250,000 DOMINOES! - The American Domino Record - Smarter Every Day 178

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[@Hevesh5]

It was so great to have you here at the Incredible Science Machine!! You brought so much energy to the team! Thanks for highlighting our event and doing this study - it was super fascinating to watch :) This is exactly what I would have predicted: the bottom of the domino slips backwards more on surfaces with less friction and the domino line topples faster. I did my AP physics project on a similar concept and found that a smaller spacing on sandpaper (frictional surface) was SLOWER than a large spacing on sandpaper. What's interesting is that my original hypothesis was the exact opposite. From experience, usually a larger spacing is slightly slower on a normal wooden floor, but I didn't account for the floor surface when I made my hypothesis. A slippery floor surface (and also domino material, hence the color to speed variation) such as glass makes the dominoes fall faster. You're right though that this is more complicated than we think, and having an unexplored area of domino physics is super exciting :) Can't wait to see what you discover in the next experiment! Also a suggestion for starting the dominoes... I feel like we need some sort of motorized toppler that very, very slowly moves forward hitting the center of the first domino near the top. If you use a small spacing, the first domino may just lean against the next domino and not topple right away, but this would allow the bare minimum force required to topple the line. You're also right that a longer line is necessary so that the speed of the dominoes can reach terminal velocity. I'm not 100% sure how many dominoes that is (this could also vary with spacing), but I'd recommend maybe 50 in the line to be safe. Thanks again for coming! And now to watch the behind the scenes :D

[@crazycomboman9248]

Oh hi there.

[@jfrilot8554]

Wooh!

[@mcb18youtube99]

Hevish!!!

[@Sarcasm_Khan]

oh yes, totally understood everything... no doubts, all clear now.....

[@smartereveryday]

Hevesh5 so far, we graphed it and it seems that 19 or 20 are needed to obtain steady state velocity.

[@wampaku2]

Trigger the initial domino by using a Newton's cradle, but just use one ball, at a consistent height. Modify cradle as needed. An even simpler way to say it: use a pendulum. Adjust the pendulum to just nick the top of the 1st domino. If you're really good: adjust the mass, and impact point of the pendulum to match the equilibrium state of falling dominoes, e.g. after 20 dominoes in your video. I'm sure this will get lost in the comments though.

[@tazou19]

No! People! Let's not let this comment get lost!

[@skaterzero807]

Exactly what I was thinking, like a Charpy impact tester!

[@---cr8nw]

Adjusting the mass of the bob wouldn't do anything. Adjusting the volume of the bob would cause it to strike slightly further. Adjusting the shape would change the center of gravity.

[@chiralSPO]

I disagree. Although adjusting the mass of the bob won't change the *frequency* the pendulum swings at, it will change the amount of energy that the pendulum can impart to the dominos, potentially having a profound effect on how the dominos fall.

[@GarrettCrosgrove]

The pendulum is what i thought of first too!!!!

[@drewliedtke2377]

That “wait a second, we’re doing this wrong” moment-that is why we need to advocate for scientific experimentation. We need more people to look at the world and think “hmm, that’s odd.”

[@connorleferink8456]

Absolutely agree

[@Keith_Kaplan]

Fire a .22 at a prince Rupert's drop and let the exploding fragment knock over the first dominos.

[@cameront4779]

This is clearly the only way to get consistent results! :)

[@Keith_Kaplan]

When you're right, you're right. Ok... .223 then (if memory serves)

[@Julia68yt]

Put the first domino into the box together with Schroedinger's cat

[@goddanbriggs]

Hold the first domino just past it's balance point resting on the fulcrum/edge leading to the others. This way, it's only the Earth adding kinetic energy to the system. (And then release it)

[@mangus8759]

Yes but the only problem is there are many fragments, they vary in size and speed, and you need to make a lot of prince rupert's drops and clean up a lot of glass

[@ElectroBOOM]

It is not too hard Mr. Smarter. Put like 1 meter of the domino train length outside the camera range and run some additional length of it in front of the camera. So dominos have time to do all acceleration and effect of you triggering it will be gone by the time the dominos reach in front of the camera, in steady state. Then you can consistently measure the speed of different material and colors.

[@torapuffs]

ElectroBOOM love your videos man 👍

[@EliBlogs]

ElectroBOOM 😍

ElectroBOOM mehdi gimme the multi meter :-P

[@WestSideRida420]

Also, something is needed to push the dominos with the same amount of pressure every time. Maybe a pneumatic arm.

[@andreim841]

Just do it using A FULL BRIDGE RECTIFIER!!! 😂😂😂

[@AntVenom]

A random, ghetto, off the top of my head idea is to eject an external cd drive, and have the tray hit the dominos. Might be a bit fast though, but it could be consistent.

[@Alec10121]

AntVenom didn't realize how many different people watch smarter every day

[@trusspike1527]

Yo

[@jasonpan6537]

Ant! What brought you here?

[@Wolfnam]

I don't know that that would be very constant, the little motor on those trays wear out fast through heat, continued testing would result in weaker and weaker pushes

[@WynSee]

i am thinking can we use a pen with spring?

[@XularusXIII]

I love how your daughter immediately goes back to standing on the left, and then on top of that, repeatedly sticks her tongue out at you. I love even more that you undoubtedly saw that and left it in while editing anyway. Had me laughing super hard.

[@natepressel6747]

Create a long string of dominoes and only measure the steady state ones at the end. That way they're triggered off a previous hit which is more like the real scenario (human trigger is the first hit but dominoes are the trigger for the next thousands of hits). I work in vibration analysis so you could approach the timing measurement with a microphone and catch the clicks of each hit and convert it into a frequency with great accuracy. An accelerometer on the table might pick it up too. And we use acquisition software from a company called LMS. It would give you actual data and numbers to go with your great footage.

[@ireallyreallyhategoogle]

+

[@wesemmert1664]

There are two issues you desire help with; a consistent start and how to deal with acceleration. Nate has the right idea to solve both issues. Use a long enough line of dominoes so that acceleration has stopped and they have reach a steady state at the time of the measurement regardless of the starting mechanism. "A long obedience in the same direction" - Eugene Peterson

[@Smileypeacefun]

The guy with the blue hair... Well that's ME! :D It was so awesome being part of the building team this year :) ♡

[@classicvoidzz772]

Smileypeacefun teach me the ways

[@jawadanwar6684]

Didn't it become boring at some point? Just asking

[@robin23200]

Smileypeacefun you ugly for a dude

[@Smileypeacefun]

Jawad Anwar Well for me it didn't become boring :)

[@srikarvalluri9621]

Nice!

