There’s just something really satisfying
about skipping a rock.
You ever skipped five or six times you might
find yourself taking a little more seriously.
See if you can get seven, eight, nine consecutive skips.
想看看自己能否让石子连续跳跃7次 8次 9次
Turns out some people take stone skipping very seriously.
They actually compete to see who can skip the most
or who can skip the farthest.
The current world record for most consecutive skips,
is probably higher than you think.
Try counting the skips in this footage of the world record.
Just don’t blink.
Do you catch it?
That was 88 skips.
Here is a amazing thing.
Models actually project the limit
could be a lot higher than that.
Today we’re gonna explore what that limit might be,
and why approaching or even exceeding it could be almost impossible.
To find out what it takes I skip stones
with the world record holder.
What was that?
You know, the thing is, I never count.
Serious? You never count?
Talk fluid dynamics with a physicist.
It hits the water,
and this back end sort of creates a wave.
And so that stone tends to rise up over that wave that it creates,
and that’s what allows it to get a lift force that gets it back in the air again, before the next impact
and over and over again.
And brought both of them together.
To see if we can figure out how a world-class stone skipper
get so many touches on the water,
and what the limit might actually be.
So we’re here today with Kurt Steiner,
he’s the world record holder in stone skipping,
specifically most consecutive skips on the water.
And how many skips was that?
That’s so remarkable, I can’t even…
I… I’m not a really talented stone skipper,
but you know if I find myself at a lake with some stones,
但这样说吧 如果我在湖边 周围有一些石头
I will do some skipping,
I think the most I’ve ever done is like 13 or 14.
And like that makes me really really happy and proud,
so 88 is like… how?
It is what makes you happy that counts more.
But I think we can get that number up a bit.
We flew Steiner and a couple boxes of rocks to Utah,
where he gave me some lessons on extreme stone skip.
Steiner makes it look easy.
But a good skip is more than just how hard you throw a stone
or at which angle.
In fact, it all starts with the stone itself.
Okay that was closer like 15, 16.
I was gonna say 15.
All right, 15, all right.
So, the most I’ve ever skipped before this
is around 14, 15.
And here on my second throw,
I hit around 14, 15,
which tells me there’s a lot to do with the rock you’re using.
Steiner’s stones made a huge difference.
The worst rock in this box
is better than the nicest rock I’ve ever skipped.
Steiner like a lot of top skippers
is very particular about his stones.
He collects his from Lake Erie,
a few hours from his home in Pennsylvania.
A lot of questions as to what kind of rock is best right,
the general category I use is just how many size is it.
Steiner isn’t just an expert stone skipper.
He’s an expert stone picker, too.
This one is pretty similar to the one I would have set the record with.
He uses different shapes for different skips and different conditions.
People like triangles.
I used to like triangles, but…
they just chew up the water too much.
You’re always kind of weighing
how much irregularity is in my rock
against how hard am I throwing it
against what water am I throwing it on to.
Steiner also showed me how to hold the stone for maximum skipping.
The first thing you ever want to do is determining which side is going to be down.
And you generally want to go with the flatter or slightly rounded.
If it’s cupped or jagged, put that up.
Especially you want to look at the outer edge
because the stone almost never touches except around,
a half inch around the edge.
But as I soon found out
there’s a lot more to skipping than just picking a good stone.
Steiner uses a variety of grips and stances
for things like distance, power and number of skips.
That’s a high spin throw,
and then there’s one here we’re a little closer to the water,
that’s a good way to get a lot of power in real close.
He’s got a classic low skimming toss and an unusual overhand swing.
But basically you’re just kind of try to swat the water
as hard as you can with the rock as flat as possible.
He showed me how to get a little more whip on my skip.
Lesson number one,
You’ve got a lot more strength than you’re using.
He suggested trailing my hand.
Yeah and don’t start pivoting your waist around and your shoulder around
until that left leg is a good foot out in front of you.
If you drag your arm.
Right, you see what I mean.
You’re almost opening up and did the throw.
It’ll pinch up across here
and then essentially your hand is catching back up to the rest of your body
and will snap out better.
All right, let’s give that a shot.
It… That actually looked a little better to me.
So now the third part is where it comes together here.
That’s where you’re gonna hit your target.
Next, Kurt had me aim for a first touch closer to the shore line.
Did you notice how when you threw rock ,
the longer stays in the air, the more it will roll over on its side.
That is always happening,
you can minimize that obviously
by lessening the time in the air,
which is one reason you want to hit close.
So we’re gonna be focusing on three things on this throw
based on Kurt’s feedback.
One, I’m gonna be delaying the start of my throw,
so I can utilize more of my bio-mechanics.
Two, I’m gonna try to throw it hard.
And three, I’m gonna try to make contact with the water really close to myself.
