Pendulum Wave Demonstration

This is a large-scale demonstration of the interaction between period and pendulum length, using 16 bowling balls hung from a wooden frame.
Here are answers to some common questions:
** What am I seeing? How does this work? **
The length of time it takes a ball to swing back and forth one time to return to its starting position is dependent on the length of the pendulum, not the mass of the ball. A longer pendulum will take longer to complete one cycle than a shorter pendulum. The lengths of the pendula in this demonstration are all different and were calculated so that in about 2:40, the balls all return to the same position at the same time - in that 2:40, the longest pendulum (in front) will oscillate (or go back and forth) 50 times, the next will oscillate 51 times, and on to the last of the 16 pendula which will oscillate 65 times. Try counting how many times the ball in front swings back and forth in the time it takes the balls to line up again, and then count how many times the ball in back swings back and forth in the same time (though it's much harder to keep your eye on the ball in back!)
** Who made this? **
This was made by Jeff Goodman, who teaches at Appalachian State University in Boone, NC. Jeff has some more information and videos about the making of this pendulum wave at celophoto.blogspot.com/2012/03...
** Why are they not perfect at the end? **
This large frame is built from wood and is outdoors, which means it expands, contracts, and flexes. Because the position of the frame changes, the cycle lengths are not perfectly aligned. Variable energy loss due to air friction and the striking of the pipe at the bottom (which creates the music) also contribute to differences. Over time, the minor differences become more pronounced.
** Can I get a copy of this video to use in my classroom? **
You are encouraged to use this video for educational purposes! If you are sharing online, please link back to this video. Contact me if you want to use it in other ways or if you need a higher-quality version. This video is available under Creative Commons license BY-SA: creativecommons.org/licenses/b...
** How can I make my own? Where can I learn more? **
Here are some links to information about the physics behind this. I don’t have the plans for it, but work through the information at these links and design your own - you’ll learn a lot about physics, math, and construction!
-- www.arborsci.com/cool/pendulum...
-- Harvard demo page: bit.ly/1qJkBr2
-- AJP paper: bit.ly/1xOcYUO
-- • Mount Shasta High Scho...
** Where is this? **
It was built on private property in the mountains of North Carolina (United States), near Burnsville. It is not open to the public. However, Jeff Goodman and I recommend some places near this that work to make the magic of the natural world a part of everyday life. The joy and wonder in our world that these places foster is exactly what drives the creation of amazing things like this pendulum wave!
-- For all the kids in your life, check out Camp Celo: campcelo.com
This is a farm-home camp for kids 7-12 (and older kids can work there!). It’s a wonderful place for kids to experience the natural world with independence and joy. No electronic entertainment, just the home-grown variety like this pendulum wave. If you don’t have kids to send there, make a donation to Friends of Camp Celo (friendsofcampcelo.org) to help send a child to camp who otherwise wouldn’t be able to go. (I am on the Board of this all-volunteer nonprofit and this video was taken at one of their events.)
-- Right next door is the Arthur Morgan School (AMS): arthurmorganschool.org
AMS is a progressive boarding and day school for 7th, 8th, and 9th graders, located on 100 acres of farm and wilderness. At AMS, students learn to question, evaluate, think creatively and work cooperatively.
**If you've read this far, will you do me a favor?**
Go to this link and vote for JJ to be the 2014 American Hero Dog: www.herodogawards.org/vote/?no...
JJ is a very special little dog who protects a very special little girl named KK's life by doing something just as magical as what you see in this video: JJ uses her nose to detect when KK is having a potentially life-threatening reaction, before any medical equipment can detect it. Her doctors think JJ is so good that they invited her into surgery at Duke Medical Center last December! You can learn more at eenp.org/main/KKandJJ. The contest ends on 9/15 and you can vote every day. If you like KK’s & JJ's page, you get a daily picture and reminder: AngelPawsforKK.
Thanks!

[@trevisbest]

This is the sort of stuff KZbin should be for.

[@timspiker]

I don't know. I think breaking my brain once is enough for one day.

[@zareh805]

It used to be

[@TheBallls]

Literally is

[@MrPoddu]

The best part of this demonstration is the audio component. There are patterns in the sound, just as there are in the visuals. I know of no other demonstration where you can hear the pendulum "sing" like this. A great touch!

