Since the conveyor belt cancels the forward movement of the wheels, the movement of the plane ceases too.
The plane would continue accelerating even as the wheels reported weird rates of turning.
Initially, for a few tenths of a second, or a few seconds sure. But, during that time, the conveyor belt would be moving faster and faster as it matched the speed of the wheels. The faster the conveyor moved, the more friction there would be, and the more drag there would be from that friction. Eventually you’d reach an equilibrium where the drag from the wheels was equal to the thrust from the engine, and the plane would cease moving forward. It would be exactly like the plane being anchored to the ground, except instead of a stationary anchor, the anchor would be a spinning treadmill in contact with a spinning wheel. In a world without a magic conveyor belt that could instantly adjust to the speed of the wheels, there would be some slight forward and backward movement of the plane, but that’s just like being attached to an anchor with a bungee rather than a rigid rope.
an affixed anchor does not allow the free motion that a wheel would.
The wheel doesn’t have free motion. By definition, the conveyor is moving at the same speed as the wheel, so the wheel is locked in place. With a real conveyor belt there would of course be some lag as the motors of the conveyor accelerated the belt, but using the hypothetical as defined, the axle of the wheel couldn’t ever move because every rotation of the wheel would be matched by a movement of the conveyor belt.
And one of a few things happen. Either the plane has enough engine thrust to overcome the acceleration induced by the wheels, and therefore takes off, or it does not.
The thrust would have to be infinite because, by definition, the conveyor is always going to match the velocity of the wheels. If the wheels were truly frictionless, then the conveyor belt would have no effect at all. But, any real wheel will have some friction that will increase with speed, so there will always be some speed where the force backwards from the friction of the spinning wheels matches the force of the engine.
As an aside, my guess is that most real airplane wheels would probably fail pretty quickly at just double the normal takeoff / landing speed. The centripetal force acting on the spinning parts of the wheel and tire increase with the square of the velocity, so 2x as fast means 4x as much force. 3x as fast and 9x as much force. So, if you did this with a real wheel, you’d destroy the wheel pretty quickly. Of course, the same applies to the conveyor belt, but I’m going to assume that it’s specially engineered to survive this challenge.
the wheels would continue spinning in increasing RPM until the plane begins moving backwards
The plane wouldn’t move backwards because if the wheels slowed down, the conveyor belt would slow down too. Of course, that’s in a world where the conveyor belt could adjust its velocity instantaneously, but for this thought-experiment you can say that if the pilot cuts the engine or something, the wheels don’t spin as fast, so the conveyor belt slows down, and the plane remains in one spot.
eventually it would take off anyhow. because the airflow over the wings would still generate lift
In the thought-experiment world, there wouldn’t be any airflow over the wings because the plane would be stationary. In reality, there would be some airflow due to the movement of the conveyor belt, but the wheels would probably melt long before that was enough air to give the plane lift while stationary relative to the world around.
