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Hello there, I'm Gav. I'm Dan. We're the Slow Mo Guys. This should be a nice simple video. How fast does glass crack?
I actually don't know but we did that one video with the Pyrex jug where we saw it
Yeah, but it was actually quite difficult to figure out the speed because the, the crack was going through a curved
Pyrex jug handle. It was about this big. It's almost like we need a really long piece of glass with foot markers on it.
Where could we, uh, get one of those, do you think?
Oh! Oh, here's one. Look at this. I wondered what this was doing here.
So in theory if we break this at one end the crack should rush through it
I'm gonna put foot lines on it and we'll be able to determine the exact speed of a glass break
What I've done here with our 7-foot piece of glass is I've spray-painted exactly a foot along the glass
Now a foot's gonna start at, from the cameras point of view the left-hand side of the blue
So this edge is gonna be exactly a foot from here. And this one's gonna be exactly a foot from here, etc
So you should be able to calculate the exact speed
For glass as we know we need very high speeds.
The Phantom Flex4K only does a thousand frames a second.
Not worth it.
Might see–it'd be couple of frames, maybe, if that.
We've got the "Twenty Five Twelve" here today. We usually use the "Twenty Five Eleven"
This is the next revision
Has a different CineMag and a much bigger internal memory. But other than that, it's the same camera
So we'll start at 28,500 frames a second.
A bit nerve-racking, this. Oh, yeah, you're telling me!
Right. You stand there.
A bit of foam I see you've got there for protection.
Yeah, you've gotta protect the glass–otherwise it'll smash before we're ready.
*gasp*
Cool. So I'll hold it here. Okay, you got it? I think so.
I'm gonna bug in a ton of shutter here 45 degrees. Oh that's noise. You never do that. Why do you know in it?
Let me just grip this with this and see if I can smash the glass with just a pair of pliers, babe. Go for it
That works not really what Oh just vanished God I didn't expect to be able to do that and then he just went oh
You really framed up on the edges aren't you yep three two one step oh
Cool that's really no I'm surprised you can even see that much with the 28,000. Yeah, it's because it's so big
This is our starting frame rate. We plan on going much faster. I also like the fact that if I speed up a bit
it's like
irrelevant of gravity it splits up and down at the same time because I guess the pressure being released just goes with
It also shot forwards and at me once it when you crack it it sort of explodes
Yeah, that's why it makes that like sort of sound or it pops because it like has the pressure built up
I guess I did this with pain instead of tape. Oh
Yeah, yeah, you could see it separating. You can actually kind of see where everything was even in the air
It stays jagged directly in line underneath each other
Faster oh, yeah
so the way you can increase the framerate on the phantom cameras is you just lower the resolution and
As you may have noticed the top on the bottom of the frame here a complete
Garbage nor a waste. So what I can do is keep the width the same but lower the vertical resolution
So maybe something like that and that way we're keeping all of the useful area
But it will give us the chance to go to
Yep, 63 get some a darker. Probably not much sure to compensate
Should be
So this time I'll get some different colors in the go
Yeah, I'm gonna start by spraying each foot marker with a different color painting with den. Yeh
I'm just gonna get on the table here are in a rush. They
That's read done I like that you're doing this across two tables so you rank both at once I won't
Enjoy that
Lovely so the right-hand side of these or your left will be a foot long. This is pretty satisfying
Slop it in there
When you get a chance, okay, let me try and fill the frame with this mad lad go for it my level
Okay, Dan, it's time for some maths
Versus I'm gonna get up the true
Time of this crack and we'll measure how long in seconds it took each foot to break
There's a slight discrepancy between each one just because of which side of the foot mark of the crack landed on that particular frame
But don't worry will a ver each term out more Matt
Giving us average time of point zero zero two
seconds per foot which is forty seven hundred and fifty eight feet per second and for the international audiences, that's
1,450 M years per second
3262 miles per hour
5250 km/h or mac
4.20
You know, my mind is blown. I don't think that there's anything that's like physical but that's quick
What's physical that that's quickly? What goes Mac 4.2 apart from spaceship?
It's almost it's weird how like none of it overtakes anything else like, okay so it starts as round right?
See that it's not rounded. Yeah, so the middle of the glass is actually ahead of the sides
But it catches up and then it's all just going in a line. Do you know I think
Right, that is not I don't expect to see there
I think it what it looks like is if this was actually a circle like if it was like a 14
Foot circle. Yeah, and you smashed the middle it would all go out in a circle
But we're just seeing like a section of that. So if you imagine that
It starts off as a small circle it gets bigger and bigger. It doesn't it's not actually flat when he gets the end
It's still slightly curved. So I'm just imagining a circle getting bigger. Therefore. The edge is getting flatter. Yeah, exactly
bloody
Mental now can't want to do it a big circle
fresh out of
14-foot glass circles, unfortunately good church window
alright, so that was
78,000 multi-coloured. Yeah, I think it's time to get carried away
This bad boys the capable of some serious, let's Lincoln. Let's let it stretch this legs
Thank you every spin
Will reduce the horizontal width as well
Lose some more on the vehicle
maybe go
To five six by
Ninety six, that's small enough giving us a frame rate over four hundred and eighty one and a half
Thousand frames a second because we're now so cropped in
I'm only gonna be seeing two colors. So there's no point painting the rest waste the paint waste a paint
Glass is cool Oh
Ridiculous, how much can you see bloody stupid? This is
She's that one pot? Let's look at this ridiculousness
It just looks like a software wipe
it's just like we took two fixes then just wiped across it just instantly turns it to like lizard skin just turns into like
Scales this cameras. So cool just records all that like that happened and it recorded it at that. Yeah this camera saw everything
final aftermath
Another pretty aftermath that is not bad. It sounds like snow - listen
Don't like snow but what's cool is the fact that cuz obviously we did it all in in color order. It's all stayed there and
Look, this is all
This looks like it's an intact piece of glass but it's actually oh, yeah, at least smash it's gone
It's just held together by there. Yeah, which is why it was good that lab
We didn't record the the paint side who recorded the front side so you can see the cracking around the color
Well, we learned the speed that a crack propagates through laminated sheet of glass
Yeah, they've temp in action. You couldn't tell with the the little video we did before but that really demonstrated
It was so fast
and and the way it starts as a circle and then basically gets
Bigger for in a circle, even though it's a flat rectangular piece of glass. I was really impressed by that
I didn't I didn't expect to see that
I guess you'd never know it unless you see a long piece of glass slow motion in my head
You were gonna crack it and it would just come across as a straight ball the whole way of outside
Oh, of course. It's gonna crack from that point and then the fact that it evened out was very cool to me
Yeah, it was awesome
Hopefully you enjoyed that video bung it alike. If you did, there's a dislike button - that's always fun. Subscribe to the slow
Mo guys and we've got a second channel any closing thoughts Daniel gets a bear get a broomis will get a get a broom
Yep for this got this grass
Glass grass grow I met grass that time. Okay. Yeah because I'm gonna sweep up the glass from the grass
Yeah