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# Dominoes - HARDCORE Mode - Smarter Every Day 182

Okay, let's just get this out there right now, I know
This is weird you probably watch this channel because you want to see slow motion phenomenon of like
bullets hitting stuff and fracture mechanics and water drops bouncing and animals squirting things
Whatever you're into
But this
is crazy.
Most people think "Oh look, the cute little nerds set up the dominoes, and they knock them down, and everyone claps and it's great." No.
This is different than that. I was naive enough to think that I was gonna set up a high-speed camera, point 'em at dominoes,
I was gonna set 'em up knock 'em down, vary the spacing and the type of floor it was on and I was going to
transcend the knowledge of dominoes instantly, you were gonna get smarter every day, and we were gonna go about our merry way.
But no. Look me in the eyes.
This has broken me.
I do not understand dominoes.
The reason this's broken me is because I've been sitting here doing all this math to determine the gap
Necessary in order for this red Domino's weight to always knock over the blue one, but when I set up with my calipers
It doesn't work, and if you think about it the same people that taught me how to do this math
Also told me if I needed to I could assume a cow is a sphere in a vacuum
Paper physics can only get you so far. If there's anything I've learned from my job as an engineer. It's that
There's no replacement for actual real-world testing
if we want to make observations of the exact times these Dominoes hit down to the millisecond
It's really hard to do it from a camera like this the reason is look over here
You can see the inside of this Domino, and then the inside of this one and somewhere in the middle it changes
So if we want to get a shot where we get all this data
We have to have a moving camera not only that but a moving camera that is
Perfectly timed right here in the middle so we can see when this edge hits this edge
Which means we're gonna have to time it perfectly
With the wave of Dominoes as it runs along the track do I want to keep making videos on smarter every day about Dominoes
Yeah, if that's what it takes to find the answer. Yes, that's what I want to do
This is about not quitting so now we're gonna give Domino's the respect they deserve and we're going hardcore mode
We're at fifteen millimeters
The second one over here
Welcome to hardcore mode...
It's the same as before only I try harder so here we go we're gonna build stuff
And we're gonna do experiments, and we're not gonna quit, and there's a twist at the end of this video. Let's do it
Okay, this is Trent. He is the contraption fabricator that I talk about on the patreon page, and this is my cousin Hayden, hey Hayden
okay, so this is a high speed camera on a skid and
Trent made this, good job Trent and we are about to try to pace
These dominoes so that we can tell the difference between a hardwood floor, and you know a surface that's grippy. Okay ready ?
That looked awesome, oh it outran us it moves a lot faster than the wood floor, and I'm so used to the wood floor
He's frustrated. I know well enough to know when he's frustrated. He's frustrated. You miss that one
Are you frustrated Trent?
No all right we're going to figure out exactly how to nail this we're gonna get all the dominoes in frame as they fall
So we can gather the timing data and figure out what steady state velocity is it took some practice because sometimes the dominoes would outrun us
And sometimes we outran them
So I keep messing up the high speed which means Hayden has to keep set up dominoes
Which means up if we're gonna my half-court shot
We got it. It'll work, it'll work this data
This is the first good run we got on felt
Watch closely and you can see that the bottoms are trying to slide out from under the Domino
But it digs into the felt and stops
I think we got it do that one more time
I feel really good about that. Oh, we did pretty good Hayden Hayden
We got it, that's the one right
This is the best run we got on hardwood if you look at the bottom you can see that
It's slipping out from under the Domino makes it rotate around its center of gravity and also if you look at the top you can
See that they're not hitting square on
So which one is faster
We've got hardwood on the bottom that slips and we got filth up top that doesn't slip and Trent and I both felt felt
Was faster so how do we know we have to like quantify this?
The answer is brute force science to figure this out
We did a ton of runs mostly filmed at 5,000 frames per second the goal is to figure out exactly
What millisecond each individual impact occurs which made for over a hundred and twenty thousand frames of data to reduce?
Your boy here has too many kids and too many jobs to reduce that much data
So I blasted out a spreadsheet template to everywhere that smartereveryday touches the Internet I compared you guys against each other Twitter
Got it done fastest people follow me on Instagram and snapchat got it done quickly
Facebook helped surprisingly the physics subreddit wasn't interested in doing physics that day the smartereveryday subreddit was great and accurate but
Patreon was by far and away the most accurate source, which makes sense because these are the best people in the world
There's a reason I gave each social media outlet its own spreadsheet. It's called the wisdom of the crowd here
You can see exactly what frame each individual chose at the impact point and the average of those selections
These averages were then graphed for each individual video file and there you have it if you average all the runs together it appears that
The non slipping felt is faster than the slipping hardwood before I go into why I think it's faster
I'm gonna let grant from the YouTube channel three blue one brown take a crack at it because this dude is
fantastic at reducing super complex mathematical systems down to quick little YouTube bytes
It's amazing you should check his channel out anyway go for it grant
Hey, Destin its grant, so I wouldn't haven't looked at some of the data that you sent and here
I'm just gonna pull up two examples one of them with Domino's on felt the other on hardwood
and these are just the plots of the average velocity of each individual Domino as they fall and
Obviously the first thing that stands out is just how chaotic this is right
they're super jaggedy and I think some of that might just be that the
Distances between each Domino were probably a little bit variable right that's probably not perfect
But the way that we were computing those velocities kind of assumed that that distance was a constant
So one pretty simple thing I did to just kind of smooth out this data is rather than graphing each
Individual velocity point take a look at the previous 20 different velocities
And then average all of those and that way if we look at the moving average
It should hopefully kind of smooth out any of the small variations and things like distances between dominoes so when you do that
It does look like that in general filth is a little bit faster than hardwood, right?
