You can also discuss this video on Reddit: stvmld.com/gm9_zcuh The sponsor is Wren: Offset your carbon footprint with Wren and we'll plant 10 extra trees for the first 100 people: wren.co/start/stevemould
I would start with the carbon offsetting by supporting solar and wind energy with long lasting batteries like LTO cells. 15 - 30k cycles with 100% C1 and only a degradation to 80%. Don't believe me check it. Looking forward to your solar cell installation video^^ , preferably with LTO battery banks.
I design ships and they can actually experience a form of parametric resonance called parametric roll. The ship’s stability is a function of its waterplane area. Waves can affect this, by changing how much of the ship is in the water at the ends. You can think of this as a torsional spring, with a variable spring constant. If the wave encounter frequency is at or near the ship’s roll frequency, the ship will begin to roll very violently, even in relatively small seas. This effect often causes container ships to lose containers over the side. They deal with this by slowing the ship down, which changes the frequency the ship *encounters* the waves at.
Thats pretty smirt stuff i actually saw a video the other day of bill nye explaining this on noahs arc and the worlds largest wooden ship it would probably be a really cool short video to check out since thats ur profession
This is actually how continuous Foucault pendulum demonstrations are typically powered in museums, since you need to keep inputting power to keep the oscillation going without pulling the bob in any particular direction or influencing the rotation of its plane of oscillation.
In my brain, this moment is filed away right next to Dennis Kucinich holding a baby doll by its neck when challenged to problem solve by David Letterman.
"The size of spring was starting to get into dangerous territory, like garage door spring" As a garage door tech I appreciate that comment. Working on your own door is statically as dangerous as working on your roof. I've known plenty of other techs and home owner with ER trips and a few that passed from being careless.
A kid in my high school was doing something with his Jeep and failed at the DIY spring compression device. He came in to school the next day with a hole in his cheek! People are way too comfortable around springs and tight cables, ropes and stuff.
You could probably do an autoparamatric resonance with a swing by both translational and rotational modes (instead of using a big spring). I'm sure I'm not the only one who as a kid remembers finding that one cheap swing with the rope attachments too close together that no matter how hard you tried whenever you tried to swing on it it you would just end up spinning eventually instead - likely autoparametric resonance between those modes.
@@MaxUgly considering that the whole weight of a car is supported solely by 4 springs, and remembering that those can withstand potholes and speedbumps without issue, shuld be enough to scare people into handling with caution. You cant compress a bike spring with your full weight, let alone a car spring!
@@TheNasaDude Well, go back in time and tell that to my classmate in 2004! sheese man you act like I told him this was a good idea.. unbelievable, I'm gonna go chew on a ball bearing now..
As a fisherman I know this phenomena all to well (parametric resonance). Any time I throw my bait over a branch or something I use this method to swing it free.
@@Wesleystewart78 on the upside you can skewer your fish with the branch lol. I usually end up going after my lures and hooks and hand retrieving them off the branch, and or taking a swim.
This video reminds me that, back in school, we were asked to do an experiment to fin out what parameters affect the period of the pendulum. I made the (what seemed reasonable at the time) hypothesis that the mass would affect it. So I set up my experiment, did lots of testing and, of course, had a negative result. Undeterred I kept testing, being very thorough. I then got told off, maybe I should try something else. I didn't get good marks for that experiment. Which I maintain is very unfair. The point of science is not have the answers before you test, but to hypothesis and then try to prove or disprove! My hypothesis may have been wrong, but my approach was, I believe, entirely correct. Everyone else in the class tested length. Statistically speaking I think the majority of them must have had prior knowledge of the answer before starting.
In fairness to you, the density and size of the pendulum will have a very small effect in atmosphere, but it would be difficult to measure that effect with grade school equipment. So you weren't entirely wrong, you just didn't have the equipment to show how air resistance and weight will change the resonance.
You are right. Science is supposed to be a relentless and thorough pursuit of the truth leaving no stone unturned until it's discovered. You should have been praised for your determination not docked marks for it.
Definitely unfair. If each student or group of students used a different hypothesis, together you would have discovered which parameters matter and don't matter. If each team did it rigorously then as a class you would have derived the truth. Honestly, your experiment was more realistic.
@@YannickBo When did it change? I finished school in 2000 and the way you describe it should be is exactly the way I aced all of my physics - a good write up that reaches the right conclusion. Lets see if I still remember how to say out a physics experiment all these years later - Hypothesis, Experiment, Results, Conclusion etc.. haa
It’s amazing how many things get discovered by pure chance from the exact right combination of things. Like cutting a grape in half (but leaving it connected by a little bit of skin)and microwaving it, turns out it refracts st exactly the length of the wave of a microwave and starts to glow white hot.
2 years late but important to note if anyone reads this, the grape does not just become glowing white hot but does in fact generate plasma and it can be a very dangerous experiment to try if you dont know what youre doing
I'm glad Steve mentioned the double pendulum that is loosely coupled. I run into a similar thing carrying my water bottle (it has a string tied to the top, making it a mass at a short distance) and lunch kit (a larger mass at a longer length). I wind up swinging my arm slightly, causing both the water bottle and lunch kit to oscillate rhythmically like a loosely coupled pendulum. Turns out the masses and lengths are such that my water bottle moves counter to my lunch kit and I can feel the resonance build up if I don't slow my arm down.
6:38 I discovered this as a child and was able to get to get as high as the bar of any swing with almost no effort in as little time as possible. Imagine the heart attacks my parents got each time they'd arrive at the park and see their 10yo (with Moderate Haemophilia) standing on a 3m-high swing going higher than the bar. The issue with your form from what I can tell is that your legs are still bent while you're travelling upward, so you're unintentionally pumping into the swing. Whenever I stand on a swing, I'll only slightly bend my legs and make sure my legs are fully straightened at the same moment I reached the bottom of the arc. I'm not sure if this is accurate scientifically (but it makes sense theoretically) but I found that it was the easiest way to go super high super quickly
You probably would have loved the "ship swings" (Schiffsschaukel) we have in Germany. Uses exactly your way to get the swing going and you can do rollovers :-) ua-cam.com/video/Ole5mThW8zM/v-deo.html
We had a wooden swing set behind our house which featured a two-person "horse", which was a plank for a seat connected by two hinged joints at either end to two other planks, each of which had foot pegs and handlebars. The swing was suspended by a pair of ropes which ran between the handles and the frame. By standing on this in a surfing posture, you could get really high *very* quickly by leaning away from the direction of travel while pulling on one set of ropes while pushing on the other--essentially what you described. The ropes weren't nearly long enough to swing the full 180 degrees, though.
7:00 - You can leave your feet in the "up" position on a swing and still "pump" by just putting tension into the rope / chain at the right time. Takes longer, but it works.
@@gibbogle The girl leans back and pulls her feet down again, like all of us do/did when we pumped. I'm saying you can remain completely stationary and still make your swing higher by either pushing/pulling to cause your center of mass to shift up, as @andrew_cobb said, or maybe it moves the seat forward/backward a bit, and gains angular momentum. I'll have to investigate this further... (Hey, kids! Time for a trip to the playground! ... for you to have fun!)
I used to have this bungie rope swing when I was little. I always used to wonder why It would bounce around all weird when I tried to swing normally. I guess this is why!
A toy infinite pendulum that constantly makes a really small timed pull to keep the pendulum seemly going forever seems like a good idea Would be really cool to have one in a desk
Whenever someone brings up resonance, I immediately think of orbits, and as soon as you said you have to put energy in when it is moving the fastest I thought "just like it being more efficient to burn at periapsis to expand/lower the orbit than any other point". Anyway, amazing video, and now I want to find other more unusual examples of autoparametric resonance :)
@@SteveMould Please make a video about an oscillator with all three modes of operation: Swinging, twisting and bouncing ! I suspect it will behave chaotically but I might be wrong.
@@oscarpatxot659 KSP was where I really started to understand orbital mechanics. At this point I've looked into it a bit outside of the game, but that's where I learned a lot (mostly from Matt Lowne at the beginning).
@@cezarcatalin1406 the wilberforce pendulum can be set up like that. But from what I remember the energy ended up being spread among two of the modes and so the pattern didn't look as pretty.
I was vaguely aware of the non-auto variant, very interesting concept. Also a fascinating demonstration seeing it shift multiple times between primarily working as a pendulum and spring... converting the energy that's in the system between the two states. At first it really seems like something that should not be happening.
I love how, after explaining the initial phenomenon, you just continue right on teaching related concepts you can showcase similarly. Definitely my favorite subscription of the past year
I have a toy kinetic double pendulum on my desk. Its powered by AAA batteries to continue motion, but the changes of phase reminded me of the spring pendulum. I love how you use other examples to get a different perspective!