[@staffehn]

10:26 - „There’s a lot more Greek letters in the math now!“ …what an accurate statement xD

[@ptanatomyrulez8608]

It’s simple. It can be explained by the conservation of momentum. The reason why ‘slipping’ ‘increases the speed’ is because when it pivots on it’s centre of mass, there is a smaller moment of inertia, therefore it can rotate faster and displace the next domino quicker, even though the clear domino’s have a slightly higher mass. It’s like a figure skater spinning with her arms open vs arms closed. She can spin a lot faster with her arms closed because she has a smaller moment of inertia in that instance.

[@Bluswede]

Bingo!...I didn't see this anywhere else in the comments. Destin states it plainly at 8:05 "translation and rotation"...that's where the extra Greek letters come in. As we all know, Greek letters slow things down, so more of 'em slows the fall!

[@steelinglamb]

That was my inclination too. For instance easier to fall over backwards on ice than a nice grippy surface.

[@illuminati.official]

Different moments of inertia is definitely the correct answer. Anything that could make the domino's movement more like pure center of mass rotation, like rounding off the corners or using a domino with less thickness (to decrease the amount of altitude the domino's center of mass has to gain in order to fall over), would speed up the process.

[@sirlaser8177]

PTAnatomyRulez I

[@brianervin]

I want to eat the thumbnail for some reason...

[@ireallyreallyhategoogle]

Yes, they look like gummies.

[@SuperTux20]

Brian Ervin it does look like gummy doesnt it

[@rh666]

Same, haha

[@reymichaelsungazornosa4040]

69th like what am ding with my life

[@DudeWhoSaysDeez]

Yum yum

[@rfldss89]

Small rebellion on your daughter's part at the beginning made me laugh out loud :p

[@TheBeccabus]

That was adorable!

[@craigcorson3036]

I wasn't sure at first if she was just being camera shy, or rebellious. Kids being kids, rebellious seems the most likely.

[@Elesario]

Sticking her tongue out behind daddy :D

[@ExperimentalFun]

Trigger- Miniature linear actuator! consistent variable speed push :)

[@ColtonHawkinsTech]

I agree. This was the first thing that came to my head as well.

[@kevinschultz7040]

Experimental Fun or a pneumatic piston

[@finnhanke]

I thought of something like a servo, but a actuator is a good idea as well

[@enoughofyourkoicarp]

Or a high speed, low pressure air valve.

[@stephenvoncrven4319]

and a proper structure to hit the dominoes at the same height in the same spot

[@MrAudienceMember2662015]

Something you don't seem to be considering about those plastic dominoes is handling. The oil from your hands builds up over time the more they're handled/used. Maybe they should all be washed before a new round of tests and clean gloves used to handle them? Or, the difference the hand sweat makes could be so minimal as to not matter? But, if you set up pieces that have been used a multitude of times next to brand new first time used pieces, the newer ones would likely slip on the surface easier than the older ones. The tipping start: A swinging weight that hits the first domino the same way each time. Locked in place with a release that doesn't propel or hamper the weight. Hope this helps. Maybe you'll come up with something else from reading this. As always, have fun! It's science!

[@brentlio5578]

Yep, rubber glove and all clean domino's can help a lot in the experiment. This is science to be solved at a very high precision.

[@MrAudienceMember2662015]

Make sure the gloves used do not have powder on them.

[@FabulousJob]

Take a servo motor and a micro controller (like an Arduino) and fix the location of the servo motor. In most cases a servo motor comes with rotors you can put on top of the servo easily. You can modify the rotor to fit your needs, but it is not necessary in our setup.

[@ThemansHomeBrew]

Fabulous Job This is probably the best idea I've seen so far. This would consistently create the very small force needed with high accuracy and without the inconsistencies of a manual trigger.

[@liveunderwater]

Use a pendulum held by an electromagnet released by termination of the power source. This should create consistent release every time.

[@fiveohfivethree]

I thought the same thing but went old school and thought they could just lift it to a predetermined stopping point and then release. Probably not as accurate as yours though.

[@The25Fantome]

Haha same but then thought that the release would not be each time similar and went the extra step to join liveunderwater set up.

[@jansteinmuller3665]

But you have to keep the air friction in mind and that the magnet wouldn’t turn off instantly. I think a stepper motor could be a good solution but you need the same voltage for every try that means you can’t use a battery.

[@emraef]

Air density isn't going to change in any significant amount, especially not when you do multiple different attempts for each surface.

[@MobiusPi]

What about a servo or slow moving stepper motor in a configuration of circular to linier motion? P.S.- I'm just a high school student and don't know if that is the proper terminology. So sorry if it is not or if there is a better way to explain it.

[@___echo___]

0:14 savage kid

[@777malkavian]

What a madlad!

[@taofledermaus]

So cool! I've watched a lot of Flippy Cat's domino videos too!

[@Nishye501]

I love your videos:)

[@2mc29]

"there's a lot more greek letters in the math now"

[@SpriceMachines]

Thanks for featuring my event in your video! It was awesome being part of this experiment!

[@SpriceMachines]

You could use motor/linear actuator or create a pendulum that swings 90 degrees to hit the domino (so the string is released from being perfectly horizontal). To make the release of the pendulum consistent, have a stick or something hold up the weight on the pendulum at this height, and pull the stick back, to allow the pendulum to drop.

[@jr52990]

0:14 ya got a little rebel there. haha

[@reghunathraja3543]

Destin: Stand on the right. Daughter:*decided to stand on the right and changes her mind*

[@funcentral2439]

She's walking back and forth from left to right sticking her tongue out at him. Lol

[@briancv83]

use a servo (or similar) to push a pin or rod. that way the speed and force are consistent every time. also I think it would be interesting to use metal dominos to test the weight theory. then you could race the normal plastic dominos against the metal ones to get, a possibly, much clearer result. another thing that might be done is to have some metal ones with a matte finish and others with a polished finish. but the finishes may be taking it too far.. just the drastic weight difference will be enough to make it interesting.

[@RPSchonherr]

How about the old fashioned wooden ones?

[@ireallyreallyhategoogle]

Yes, that would give significant results.

[@briancv83]

Robert Schuster ya! good idea!

[@alex_ottomano]

Exactly what I was thinking!

[@HowToOutdoors]

Brian Vaughan yes, I agree, a servo

[@Stephanbitterwolf]

Use a stepper motor to topple the dominoes the same way every time!

[@sheepieworks4974]

this due got the right idea. i tried to tell this but i couldn't find the right words for i am not a native english speaker

[@michaelcaplin8969]

By the way, I see why the frictionless domino's fall faster. It's all about energy, and considering that it's a pivot; it to top portion is allowed to fall forwards and the bottom portion allowed to rise backwards at the same time(which is what ALL domino blocks want to do, regardless of friction), the energy will not be absorbed much at all until it hits the next block and transfers it's energy. But if we introduce friction on the bottom half of the domino, then the same motion will happen, but the upwards/backwards motion of the bottom part of the pivot (block) will be hampered by friction, which will absorb some of that energy, and actually counteract it, which means it takes the upper half of the pivot a little bit longer to hit the next block, as some of that forward momentum is gone. I wish I could draw a model, but that's at least part of what is happening.