But that's not always consistently true like here if we look at the last few Falls
It seems like the hardwood sort of catches up with it, and this is just two examples
But I saw this in a lot of the other ones so if you just look at the overall average
Velocity felt definitely does look faster, but it wouldn't be comfortable saying that it's consistently faster
I think there's probably a lot of other variables at play here that sometimes might pull hardwood ahead grants
Channel is amazing you should really go check it out, but you gotta skimmed over the chaotic part of the graph and for me
that's the most fun part when you track a rocket with a radar you get a general idea of the
Acceleration profile by looking at the distance versus time plot
But the magic is over here in the noise
When a rocket makes a correction usually that shows up as a perturbation in the raw data
And I'm seeing perturbations in this data
and there seems to be an actual pattern here a
Natural undulation of the curve initially I didn't have enough Domino setup to determine a steady state velocity
But now I'm wondering if there. Even is a steady state velocity because if you look at the data
It goes faster and slower over and over again. I think this might be happening for two reasons number one
You can see little twists
You can see that the Domino's aren't hitting each other
Square and in fact the twist gets worse and worse and slower and slower until it gets so slow that the pushers behind it fall
Down and straighten them back out this slam down is that velocity spike that we're seeing watch this
twist
Things are stacking up and
Slam see that spike. It's a natural cycle in the graph
there's a twist a
twist
Twist
They're starting to stack up and
slam
The twist is energy lost in the system
And the slam is the positive
correction the second thing I'm seeing becomes more clear when we spread out the
Domino's where each Domino hits the next one seems to determine how much it rotates versus how much it's pushed watch this
When a Domino is hit down close to the center of gravity the impact will tend to?
Translate the Domino forward instead of rotating it because this
Translation calls it to still be upright when it hits the next one it hits it up high
which makes the next one rotate faster the next one gets hit down low and you see that a
back-and-forth pattern emerges
I'm not really sure how this plays in but it's clear to me that where a Domino's hit on its back determines
How it falls forward when you spread the Domino's out farther the effects of these phenomena are amplified even more for example watch this case
one Domino in the entire chain
Doesn't fall all right, so
This is curious, so we see how that happen
Check this case out where the chain stops altogether due to the twist error building up past the point of recovery
Okay, here's the twist to all this this video is not about dominoes this video is about creating an experiment
To understand what seems like a simple system at a very very
Complex level now that you know what to look for you're able to see very
Intricate interactions in this Domino chain right now right in front of you. There's no real direct
Application so why do we do this, this is what we call basic research, and it's very very important
It's not like Applied Science where you're inventing things using some technology
It's about being able to
understand and predict
Natural phenomenon humans weren't able to go to the moon because they suddenly felt like it it started by wanting to understand how birds fly
Someone had to first answer that
Question before we could ever start on our way
Cancer won't be cured because we walk into a lab with a lot of money and want it to go away
It's gonna involve basic research like how cells work these complex
Building blocks to understand the world are right there in front of us all the time
But we have to make that first little push into the unknown
to start the chain reaction
So here's the point ask
The simple questions keep an eye out for those little things that end up being building blocks that lead to the bigger stuff
At work my favorite people are the ones that ask questions in meetings that might sound silly
but they're not because for every 10 they ask there's one that they'll ask that'll start this chain of discovery and
Pull us all towards the profound
So that's the take away ask the simple questions and dare to try to answer them
I'm Destin you're getting smarter every day. Have a good one all right
I'm gonna travel for my day job, so sorry for the weird transition here
This is the hotel room that I'm staying in I want to say. Thank you to everyone who worked on the data
That was a big deal
It would've taken dozens of hours
So thank you everyone that did that especially the patrons who helped me fun things like Trent making the little high-speed camera cart
I also want to say. Thanks to the sponsor, which is 23andme 23andme is a personal DNA service
They send you this kit
And then you send off a sample and you get all kinds of info
And back about your DNA in about six to eight weeks now
I wanted to know what happened in that six to eight weeks so in another video on smarter every day
I went to the labs where they actually process the samples and I got to see exactly what happens there
It was awesome, and I feel really good about the process
I personally enjoyed doing the service because I got to share my DNA family history with my dad
And so we got to connect over that it was really cool
And I'm totally gonna give it as a gift if you want to check this out and learn more about your DNA then go to
23andme comm slash smarter you can get yourself a kit do it yourself. It's really a fun thing to do again
That's 23andme comm slash smarter doing that support smarter every day
And you get to learn more about yourself in the process alright. That's it
Thank you to everyone who follows me on all the social media yet reddit Twitter Instagram obviously
I'm not like an Instagram model, but I try to do intelligent stuff or at least things
I'm thinking about which is normally kind of abnormal stuff, so thank you for following me on that and also
Thank you for answering the call when I have that data problem if you're new here
And you like the idea of crowd science feel free to consider subscribing to smarter every day
To help me do stuff like this when I blast that out on social media or whatever
I really appreciate the consideration for subscriptions and follows on all that stuff
I'm just a dad that works for a living so whatever. Thank you anyway. I'm Destin. Thank you again. Have a good one
Okay, you can do it! Trigger!