Oh God, I just pictured of a Bungee jump going horribly wrong by bouncing off to one side instead of up and down. Falling to the lowest point and instead of going up... bouncing off sideways into a rockface.
@@MOSMASTERING Bungee cables are always tuned in terms of length and weight for precisely that reason. And that's also why you need to make sure you're working with proper professionals.
Bungee cords are *way* less durable, especially when exposed to UV radiation. Placing a metal spring out of reach of the rider would be a better option
He could just go toprope climbing and swing on the climbing rope at the highest wall his local climbing gym has (preferably not that high off the ground). Climbing ropes are dynamic ie. they are springy and the longer the rope, the more pronounced it is.
@01:31 - A tip for pushing kids on a swing- It might be a better idea to stand in front of the swing and push the kid's knees/ lower tummy. That way one can 1. Avoid the possibility of kid slipping off of the swing by the push (the naturally leg gets stuck at the knee joint) 2. have better conversation with them when you are facing them. 3. get to look at their cute little smile as they enjoy the ride. 😍
@@davishall 😂😂 Worth the risk??🙃 You actually need to stand a bit offset from the line of motion of the swing. Otherwise your arm can not really reach the kid.
Oh boy, the normal modes are bringing back nightmares of my mechanics class. We did a whole chapter on coupled oscillators and basically what happens is you have a matrix differential equation and the normal modes correspond to the eigenvectors. They're important because all the other solutions are linear combinations of the normal modes.
thanks for explaining something I've done instinctively as a child to make the swing go faster/higher. I basically pulled the ropes in a way that shortened, or released them to make longer, because then I didn't need somebody to push on the swing to get this effect. Didn't know why it worked, just that it did.
You can see the parametric resonance in action in swiss rings (Schaukelringe), which is a gymnastics skill I learned in college. It's really fun feeling the acceleration when you get the timing right
Now I want to see a swinging Wilberforce pendulum, maybe even one linked to another to throw in some driven resonance as well. Maybe bungee cord would be a safer alternative to making a science swing?
𝐒͠𝐩͠𝐞͠𝐜͠𝐢͠𝐚͠𝐥͠ 𝐝͠𝐚͠𝐭͠𝐢͠𝐧͠𝐠͠ 𝐟͠𝐨͠𝐫͠ 𝐲͠𝐨͠𝐮͠➺ sexy-nudegirls.host Anna is a beautiful girl. He's the person I love, he's my light day. The way the music flows and sounds is extravagant and fun. Anna is icon, legend, beautiful girl, princess, inspiration, a star. I could go on and on, understand this. I love NBA Anna.#垃圾
@Casey Lewis They come around every few months. Some hacker finds a vulnerability, UA-cam bans the bot accounts, UA-cam patches the vulnerability, rinse and repeat.
I remember learning this in my advanced mechanics class. I had never seen the spinning/twisting mass on a spring one though. That was super cool to see.
I just realized that I have stumbled upon this phenomenon in-person while I was trying to work my way up a half pipe starting from the bottom, going back and forth and timing the balancing of my body weight to work my way up progressively higher up the ramp
Reminds me of the relationship between inductors and capacitors. In an LC circuit, energy is constantly exchanged by the two components, each being stored in a different field. Capacitors store energy as electric potentials and and inductors store it as magnetic potential. As one discharges, it charges the other which then discharges and starts to charge the first.
The Mathieu equation, (pronounced matew or mathew) is a fun equation. There are papers written that describe what happens when tweak various parameters. Parametric excitation is a fascinating topic. If you perform a multiple scales expansion (I would guess a first order would be sufficient) on your model you will be able to see the slow change from swinging to bobbing in your spring pendulum.
That's torque free rigid-body precession, which is very cool, but not related. It just falls out of the conservation of energy and angular momentum for a body with three distinct principle moments of inertia.
YEAH! I was just thinking about that but I couldn't remember the name of the effect. It's crazy how this one concept applies to so many fields, yet most people know nothing of it.
Not sure if that really is an analogy. The Oberth-effect is the most efficient way of increasing an orbit because of the conservation of impulse, not resonance
@@youngtschakaloff Both examples; adding force to the pendulum and efficiently increasing velocity of a spacecraft, follow the principles of Newton's law of motion.
Couldn't figure out why my sound wasn't on, but also was fortunate enough to discover that watching Steve push a child on a swing in slow motion is quite relaxing stock footage.
1:00 A flute or a whistle isn't actually resonance. There is no rhythmic external influence here. Just continuous airflow. And another parameter of a pendulum that's relatively easy to adjust is the distribution of mass. Is it all bunched up at the center of mass or spread out? A more spread out pendulum (along the radial direction, at least) will be slower than a more concentrated pendulum with the same distance from center of rotation to center of mass. Also happy to see someone that's not afraid to use centrifugal force. Too many were taught "There is no such thing" in school and stay in that narrow frame of mind the rest of their life.
No resonance? Then what, pray tell, determines the pitch of the tone? Yes, the input airflow is continuous, but do you understand how a whistle works? The airflow at the fipple is not continuous. That's precisely why there is a blade across which the air passes. If you look around, you can probably find some good Schlieren imagery of the airflow at the blade edge. (Perhaps Steve needs to do a video on how whistles and flutes work.)
@@michaelsleator6326 Yes, no resonance, precisely because the input airflow does not have that frequency to it. The input airflow isn't perfectly smooth, and that's enough. The whistle makes the frequency all on its own. The pitch in a whistle is decided by the size of the chamber and the speed of sound. Many physical systems have such a "preferred" oscillation frequency, called the eigenfrequency. And they will oscillate at that frequency when acted upon, regardless of the frequency of the input. Yes, they will oscillate way, way more with way weaker influence if the input oscillates with a frequency that matches. This is resonance. But it doesn't have to match. Like in a whistle. Like Tacoma Narrows bridge. Like a guitar string (the string itself, mind you, not the box it's attached to and the air inside that; I don't know whether that's true resonance, but at least the influence of the string is very rhythmic, so I won't exclude it without knowing more). Like a xylophone. Like a car hurtling down the freeway with one window slightly open. Like swings in the wind.
𝐒͠𝐩͠𝐞͠𝐜͠𝐢͠𝐚͠𝐥͠ 𝐝͠𝐚͠𝐭͠𝐢͠𝐧͠𝐠͠ 𝐟͠𝐨͠𝐫͠ 𝐲͠𝐨͠𝐮͠➺ sexy-nudegirls.host Anna is a beautiful girl. He's the person I love, he's my light day. The way the music flows and sounds is extravagant and fun. Anna is icon, legend, beautiful girl, princess, inspiration, a star. I could go on and on, understand this. I love NBA Anna.#垃圾
What a wonderful explanation, parametric oscillation never heard before ,but always wanted an explanation why pumping a swing, increases the velocity of it.This is amazing.
Love the video, as always, and I don't have an issue with your sponsor. I do think they're doing good things. What I have a problem with is the fact that we have been brainwashed into thinking that our individual carbon footprint is the issue to the point that a company like this was started. We should be holding those actually responsible for the majority of carbon, and other greenhouse gas emissions, responsible for their actions. Instead, through the media, the energy companies have turned the tables on us by telling us to be more responsible for our personal carbon footprint. While I agree that in a small way our individual impacts added together are significant, and that I and everyone should try to change even if slightly to help the planet. What really needs to happen is to hold these greedy planet destroying emitters responsible. Make them fund the projects to undo the damage that they have caused. Sorry about that. /rant
The complication is that corporations aren't just causing carbon emissions for no reason. Manufacturers try to keep production pretty well in line with demand, so it's not insane to say you as an individual are responsible for the carbon emissions associated with all of the items you buy. If you didn't buy that stuff, the manufacturer wouldn't have to make as many, and thus their carbon emissions would be lower. You also have the option of trying to find a manufacturer who produces a similar product with less emissions. That said, I do think it would be easier to just collectively vote on regulations and deal with price increases later rather than all individually trying to vote with our dollars. But the dollar cost of the changes are most likely going to be passed on to the consumers either way.
@@danieljensen2626 - This is still passing the buck to where it doesn't belong. Corporations only worry about their bottom line and as such, created the narrative that climate change didn't exist, moved the responsibility of who's responsible once they couldn't ignore that it exists, and continue to avoid responsibility in order to avoid the cost of change. You say it's us who need to change what we buy, yet the oil and car industries stalled progress on public transportation, electric cars, nuclear and solar/wind energy, and so on. The burden is not on individuals, but it's on our government and on corporations to shift from a model of profit at all costs to a model of responsibility.