[@owenbartrop8963]

Yeah but it puts everything out of whack pretty quickly the ones with a shorter oscillation lose more energy than the ones with a higher oscillation and by the end they aren't lining up at all, well slightly.

[@Greenredblueyellowpurple]

“Sing”?

[@JosephOster]

Except for the coughing. :(

[@JosephOster]

@@owenbartrop8963 Would be better without physical contact, using a light beam to trigger sounds.

[@jgbelmont]

You have not been around long.

[@johnnyfreedom3437]

This is just unbelievably cool! I never would have guessed they would have split apart into a disjointed mess and come back together and do it over and over again! I'd love to hear the science lecture that goes with this! Almost 70, never too old to learn!

[@bobh6728]

The strings are different lengths which affects how long it takes to swing, that is the period. If you ever had a grandfather clock, the pendulum could be adjusted by raising or lower the weight on the end so that it swung exactly once per second. (The numbers following may not be the ones used in this demonstration but it illustrates the point). So what they did was determine how long to make the string so the first ball swung 50 times in 60 seconds. The next one is slightly shorter so it swings faster at 51 times in 60 seconds. The next 52 times and so on. At the end of 60 seconds they will all have completed a different number of COMPLETE swings so they will all be back in the original alignment. At 30 seconds the first ball will have completed 25 swings, the third ball completed 26 swings, etc. So every other ball are now lined up. The ball that completes 51 swings in 60 seconds completes 25-1/2 swings in that 30 seconds. So it is opposite the first group. The same with the balls that are “tuned” to 53, 55, etc in 60 seconds because they complete 24-1/2, 23-1/2, etc swings. It is the fraction of a swing that determines where each ball will be in relation to the others. At one point you see 4 lines of balls. That is when some have completed full swings, some half a swing past a completed swing, some 1/4, and some 3/4. All of the other patterns can be explained the same way. The “snake” is when the first completes a swing the next circle completes a fraction (say 1/10) more the next another 1/10 more and so on, so it looks like they are following each other. A lot looks like total chaos, but will eventually come back to where they all complete a swing at the same time.

[@fasterpussycatkillkill9650]

No, you never are! Keep looking and learning.

[@fredgervinm.p.3315]

​@@bobh6728 Teachers are a special breed, they make all the difference in learning...

[@tampazeke4587]

To correct the lady. The ones on longer strings don't go slower. They actually go the same speed. They just go further since their wave cycle is longer than those on shorter strings. Because their cycle is longer, the period to complete the cycle is longer giving the illusion that they go slower.

[@luke_fabis]

I think they were going by the colloquial meaning of slower. Not that the velocity is lower, but that it takes longer to complete a cycle.

[@Duben-ym5vi]

I. am 73. I never saw this before. Fascinating!

[@fauxque5057]

There's much better examples of it. This one was pretty crude.

[@user-ts6re4ly9x]

Конечно не видел. Раньше не было ютуба

[@khidaral-mukhtaar7327]

Did you ever wonder why you got into “the Corp” so easily?( no disrespect guys…joke).😂

[@boereseun]

We are all the same age on the Internet, because of it

[@tomshimko4688]

This is truly incredible. On a similar note, back when I was in high school (almost 60 years ago), the chemistry teacher had a demo showing water boiling at room temperature. An incredible "aha moment" for me. Became a chemist.

[@highdownmartin]

Vacuum bell?

[@enekaitzteixeira7010]

Boiling at room temperature? Do you mean evaporation?

[@FranktheDachshund]

Water in the vacuum chamber did it for me too, alarm clock in the vacuum chamber was another good one.

[@user-ht1hu5ip9r]

A mathematician can explain this....😳

[@bobh6728]

@@enekaitzteixeira7010No, it would be boiling.

[@SprigganFR]

This is the kind of creative teaching that can really make an impact on a student. Kudos to this teacher. For me it reminds me of orbital mechanics, and how they can be so chaotic and so synchronized at the same time.

[@danamathews5712]

He is ONE AWESOME teacher - a true educator!!!!! I loved his classes and his hands-on approach.,

[@TheHunted385]

Except, theyre saying that its God doing this... No, its physics.

