Hello, there I'm Gav.
I'm Dan.
We're the slow Mo guys. It should be a nice, simple video.
How fast is 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
'cause 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 get one of those? Do you think?
Oh here's one. Look at this.
I wonder what this is doing here.
So in theory, if we break this at one end,
the crack should rush through it.
I'm going to 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 seven per foot piece of glass
is I've spray painted exactly a foot along the glass.
Now the foot's gonna start and
from the camera's point of view,
the left hand side of the blue
So this edge is going to be exactly a foot from here
and this one's going to be back here from here, et cetera.
So we should be able to calculate the exact speed.
For glass. As we know, we need very high speeds.
The Phantom flex 4k only does a thousand frames a second.
Not worth it. Won't see it.
Maybe couple of frames maybe, if that.
Maybe if that we've got the 2512 here today,
we usually use the 2511.
This is the next revision has a different cinema.
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 nerveracking, this.
Oh yeah. You're telling me.
All right you stand there.
A bit of foam I see you've got there for protection.
Yeah. You got to protect the glass.
Or else it'll smash before we're ready.
Oh cool. So I'll hold it here.
Okay. You got it?
I think so.
I'm going to bung in a ton of shutter here.
45 degrees.
Oh, that's naughty. You never do that.
Bloody naughty yeah.
Let me just grip this with this
and see if I can smash the glass with just a pair of pliers.
Ready? Go for it.
That worked.
That really worked.
It just vanished.
Whoa. Gosh, I didn't expect it to be able to do that.
And then it just went poof.
You really framed up on the edge there aren't you.
Yeah. Three, two, one snap.
Whoa, cool.
That's really cool.
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 it 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 bing.
It also shot forwards and at me.
So once when you crack it, it sort of explodes.
Yeah.
That's why it makes that like
sort of sound where it pops.
'Cause it like, has the pressure built up
I'm glad we did this with paint instead of tape.
Oh, Whoa.
Yeah. Cool. 'Cause then yeah,
You could see it separate and you can actually kind of see
where everything was even in the air.
It stays directly in line underneath each other
for ages there.
A bit faster?
Oh yeah.
Faster.
So the way you can increase the frame rate
on the Phantom cameras is you just lower the resolution.
And as you may have noticed the top and the bottom
of the frame here, are complete garbage they're 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 63.
It gets a bit darker. We'll open up a shutter to compensate.
That should be additional information.
So this time we got some different colors on the go.
Yeah I'm gonna start by spraying each foot marker
with a different color.
Painting with Dan. Yay.
I'm just gonna get it on the table here,
but we're in a rush so.
That's red done.
I like that you're doing this across two tables.
So you ranked both at once.
I wanted to return one of them as well.
I enjoy that.
Lovely.
So the right hand side of these or your left
will be a foot long.
This is pretty satisfying.
Slip it in there.
When you get a chance.
Okay. Let me try and fill the frame with this mad lad.
Go for it. Higher level
Oh, look at that.
Okay. Dan, it's time for some maths.
Okay.
Just reverse this.
I'm gonna get 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.
We'll average them out.
More maths.
Giving us an average time of .002
seconds per foot, which is 4,758 feet per second.
And for the international audiences,
that's 1,458 meters per second, 3,262 miles per hour,
5,250 kilometers per hour or mach 4.2.
Oh, you know my mind is blown.
I don't think that there's anything that's like physical
that that's quick.
What's physical that's quick?
Like what goes Mac 4.2?
Apart from spaceships.
Nothing.
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 starts 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 what I think
That is not. I didn't expect to see that.
I think what it looks like is
if this was actually a circle.
Like if it was like a 14 foot circle
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
and it gets bigger and bigger.
It doesn't, it's not actually flat when it gets to 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 kind of want to do it with a big circle.
Fresh out of 14 foot glass circles unfortunately.
Gotta church window?
All right so that was 78,000.
Might be covered yet.
I think it's time to get carried away.
This bad boy is capable of some serious,
what are we thinking?
Let's let it stretch it's legs.
Let it go out for a spin.
We reduce the horizontal width as well.
Lose some more on the vertical.
Maybe go
256 by 96.
That's small enough?
Giving us a frame rate.
481 and a half thousand frames a second.
Because we're now so cropped in.
I'm only going to be seeing two colors.
So there's no point in painting the rest.
Waste of paint.
Plus is cool.
It's wicked isn't it.
Ridiculous.
How much can you see?
Bloody stupid this is.
Jeez. That one popped
Let's look at this ridiculousness.
It just looks like a software wipe.
It's just like we took two pictures
and then just wiped across.
It just instantly turns into like lizard skin.
It just turns into like scales.
This camera so cool.
It just records all that.
Like that happened and it recorded it at that.
Yeah this camera saw everything.
Final aftermath.
Another pretty aftermath actually.
Yeah it's not bad.
It sounds like snow too, listen.
It sounds like snow, but what's cool is the fact that,
'cause 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 intake piece of glass,
but it's actually.
Oh yeah. Really smashed.
It's gone.
It's just held together by the.
Yeah.
Which is why it was good that
we didn't record the paint side.
We recorded the front side.
So you can see the cracking on the color.
Well, we learned the speed that a crack propagates through
laminated sheet of glass.
Yeah a bit of tempered action.
You couldn't tell what the,
the little video we did before
but that really demonstrated it.
It was so fast.
And the way it starts as a circle and
then basically gets bigger from 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 in slow motion.
Yeah in my head, you were gonna crack it.
And it would just come across as a straight wall
the whole way. But I said, Oh, of course,
it's going to crack from that point.
And the fact that it evened out was very cool to me.
Yeah, it was awesome.
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Any closing thoughts Daniel?
Guess I better get a broom.
Better get a broom.
Yup. For this, glass. This grass.
Glass grass?
I meant grass that time.
Yep okay, good.
Because I've got to sweep up the glass from the grass.
Yeah.