@@kruks I think the buck doesn't belong in a single place. We should see this as everyones problem. Make individual changes to the way we live to reduce our carbon footprint and absolutely hold companies to account too. And they will need regulating I agree, the cheapest way is often not the most environmentally sustainable way so an incentive or disentive needs to be applied by government. But don't discount your own part in this
There is a phenomenon, I noticed it decades ago with a super ball, bounce the ball about 3 feet high, on a smooth driveway, the ball bounces straight up with lots of spin on it, then the next bounce it travels forward about 2 feet but with no spin on it, then hits the ground again and bounces straight up with lots of spin on it but no forward motion, and it repeats, up with spin then forward with no spin...gain and again, and i could tell it was periodic, physics is interesting.
I love these! Just as the simple pendulum swings from side to side, alternating between kinetic and potential energy, these autoparametric systems swing through phase space, alternating between energy in the spring and energy in the pendulum.
Can we all appreciate how much this is just how so much science was found. That, sure, Steve isn't *discovering* anything here, not in the big picture. But so much of science started as "person is doing some unrelated thing, and notices by coincidence some weird phenomenon". It's so great that the internet exists for us to notice these things and find an answer, but it is also how ACTUAL science works too! We should definitely all treat these as moments of discovery and self-led experimentation. Make predictions, then go find an answer - even better with your families and children.
That statement triggered my acrophobia, which has worsened (from a base of zero) as I've aged. You have fun your way I'll sit in my recliner watching Steve Mould videos.
Here's a fun swing related question that I've been meaning to sit down and find a general solution to: what is the ideal angle to jump off of a swing to maximize horizontal distance? Its not 45°, because at 44° I think you're moving faster than the benefit you gain from the ideal launch angle. But then is the same thing true at 43°? It's a surprisingly tricky problem to work out, and I've been meaning to get to it, but you're free to beat me to it.
I always fel it was near 68°, enough to get the momentum from the downward motion through the center with about half the lift from the upswing before you started to lose momentum.
I dont think there is a definite answer to that like on a throw because it should depend on the length of the swing which varies your jumping height. I guess on a swing you dont really jump as well you just let go at one time and get the angle perpendicular to the swing angle and the speed at that point
@@fbrickerlp I did a brute force test of this and found that the variables for determining the answer were pendulum length, how high up you swing from, and height from the ground at the lowest point. All that considered, I only saw a 2-3° difference in results. Somewhere around 25° if I remember right.
@@fbrickerlp a fun thing about the geometry of the problem: the angle of the rope of the swing (assuming vertical is 0°) is equal to your launch angle from the ground (assuming horizontal is 0°).
I accidently found this out myself. when I set uop a small kids swing in the shed. Instead of using normal rope I using elastic rope, and I added one of those tool weight relieving spring attached above it. This meant depending on how I started it I could get normal swing motion, Inverse motion where the middle was the highest and also a straight line backwards and forwards. My kids enjoyed it.
When you pump a swing, don't you change the centripetal force vector so that it is in the direction of travel more of the time? Perhaps that just boils down to angular momentum in the end?
𝐒͠𝐩͠𝐞͠𝐜͠𝐢͠𝐚͠𝐥͠ 𝐝͠𝐚͠𝐭͠𝐢͠𝐧͠𝐠͠ 𝐟͠𝐨͠𝐫͠ 𝐲͠𝐨͠𝐮͠➺ sexy-nudegirls.host Anna is a beautiful girl. He's the person I love, he's my light day. The way the music flows and sounds is extravagant and fun. Anna is icon, legend, beautiful girl, princess, inspiration, a star. I could go on and on, understand this. I love NBA Anna.#垃圾
The most natural phase diagram will have 4 dimensions. You can get it down to three by assuming constant energy, which removes one bit of reality but it would still capture the interplay between the different modes - the orbits would likely be something like lissajous figures, at a guess, but distorted by the non linearity of pendulums to gradually nudge it from one bunch of orbits to another.
I'd like to see a graph of the meta-period (the time between shifts from bouncy oscillation to swingy oscillation) as a function of the ratio of bounce period to swing period.
Holy smokes! The spring pendulum in auto parametric mode describes the same pattern as the Lorenz Attractor: repeating patterns within an outwardly chaotic system. Fascinating stuff, Steve!
2 роки тому+15
You can vary the "gravitational constant" by making the mass out of ferromagnetic material, and varying the magnetic field.
"That's clearly a bird doing a poo" Hahaha, I thought for sure you were going to point out how well the area has been conserved based on the wildlife or something, but no, bird doing a poo :D BTW I've been meaning to sign up for Wren for a while, this was what finally inspired me to follow through and I did it. Turns out that to offset 100% of my family's emissions is $42/mo (no coincidence it's answer to life the universe and everything), well worth it to do my part in the Climate Crisis and get some peace of mind, cheers!
when me and my sister were kids we had this trampoline and when we took it down for the winter we actually hooked all the springs together and used them as a swing once. it was fun and surprisingly no one was hurt :)
8:33 the math (extension by another third) checks out. If the extension of spring is F = m*g = k*l, then the extended-by-a-third total length is 4*l. Frequency of pendulum is sqrt(g/L), and frequency of spring oscillation is sqrt(k/m). Putting the above condition L = 4*l is equivalent to setting frequency of spring = 2* frequency of pendulum, ie parametric resonance. 👍🏻
I have had great experiments using strong monofilament fishing line for 3/4+ of the length, the rest is a rubber baseball with a 3-4' length of black eleastic threaded through it. The other end is attached to a drain opening in the street/overpass overhead. The ball hangs at rest at about shoulder height. From there up to the drain is maybe 20+ feet. This allows for pitching practice with a kick. As a juggler since 1976, I have heard many assume I am ambidextrous. This is not the case with me. However, I used my nifty hanging rubber ball to practice throwing with my subdominant side. Great fun. The elastic makes for many interesting returns, too. It's a fun rig to use in the warmer months, until the vandals tear it down. It's down by the tracks, a common place for some rough folks. All the cement walls are covered with graffiti. I hope that some had fun with the rig before it went. It can be a rough world out there, so I figure some random cool thing to stumble upon, like a ball on an elestic hanging, might be good fun for others to, heaven forbid, Play with and let off some steam. One can be quite aggressive with such a rig, depending on how hard the ball is thrown and at what trajectory. It can go from a polite pendulum swing to a really wild, unpredictable return with a punch. Maybe the rig outsmarted some of the vandals and came back to bite them. One can find the ball-on-elastic toy at Dollar Stores and the like.
There is also a fantastic analogy with quantum mechanics. You can imagine to start your system as two decoupled oscillators. This is described by a diagonal hamiltonian whose eigenstates are the two oscillators doing their thing independently. Then you introduce a certain coupling between the two oscillators, i.e. an interaction. This corresponds to an off-diagonal element in the hamiltonian, which you can diagonalize to find the two new eigenstates, i.e. the two "stable" oscillations shown in this video. In quantum mechanics, if you prepare your system in a state which is a mixture of two eigenstates and then let it evolve, the system will oscillate between the two eigenstates, exactly as shown here. Instead, if you prepare your system in an eigenstate to start with, then it will remain in your eigenstate indefinitely.
That's an example of two coupled pendulums. It's not autoparametric resonance. That would be if the Hamiltonian somehow changed depending on the state of the system.
Met this guy in real life when he came for a lecture in Newcastle he even called me on stage to guess which numbers I wrote lol. He probably won’t remember though 😅
3:25 I think that movement is being introduced by the flexing stand, I'd like to see you do it with the stand fixed as well. And as well as the stand moving, the rope being pulled over the bar would push away from the bar slightly as you pull. That and the flexible stand are adding horizontal movement to the system. The harder you pull it, the more it affects the system, the more it flexes, the more the bending string pushes it away. You need a setup that introduces no horizontal movement whatsover, only vertical. Even with your spring setup, you are still imparting horizontal movement when you first pull it down, I guarantee you aren't pulling it straight down.
Another good example of resonance is the expansion chamber in the exhaust of a two stroke engine, the pulses acting against each other at low rpm, but when rpm is increased they hit a point where the timing lines up and they build off of the frequency of exhaust pulses causing an increase in power (power band)
I thought it was pretty cool that when they're a quarter out of phase, the moment they switch is when one part of the pendulum reverses its phase. I didn't look at which is which for this, but it appears then that the pendulum that's either ahead by 1/4 or behind by 1/4 becomes the consumer of the other pendulum's momentum, and when one of them is entirely "eaten up" and reverses direction, this relationship switches (because the swinging shifts by 1/2 phase) which is why they keep going back and forth between modes like that :) Thinking on it (still without looking at the video again because thought experiments are more fun) I'm going to say the behind-phase one is the consumer. I assume this intuitively because I spent a lot of my childhood jumping on trampolines with my friends, and to give my friend all my bounce I'd stomp down on the trampoline a little bit before them. Likewise stomping just after them landing lets you kill their momentum, but I rarely did that because that energy is all absorbed by the legs and hurts quite a bit when you're not prepared for it. Edit: now I'm actually getting a little bit unsure of if I got that right, because originally I said stomp ahead of them for both and I can't decide which is which. Memory is unreliable and I don't have a trampoline and friend handy...
