The Magic of Bird Flight with David Lentink

Рет қаралды 60,807

8 жыл бұрын

There’s so little we understand about how birds fly. Through incredible photography and observations in his lab’s wind tunnel, engineering professor David Lentink highlights rarely detected bird behavior. By studying nature, his lab seeks to build better drones.
David Lentink is an assistant professor of mechanical engineering and member of Bio-X, an interdisciplinary biosciences institute at Stanford. Professor Lentink’s multidisciplinary lab studies biological flight-bird flight in particular-as an inspiration for engineering design. He serves as a member of the Young Academy of the Royal Netherlands Academy of Arts and Sciences and received the Dutch Academic Year Prize for the Flight Artists, in which Professor Lentink crowdsourced high-speed camera footage to capture flight movements. In 2013, the World Economic Forum named him one of 40 scientists under 40. His publications range from technical journals to cover publications in Nature and Science.
This Stanford+Connects micro lecture was filmed on location in Washington, DC. Stanford+Connects is a program of the Stanford Alumni Association.
Watch, learn and connect: stanfordconnects.stanford.edu/

Пікірлер: 32

@Chompchompyerded Жыл бұрын

If they are mating in air, I guess you could say that those swifts fly United then. I have seen canada geese fly inverted like that graylag goose is doing. The lead bird in a "V" formation will often do that to dump speed and altitude quickly so that it can move to the back of the "V" when it's term as flight leader is up. There is a whole communication thing going on when they change leaders. It's really fascinating to watch and see. It's not only their flight which is amazing, but also their minds and ability to accurately communicate. I'm not sure how we think we are going to recognize extra-terrestrial intelligence and communication when we can't even tap into and understand the self-aware, sentient, intelligence we have on our own planet. The thing which I haven't seen anyone address yet is the way the wrist affects flight in many bird species. You will see many birds bend their wrists downward during sustained powered flight over distances. You won't see it as much in short flights where they are doing more of a fluttering movement, but you will see it in ducks, geese, and many other birds after they have finished climbing and are at their cruising speed. You can see it a little bit with the birds flying in the wind tunnel, but it is really marked in larger birds. There is something going on with that geometry which must be aiding them in their flight, or they wouldn't be doing it. Canada geese get the wing past their wrist almost perpendicular to the wing from the elbow to the wrist at a specific point in the downstroke. The only exception to this is when they are signalling that they are going to change leaders, at which time one bird will clap it's wings together once above it on the upstroke, and once below it on the downstroke. That will then propagate throughout the entire flock, after which the lead bird will roll upside down (like the graylag goose in this video did) in order to dump speed and a little bit of altitude so that it can easily coast to the back of the "V" without running into any of the other birds. I am pretty sure that the claps are accompanied by a honk, but I can't say for absolute certain because it takes so long for the sound to reach the ground. To my ear, taking in to account the delay of the sound, it seems to correspond with the time it is related to when they did their wing clap, and it also correlates well to an increase in the sound coming from the flock. I'd give an arm and a leg to get a drone with video and sound up there with them to verify that, but I don't know of anyone who would accept an arm and a leg in exchange for such a sophisticated drone. Maybe someday (probably after I'm long dead) someone will do that. Wing geometry from the wrist changes a lot at various times in both the downstroke and upstroke. In addition to what I mentioned above, the wing from the wrist will fold back at points in both the bottom of the downstroke and at the top of the upstroke. My guess is that this might reduce resistance as the wing travels up and down, but it is possible that it may also play a role in the trust component of bird flight. In every mechanical imitation of bird flight which I have seen, no one ever models that. They always have a wing that stiffly flutters up and down, with no wrist joint at all. That wrist is all important for controlled bird flight. Bird keepers know this well. It is why the cruel practice of pinioning is done. While it does help in terms of steering, that's not all there is to it. If a bird is in straight and level flight, they still use that joint extensively, but they just do it equally on both sides. I wish I could have been an ornithologist instead of a classical violinist. But since I was a child prodigy, I was told to go with that strength. My passion has always been for birds though. If my life were twice as long, I think I would have started on a new career when I hit retirement age. Unfortunately, I ended up severely disabled, and am slowly dying, so there will be no time or ability for that second career. I hope that there will be others who will ask these questions, and find answers. These creatures are amazing, and we have only begun to scratch the surface of what they are about.