[@yoavzack]

Do you basically say that the energy is absorbed by the friction? If I'm correct, it shouldn't have such a large effect is such small duration of time and distance. The energy lost to friction depends only on the horizontal distance moved, and the distance here is very small.

[@davegrox3150]

Actually, it's not that complicated. Since the speed of dominos is determined by how fast the previous block touches the next one, both rotational and translational motion accomplish that goal. (Just a thought, haven't done any calculation yet)

[@davegrox3150]

Yoav Zack btw no slipping means no friction energy loss at all.

[@jaxxinator5999]

Ollyweg 0 At the same time, however, the dominos which slide more have longer to fall in order to reach the next domino.

[@yoavzack]

Dave Grox But there is a little bit of slip right at the start, that means a little bit of energy loss

[@joshuacanova1678]

As the trigger mechanism, if you place some sort of weight on a string creating a pendulum, with the axis directly above where you plan the first domino to be, you can raise the pendulum to a consistent height ensuring the potential energy going into the system is the same every time.

[@BillySugger1965]

Hi Destin, a couple of things: To consistently start the dominos, glue a small ball bearing to a thread to make a pendulum. Make a rig to suspend the pendulum above the first domino at a consistent height, with an electromagnet holding it back a fixed distance (and height) from the domino. The fixed height gives it a fixed impulse when you turn off the electromagnet and let the pendulum swing. Secondly, a domino on a sticky surface will rotate about (close to) the leading corner rather than the centre of mass, so it has a much greater moment of inertia and so takes longer to rotationally accelerate.

[@fireblade3655]

use a small light pendulum and release it from the same point every time, using a marker, so that the bob hits the domino when at mean position.

[@TheCampnFool]

Fire Blade Yep - A set weight at the end of a stick, pivot point at the other and starting its swing from a constant/set point and striking the domino in the same position each time would be the easiest way to guarantee a consistent result. Tho you would have to rig the weight to release the same each time... Small details such as changes in friction at the pivot point etc will also introduce small variations, but overall a stick pendulum is the way to go. That's a long winded way to say: I Agree.

[@jeffmarquis4612]

I would add a stopper so that the pendulum doesn't follow through too far after contact. You might also want to mechanize the release.

[@Kaalyn_HOW]

Yeah, you'd also definitely need a stopper for after it taps the first domino...otherwise it will slide right through and push the first few dominoes along with added force.

[@chewdog_82videos46]

Fire Blade i should have read the comments before commenting myself. I think this is a great trigger idea.

[@guangjianlee8839]

same

[@banescar]

* laughs in Domino Day *

[@sparklypink7792]

I don't know what to say.

[@michaelbateman8469]

Destin a doorbell solenoid. It can be mounted at a set height, the stacking jig can be at a set distance, and so long as you have a consistent power supply it will exert the same amount of force everytime.

[@BinyaminTsadikBenMalka]

The reason why slipping is faster (Physicist here) I'm going to try to articulate this as best I can. First, a falling structure's center of mass accelerates at g, this means the upper part of the structure will accelerate faster than g and the lower part will accelerate slower than g. Second, we don't care how long it takes for the domino to hit the rest floor, we care how long it takes for the domino to hit the next domino. So, a horizontal motion is more important than a vertical motion. So the slipping will cause the vertical motion to slow down, but the horizontal motion to speed up because the axis of rotation moves closer to the center of mass. Because the experiment is done in quantity, you don't need to understand the single domino, because each single domino will be slightly different. You should try to statistically understand the group of dominoes. So you can approximate and average the point of rotation which will be somewhere between the center of mass and the bottom tip. The more friction, the closer the rotation will be to the ground. When dominoes reach a steady state, they will have an initial angular momentum because of the initial impact and follow the following force diagram: docs.google.com/drawings/d/e/2PACX-1vSIyIdoI7PuXH7tXx_6yJKgbQ7FuJSe1RwWdZPci9bQL4IA423uNoSjjOQrPYzJJclWnfd-I_y_VcBI/pub?w=960&h=720

[@vega1287]

you know you can go on these 3 dots on the side and there is the functon edit

[@tristanseaver9054]

As far as a triggering method, a reliable one would be to have a pendulum-like trigger that can be set to a specific angle. (weight on a string pulled back to a 90-degree angle) Same fall distance, same force applied to the initial domino. Hopefully.

[@hpewd]

A swing mechanism, kind of a pendulum, might help you out here. this way only gravity acts upon it and it is easy to setup and calibrate for you know the pendulums mass and velocity and thus its momentum.

[@MetaalMeerkat]

Yes but not at a 90-degree angle, if you want to use a pendulum trigger you would be better off between 30 and 50

[@hpewd]

Well, doesn't it depend on how much and how fast the pendulums can swing past the contact point without pushing "to far"?

[@rohitraghunathan]

Anyone else notice his daughter in the background blatantly changing lanes? 0:17 Hilarious

[@eldest3171]

Rohit Raghunathan she is also sticking out her tongue

[@hamiltonpianos]

Hi Destin, another great video - many thanks! Could I ask what sort of high speed camera you are using?

[@Lumencraft-]

I really enjoyed the educational bit at the end with the high speed camera. Nice job.

[@drkastenbrot]

Use a servo with a servo tester to trigger it. If you reset it, set it to the desired angle, and then power it, you should get the same speed everytime.

[@AviRotstein]

might still be too fast, then you would need a microcontroller such as an arduino to produce a slower servo ramp

[@BoojumFed]

If the servo itself is too fast, is there any particular reason it can't simply be geared down? If the servo is providing the momentum the output would be just as consistent as if it were directly pushing the domino, wouldn't it? A simple pivot with uneven lengths should do the trick.

[@cchpm]

Use a pendulum to trigger the dominoes, it should be the easiest way to get consistent force to trigger the fall. The more expensive way, but maybe a little bit more consistent would be stepper motors to push a slider I believe.

[@tguajard]

Vic Ch came here to say this same exact thing

[@dokukin]

Tomas Guajardo me too

[@jrdn.lauren]

A pendulum with a stiff arm. someone mentioned a cd tray. I think thats smart. Since its the same speed and force hitting both rows. I don't know how consistent they are, but it can't be too bad.

[@betaich]

Either that or use a marble from a ramp with a bar. Every time same height should equal every time same force.

[@jakthesmack]

Vic Ch I had almost identical ideas. Great minds... :D

[@nerdgarage]

This might be your best video yet ! Your "eureka" moment was awsome. In addition to the base friction though, something that I didn't see mentioned is that the friction of domino against domino is going to matter too. Rougher dominos will have more friction between them as they fall than slick dominos. This may also affect the base slipping. And for triggering I thought why not just use a small arm on a servo mounted in a fixed position relative to the first domino.