Very interesting stuff, I'd had loved it if you had discussed the math behind it a bit more (I know math is scary to most people, but ultimately it is the functional language to understand natural phenomenon).
6:55 By moving your legs out you are indeed changing your center of mass to gain momentum on the down-swing. The top of the pendulum isn't the only pivot point at play either, as when you move your legs out and push with your butt, you pull with your hands, so you definitely change the center of mass vertically.
A pendulum in circular motion has a fixed tension in the line-spring. I think it would not drive the spring to go into oscillation. But there can be other modes maybe.
When I was a kid, my father made me a swing that was hung on springs. I loved it, but as I grew bigger, one day one of the springs snapped and that was the end of the Moonwalk Swing. :-(
It was actually a rather ordinary wooden swing on ropes which were connected to hooks using a few sets of springs which my father got out of a few dismantled chest expanders. It had a vertical leeway of around 30 cm which enabled one to swing and hop at the same time, hence “Moonwalk”. My father is a technician and a notorious junk collector who keeps every bit of old equipment, for once it will be good to provide parts for some ingenious contraption... :)
Honestly I think Steve Moulde is one of the few good science teachers I feel like a lot of science teachers are passionate but end up being basically glorified magicians Showing us that something can be done without really explaining the how of it
I recall feeling the breath of fresh air when the 'period of a simple pendulum' formula was recently made precise and concise using the Gauss AGM function.
Every push your beautiful child got and the swing I was panicking about the concrete step exactly at head cracking ground zero should they fall 🧡 I'm still stressed 🧡
𝐒͠𝐩͠𝐞͠𝐜͠𝐢͠𝐚͠𝐥͠ 𝐝͠𝐚͠𝐭͠𝐢͠𝐧͠𝐠͠ 𝐟͠𝐨͠𝐫͠ 𝐲͠𝐨͠𝐮͠➺ sexy-nudegirls.host Anna is a beautiful girl. He's the person I love, he's my light day. The way the music flows and sounds is extravagant and fun. Anna is icon, legend, beautiful girl, princess, inspiration, a star. I could go on and on, understand this. I love NBA Anna.#垃圾
11:27 This is kind of remotely similar to photons! (electromagnetic waves). They have 2 properties, electric & magnetic, and if you graph them you end up with a Sinus & CoSinus wave (or 2 sive waves, but one is offset to the right with 1/4 frequency, or something like that, don't remember exactly.)
CLOSE and nicely DONE👍! By tugging the string at each end of the swing you're 1. momentarily shortening the RADIUS of the swing ( pulling IN the arms of the spinning ice-skater ... ) at the SAME time as you're 2. RAISING the height of the mass thus adding to ITS internal Gravitational Potential Energy. When PUSHING -horizontally - your child on a swing at JUST the right time ONCE in the pendulum swing (twice if your wife is in front - strategically chosen by you to avoid the "swinging-legs-impact" or "getting kicked on the noggin" phenomenon 😉) you're participating in the resonance of the system , but shortening or lengthening the radius and adding potential energy while part of the closed system, is parametrically primary to the secondary effect of "resonance" even tho the "timing" makes ALL of it part of the resonance youre - very _nicely_ describing ! Think of the kid's "pumping and leaning" to increase the height of the swing and you get an idea of internal system "resonance" adding amplitude to the swing. All of your "pulling-string" is injecting EXTERNALLY SUPPLIED ENERGY _into_ the "System" . The spring alone works off of ONLY the initially-imparted energy. Good Vid, and overall good description of the phenomenon 👍! Fun diversion, too ! The COOL part tho, in MY opinion , is- There are a whole HANDFUL of factors all coming into play, that at first don't seem obvious or connected, but when brought out as you have here make for a very interesting look at a basic bit of Physics !! Science is INTERESTING - and Engineering makes Science _ FUN_ !! Thanks and ALL the _BEST_ 👍!! -C.
You can also discuss this video on Reddit: stvmld.com/gm9_zcuh
The sponsor is Wren: Offset your carbon footprint with Wren and we'll plant 10 extra trees for the first 100 people: wren.co/start/stevemould
Love your videos Steve! Bluest eyes on youtube :P
+Cryptogenik
ua-cam.com/video/5sgRTbTm91Q/v-deo.html
I would start with the carbon offsetting by supporting solar and wind energy with long lasting batteries like LTO cells. 15 - 30k cycles with 100% C1 and only a degradation to 80%. Don't believe me check it. Looking forward to your solar cell installation video^^ , preferably with LTO battery banks.
Wren is a scam just like all other carbon offsets
isnt bungee jumping basicly a swing with a "spring" in it?
I design ships and they can actually experience a form of parametric resonance called parametric roll. The ship’s stability is a function of its waterplane area. Waves can affect this, by changing how much of the ship is in the water at the ends. You can think of this as a torsional spring, with a variable spring constant. If the wave encounter frequency is at or near the ship’s roll frequency, the ship will begin to roll very violently, even in relatively small seas. This effect often causes container ships to lose containers over the side. They deal with this by slowing the ship down, which changes the frequency the ship *encounters* the waves at.
That is amazing and scary. Amazing that it's such a universal concept.
one step forward two steps back 🚢
That's a fascinating example. Thank you!
How long does it take for you to design a ship?
Thats pretty smirt stuff i actually saw a video the other day of bill nye explaining this on noahs arc and the worlds largest wooden ship it would probably be a really cool short video to check out since thats ur profession
This is actually how continuous Foucault pendulum demonstrations are typically powered in museums, since you need to keep inputting power to keep the oscillation going without pulling the bob in any particular direction or influencing the rotation of its plane of oscillation.
Oh cool!
O cool!
Foucault, arch-enemy of flattards.
Owe cool!
I had wondered about that, but never bothered to look into it. Neat!
*"You're just shoving the thing, repeatedly."*
-Steve Mould, describing the gentle act of pushing a child on a swing, 2022
accidenaly breaking the childs back
shortly before giving the child whiplash to make a scientific point
Physics doesn't care about the child, any object of the same mass would have sufficed.
gentle act? that child's spine was shattered in the end.
In my brain, this moment is filed away right next to Dennis Kucinich holding a baby doll by its neck when challenged to problem solve by David Letterman.
"The size of spring was starting to get into dangerous territory, like garage door spring"
As a garage door tech I appreciate that comment. Working on your own door is statically as dangerous as working on your roof. I've known plenty of other techs and home owner with ER trips and a few that passed from being careless.
A kid in my high school was doing something with his Jeep and failed at the DIY spring compression device. He came in to school the next day with a hole in his cheek! People are way too comfortable around springs and tight cables, ropes and stuff.
You could probably do an autoparamatric resonance with a swing by both translational and rotational modes (instead of using a big spring). I'm sure I'm not the only one who as a kid remembers finding that one cheap swing with the rope attachments too close together that no matter how hard you tried whenever you tried to swing on it it you would just end up spinning eventually instead - likely autoparametric resonance between those modes.
@@MaxUgly considering that the whole weight of a car is supported solely by 4 springs, and remembering that those can withstand potholes and speedbumps without issue, shuld be enough to scare people into handling with caution.
You cant compress a bike spring with your full weight, let alone a car spring!
@@TheNasaDude Well, go back in time and tell that to my classmate in 2004! sheese man you act like I told him this was a good idea.. unbelievable, I'm gonna go chew on a ball bearing now..
@@MaxUgly I was just pondering, not lecturing you. And pass me the ball bearing, I want to chew some too
As a fisherman I know this phenomena all to well (parametric resonance). Any time I throw my bait over a branch or something I use this method to swing it free.
With my skill I usually tug a bit too hard and end up hooking the branch like a grappling hook lmao
@@100GTAGUY yup I have this luck then I switched to spiderwire 80lb and now I either straighten my hook or get a free branch lol
@@Wesleystewart78 on the upside you can skewer your fish with the branch lol.
I usually end up going after my lures and hooks and hand retrieving them off the branch, and or taking a swim.
Oh wait... You're right!
also very evident in the flyfishing casting techniques
This video reminds me that, back in school, we were asked to do an experiment to fin out what parameters affect the period of the pendulum.
I made the (what seemed reasonable at the time) hypothesis that the mass would affect it.
So I set up my experiment, did lots of testing and, of course, had a negative result. Undeterred I kept testing, being very thorough.
I then got told off, maybe I should try something else.
I didn't get good marks for that experiment.
Which I maintain is very unfair. The point of science is not have the answers before you test, but to hypothesis and then try to prove or disprove!
My hypothesis may have been wrong, but my approach was, I believe, entirely correct.