[@user-wo5ii3he6s]

The thing about orbital mechanics that always makes me crazy is the fact that if it's here for you to see, it's a stable system. If it were chaotic, it wouldn't be here. Just a long for the ride, hoping to overcome physics before our host star dies.

[@squidvis]

​@@TheHunted385 And we have physics because of.... You're sooo close to getting it.

[@TheHunted385]

@@squidvis We dont know why we have physics. Claiming its God is just as speculative as claiming were in a simulation or its made of magic.

[@MrAmazingChris]

And Kids asked their teacher: "Why is this happening, how does it work?" He replied "I have no idea, but this is awesome, right?"

[@SammyJoeLouis]

Lol 😆

[@snowy_1028]

Because time of pendulum depends on length of pendulum Longer needs long time 🤠

[@A3ternusA]

It's because the string that's holding each mass is shorter/longer

[@thePronto]

Maybe read the video description? He knows exactly.

[@Nykkynn]

It’s magic Timmy, shut up n watch the friggin’ balls 😂

[@bunnyfeet1005]

Simply amazing. This reminds me the importance of experiment and see the real thing working, not just computers simulation

[@SmaugDaDragon]

And then the teacher said; "now kids we have the obstacle course ready" - first one through get's a free dinner!

[@Josh-yr7gd]

I thought it was an obstacle course too, looking at the thumbnail.

[@sarahdeason5875]

😂

[@keepcalmandenjoythedecline]

Class buffoon: -¡Leeeeeroy Jjjjjjjjenkiiiiiiins! Muah-hahaha!

[@AmpDecay]

The polyrhythms this creates are absolutely beautiful, music in a pure form

[@jvg122ifly]

I had seen the Harvard video a couple years back and had to make one. My kids and I used golf balls, PVC pipe for the frame and fishing line. It worked great! A lot of fun. At a couple science fairs the kids would line up to take turns to lie under the pendulum wave as it cycled through ... Good stuff.

[@iravi04]

It's amazing to think how far we have come with science and yet such a simple thing is so mesmerizing and beautiful.

[@colin_hart]

There are 16 balls total and according to the comments they swing between 50 and 65 times over the whole period until they are synced up again. Assuming simple pendulum, T=2pi*sqrt(L/g)So the longest one is 1.65x the length of the shortest one. The slowest one (longest) is 1.0404x longer than the second slowest. The second fastest one is 1.03149x longer than the fastest one.The longest one is 8' 4 5/64" (2.5419m)

[@rustneversleeps01]

That hurts my brain just reading it

[@timothyblazer1749]

Also, they are all connected to the same pipe. There is a small amount of energy being transmitted through that pipe continuously that harmonizes the action as well. This is simply provable with metronomes that do not sync when isolated.

[@bobh6728]

@@timothyblazer1749They could all be suspended from different supports and it would still behave this way. It is not dependent on any feed back mechanism. It is strictly the different periods of oscillation because of the length of the strings.

[@timothyblazer1749]

@@bobh6728 I would bet money that it would be similar, but different in practice. I'm familiar with pendulums, and I did some work with double pendulums back in college. I don't think it would be as smooth.

[@Skyhawker6177]

Curious: were the small lengths of pipe that the pendulum balls swung over magnetized? Seems to me that the orbs would have come to complete stop after so many swings without some sort of energy to keep them energized. I'm just a layman but isn't friction a big factor here that should inhibit the orbs from swinging continuously? Just saying..

[@DonoVideoProductions]

I hope that kid survived whooping cough.

[@Hoaxer51]

I think he hacked up part of his lung watching this demonstration. Lol

[@KiryokuYT]

I feel so horrible for laughing as hard as I did at this comment.

[@fauxque5057]

Thought it was the vid

[@definitelynotanAIchatbot]

It's AIDS. Believe me, I would know.

[@hollyfleur6144]

poor child. he sounded really ill. i hope no one else came down with whatever he had.

[@theurbangentry]

One of the most amazing things I have ever seen.... its breakdown of music theory by the magic of maths and physics really reminds me really how incredible the universe is. Thank you so much for sharing.

[@CatherineSTodd]

kzbin.info/www/bejne/sHLbhWOjh6yopbs

[@MarttiSuomivuori]

Well formulated. I tried to say the same thing, no success.