[@NovaGreen333]

I loved that high speed camera experiment! So interesting! I actually feel smarter lol

[@mattjmwmatt]

I wouldn't personally make a special rig to push the Dominoes.The key point is to make the row longer enough, just so it is in steady state(since you pointed out initial acceleration increases).First you should determine the minimum domino number that cuts the mustard. Assuming heavier dominoes have more mass (and thus more energy storing potential), all you'll have to do is get the "transient domino length" for the heavier dominoes(steady-state length). And finally test all types with this length, and analyze just the steady state region.Since lower mass should mean less energy and consequently less "transient length", you should be covered.

[@Sax4565]

I agree with the transient lenght, but wouldn't pushing the first dominoe give more "beginning speed" (technical terms in English are not my specialty :D) to the system that stays inside it or would that really cancel out over enough dominoes? I'm not sure whether a faster initial dominoe would just give his speed to each following one or if they would actually (quickly enough!) converge towards the _same_ steady state speed. Nevertheless, this is unexpectedly interesting :D

[@silentsnooper3307]

Hey Destin, I work at a cafe and have been wondering something for a long time. I've noticed that when I begin to steam milk or water for people's drinks, that the pitch starts off high, and then as the liquid gets warmer, the pitch drops; and as the boiling point approaches, the pitch almost disappears altogether. You can also hear this when you turn on the hot side of your bathtub faucet, the sound of the water will lower in pitch. I'm wondering if this is due to energy transfer, and as the boiling point approaches, the amount of energy able to be put into the system is reduced. I know as things get warmer the molecules get really excited and full of energy, but I'm wondering if this is the actual cause, or if I'm way off the mark. I know it's probably not anything to make a video about, but I do wonder if you ever noticed the pitch change as liquids warm up? And what is the cause? Keep making amazing and interesting videos! All the best to you and your lovely family, ~Pete

[@RayDrouillard]

My hypothesis is that the pitch goes down because the speed of sound in water goes up. I looked it up and found that the speed of sound in water does, in fact, increase as temperature increases. It maxes out at about 75 degrees centigrade. commons.wikimedia.org/wiki/File:Speed_of_sound_in_water.svg

[@WhoEls]

It's all about the bubbles. The denser the liquid, the higher the sound. High sound travelling speeds result in a higher frequency. So because sound travels faster in dense liquids, as soon as you mix your coffee, you force air into the liquid, which slows down the sound waves.

[@williamthomasmi10]

I second Miche here. This is a great video. What you're hearing... you already know what it is, you just don't KNOW that you know it... trust me, watch that video!

[@elraviv]

"It's starts with one" (as the song says...) - first use only 1 domino brick, photograph it on different surfaces, getting hit at different heights, with different forces using a pendulum (as suggested by Miles Johnson). when you understand how 1 brick behave then you can move to more bricks at different spacing. I am enjoying your work so much - keep it up!!

[@Zakyamuni]

I'm excited about seeing the new logo!!!

[@vel0city96]

250,000? Just today they're doing 250,000? Us Dutchies did Domino Day back in the day. In we got over 4 million domino's to topple. 4 *million* .

[@bluejayjason4576]

Vel0city Still impressive though, I can't set up a ten stone line without accidentally setting it off.

[@betaich]

They used self build breaks to stop stones from falling to soon. It also was a cooperation with German television who broadcast the falling stones live. It was a hit in the late 1990s early 2000s the last show was 2009 and they build 4,8 million stones and 4,4 million stones did fall.

[@InvisibleOcelot]

Seriously, what's up with the Americans? That was tiny compared to every European Domino Day.

[@wolvenar]

Apatheism Might want to verify things before you make a fool of yourself. This is just one... older example. kzbin.info/www/bejne/Z53Ql6Z5jMllhsU

[@Roxanne13579]

Domino Day was great, and you can see domino day's influences in pretty much all domino builders today :3 Like the Nerve-wrecking builders challenges!

[@jeavalos]

Try audio recording the fall of the domino's. But the visual spectrum on computer and you will be able to analyze the wave form to get the Beats Per Minute on a pre set amount of domino's per foot. That's how us DJ'S get the speed of a song, but we follow the bass line because it's constant.

[@stevenwolgast3069]

Just came here from an American Physical Society article link on domino friction research, even though I was here 4 years ago. Congratulations on the citation/credit from this important academically respected institution! Well deserved; you do some of the best science on KZbin, and your enthusiasm for it is infectious.

[@zevvery]

Hey Destin - a couple thoughts on your domino experiments: 1. I wouldn't worry about your initial tipping mechanism. As long as you have enough dominoes to get to steady-state, the initial push shouldn't change much. 2. If you don't worry about the initial push, the only thing you can't do is a "race" between two types of dominoes like you did in this video. But it was a little difficult to see. You can probably make up the difference in post by aligning two different runs top and bottom to get the same effect. 3. More slippery domino or surface means less friction, which should make the domino fall faster because the friction with the ground works against the direction of rotation, making them rotate and fall more slowly. 4. That being said, the dominoes with more friction should fall further forward for the same reason, allowing the grippy dominoes to be spaced even further apart, (slowing them down even more?). You saw the opposite in your tests so far, but that may have to do with how close the dominoes are spaced - if they are too close for this effect to matter, the more slippery dominoes may end up falling "further" because when the last one or two get "squished out" at the end of the drop, they can slide further before stopping. This may mean the speed difference between high and low friction also depends a lot on spacing. 5. I feel like heavier/lighter dominoes shouldn't play a huge roll. Think of the effect of dropping a heavy and light ball of the same size (Veritasium has some great videos on this). They end up falling at the same rate. But we're not dealing with spheres here, so it's possible rotational inertia has some different effects, and my instinct is way off. Great work!

[@Milesjohnsonn]

you should use a pendulum and pull it back the same amount every time to start the dominoes

[@oresteszoupanos]

Pendulum ideas sound awesome! One more step to eliminate another variable (the different masses of different block types) would be to *use a block of the same type you are testing as the pendulum weight*. So if you are testing those clear, glass-like pendulum blocks, use a clear glass block to give them the initial knock. This will give each different test the same initial acceleration, making the tests more consistent and comparable with eac other ;-)

[@R1C4RD097]

also, the pendulum itself should be always straight. a rope shouldn't be used

[@HuskyStudios]

To trigger it have a small ball on a slight ramp where you can put it at the top and let it hit the dominoes

[@sheepieworks4974]

lots of things that have variables in that. like frictiona nd if the ball has a slight defect or anything it will go slower and how do you push the ball? that also changes the speed of the ball and if you just drop it on the ramp you need to drop it from the exact same height and distance every time

[@HuskyStudios]

SheepieWorks I guess that's a good point, but its still better than pushing it lol

[@sheepieworks4974]

true but antoher guy had a good idea about useing a stepper electrical motor to push it. which is better imo

[@segatore1295]

But the ball would hit the first Domino and I might roll off at Domino hit second Domino and maybe more which could change the effects

[@chuck1527]

I thought a good/similar option might be to pendulum something into it from a fixed point, with a constant release. If too heavy and bowling down the dominos, use something lighter.