Everyone else in the class tested length. Statistically speaking I think the majority of them must have had prior knowledge of the answer before starting.
When we found out that our hypothesis was wrong and we could explain why we could still get full marks, that's how it should be
In fairness to you, the density and size of the pendulum will have a very small effect in atmosphere, but it would be difficult to measure that effect with grade school equipment. So you weren't entirely wrong, you just didn't have the equipment to show how air resistance and weight will change the resonance.
You are right. Science is supposed to be a relentless and thorough pursuit of the truth leaving no stone unturned until it's discovered. You should have been praised for your determination not docked marks for it.
Definitely unfair. If each student or group of students used a different hypothesis, together you would have discovered which parameters matter and don't matter. If each team did it rigorously then as a class you would have derived the truth.
Honestly, your experiment was more realistic.
@@YannickBo When did it change? I finished school in 2000 and the way you describe it should be is exactly the way I aced all of my physics - a good write up that reaches the right conclusion. Lets see if I still remember how to say out a physics experiment all these years later - Hypothesis, Experiment, Results, Conclusion etc.. haa
Steve's dedication is just amazing! He's spent years to raise his latest physics teaching prop.
lol
Eh, here I thought we are going to have a new Mould Effect, but instead it already has a boring name as Autoparametric Resonance
It saves us all a month of argument though.
Hey Mehdi!'
Love your videos
Any idea on the next topic?
What about a rotational oscillation that switches to an up and down oscillation that switches to a pendulum oscillation? Do you think this works?
Why did i read this in his voice ???🧐😯
youDisinform.
It’s amazing how many things get discovered by pure chance from the exact right combination of things.
Like cutting a grape in half (but leaving it connected by a little bit of skin)and microwaving it, turns out it refracts st exactly the length of the wave of a microwave and starts to glow white hot.
Which sane person microwaved grapes after failing to cut it in half
@@brianevans9231 which is why insane people make discoveries lmao
hmm... interesting
the wavelength of a 2.4 GHz microwave is 12.5 cm. So the grape antenna must be some fractional wavelength.
2 years late but important to note if anyone reads this, the grape does not just become glowing white hot but does in fact generate plasma and it can be a very dangerous experiment to try if you dont know what youre doing
I'm glad Steve mentioned the double pendulum that is loosely coupled. I run into a similar thing carrying my water bottle (it has a string tied to the top, making it a mass at a short distance) and lunch kit (a larger mass at a longer length). I wind up swinging my arm slightly, causing both the water bottle and lunch kit to oscillate rhythmically like a loosely coupled pendulum. Turns out the masses and lengths are such that my water bottle moves counter to my lunch kit and I can feel the resonance build up if I don't slow my arm down.
6:38 I discovered this as a child and was able to get to get as high as the bar of any swing with almost no effort in as little time as possible. Imagine the heart attacks my parents got each time they'd arrive at the park and see their 10yo (with Moderate Haemophilia) standing on a 3m-high swing going higher than the bar.
The issue with your form from what I can tell is that your legs are still bent while you're travelling upward, so you're unintentionally pumping into the swing. Whenever I stand on a swing, I'll only slightly bend my legs and make sure my legs are fully straightened at the same moment I reached the bottom of the arc. I'm not sure if this is accurate scientifically (but it makes sense theoretically) but I found that it was the easiest way to go super high super quickly
You probably would have loved the "ship swings" (Schiffsschaukel) we have in Germany.
Uses exactly your way to get the swing going and you can do rollovers :-)
ua-cam.com/video/Ole5mThW8zM/v-deo.html
That sounds incredibly terrifying, God bless your parents
I'm doing this the next time I find a swing
We had a wooden swing set behind our house which featured a two-person "horse", which was a plank for a seat connected by two hinged joints at either end to two other planks, each of which had foot pegs and handlebars. The swing was suspended by a pair of ropes which ran between the handles and the frame. By standing on this in a surfing posture, you could get really high *very* quickly by leaning away from the direction of travel while pulling on one set of ropes while pushing on the other--essentially what you described. The ropes weren't nearly long enough to swing the full 180 degrees, though.
I've seen acrobats do the same thing :)
@@miso2923I've done that as a child and thinking back, that sh!t's terrifying.
7:00 - You can leave your feet in the "up" position on a swing and still "pump" by just putting tension into the rope / chain at the right time. Takes longer, but it works.
Yes. The girl is doing that.
Cool
I'll try doing that
Or by pushing/pulling the rope with the right timing. Takes even longer. Must raise/lower your centre of mass just a bit.
@@gibbogle The girl leans back and pulls her feet down again, like all of us do/did when we pumped. I'm saying you can remain completely stationary and still make your swing higher by either pushing/pulling to cause your center of mass to shift up, as @andrew_cobb said, or maybe it moves the seat forward/backward a bit, and gains angular momentum. I'll have to investigate this further... (Hey, kids! Time for a trip to the playground! ... for you to have fun!)
You playing that flute is gonna become a meme, that I can guaranty
guarantee
Makeing it now 🤣
It’s already a meme. It’s the Titanic Flute Meme
Yep
Recorder
I used to have this bungie rope swing when I was little. I always used to wonder why It would bounce around all weird when I tried to swing normally.
I guess this is why!
I do not hold any knowledge about this but this phenomenon looks so interesting and cool
A toy infinite pendulum that constantly makes a really small timed pull to keep the pendulum seemly going forever seems like a good idea
Would be really cool to have one in a desk
Would you buy one? I wonder if could be integrated into a ball clicker.
"If swings had springs" sounds like a relative of "if wishes were fishes"
I've always heard it as "if wishes were horses, beggars would ride".
@@kencarpenter1363 "If wishes were fishes, we'd all cast nets" comes from Frank Herbert's novel "Dune"
@@kencarpenter1363 “if wishes were horses we’d all be eating steak” can’t remember the show, but I feel like it was said by Jayne Cobb 🤔
If if was a fifth we'd all be drunk.
We would live in the sea.
Whenever someone brings up resonance, I immediately think of orbits, and as soon as you said you have to put energy in when it is moving the fastest I thought "just like it being more efficient to burn at periapsis to expand/lower the orbit than any other point". Anyway, amazing video, and now I want to find other more unusual examples of autoparametric resonance :)
Cool!
@@SteveMould
Please make a video about an oscillator with all three modes of operation:
Swinging, twisting and bouncing !
I suspect it will behave chaotically but I might be wrong.
I’ll have to thank Kerbal Space Program for letting me understand your comment
@@oscarpatxot659 KSP was where I really started to understand orbital mechanics. At this point I've looked into it a bit outside of the game, but that's where I learned a lot (mostly from Matt Lowne at the beginning).
@@cezarcatalin1406 the wilberforce pendulum can be set up like that. But from what I remember the energy ended up being spread among two of the modes and so the pattern didn't look as pretty.
I was vaguely aware of the non-auto variant, very interesting concept. Also a fascinating demonstration seeing it shift multiple times between primarily working as a pendulum and spring... converting the energy that's in the system between the two states. At first it really seems like something that should not be happening.
You know it's good quality when he's willing to break his child's back for the video
I love how, after explaining the initial phenomenon, you just continue right on teaching related concepts you can showcase similarly. Definitely my favorite subscription of the past year
I like this part the best 14:42
Swings on springs would indeed be autoparamedic.
Bruh. Report that bot, they are popping up everywhere recently. I’m sure that by clicking the link you get your account stolen.
@@mixer0014 it's upto the creator to run the thioJoe script us viewers can't do anything since the bots will exist even after reporting
@@YellowLAVA eventually, youtube will ban them.
But would only work for swingers with the right mass.
@@mrnerd3143 I've been thinking that for over a year now. I think Google gave up the fight.
I don't know why but watching the pendulum gain amplitude from the resonant tugging is very satisfying
Isn't it!
@@SteveMould I encourage you to try ThioJoe's spam comment removal tool. These bots are real annoying.
@@SteveMould linus tech tips had posted a video about removing these kinds of spam.
@@kanjakan If he does that then how am I supposed to find special dating?
@@lasagnahog7695 suddenly all the hot singles in my area go silent. Curious
I have a toy kinetic double pendulum on my desk. Its powered by AAA batteries to continue motion, but the changes of phase reminded me of the spring pendulum. I love how you use other examples to get a different perspective!
wow, i love it. And who else tried to scrape of the dirt off the monitor at 8:28?
You could probably use bungee cords instead of springs for a real-life version of this sort of swing
Oh God, I just pictured of a Bungee jump going horribly wrong by bouncing off to one side instead of up and down. Falling to the lowest point and instead of going up... bouncing off sideways into a rockface.
@@MOSMASTERING Bungee cables are always tuned in terms of length and weight for precisely that reason.
And that's also why you need to make sure you're working with proper professionals.