@bikinibottom1252 3 жыл бұрын

800 years ago this man would have been called a witch and probably be burnt to death. We live in the time of informations because it is a powerful tool.

@MrFujinko 3 жыл бұрын

Gotta review your history, virtually only women ever got burned for alleged witchcraft.

@Chompchompyerded Жыл бұрын

@@MrFujinko I think the writer means "heresy". In any event, the meaning was obvious.

@Chompchompyerded Жыл бұрын

I agree. It's a wonderful time to be alive. We can set our brains free, and in the act of thinking and learning, and through the joy of discovery, we can get those endorphins flowing to make for ourselves a more happy life.

@alazar3667 4 жыл бұрын

the bird are more high tech than anything i know,visualizing hearing,smelling,digesting,flying reprodusing all in one packege

@lakshmyvineeth1970 3 жыл бұрын

he inspired me to make a presentation . it will be finished on 24th December.

@Chompchompyerded Жыл бұрын

Was your presentation recorded? I would love to know what it was about and see/read what your findings were.

@SuperHyee 3 жыл бұрын

Thanks !

@goldenbuglab Жыл бұрын

새가 나는 방법에 대한 책을 쓸까 하고, 기존에 알려진 지식을 찾아다니다가 이 영상을 보고 많은 걸 알게 됐습니다. ^^

@Chompchompyerded Жыл бұрын

사과드립니다. 내 한국어는 나빠 책을 써주세요! 새에 대한 우리의 이해에 대한 귀하의 기여는 소중합니다. 나는 당신이 그렇게 하도록 충분히 격려할 수 없습니다. 그 노력에 행운을 빕니다. 완료되면 결과를 읽고 싶습니다.

@bettylutz4578 7 жыл бұрын

nice

@johnlaccohee-joslin4477 2 ай бұрын

Would i be correct to make the observation that a bird in fact is doing the very say thing we do when chaning tbe medium in which it perform best, in flight, but actually swimming using air as we use water. It struck me having spent many a hour watching every thing it soes while in flignt. It can and does create turn by Ltering its wing struckture as well and swisting its tailfeathers to create a force that with turn it left or right and well as using the same to create thevsame effect when landing as an aircraft lowers its flaps to trap air, and also puts its bodyinto acstall position, but does so withuting its tail feathers cspead out as an air break. The swimmung bit really has me really much interested in its controlled flight and landing, some better equiped to do this better dependingnon tbectype of bird wecare looikooing at. I am interested to copy the action so that is a direct copy of just what happens on each stroke both the down stroke as well as the up stroke, It strikes me that there is a rolling action at the should, very much thevsame as a helechopter preforms a rolling of the rotor at every rotation, where when coming to the front it rolls one way znd does a reverse as the rotor goes toward the back of the aircraft. Not only soes this appear to be the case but also the shape of the wing is change depending weather or not it is a power stroke to create lift.The As far a i can see, by doing so it also alteres its centre of gravity at each stroke, effectively movingnthe wing slightly forward on the down stroke. The whole subject seems to have perplexs mankind from day one, because it is does so easily and for long periods when migrating. The also seem able to sleep while doing all this, not a deep sleep but enought to be able to preform such long trips that we see every year, truly amazing as some of the most travelled bird are not small and although built to teduce weight, they are none the less, for the bigger birds like duck and geese really built to perform this long trip many times duringntheir lives.

@timothyhill1149 2 жыл бұрын

I threw a feather out of the window and it went up. isn't there a parachuteness to a wing a airborne buoyancy?