[@LivingCartoon805]

I was about to comment on the inconsistent starting mechanism when you brought it up yourself. Great video Destin.

[@laiskashit]

Hi! Thanks for the great video once again! As a solution for starting the domino fall, I thought about using a motor, maybe a stepping motor / servo motor that you can rotate really slow and just for one turn. Attach a wheel to it and and off center shaft that acts like a pushrod just like in a simple piston engine. You could easily adjust the height at which it pushes the dominos and also the distance how long it pushes the domino. It would always push the same speed/spot if you align it with the tool that you use to build the line of dominoes. I think that would be a good solution for getting reliable results in future experiments. Looking forward to see the video!

[@ardenthebibliophile]

For your experimental setup, you could use a spring or a pendulum to set it off with a reproducible force. Using a computerized motor would work too, but it feels less like old-school physics experiments if it doesn't have a spring or pendulum! Also I have a theory as to why the slippage goes faster; I'm thinking in the limit where you have a frictionless surface and only rotation. Essentially your lever arm is shorter so you'll have less resistance to turning for a given input force. It'll have a higher rotational velocity and hit the next domino faster.

[@metroidandroid]

It really makes sense

[@danielstark8258]

Do it with a servo and esc

[@Nevir202]

daniel PC/ Xbox I see someone beat me to it.

[@linusb3406]

daniel PC/ Xbox a small weight swinging from a defined heigth is way easier and much more acurate

[@stewarthornick5355]

Julius Meier $35 arduino uno, cheap servo, a couple jumper wires and most of the code is already provided as an example in the programming software. Doesn't seem that complex and pretty consistent

[@mr.sandman5311]

yeah I was thinking just using a rack and pinion setup with an electric engine

[@linusb3406]

well with a swinging weigth you can calculate very exactly the speed of the weigth and amount of energy introduced to the system, making the experiments easily reproducable. The servo wont be as consistant due to bad quality potentiometers or wear.

[@Kraigon42]

I love the "you get a free time machine" line you tell your kids. It was hilarious and incredibly cute.

[@felixbaum2180]

How much energy was stored in all those dominos? I really can't estimate that, but it should be calculateable!

[@KasperMeerts]

A domino weighs about 9 grams and is about 4.5 cm tall. So the center of mass is 2.25 cm above the ground. Multiplying those numbers with g gives us about 2 millijoule per domino, or 500 joules for the entire setup. So about the energy content of 0.01 grams of gasoline. Not a lot

[@felixbaum2180]

Kasper Meerts well not exactly, in the structure is more potential energy stored

[@mattjmwmatt]

Kasper Meerts I think you forgot to subtract the domino length/2.That would make it about 450 joules for 250k dominoes and a 0.5cm length each.If g=9.8182 then it goes down to ~441.8 joules.

[@mattjmwmatt]

Felix Baum Hes calculating just the stored energy. E=m*g*h

[@felixbaum2180]

Matheus Rotta yes i understand it, but the dominos that are higher up on a structure have more Energy. Just like you said: *h

[@alexheschong2717]

So it's fair to say that we should expect at least one more video on the physics of dominoes.

[@freitschi1]

This is just amazing. Thank your for this video:)

[@Alexis-in2xl]

Awesome Videos as always. As a trigger mechanism I would recommend a high quality servo ( in order to provide the same force for all the tests) connected to an adruino.With this type of set up you can eliminate any torque "errors" because you hit the domino in the same spot.Also I would recommend the servo set up to be an alignment tool as well combined with the Domino set up tool. Thank you for the awesome Videos and keep up the good work :)

[@jhboulder]

For consistency, I would initiate the domino chain using a steel ball on a string (pendulum) held at a point of positive potential energy (does not have to be high, just consistent) with an electro magnet. By disconnecting power to the electromagnet, the ball will be released with the same kinetic energy each time (consistency of pendulum periods). Hit me up, lets make some stuff !!!

[@CilusseYT]

Trigger it with a DVD player tray That’s what I did for a school project when we needed to push a toast from a table and tried to find what causes it to fall on the butter side

[@davidmayer4922]

You should have done physics instead, it would probably have been easier.

[@jhboulder]

Beakman's World did that one about 20 years ago...

[@CilusseYT]

In physics class, in France, there is a special exam for which you have to follow a scientific path in order to answer the question of your choice. I did this "experimentation" with some friends and we even obtained a very good mark (19/20). So yes, I did physics.

[@TheHilariousGoldenChariot]

#cilusse because the butter side is heavier

[@CilusseYT]

Nah, it's related to the height of the table. There are thousands of videos about this online :)

[@carlred4229]

Hi Destin big fan of SmarterEveryDay here. I have a hunch of using a graph of Coefficient of Friction vs. Time to prove if friction truly is helping to speed up the topple or slow it down. Also try triggering the fall in different areas of the dominoes e.g. In the CG, In the Upper surface, and etc. Thanks for the cool knowledge every video. :D Kudos!

[@melissahilaire2343]

Great video! I learned that the speed in which the dominos slip depends on the friction of the dominos and the surface.

[@lukealexanderhwilson]

A domino that slips rotates about its center of gravity as opposed to rotating about its edge. The moment of inertia about the center of gravity is smaller than that about its edge (see parallel axis theorem). Therefore a slipping domino will have a faster angular velocity than a pivoting domino. However, a slipping domino's reach is half that of a pivoting domino. As a result, the maximum reach for a slipping domino (approximately half of its height), would require 90 degrees of rotation, compared to 30 degrees for a pivoting domino. Since the distance function is sinusoidal (reducing horizontal velocity of contact edge as the angle increases), we can expect that pivoting dominos will perform better relative to slipping dominos with larger distances between dominos. We can see that the stack of fallen dominoes reinforces the falling domino and can assume that potential energy is not lost in a slipping domino compared to a pivoting domino. Mass shouldn't effect speed in a vacuum. Hypothesis: -slipping domino will be faster than a pivoting domino when spaced close together -pivoting domino will be faster than a slipping domino when spaced far apart -mass will have a negligible effect on velocity once the falling dominos have reached steady state

[@PlektrumPlays]

Luke Wilson Good one 👍

[@kitizz548]

Totally agree! Was having similar thoughts, myself

[@steveroberts343]

You can try using a pendulum to start the domino?