Cords are still springs and since they have same energy capacity - till take your arm off just as well.
Bungee cords are *way* less durable, especially when exposed to UV radiation. Placing a metal spring out of reach of the rider would be a better option
He could just go toprope climbing and swing on the climbing rope at the highest wall his local climbing gym has (preferably not that high off the ground). Climbing ropes are dynamic ie. they are springy and the longer the rope, the more pronounced it is.
@01:31 - A tip for pushing kids on a swing- It might be a better idea to stand in front of the swing and push the kid's knees/ lower tummy. That way one can
1. Avoid the possibility of kid slipping off of the swing by the push (the naturally leg gets stuck at the knee joint)
2. have better conversation with them when you are facing them.
3. get to look at their cute little smile as they enjoy the ride. 😍
4. A nice kick in the balls
@@davishall 😂😂
Worth the risk??🙃
You actually need to stand a bit offset from the line of motion of the swing. Otherwise your arm can not really reach the kid.
They will kick you in the face sooner or later.
Oh boy, the normal modes are bringing back nightmares of my mechanics class. We did a whole chapter on coupled oscillators and basically what happens is you have a matrix differential equation and the normal modes correspond to the eigenvectors. They're important because all the other solutions are linear combinations of the normal modes.
Beautiful video! My girlfriend is crying while watching for some reason tho. Very emotional content.
thanks for explaining something I've done instinctively as a child to make the swing go faster/higher. I basically pulled the ropes in a way that shortened, or released them to make longer, because then I didn't need somebody to push on the swing to get this effect. Didn't know why it worked, just that it did.
You can see the parametric resonance in action in swiss rings (Schaukelringe), which is a gymnastics skill I learned in college. It's really fun feeling the acceleration when you get the timing right
I used to do it on a swing along with moving my legs, doing both really gets you a lot of speed
Now I want to see a swinging Wilberforce pendulum, maybe even one linked to another to throw in some driven resonance as well.
Maybe bungee cord would be a safer alternative to making a science swing?
𝐒͠𝐩͠𝐞͠𝐜͠𝐢͠𝐚͠𝐥͠ 𝐝͠𝐚͠𝐭͠𝐢͠𝐧͠𝐠͠ 𝐟͠𝐨͠𝐫͠ 𝐲͠𝐨͠𝐮͠➺ sexy-nudegirls.host
Anna is a beautiful girl.
He's the person I love, he's my light
day. The way the music flows and sounds
is extravagant and fun. Anna is
icon, legend, beautiful girl, princess, inspiration,
a star. I could go on and on, understand this.
I love NBA Anna.#垃圾
University of Michigan has a swingset like this on the engineering campus
You beat me to it. We have one of those pendulums in my department and I tried doing that just last week lol
@Casey Lewis They come around every few months. Some hacker finds a vulnerability, UA-cam bans the bot accounts, UA-cam patches the vulnerability, rinse and repeat.
@@TheHongKonger Do you know if it helps reporting them?
Would love to see the first one with an LED attached, in a low light setting!
Yes, perhaps with a very long exposure to map the locations.
I have never felt so entertained by a simple breakdown of a complex mechanism. The bird going poo was icing on the cake!
I made a swing of springs for my daughter. Great fun. Look for hose tender springs, they usually go under a trailer or behind a semi to hold hoses up.
I remember learning this in my advanced mechanics class. I had never seen the spinning/twisting mass on a spring one though. That was super cool to see.
I just realized that I have stumbled upon this phenomenon in-person while I was trying to work my way up a half pipe starting from the bottom, going back and forth and timing the balancing of my body weight to work my way up progressively higher up the ramp
Reminds me of the relationship between inductors and capacitors. In an LC circuit, energy is constantly exchanged by the two components, each being stored in a different field. Capacitors store energy as electric potentials and and inductors store it as magnetic potential. As one discharges, it charges the other which then discharges and starts to charge the first.
The Mathieu equation, (pronounced matew or mathew) is a fun equation. There are papers written that describe what happens when tweak various parameters. Parametric excitation is a fascinating topic.
If you perform a multiple scales expansion (I would guess a first order would be sufficient) on your model you will be able to see the slow change from swinging to bobbing in your spring pendulum.
1:29 Props to having a child just to explain this analogy - that's true dedication right there!
This reminds me of the spinning T shaped thing they showed on the ISS, and how it was oscillating between different axes of rotation.
Yes! Veritasium did an awesome vid on it: ua-cam.com/video/1VPfZ_XzisU/v-deo.html
That's torque free rigid-body precession, which is very cool, but not related. It just falls out of the conservation of energy and angular momentum for a body with three distinct principle moments of inertia.
That was mind blowing. I was looking at that video and scratching my head.
The tensioning at the right point is actually a perfect analogy of the Oberth effect, which is used to accelerate spacecrafts.
YEAH! I was just thinking about that but I couldn't remember the name of the effect. It's crazy how this one concept applies to so many fields, yet most people know nothing of it.
Not sure if that really is an analogy. The Oberth-effect is the most efficient way of increasing an orbit because of the conservation of impulse, not resonance
@@youngtschakaloff Both examples; adding force to the pendulum and efficiently increasing velocity of a spacecraft, follow the principles of Newton's law of motion.
@@Element4ry well a man walking and a spacecraft also both follow the principles of newton's laws of motion. not exactly analogous though.
@@ClashBluelight They do. But the point is about efficiency in doing so.
Excellent explanation. As usual: breaking down the problem into understandable parts. Respect👍
Couldn't figure out why my sound wasn't on, but also was fortunate enough to discover that watching Steve push a child on a swing in slow motion is quite relaxing stock footage.
0:57 beautiful, brings a tear to the eye.
1:00 A flute or a whistle isn't actually resonance. There is no rhythmic external influence here. Just continuous airflow.
And another parameter of a pendulum that's relatively easy to adjust is the distribution of mass. Is it all bunched up at the center of mass or spread out? A more spread out pendulum (along the radial direction, at least) will be slower than a more concentrated pendulum with the same distance from center of rotation to center of mass.
Also happy to see someone that's not afraid to use centrifugal force. Too many were taught "There is no such thing" in school and stay in that narrow frame of mind the rest of their life.
No resonance? Then what, pray tell, determines the pitch of the tone? Yes, the input airflow is continuous, but do you understand how a whistle works? The airflow at the fipple is not continuous. That's precisely why there is a blade across which the air passes. If you look around, you can probably find some good Schlieren imagery of the airflow at the blade edge. (Perhaps Steve needs to do a video on how whistles and flutes work.)
@@michaelsleator6326 Yes, no resonance, precisely because the input airflow does not have that frequency to it. The input airflow isn't perfectly smooth, and that's enough. The whistle makes the frequency all on its own.
The pitch in a whistle is decided by the size of the chamber and the speed of sound. Many physical systems have such a "preferred" oscillation frequency, called the eigenfrequency. And they will oscillate at that frequency when acted upon, regardless of the frequency of the input.
Yes, they will oscillate way, way more with way weaker influence if the input oscillates with a frequency that matches. This is resonance. But it doesn't have to match. Like in a whistle. Like Tacoma Narrows bridge. Like a guitar string (the string itself, mind you, not the box it's attached to and the air inside that; I don't know whether that's true resonance, but at least the influence of the string is very rhythmic, so I won't exclude it without knowing more). Like a xylophone. Like a car hurtling down the freeway with one window slightly open. Like swings in the wind.
This is one of the best science channels I have ever seen. I can’t wait to show your videos to my toddler when he’s a bit older!
There's other science channels if your interested I can send?!.
Love the videos and the concepts Steve. Always a great watch
𝐒͠𝐩͠𝐞͠𝐜͠𝐢͠𝐚͠𝐥͠ 𝐝͠𝐚͠𝐭͠𝐢͠𝐧͠𝐠͠ 𝐟͠𝐨͠𝐫͠ 𝐲͠𝐨͠𝐮͠➺ sexy-nudegirls.host
Anna is a beautiful girl.
He's the person I love, he's my light
day. The way the music flows and sounds
is extravagant and fun. Anna is
icon, legend, beautiful girl, princess, inspiration,
a star. I could go on and on, understand this.
I love NBA Anna.#垃圾
What a wonderful explanation, parametric oscillation never heard before ,but always wanted an explanation why pumping a swing, increases the velocity of it.This is amazing.
Although the content was bouncing around a little bit, the real message really resonated with me. I’m sure I’ll swing back later when I feel tense.
Love the video, as always, and I don't have an issue with your sponsor. I do think they're doing good things. What I have a problem with is the fact that we have been brainwashed into thinking that our individual carbon footprint is the issue to the point that a company like this was started.