@Chompchompyerded Жыл бұрын

Feathers are light, and depending on what sort of feather it was, it can catch the breeze or a thermal, and go up just like a bit of fluff or a dandelion seed. A birds primary flight feathers (the long ones from the tips of the wing) are heavy and won't go far unless there's a gale force wind blowing. The down, however, is very light, and it has a lot of surface in a compact area. Air, warmed by the sun hitting the side of your house, is hotter than the surrounding air, and rises upward. Such a light object as a bit of down will ride on that rising air, and float on it wherever it goes. Eventually, it will get into air which is either descending, or is calm. then gravity will take hold, and it will fall gently toward the ground. Bird primary feathers do have an aerofoil shape to them, like an airplane wing, and they provide lift and directional stabilization for the birds wing. They can lose a few of those feathers and can still fly, but when they drop them all at one time during the moult, they are essentially left flightless for a few days while the new ones grow in. I hope this helps answer your question. It is a good one. If you have more questions, please feel free to ask. I'm sorry that I did not come across this one until a year after it was posted.

@tsraikage Жыл бұрын

will taxidermied owl glide like a paper airplane?

@Chompchompyerded Жыл бұрын

No.

@janatlmb2770 6 ай бұрын

yes, wight and speed are the factors

@flaviafuas3934 Жыл бұрын

yes all birds loop swallows, eagles seagulls ....

@budekins542 6 жыл бұрын

Intelligent Design.

@h7opolo 2 жыл бұрын

4:28 how society ought to function, i.e. reward system.

@Chompchompyerded Жыл бұрын

Sometimes, though, discovery, and helping others (including other species) is its own reward. When we learn that, we are truly free and happy.

@wilsonblauheuer6544 6 жыл бұрын

Doth the hawk fly by thy wisdom, and stretch her wings toward the south? Job 39th chapter, 26th verse

@user-bw1kz8eg3l 7 ай бұрын

You are totally wrong. The weight of the truck won’t change at all even if all the birds inside the truck fly and stay in the air.

@mars84uk 6 жыл бұрын

Do they not see the birds above them with wings outspread and [sometimes] folded in? None holds them [aloft] except the Most Merciful. Indeed He is, of all things, Seeing. Quran 67:19

@aheadofthecurve2352 Жыл бұрын

Sorry but this is laughable at best. The characteristics of bird flight can easily be seen, documented and reproduced. I have zero college education and can easily describe all mechanisms involved. If only the establishment had listened to those it so viciously attack and discredited it would be common knowledge. Apparently its easier to just reassign credit to a more connected "to the manor born" individual who tows the corporate line. Vtol flight produces vortexes over the back of the wing and doubles back on itself getting up under the feathers along the back of the wing where it caught by the down and lifts the bird. Birds do not fly, they are flown. Fish do not swim they are swum. Even Joe Rogan had a guy on thay proves this theory with a dead fish advancing ahead in oncoming waters. Child's play.