[@kingsize55]

At the dutch domino day records back in the day they actually implemented a pendulum during the tv commercial break so the viewers wouldn't miss any of the action

[@JoelHudson]

Steve Roberts I like the idea of a pendulum but it needs a set starting point.

[@Hahnsuk]

Steve Roberts I like it because now we are relying solely on the pull of gravity to set the acceleration as long as the point the pendulum is let go stays the same. Because gravity is constant, the starting point is the only determining factor of how much energy the pendulum transfers given every other factor like the material of the pendulum is kept the same throughout the experiment

[@rikwisselink-bijker]

Just make sure to have a stop to standardize height. A pendulum was my idea as well, so I came to see if I could promote someone else also floating that idea. You can even make one out of lego (you need to make sure the blocks are placed in a constant position relative to the pendulum)

[@inzen86]

Wanted to say this. Maybe make sure it'a a relatively light pendulum.

[@TheHarberHangar]

For measuring relative speed differences between domino types and surfaces, you should just be able to center your video frame after the 'terminal toppling' point; that way the method of starting shouldn't be a factor. If you want to measure the acceleration differences, then consistent toppling is needed A few ideas for consistent domino toppling: 1) Ping-pong ball pendulum. Fix a ping-pong ball on a stick or string, suspend stick/string from above, pull the ping-pong ball back to a consistent angle and release for a simple repeatable and gentle touch. 2) RC airplane/car/robot servo. You can hook one up simply with a servo tester, no programming required, and position the servo arm such that at the end of its swing it just barely contacts the first domino. That way you get just a simple "touch", and no externally-imposed acceleration in the initial topple. Put a short arm on the servo for the slowest tangential velocity. OR put a cam-shaped arm on instead for an even slower touch-speed.

[@nebuladusk8839]

I can't wait to see the next video- also I suggest making a small contraption to push the dominoes at a specific point every time

[@taytekunne9559]

Smarter every..........midnight

[@taytekunne9559]

I’ve never got this much likes

[@runforitman]

(3 ideas) Here’s the ideas for pushing them: 1: Use a solenoid, with a constant voltage from a power supply (so it’s exactly the same), to trigger the falling Mount the solenoid to the surface an mark a distance from it so the hit is at the same velocity each time 2: Now a solenoid may be too fast, so you could try some sort of small pneumatic piston Maybe even a lego technic one With a set pressure to go in each time Set it up the same as the solenoid 3: Again even that maybe too fast Or difficult Another way is to put a little paddle on a DC motor and put a constant voltage into it to push it I say this because it’d be the slowest way And if you want it even slower, you could put a gear train on it (Mounted the same as the first two; at a constant distance from the first domino to take that out of the equation) And all this takes out the human error Hope this helps!!!

[@RayDrouillard]

The advantage of using some kind of a slow actuator is that you can set it to carefully tip the domino so that it has very little starting velocity. That way, all of the energy comes from gravity. The idea is to nudge it just past the balance point and let it fall freely.

[@rchandraonline]

stepper motor. pulse it at any rate you'd like up to the electromechanical limits of the device. Like MythBusters, when consistency is needed, build a robot

[@smokybros1267]

Trigger method: Have a pendulum, bolted down to a stable surface, triggered by a quick release (potentially magnet) that is raised to a specific height. The height of the pendulum, and the mass of the pendulum would be the same, so it should exert a very similar force each time, with the only variable being air resistance changes, and position of first domino, which will be solved by next paragraph. Domino set-up: Use your measuring stick to mark specific lines on the surface, by which you will not only be able to place the dominoes in the exact same place for each fall, but be able to exactly measure the slippage amount. Camera set-up: The pendulum should trigger the initial block, and the camera focus should start at block 30, and from above, not the side. If you are indeed seeing that it takes 20+ dominoes to reach a stable fall speed. If the fall speed is consistent, then the rate of fall can be measured with differing systems. With the side camera set-up, you do not clearly get a view of the back row of dominoes, to compare velocities and times of impact.

[@faithordway7]

Crazy cool video! I was looking through your old stuff and I sae you did some sports science stuff! Do you think you could do a video on table tennis! That stuff is crazy!

[@ChristopherSmith313]

Use a stepper motor with a linear actuator. You'll get precise motion characteristics top start your tip. Also, you might consider measuring the frictional constants of your surfaces so you can evaluate that variable.

[@RayDrouillard]

If the surface is soft, the effective coefficient of friction will vary with the pressure on the surface. We can see that in the slow motion footage. The domino initially slips, but stops as the edge of the domino digs into the surface.

[@gilamonstereac]

Ooh good idea but does a stepper motor really fit with the rube goldberg spirit of domino trains? ;p

[@qtexasbrumley]

Christopher Smith ( SCIENCE )

[@bpal7006]

Yeah, what he said.

[@brand-x7049]

There is precedent for this. Go look at how casinos produce their dice for the craps table; also, look at how people "load" dice to make them more likely to come up on a desired face.

[@ES-wy2xj]

Newton's cradle; try to keep the potential energy of the first ball equal, maybe set an electric magnet on a rod and let and turn it on to hang the first ball and off to release the ball. And try to keep the cradle just high enough to touch the dominos and not annihilate the whole setup

[@gilamonstereac]

I like this idea except you just need one ball/striker as a pendulum as suggested above, and have everything mounted at exactly the proper distance so it only just kicks over the first domino. Also have the mount be adjustable so you can see how different strike points on the domino affect the action. But the electromagnetic is good because it can be precisely triggered every time. Also, do different striker materials have an effect on the action?

[@maloriezastrow971]

My suggestion on your setup would be to have a runup line of dominos that remain the same so that your inconsistency in the way you trigger the line has a chance to be removed by the time your test dominos are triggered. You could further remove that inconsistency by making your trigger at the beginning of that runup be more mechanical like a falling weight or solenoid or something like that. BTW Destin, I love your channel. Your excitement for the act of discovery is infectious. Thanks.

[@agerven]

Hi Julien, fascinating (I'm a physicist too, as well as a fan of Hevesh#5). Lili does know something to get a reproducible start of the toppling. In some of her videos she has a little motor, rotating a vertical axis on which a small lever of wood is mounted. That topples the first domino in a reproducible manner. Would love to see some more results of this investigation, as well as a comparison with the sonimods, a Lili invention, where the dominoes topple backwards while still giving a forward domino effect. Thanks for this video, in which two of my favorite youtubers combine their presentation and skills. Really cool!

[@RJKT]

I like how they went from really serious before the event, to super happy right after. It shows how much passion they have for what they do, and that's really dope.

[@RJKT]

.

[@neoklenings6931]

same

[@jrjunior6277]

Yes dude!

[@15october91]

Mind blown, they slip not just pivot.