We should be holding those actually responsible for the majority of carbon, and other greenhouse gas emissions, responsible for their actions. Instead, through the media, the energy companies have turned the tables on us by telling us to be more responsible for our personal carbon footprint. While I agree that in a small way our individual impacts added together are significant, and that I and everyone should try to change even if slightly to help the planet. What really needs to happen is to hold these greedy planet destroying emitters responsible. Make them fund the projects to undo the damage that they have caused.
Sorry about that. /rant
UA-cam needs to get a handle on these Bot-Accounts
I can't fathom how they can successfully pull the same trick twice. It's keep america beautiful campaign all over again.
The complication is that corporations aren't just causing carbon emissions for no reason. Manufacturers try to keep production pretty well in line with demand, so it's not insane to say you as an individual are responsible for the carbon emissions associated with all of the items you buy. If you didn't buy that stuff, the manufacturer wouldn't have to make as many, and thus their carbon emissions would be lower. You also have the option of trying to find a manufacturer who produces a similar product with less emissions.
That said, I do think it would be easier to just collectively vote on regulations and deal with price increases later rather than all individually trying to vote with our dollars. But the dollar cost of the changes are most likely going to be passed on to the consumers either way.
@@danieljensen2626 - This is still passing the buck to where it doesn't belong. Corporations only worry about their bottom line and as such, created the narrative that climate change didn't exist, moved the responsibility of who's responsible once they couldn't ignore that it exists, and continue to avoid responsibility in order to avoid the cost of change. You say it's us who need to change what we buy, yet the oil and car industries stalled progress on public transportation, electric cars, nuclear and solar/wind energy, and so on.
The burden is not on individuals, but it's on our government and on corporations to shift from a model of profit at all costs to a model of responsibility.
@@kruks I think the buck doesn't belong in a single place. We should see this as everyones problem. Make individual changes to the way we live to reduce our carbon footprint and absolutely hold companies to account too. And they will need regulating I agree, the cheapest way is often not the most environmentally sustainable way so an incentive or disentive needs to be applied by government. But don't discount your own part in this
There is a phenomenon, I noticed it decades ago with a super ball, bounce the ball about 3 feet high, on a smooth driveway, the ball bounces straight up with lots of spin on it, then the next bounce it travels forward about 2 feet but with no spin on it, then hits the ground again and bounces straight up with lots of spin on it but no forward motion, and it repeats, up with spin then forward with no spin...gain and again, and i could tell it was periodic, physics is interesting.
That's not physics, you lived near a witch. I'll pray for you
I know exactly what you’re talking about!
That’s really cool!
If you spin a superball and throw it under a low table, it will come back out because of this effect.
We tried to Max out spin rates, measuring how wide was the left/right bounce..
I love these! Just as the simple pendulum swings from side to side, alternating between kinetic and potential energy, these autoparametric systems swing through phase space, alternating between energy in the spring and energy in the pendulum.
I must say the weight switching from spring to pendulum oscillation is simply beautiful.
Can we all appreciate how much this is just how so much science was found. That, sure, Steve isn't *discovering* anything here, not in the big picture. But so much of science started as "person is doing some unrelated thing, and notices by coincidence some weird phenomenon". It's so great that the internet exists for us to notice these things and find an answer, but it is also how ACTUAL science works too!
We should definitely all treat these as moments of discovery and self-led experimentation. Make predictions, then go find an answer - even better with your families and children.
I've used the string technique while climbing to help someone swing back to a wall when they fall off a large overhang. I never knew why it worked
That statement triggered my acrophobia, which has worsened (from a base of zero) as I've aged. You have fun your way I'll sit in my recliner watching Steve Mould videos.
2:28 this is revoltingly unsatisfying!
Here's a fun swing related question that I've been meaning to sit down and find a general solution to: what is the ideal angle to jump off of a swing to maximize horizontal distance?
Its not 45°, because at 44° I think you're moving faster than the benefit you gain from the ideal launch angle. But then is the same thing true at 43°? It's a surprisingly tricky problem to work out, and I've been meaning to get to it, but you're free to beat me to it.
I always fel it was near 68°, enough to get the momentum from the downward motion through the center with about half the lift from the upswing before you started to lose momentum.
I dont think there is a definite answer to that like on a throw because it should depend on the length of the swing which varies your jumping height. I guess on a swing you dont really jump as well you just let go at one time and get the angle perpendicular to the swing angle and the speed at that point
@@petertrudelljr how do you define the angle?
@@fbrickerlp I did a brute force test of this and found that the variables for determining the answer were pendulum length, how high up you swing from, and height from the ground at the lowest point. All that considered, I only saw a 2-3° difference in results. Somewhere around 25° if I remember right.
@@fbrickerlp a fun thing about the geometry of the problem: the angle of the rope of the swing (assuming vertical is 0°) is equal to your launch angle from the ground (assuming horizontal is 0°).
I accidently found this out myself. when I set uop a small kids swing in the shed. Instead of using normal rope I using elastic rope, and I added one of those tool weight relieving spring attached above it. This meant depending on how I started it I could get normal swing motion, Inverse motion where the middle was the highest and also a straight line backwards and forwards. My kids enjoyed it.
I appreciate that Professor Mould’s grey hairs take up the duty of being the least ruly of the bunch. I shall watch their progress with interest.
I love how steves videos are getiing better and better. First the ballerina cosplay and now this. Great work man, great work
You need to do one with all 3 modes: twisting, swinging, and springing
YES
Chaos ensues
+
Bop it! Twist it!
The opening scene technically had that.
That'd be some neat choreography.
Steve, you don't have to use a spring for this, you could use a bungie cord.
Which is just a different type of spring
6:36 this was definitely the most wholesome shot I've ever seen on UA-cam 🤣
I'm a science channel addict but for some reason I havent seen this channel until now! Subscribed for sure!!
My childhood would’ve been a lot more fun…and a bit more dangerous 😂
How are all of them bots!!!?
When you pump a swing, don't you change the centripetal force vector so that it is in the direction of travel more of the time? Perhaps that just boils down to angular momentum in the end?
I'd love to see the phase diagram between the length of the spring and the amplitude of the pendulum
𝐒͠𝐩͠𝐞͠𝐜͠𝐢͠𝐚͠𝐥͠ 𝐝͠𝐚͠𝐭͠𝐢͠𝐧͠𝐠͠ 𝐟͠𝐨͠𝐫͠ 𝐲͠𝐨͠𝐮͠➺ sexy-nudegirls.host
Anna is a beautiful girl.
He's the person I love, he's my light
day. The way the music flows and sounds
is extravagant and fun. Anna is
icon, legend, beautiful girl, princess, inspiration,
a star. I could go on and on, understand this.
I love NBA Anna.#垃圾
The most natural phase diagram will have 4 dimensions. You can get it down to three by assuming constant energy, which removes one bit of reality but it would still capture the interplay between the different modes - the orbits would likely be something like lissajous figures, at a guess, but distorted by the non linearity of pendulums to gradually nudge it from one bunch of orbits to another.
I'd like to see a graph of the meta-period (the time between shifts from bouncy oscillation to swingy oscillation) as a function of the ratio of bounce period to swing period.
I freaking love this channel! Steve you are such a talented and goofy guy, as an artist and audio engineer I really love these especially!
Stay curious!
Holy smokes! The spring pendulum in auto parametric mode describes the same pattern as the Lorenz Attractor: repeating patterns within an outwardly chaotic system. Fascinating stuff, Steve!
You can vary the "gravitational constant" by making the mass out of ferromagnetic material, and varying the magnetic field.
Yeah but that's not _actually_ varying the gravitational constant.
brb grabbing a compass
"That's clearly a bird doing a poo" Hahaha, I thought for sure you were going to point out how well the area has been conserved based on the wildlife or something, but no, bird doing a poo :D BTW I've been meaning to sign up for Wren for a while, this was what finally inspired me to follow through and I did it. Turns out that to offset 100% of my family's emissions is $42/mo (no coincidence it's answer to life the universe and everything), well worth it to do my part in the Climate Crisis and get some peace of mind, cheers!
child: my dad is a scientist
dad: 6:46
You earned my like with the flute solo. You earned my subscription years ago.
I love these deep rabbit hole dives.
Thank you friend.
when me and my sister were kids we had this trampoline and when we took it down for the winter we actually hooked all the springs together and used them as a swing once. it was fun and surprisingly no one was hurt :)
The "other" way to pump a swing is the more powerful one, and the one you normally use to swing 360 degrees all the way around
Thanks for telling about that.
Wait, you can get it to go all the way around? I always ended up falling off the swing when I got to about 120°.
8:33 the math (extension by another third) checks out. If the extension of spring is F = m*g = k*l, then the extended-by-a-third total length is 4*l. Frequency of pendulum is sqrt(g/L), and frequency of spring oscillation is sqrt(k/m). Putting the above condition L = 4*l is equivalent to setting frequency of spring = 2* frequency of pendulum, ie parametric resonance. 👍🏻
When I was a kid, pumping a swing was one of my absolute favourite things. It's such an exhilarating feeling!