[@marybethleib8286]

Oh... I thought the universe happened by random accident!!!!!

[@chumleyk]

Pretentious chav.

[@bamzegratteux]

That's pretty awesome to see there's so many different patterns in a simple wave...

[@elizabethscott6798]

I love the incorporation of sound to the visuals of the wave!❤

[@lasarack]

10/10 Thank you for all that information in the description! that vote was well deserved

[@ShikamaruXT]

These kids are never going to forget this day. And some might even learn a physics Job later.

[@sandradavis7862]

im not a very science person but this was very interesting and made me want to learn more....loved it

[@NickMoore]

YES! Thank you for this awesome demo!

[@Vacardi]

Very well done! Fantastic visual explanation!

[@annabrown4251]

Love this! Makes me miss our place up there in those mountains! Great folks up there!

[@10231898]

Wonderful pendulums is so fascinating. Great artwork! Congratulations on a great video too!.

[@chronoallusion3172]

Summer camp gauntlets have come a long way

[@cyn4476]

I'm not sure how you didn't get more likes. I'm still chuckling over here.

[@albertdorio7189]

I could watch and listen to that for hours on end!

[@PinoyBowlerGS92]

As a Youth Bowler myself, this is very creative. Great job !

[@ValeraCarpenter]

Классное видео! Физика!

[@fokkenhotz1]

from sync to kaos to sync so kool. show this to the kids i will. Thaank you Maria

[@TheGentlemanPhysicis]

This is such a cool demo

[@spiritflower6640]

This was wonderful to watch.Thank you for sharing it. I am grateful also to the people who took the time, care and know how to build thisI only wish that they had filmed it until it returned back to as it started

[@AzriRich88]

That's how all the planet is moving around the sun, dancing.😊

[@Blues40]

One of the best videos on KZbin

[@RayPublicHealth]

Thank you for posting and for your wonderful post explaining it and including links. :-)

[@cameddy4081]

Very well built !! Giant -so cool 💫👏👏👏

[@RoseblueShaman]

Bravo! Clap, Clap!!! Very intriguing... Loved it. Thanks for the awesome video!!

[@erasure999]

Someone get that damn kid with a cough some Robitussin.

[@jimmyday656]

Yeah after the VID I still look at a coughing person like they are a serial killer

[@Gardenowl]

I love this and am bent on getting a few built in Indy!

[@bonniejanson8662]

I LOVE this!!! Gotta share!

[@Travelightly1]

I love how this brought out such enthusiasm from the kids! Yay teachers :)

[@edlauren9434]

Шикарно! Я смотрел затаив дыхание! Очень показательно и доходчиво! Спасибо!!

[@STUCKINTH3SYSTEM]

This makes all the sense in the universe!

[@sandraross4905]

So cool! Thanks for sharing! :)

[@bonobonation9892]

in the last moments of the video you can hear the person explaining how the physics work: #God did it. Pity to see such natural beauty soiled with #superstition .

[@ZarahMcIntosh]

If God is all then how could it had not been God? duh. lol

[@shaneoshea8431]

Zarah McIntosh "God" isn't all, that's how. Fairy tails are for children.

[@ZarahMcIntosh]

Shane Oshea lol then it means we all have different definitions for "God".

[@VigilantPigeon]

Zarah McIntosh And most likely they're all wrong.

[@ZarahMcIntosh]

Vigilant Pigeon I know I'm not wrong :) and there's nothing anyone else can do about it.

[@jujjuj7676]

This is also amazing demostration of how you can nurish 1000 mosquitos in the quickest time. Nice job..😂

[@marymactavish]

three minutes of staring ... wow. #physics

[@TamaraTemple]

Thank you!

[@TraceurGonzo]

This is so relaxing to watch =) It will never work 100%,especially since you have them contacting objects (although barely), though this very contact is enough to throw off the whole flow. I do like the noise from the contact though, it allows you to both here and see the general patterns it forms. Great Video!

[@tomadams928]

The entire history of the Universe and its cycles in this wonderful short experiment

[@andrewjenery1783]

I almost got myself hypnotised watching this

[@littlewoodimp]

Amazing thing to do outdoors with kids! Just fantastic. I love all the Oooohhhs and Ahhhhs!

[@pyb.5672]

You’re not exploring how the world works, but how your mind works.