[@Devrij]

Really enjoyed this, particularly the analysis at the end. I want to see the rebuilt rig! Solenoid or servo to trigger the fall? Servo might allow you to control the actuation speed better.

[@MWaheduzzamanKhan1]

Can you use a stepper motor to trigger for consistency?

[@idkmaniranoutofideas]

Let's all appreciate that Domino Day will stay as the Nr.1 in Dominos With over 4'000'000 Domino Stones it holds the World Record in the Netherlands

[@333ryansmith]

i love domino’s pizza

[@falkenturn14brz]

Ryan Smith Marry it

[@Yelawolf269]

Ryan Smith haha same

[@josiahhill4993]

ya beat me to it

[@unlokia]

I don't think you'd like a pizza *made of dominoes* - OUCH!

[@bpal7006]

I'm sorry to hear about your taste bud deficiency.

[@carlachameleon8281]

A thought on a simple way to trigger the first domino: Use a rubber band cut in half with the ends stapled to some sort of stable surface. Make sure that the center of the rubber band is taut. You can pull the center back to another constant and stationary point with some sort of a clip that can be pulled out to release the rubber band. If the rubber band is taut enough to begin with you would not need a very large snapping motion to trigger the first domino, and the mechanism should be fairly consistent. Essentially a slingshot mechanism.

[@joelbourne1]

Thank you so much for this video! My kids and I loved it!

[@danb.cooper1778]

Its 4am for me im watching guys at 4am play with dominoes

[@bobsjepanzerkampfwagen4150]

haken2s2k 09:12 for meh

[@samuelunderwood5286]

The more mass, the more potential energy when standing, the more kinetic energy when falling. But, on the other hand. The more mass, the more force it takes to accelerate. I can't decide which of these factors is more important, or if they equal out.

[@thermophile2106]

Samuel Underwood Normally they cancel. This is why two things of different mass fall at the same speed (accelerating at 9 m/s/s) disregarding air friction. However, because of friction between multiple surfaces, this might not be quite the case with dominoes.

[@uniqnefreak]

but also more mass more normal force more friction the more it acts like a hinge

[@thermophile2106]

CaptainLeviathan Friction is normal force times the coefficient of friction ( a number that describes how much friction is between two surfaces) so in most cases friction scales with mass. If you slide two dominoes down a ramp, as long as air friction is the same, and the surfaces are the same, they will accelerate at the same rate, regardless of mass. The same should work for dominos falling. The more mass, the more friction, but the more resistance to acceleration, and the same end result.

[@thermophile2106]

That is what one would assume. But the dominos have friction between each other, the ground, and air, making this problem much more complex.

[@EpitomEngineer]

Does the vertical height that you tap the first domino affect the acceleration of the first 20 dominoes?

[@millercoleman6119]

Hey there, I recently found your channel and have only seen a few videos and I love them. I'm an Eagle Scout and love camping up here in Washington. While camping, I use char-cotton to start the campfire. I personally think char-cotton, known other as char-cloth, would be an awesome video.

[@snepNL]

The dutch record stands on 4,491,863 dominos. I feel proud.

[@sean3533]

snepNL My deep sense of Anericanism wants me to go out and beat this. 5 million dominos.

[@khangbanh8051]

I contributed in choosing that thumbnail 👊🏻

[@jonathanstef3218]

Hi! Loved the video, and enjoyed wracking my brain around creating an experiment to get representative results. First, the question that originated the experiment will help to simplify some things. Since you are looking to see what factors impact steady state domino fall velocity, you should ignore data from however many dominoes it takes to reach steady state (in the video you said roughly 20) and the last few dominoes (since they don't fall on other dominoes in the same way the last 2-5 fall further and will skew your results). This first change helps your triggering issue because there should be convergence to a single steady state velocity when triggered at any speed below the steady state velocity, although if it still bothers you, you can achieve better precision with a pendulum with fixed starting height and mass. The second change is to alter only one parameter at a time to get the effect of that single parameter on velocity using a truth-table to construct your test cases (I assume you are already doing this, but didn't mention it in the video, so I thought I would add it). Lastly, I think it would add interest to mark out the center of gravity (on the side of each domino) so we can track the movement of the center as well as that of the leading edge (maybe easier to do that with a pen and jig rather than in video post-processing). Thanks!

[@009Shazbot]

I can’t wait for the follow up on your next domino analysis. This is super cool.

[@Aarrgghh1]

When the domino goes from rotating at a point near it's Centre of Gravity (CoG) to a pin joint at the base, the lever arm becomes the distance from the pin joint to the centre of force (the preceding domino's inertia), so you would get a higher velocity at the top of the domino as the distance over which the force is acting has almost doubled. I assume that the heavier domino's would have a greater inertia and therefore a higher velocity? You'd have to devise a method of calculating frictional forces (between dominoes, dominoes and floor etc) to work out whether you'd actually go faster with lighter or heavier dominoes (only way colour could have different speeds in eu is different weights between colours).

[@nytmare3448]

Aussie Dave different colours could also modify the surface of the dominoes leading to slightly different friction coefficients

[@chimpornator]

But why does the case where the top of the domino is moving at a higher velocity result in a slower translation (assuming that is the case and is not measurement error due to inadequate testing conditions)? My understanding of it is as follows: when the domino is held at the base, the domino is forced to rotate about its base, increasing the moment of inertia vs the case where it is free to slip, and rotates nearer its COM. The higher rotational inertia slows the acceleration of the top edge of the domino, and the domino consequently impacts the next in the chain later. The domino-chains velocity of collapse is simply the distance between neighbouring dominoes/ time between collisions, and as the time between collisions is increased on a grippy surface, the wave velocity is slower. This is a similar argument to the analysis of what distribution of mass on a wheel rolls down an incline the slowest: a hollow cylinder. But there is some ambiguity: the lower energy of collision with the neighbouring domino would slow the time it takes for the domino to go from its stable upright configuration to a falling configuration, which would slow the initiation period. That suggests that the dimensions of the domino will have a significant impact on the velocity. also RE color, it is possible that the coloring process modifies the coefficient of friction. For example a black domino could be produced by mixing graphite with the plastic, which would slowly wear out on the surface of the domino. Self lubricating plastics employ this concept: graphite is constantly released on a microscopic scale resulting in lubrication as the part wears down.