I have had great experiments using strong monofilament fishing line for 3/4+ of the length, the rest is a rubber baseball with a 3-4' length of black eleastic threaded through it. The other end is attached to a drain opening in the street/overpass overhead. The ball hangs at rest at about shoulder height. From there up to the drain is maybe 20+ feet. This allows for pitching practice with a kick. As a juggler since 1976, I have heard many assume I am ambidextrous. This is not the case with me. However, I used my nifty hanging rubber ball to practice throwing with my subdominant side. Great fun. The elastic makes for many interesting returns, too. It's a fun rig to use in the warmer months, until the vandals tear it down. It's down by the tracks, a common place for some rough folks. All the cement walls are covered with graffiti. I hope that some had fun with the rig before it went. It can be a rough world out there, so I figure some random cool thing to stumble upon, like a ball on an elestic hanging, might be good fun for others to, heaven forbid, Play with and let off some steam. One can be quite aggressive with such a rig, depending on how hard the ball is thrown and at what trajectory. It can go from a polite pendulum swing to a really wild, unpredictable return with a punch. Maybe the rig outsmarted some of the vandals and came back to bite them. One can find the ball-on-elastic toy at Dollar Stores and the like.
Fascinating! For all we know, we know so very little. The mysteries of life intrigues me to no end.
The strongest selling point of this idea is all the concussions it would give to children as they try to dismount
There is also a fantastic analogy with quantum mechanics.
You can imagine to start your system as two decoupled oscillators. This is described by a diagonal hamiltonian whose eigenstates are the two oscillators doing their thing independently. Then you introduce a certain coupling between the two oscillators, i.e. an interaction. This corresponds to an off-diagonal element in the hamiltonian, which you can diagonalize to find the two new eigenstates, i.e. the two "stable" oscillations shown in this video.
In quantum mechanics, if you prepare your system in a state which is a mixture of two eigenstates and then let it evolve, the system will oscillate between the two eigenstates, exactly as shown here. Instead, if you prepare your system in an eigenstate to start with, then it will remain in your eigenstate indefinitely.
Simone, man, you're way too smart for me to understand.
That's an example of two coupled pendulums. It's not autoparametric resonance. That would be if the Hamiltonian somehow changed depending on the state of the system.
Met this guy in real life when he came for a lecture in Newcastle he even called me on stage to guess which numbers I wrote lol. He probably won’t remember though 😅
3:25 I think that movement is being introduced by the flexing stand, I'd like to see you do it with the stand fixed as well. And as well as the stand moving, the rope being pulled over the bar would push away from the bar slightly as you pull. That and the flexible stand are adding horizontal movement to the system. The harder you pull it, the more it affects the system, the more it flexes, the more the bending string pushes it away.
You need a setup that introduces no horizontal movement whatsover, only vertical.
Even with your spring setup, you are still imparting horizontal movement when you first pull it down, I guarantee you aren't pulling it straight down.
Another good example of resonance is the expansion chamber in the exhaust of a two stroke engine, the pulses acting against each other at low rpm, but when rpm is increased they hit a point where the timing lines up and they build off of the frequency of exhaust pulses causing an increase in power (power band)
Is anyone going to talk about how he broke that child's back 2:21
I thought it was pretty cool that when they're a quarter out of phase, the moment they switch is when one part of the pendulum reverses its phase. I didn't look at which is which for this, but it appears then that the pendulum that's either ahead by 1/4 or behind by 1/4 becomes the consumer of the other pendulum's momentum, and when one of them is entirely "eaten up" and reverses direction, this relationship switches (because the swinging shifts by 1/2 phase) which is why they keep going back and forth between modes like that :)
Thinking on it (still without looking at the video again because thought experiments are more fun) I'm going to say the behind-phase one is the consumer. I assume this intuitively because I spent a lot of my childhood jumping on trampolines with my friends, and to give my friend all my bounce I'd stomp down on the trampoline a little bit before them. Likewise stomping just after them landing lets you kill their momentum, but I rarely did that because that energy is all absorbed by the legs and hurts quite a bit when you're not prepared for it.
Edit: now I'm actually getting a little bit unsure of if I got that right, because originally I said stomp ahead of them for both and I can't decide which is which. Memory is unreliable and I don't have a trampoline and friend handy...
Very interesting stuff, I'd had loved it if you had discussed the math behind it a bit more (I know math is scary to most people, but ultimately it is the functional language to understand natural phenomenon).
6:55 By moving your legs out you are indeed changing your center of mass to gain momentum on the down-swing. The top of the pendulum isn't the only pivot point at play either, as when you move your legs out and push with your butt, you pull with your hands, so you definitely change the center of mass vertically.
Love the videos, the channel, but also, and this is rare, the comments. All very informative and interesting
If the spring-pendulum were hanging from the ceiling instead of the wall, would it swing in a circular motion?
Good question!
A pendulum in circular motion has a fixed tension in the line-spring. I think it would not drive the spring to go into oscillation. But there can be other modes maybe.
If could precess maybe, but I don't think it would start to go around.
Like a 3D spirograph!!
I doubt it. It's hanging from a single point, whether that point is hanging from the wall or the ceiling shouldn't matter.
When I was a kid, my father made me a swing that was hung on springs. I loved it, but as I grew bigger, one day one of the springs snapped and that was the end of the Moonwalk Swing. :-(
It was actually a rather ordinary wooden swing on ropes which were connected to hooks using a few sets of springs which my father got out of a few dismantled chest expanders. It had a vertical leeway of around 30 cm which enabled one to swing and hop at the same time, hence “Moonwalk”. My father is a technician and a notorious junk collector who keeps every bit of old equipment, for once it will be good to provide parts for some ingenious contraption... :)
Honestly I think Steve Moulde is one of the few good science teachers
I feel like a lot of science teachers are passionate but end up being basically glorified magicians
Showing us that something can be done without really explaining the how of it
I recall feeling the breath of fresh air when the 'period of a simple pendulum' formula was recently made precise and concise using the Gauss AGM function.
Have missed your videos, including our zany sense of humour and your amazing descriptions of your discoveries!
Every push your beautiful child got and the swing I was panicking about the concrete step exactly at head cracking ground zero should they fall 🧡 I'm still stressed 🧡
𝐒͠𝐩͠𝐞͠𝐜͠𝐢͠𝐚͠𝐥͠ 𝐝͠𝐚͠𝐭͠𝐢͠𝐧͠𝐠͠ 𝐟͠𝐨͠𝐫͠ 𝐲͠𝐨͠𝐮͠➺ sexy-nudegirls.host
Anna is a beautiful girl.
He's the person I love, he's my light
day. The way the music flows and sounds
is extravagant and fun. Anna is
icon, legend, beautiful girl, princess, inspiration,
a star. I could go on and on, understand this.
I love NBA Anna.#垃圾
I had a stroke reading that
1:34 pull your pants up Steve LOL
11:27 This is kind of remotely similar to photons! (electromagnetic waves).
They have 2 properties, electric & magnetic, and if you graph them you end up with a Sinus & CoSinus wave (or 2 sive waves, but one is offset to the right with 1/4 frequency, or something like that, don't remember exactly.)
CLOSE and nicely DONE👍!
By tugging the string at each end of the swing you're
1. momentarily shortening the RADIUS of the swing ( pulling IN the arms of the spinning ice-skater ... ) at the SAME time as you're
2. RAISING the height of the mass thus adding to ITS internal Gravitational Potential Energy.
When PUSHING -horizontally - your child on a swing at JUST the right time ONCE in the pendulum swing (twice if your wife is in front - strategically chosen by you to avoid the
"swinging-legs-impact" or "getting kicked on the noggin" phenomenon 😉) you're participating in the resonance of the system , but shortening or lengthening the radius and adding potential energy while part of the closed system, is parametrically primary to the secondary effect of "resonance" even tho the "timing" makes ALL of it part of the resonance youre - very _nicely_ describing !
Think of the kid's "pumping and leaning" to increase the height of the swing and you get an idea of internal system "resonance" adding amplitude to the swing.
All of your "pulling-string" is injecting EXTERNALLY SUPPLIED ENERGY _into_ the "System" .
The spring alone works off of ONLY the initially-imparted energy.
Good Vid, and overall good description of the phenomenon 👍!
Fun diversion, too !
The COOL part tho,
in MY opinion ,
is-
There are a whole HANDFUL of factors all coming into play, that at first don't seem obvious or connected, but when brought out as you have here make for a very interesting look at a basic bit of Physics !! Science is INTERESTING - and Engineering makes Science
_ FUN_ !!
Thanks and ALL the _BEST_ 👍!!
-C.