[@NudePostingConspiracyTheories]

He-ey !!

[@dianasoria5798]

LEGENDARY!!

[@christophermartin7098]

I am reminded of harmonies separated by octaves

[@HotCuppaCoffee]

Physics is so cool. And building big examples of complex physical principles, in your backyard, is just plain awesome!

[@MevaRaj]

Terrific!

[@jorgefernandez9310]

That is cool!

[@g.p616]

Amazing !!!!!!

[@MajidMagi-fj5ux]

Very Cool!!!

[@boydb56]

Friggin sweet!

[@watchguy79]

So cool!

[@Numba003]

This was mesmerizing! Thank you for posting the fun video. I may show this in my classroom when we do waves this fall. God be with you out there, everybody. ✝️ :)

[@KS-xx5xq]

Most. Satisfying. Vid. Ever.

[@user-be7eh5kv8d]

More please and thank you..

[@asdasdasdasd7483]

woah dude, radical! ;)

[@AhJodie]

Very fun!

[@deborahlawrence8086]

Awesome

[@mikerugotv3918]

Amazing

[@JayGiglia-mb5fl]

Very cool

[@RussTillling]

Awesome! 🇬🇧❤

[@rosceiatahubbard2225]

Awesome!!!!!

[@rosceiatahubbard2225]

Jaw dropping!!!!

[@droidverse]

The explosion at the end was the best

[@michaelford2517]

Very cool!

[@JonasSmith-yy6hx]

So cool

[@RedTearsBlackWings21]

Very cool.

[@MichaelMolli]

It's some kind of relaxing watching this.

[@coasternut3091]

This is neat

[@samikaziable]

My science teacher Mrs. Ellis said this is her favorite video and she watches it everyday

[@tylersnidow8752]

beautiful physics.

[@betabenja]

lovely.

[@chrisbarrington798]

I was waiting for someone to run through the dam thing 😂

[@Antonio928]

very cool

[@marcosantonioattie6364]

lindo e perfeito

[@taranciucgabrielradu]

Everyone should watch this at least once in their life

[@danielcarter5537]

The best way to study the physics behind this contraption is to have each kid run through it infividually. The kids that make it to the other side without getting knocked unconscious will have a proper understanding of the laws of motion. The kids that don't make through will understand how the concept of force works! I call it a hands on approach to learning.

[@chrisose4585]

They’ve got some balls showing this

[@medalion1390]

Some big brass balls

[@chharlessweeney]

Top class observation!!!

[@doctajuice]

it's a really large, really complicated polyrhythm!

[@utubesux1]

Best illustration of life I have ever seen. I'm 54

[@user-js9yp6lb2l]

この大きいサイズは良いね👍✨

[@TigerDan925]

Wow that was amazing. Bet it took ages to configure. awesome results though

[@graysonnolen1653]

He was my professor last year! Awesome awesome guy who makes some super cool stuff and is a super cool teacher! haha

[@davidmichael2536]

+Grayson Nolen What's his name and how do I contact him?

[@graysonnolen1653]

+David Michael His name is Jeff Goodman and his email is [e-mail].

[@SuV33358]

Too cool

[@aaronspain1735]

Nice one! The size of it takes it from impressive to magical. I built one too, well a few but only have one video. It's not a great video but it's a pretty good demonstration, along with other forms of harmonic systems. You should check it out.

[@jameswebster2605]

They all sound so chimey and cheerful, except the one closest to us… that one sounds like a death knoll

[@handmudra]

Cooool!

[@user619tlsdca5]

Air drag or wind drag. If this was in controlled enclosed area of a wind tunnel test you would see the only 2 balls at opposite ends started out with 1 side dragging air while the rest riding momentum of both sides less drag resulting in these motions done out of the rhythm of the air drag. Im just wondering if the hang hooks all aligned straight up top of across.

[@danielleinlondon6834]

I saw it mounth ago and it still breaks my legs!!!

[@porkyV2]

+Daniele Silva did it also pick your pocket? haha!

[@ALBINO1D]

I love how humans will gather and stare in expectation together. Just staring.

[@Nobushido]

Top beam is forced into a waveform flex by the weight of the initial force... Thereafter the waveform forms in the objects below and the rest is just momentum conservation.