[@Jtsaints13]

Aussie Dave iii

[@Aarrgghh1]

+Tim Sherry - agreed that rotational inertia slows the system where the base is pinned, leading to slower wave propagation. My comment was based on initial conditions in contrast to the diagram shown at 10:16 (my bad for being lazy). 9:20 shows the case where the heavier dominoes have more inertia, overcoming the pinned base where it then slips, leading to reduced friction in the system overall as the momentum of the preceding domino overcomes the base friction resistance in the next, and increased wave velocities. The lighter dominoes aren't quite able to overcome the friction at the pinned base, where the wave moves slower (If that is accurate Tim?). I think the diagrams referenced at 10:16 state the case where base friction is overcome and you see the rotation of the domino about it's COG. Really interesting to think about how the dominoes interact and what edge effects occur - base friction, friction between dominoes, wearing leading to reduced resistance (i.e. Tims case above), does the weight from 2 dominoes back have an impact on the domino being accelerated? Would a domino with higher friction move faster or slower? Does the time it takes to transfer weight from one domino to the next due to inter-domino friction greatly affect speed?

[@chimpornator]

Yeah I'm with you on the heavier dominoes being able to overcome friction more readily, and that being a factor in the wave propagation. Also I'm just putting forward a theory, which seems to fit the observation, I don't know if its the actual cause. I'm interested in what the answer is, its clearly not straightforward. Destin suggests that what happens when the domino is on a surface where it can slip is an open research question. Someone should get on it or point us to a paper haha. I found a paper from 2014 where they used rubber as the table surface specifically so they could suppress sliding over the table, so maybe this is well known in the world of domino dynamics. The paper is called "Effect of particle shape on domino wave propagation: a perspective from 3D, anisotropic discrete element simulations".

[@natewyliestudios]

Imagine the reaction if there was a earthquake right before they started

[@---cr8nw]

That's probably why it's in Detroit. I can't think of any other reason they'd pick Detroit.

[@natewyliestudios]

David Silverstein good point lol

[@Chunkboi]

That’s a huge problem when they set up domino falls in Japan (and they set up some big ones)!

[@jaypob]

This video is awesome because it shows how to see your flaws, stop, regroup, and go again. Bravo!

[@aleksandrsnaumovs4277]

Destin, thank you for the video...made me flex my brain again. Bud...I would start by isolating variables. Construct a setup where the dominos are fixed at the leading edge (a hinge if you will) That way you'll have isolated to sliding factor. Make enough of them to achieve a steady rate of fall. You should be able to increase/decrease the mass of each individual domino to observe different response of the system. Comparing the results of the constrained system with the a free system should give you an understanding of what effects what. Looking forward to it!! Alex

[@FlyingJetpack1]

You can use a mini electric motor for a more consistent push, and you can also bind a small plank to it so it could push multiple rows. And for the acceleration problem you can lay down a longer path of dominoes then just focus the end of your trail with the high speed camera. As for how you could tackle Tribology, usually physical systems behave in a characteristic fashion, so it might be possible to still be able to simplify the explanation of the dominant forces in play and explain to us how it all works together. Who knows, you might figure out something that domino builders will have to take into account in the future for things like timing very long trails. Because there might actually be a way to make a 1 in [number] correction to the difference in dominoes in use. (ex. having two long branches where one uses 500 more acrylic dominoes that need to come together at the end) As a side note i wonder how the max speed behaves in different friction surfaces, and what exactly happens if you move from one surface to another

[@Germanwtb]

*Trigger* : I think a *solenoid* would be best. You can use the signal, used to trigger the solenoid, to trigger the camera. That way you can *compare Time* more easily.

[@Scifiandscience]

I dont think triggering the camera would be an issue. Many of these high speed cameras record continuously and incorporate the couple of milliseconds before the trigger is pressed into the final shot.

[@biscottypuff]

I agree with the solenoid. I think a solenoid would just be a lot more consistent. You don't need it to have it synchronized with the camera but otherwise I agree. I would also have the first domino in the same start point so you don't have variability in how long the solenoid is contacting the first domino.

[@LeonardChurch33]

I thought about the solenoid too but it might hit a little too hard and throw the first domino into the later ones. Using something like a micro-servo to push them over might be more consistent and gentle.

[@Germanwtb]

Scott Curtis The synchronization might be helpful for determining the exact speed differences. A LED would do, i just think the eyeballing method might be insufficient to detect the minute differences we are talking about.

[@wes7235]

I watched this video 2 years ago. Last weekend, my family traveled to Michigan for a wedding. My 11 year old daughter had never flown before, so it was a whole new experience for her. We were hustling through the Detroit airport on the way to the baggage claim. Out the blue, my daughter says "hey Dad, isn't that the fountain with laminar flow." How awesome is that? Thanks Destin for your great videos. They're always informative and fun.

[@notn0t]

You can get a consistent trigger by setting up a simple pendulum that you always release from the same point. To assess the speed of a chain tipping about the bottom leading edge, make a jig that constrains the dominoes for sliding backwards. Please check the variations of the different types of dominoes too. What is the statistical variation in mass, geometry, friction coefficient? Thanks for a great channel!

[@boebrow]

what are the requirements for the records? I know here in the Netherlands we have a record of around 4.5M I guess we just have way to much time on our hands... For the suggestions I would say put a big row of dominoes before the ones you are measuring and let it either end abruptly (if this helps with calculations) or put more dominoes at the end so the last one you measure falls on (and has friction with, or resistance from) the next dominoes. A long start might eliminate the factor of the topple speed of the first domino. But to topple the first one you could use a mounted 'spring device' just like a (clicking) ballpoint pen. But it would be better to use a motor with an 'arm' turning very slowly. Either get the arm into the same position each time before turning it on, or let it turn so slow you could move the motor in (and come to a halt again) before it topples the first one. p.s. Some fun suggestions that might not be very accurate. 1) Let the line start in front of the camera, let it loop around and end behind the dominoes that have already fallen. 2) Test friction between dominoes by placing them together as close as possible. 3) What happens if you tape dominoes together in pairs? And could you simulate the "double domino effect" with it? or would that make it a "double double-domino effect"? ha-ha... 4) Dominoes under water!? If they don't float of course. I can go on for ages but I should better stop, before no one in their right mind will ever read all of it!

[@rinus454]

The main requirement seemed to be money and not time.. Domino Day was broadcasted live in a bunch of countries and had a good number of sponsors. That is what allows you to rent a large space and spend weeks just placing bricks.

[@boebrow]

rinus454 haha yes I know! I just figured Americans might have done something similar, or at least something bigger than this, including sponsor deals and all! Maybe it isn't such a big thing over there... But then again popularity also dropped a lot over here (and in Europe) as far as I know...

[@seigeengine]

I feel like getting this excited about tiny plastic blocks falling over is more of a European thing.

[@rinus454]

Apparently EndeMol-productions had trouble finding sponsors for it because of the financial crisis. Because of this, the 2010 attempt got cancelled. There was supposed to be one in 2011, but I guess they were unable to get it together then too. Probably wasn't any interest in it anymore at that point. I don't know.. This all doesn't seem that expensive to pull off. I feel like once you have the initial bricks, the cost shouldn't be THAT high. I mean.. They don't HAVE to broadcast it live. :\