There it is.
So that looked like high-teens to me.
Immedia… immediate improvement.
And that was your first try.
Yeah yeah yeah!
That’s so cool!
Every throw is a complete new puzzle.
So how is it that someone like Steiner can skip stones so many times?
To find out, we asked Tadd Truscott,
为了找到原因 我们拜访了Tadd Truscott
who runs the Splash Lab at Utah State University in Logan.
Yeah, the Splash Lab, welcome.
You got a lot of really cool stuff in here .
Yeah it looks like junk but we’re using all of it.
Yes, it’s a real lab,
and the work they do there is amazing.
And then this tank here where I shot bullets into it
for my thesis, my PhD thesis.
You shot bullets into this.
Yeah, yeah, absolutely.
They were modified 22 bullets.
-Is that what that hole is? -Yeah, yeah.
-就是那个洞吗 -对 没错
It’s where we missed, that that’s a misfire but yeah!
To study stone, skipping Truscott and his team recorded
Steiner hurling stones into a tank at thousands of frames per second.
To figure out how many skips are possible,
you have to first understand just how a skip works.
Here’s what happens.
So you have a stone it’s in your hand,
and you throw it,
and as you do that, you release it off your fingers,
and that causes it to have some spin.
So this spin is really important
we call it gyroscopic stabilization.
It essentially holds the attack angle of the… of the rock
with respect to say the surface of the water.
So then when you hit the water it deforms the water,
and pushes a wave out in front of it.
But the velocity of the stone is much faster than the wave that it creates,
and so it ends up rising up on that wave that it created,
and this causes a little lift force,
the rock is able to go back into the air,
and then back down.
As this happens over and over and over again
and for a good rock skip right.
And that gyroscopic stabilization is what keeps that attack angle correct.
And friction is really the only other thing that’s like reducing your ability to keep going.
The Splash Lab isn’t the only one studying in stone skipping.
A group of French scientists first figured out a model of ideal skipping in 2004.
These researchers in France found out
that the optimal angle for a disk to skip on the water’s surface
is about 20 degrees for both the attack angle and also that velocity vector.
That coupled with…
you know how fast it is thrown
as well as how much gyroscopic stabilization it has
sort of set up the problem to find out
what the maximum number of skips you can get
or the number of skips you can get based on what that spin rate is
and what that velocity is and that impact angle.
Now, you might think that studying stone skipping is a bit frivolous,
but Truscott says there are practical applications.
Yeah, definitely. So a spacecraft it was proposed that would bounce off the atmosphere
as it kind of came back towards Earth,
and use that to keep itself out.
You know, if you want to land on say the moon of Titan, you may want to…
you may want to come in for a soft landing,
knowing how skipping works might be a great way to do that.
To figure out how Steiner skips so many times,
Truscott his lab also went into the field
to gather data on his arm speed
and the rotation of the stones.
That was it, dude?
Steiner’s maximum speed is around 50 miles an hour.
His world-record skip was calculated at 43 miles per hour,
but he also has years of experience,
even his dud throws put my best efforts to shame.
But could someone best his record.
I’ve seen one or two people who have a technique that could maybe beat that.
But it’s almost impossible.
Now you might remember from our previous episode on the fastball
that pitchers are about maxed out on speed at just over 100 miles per hour.
Truscott applied that metric to stone skipping,
and came up with some amazing calculations.
A really safe place on our chart puts you around 93 mile an hour throw,
because these are a little heavier than a, than a baseball.
And they’re a little… they have a bigger radius which makes their moment of inertia larger,
so you need a little more energy in that side of it.
So 93 miles an hour is about where you’re topping out.
You’re gonna have about 2,800 to 3,000 revolutions per minute.
And if you can get there that’s of close to 164 joules.
You were gonna probably get close to 300, 350 skips.
Yeah, under the current idea, yeah.
Is that even possible? Under it already just seems ridiculous! Right?
I don’t even know who could count that like I couldn’t count 10 today.
Steiner thinks the limit is probably closer to 200.
That’s what the number says I’d like to go test it.
Truscott and other scientists have modeled their projections using a perfectly round disc.
But as Steiner showed me, there are no uniform stones.
Because mother nature never sees fit to make two of the same thing.
I have to get on about that.
So skipping a stone might seem like a simple thing.
But it’s actually this beautifully complex mix of skill, athleticism and fascinating physics.
It’s such a miracle to me what’s going on you know it’s this…
weird dance of water and stone in there.
So will we ever see 300 consecutive skips or 350?
That’s a good question.
It’ll probably take someone with a major-league caliber arm
and Kurt Steiner’s devotion.
But what we’re seeing these days from the world’s top skippers
is already almost impossible.
There’s just something really satisfying