@Chompchompyerded Жыл бұрын

Okay. Then what is the purpose of the way the wrist bends, flexes, and unflexes in the the course of a downstroke and upstroke? Please not only describe the mechanisms, but also the purpose. Use the Canada goose as an example since all the phases of the wing in flight are most obvious in this species, plus video of it is easy to find. I was not manor born, nor do I two the corporate line. Many of the highly educated people I know are also that way. I was born on a small farm in Nebraska, and my parents struggled to make ends meet. I worked my hind end off in school to get top grades. Then after school, I worked to make money to save for college. My hard work payed off, and I only got one "B" and that was back in grade school. I was otherwise a straight "A" student, and yes, I was one of those unpopular nerds. I worked hard in my college courses and continued to work to earn money for tuition, books, and housing because my parents could not afford to help. I graduated with a 4.0 grade point average and Magna cum Laude from one of the United States' top 5 universities (academically, not sports). I went on to work my way through a masters' degree and a PhD at the world's two best universities. I never had time for anything other than school and work. I didn't even have time to take anyone up on an offer of a date. But I did manage to land a good job in my field of study. I am sorry that you were unable to do the same. That doesn't mean though, that we are all "manor born" or beholden to corporate interests. If you are using Joe Rogan as a teacher, then you have chosen a poor one. Regarding the word "swum". it is used incorrectly in your example. "Swum" i a past participle. You would then have to put the word "have" in front of it. "Are swum" is a nonsense phrase. Present tense: fish swim. Past tense: fish swam. Past participle: fish have swum. It makes a huge difference to the meaning. Likewise, Present tense, birds fly. past tense, birds flew. Past participle: birds have have flown. Once again, "Birds are flown" is a nonsense phrase. As for the dead fish example, the dead fish didn't swim. It didn't do anything. It was moved either by the person holding it, or whatever was attached to it which moved it along. The fact that it stayed oriented in the right direction had to do both with the force pulling along, and the hydrodynamic shape of its body allowing the water to pass by it in the most efficient way. Animals generally evolve to be able to negotiate their environment in the way which will cost them the least expenditure of energy. When the expenditure of energy becomes too great, if they're alive, they hunker down where they can use up the least amount of energy and wait for conditions to improve. Even humans do that. If hurricane is blowing outside, if you're particularly brave, you might go out into it for awhile, but eventually you'll get wet and exhausted from fighting the wind, and will need to go inside, if for nothing else than to grab a bite to eat (restoring energy), to dry off, and to rest a bit before going out and confronting that crazy force of nature again. You absolutely can't fight an EF-5 tornado, so you have no choice but to hunker down and hope you don't get killed by flying debris. Is this making sense? If not, please ask questions. To me, the only question which is a bad question is the one which goes unasked. If you ask, hopefully it will show up on my notifications, and I can then try to help. Education is not something which is exclusive and should only be reserved for certain people, and to the extent that I can and am qualified to do so, I am always willing to help people learn. To me, the passing on of tested and confirmed knowledge is the best thing we can do as human beings. I'm sure that you have done that in one way or the other in your lifetime, and I believe that it was what you were trying to do here. It's not your fault that Joe Rogan's guest passed on bad information to you. I am sorry that it took two months for me to find your comment and respond to it. All I can do now is hope that you read all of this, and that if you have questions that you will ask. As you say at the end, it really is child's play, as long as you aren't accepting bad information. The part which isn't child's play is sorting out the good information from the bad information. That's why you should seek information from people who have had such a passion for the subject that they have committed a lifetime to the study of it. The universe is a big place, and we can never know everything. The best we can do as humans is to concentrate on one or two specific areas and become expert in those areas. Everyone who holds down a job, no matter how prestigious, is to a greater or lesser degree an expert in that. The guy at the greasy spoon down the street who makes me a really great burger every time I go there, even though he's probably only making minimum wage, is an expert at cooking great tasting hamburgers. I respect really respect that. The same goes for the guys who are repairing a street a few blocks from here. What would we do without them and their expertise? Our roads would suck and life would be a lot more miserable without them. Just of curiosity, what is your area of expertise? At what do you work and devote your life to? It can be either what you do for work or what you do as a hobby. I know you're an expert in something, and there are probably things which you could teach me, even if you didn't graduate from middle school, or even if you didn't go to school at all. I hope you'll take the time to read this all, and if you do, I await your reply with real interest.

@rebeccasilveous8898 5 жыл бұрын

First of all we don't live on a ball, sphere, globe Earth! We live on a flat plane. "Air" plane..."Level" plane..."Horizon" not CURVIZON.

@angertubby2787 4 жыл бұрын

We really don't..

@sometree2744 3 жыл бұрын

What keeps the earth together? What causes things to fall? What keeps the earth from flipping over or anything like that? What keeps the sun and moon from smashing down into the earth? Are they not "heavy"? What keeps the atmosphere from draining off the sides of the earth? Does air not exist? If so, how is it that putting a plastic bag on your head is lethal? How do the other planets in the sky work? How are they all round, when the earth is flat? Wouldn't people at the edge of the map see a really wierd horizon?

@BN99239 4 ай бұрын

@@sometree2744 Acceleration.