04x05 - Volcano Boarding

[bunniefuu]

[Dallas]
This is the Science of Stupid.

[reading onscreen text]

Yes, this is the show
that follows ordinary people

squaring up to science
and coming up short,

as they attempt acts
of eye-watering idiocy...

with agonizing results.

[groans]

We'll analyze what went wrong and why...

[groans]

...when they went up against
such scientific principles as...

frictional resistance...

Newton's first law...

and that old favorite, turning effect.

So please don't try any of this
at home or anywhere else.

Watch out...

it's the Science of Stupid.

[electricity crackling]

In this show, we'll tackle...

angular momentum...

glide ratio...

and the conservation of energy.

But first this...

[electricity crackling]

Going down a slide...

fun, efficient, simple,

even a child can do it,

so it makes absolutely no sense
that bigger people have come along

and tried to complicate things
by adding extra layers of difficulty.

Such as...

obstacles...

vehicles...

-...and...
-[man] Come on, man.

peer pressure.

[laughter]

When it comes to going
down slides on other stuff,

there are lots of way to go wrong,

like even attempting it.

But luckily for our fearless researchers,

behind every act of stupidity
is the guiding light of science.

[dynamic music]

Our man is accelerated
down the slide slope

by gravity...

Sliding on a smooth box
gives less frictional resistance,

which means he accelerates more quickly.

Add some wheels to the mix

and he's not slowed down by friction,

only rolling resistance,
and that's a lot lower,

but it could lead to those wheels

accelerating out from under him.

When he lands,
a sudden increase in friction

can generate an unwanted turning effect,
sending him into a spin.

So when it comes to speed,

it's all about maximizing
the steepness of the slide

and minimizing
the coefficient to friction,

and that's best accomplished
with a smooth object.

So let's see how smooth
we can get, shall we?

Plastic on plastic,

that's less than half
the friction of skin on a metal slide.

[woman] Go!

[Dallas] Or don't go?

The friction was low enough
that he quickly built up speed...

but not as quickly as he lost it again.

These guys are in plastic boxes,
so it'll be hard to fall out.

[groaning]

Hard, but not impossible.

[man] Oh! [bleep]

When they landed,

that sudden increase in friction...

spun them out of control.

[bleep]

Oh, my God!

Once again, don't try this

on your local slide, or any other slide.

So, as we've seen, a lack of friction

can be extremely dangerous,

but shall we up the ante
and stick on some wheels?

Now science tells us in order
to stop those rolling rascals

accelerating out from under you,

it helps to crouch down

and lean your center
of mass slightly forwards.

And if you get that right,

you could look like this...

[cheering]

Yeah, whatever.

But that's not really
what we're about on this show.

Back to school, you lot.

Let Dad have a go.

But is that slide really for grown-ups?

Whoo!

-Eh... No, I don't think it is.
-[laughter]

By not leaning
his center of mass forwards,

he let those wheels
accelerate out from under him...

hitting the deck with a force

of two and a half times his body weight.

Yeehaw!

[Dallas] Yes, this is more like it.

He's getting into position...

[man] Go on...

Easy for you to say.

[laughter]

Ha ha.
Oh, science, you are naughty.

OK, for extra safety,
let's try lying down.

Whoop, whoop...
I'm Zac, this is the torpedo.

Zac, you forgot about
that high friction on landing.

Less torpedo, more, eh, wet fish.

[electricity crackling]

Whenever I visit my local pool,

I like to exert my dominance

over the other swimmers
with a simple demonstration

of my physical prowess.

I like to think
it looks something like this...

But I've seen the videos

and it actually looks
a bit more like this...

-[man gasps]
-[all] Ohh!

Yes, we're talking
about the pool handstand.

Now, I shouldn't need to tell you

that combining gymnastics, sharp edges,

and slippery surfaces
isn't exactly the best idea,

but just so we are clear why,
let's consult the science.

[Dallas]
Our man starts by generating

enough vertical momentum
to carry him up into position.

Then to stay vertical, he must maintain

a rigid body position
by tensing his mid-section.

If he's going to fall,
it'd be better to fall backwards

into water rather than forwards
onto the ground,

as from there,
water will decelerate him more slowly,

exerting a smaller impact force.

It's all about generating enough momentum

to get into position

and keeping your body rigid to stay there.

Now what was the other thing
you needed to watch out for?

[shouting indistinctly]

[laughter]

[Dallas] Ah, yes, wet floors!

Oh, hello. One, two, three...

[woman gasps, screams]

[man screams]

Yeah, a good run-up,

but after he slowed down,
he couldn't generate

enough vertical momentum
to get him up into position.

I'm no doctor, but I think
that might have hurt.

That is a nice shirt.

You wouldn't wanna get that wet.

[groans]

Ah, spoke too soon.

He managed to maintain
a rigid body position

and stay upright, until he didn't.

[groans]

Well, that's what the water's for.

[man] Oh, my gosh.

Let's hope
that shirt's not dry clean only.

We've learnt something today,

that when it comes to the pool handstand,

it pays to have a good exit strategy,

and as water can decelerate
our toppling amateur gymnasts

in a much more forgiving manner,

a fall towards the pool can ease the pain
and boost your street credibility,

something this lot
would do well to remember.

[lively music]

[woman groans] Ow.

[Dallas] Yeah, you can't expect
water to decelerate you slowly

if you're nowhere near it.

[all screaming]

Is that the lotus crab position?

Impressive flexibility...

but what did I say
about landing on water?

Absolutely fine. Must be all that yoga.

[electricity crackling]

Ah, Sundays, the perfect day
for a little light gardening,

but can you guess what
seedling of science

this keen landscaper is about to show us?

[electricity crackling]

[Dallas]
This green-fingered gardener's

doing a spot of weeding, but I asked

what scientific principle
is he about to demonstrate?

It's a force couple.

With each rev, the buggy experiences

a forward force at the wheels...

but when the bush refuses to budge,

the towing line exerts
a backward reaction force

to the buggy.

Because these opposing forces

are not aligned,
a force couple is created...

and a rather large turning effect.

And they tell me gardening's relaxing?

[electricity crackling]

The motorbike.

Light, agile, great for pulling
off impressive jumps,

but sadly,
we're not looking at motorbikes.

The all terrain vehicle...

relatively slow, fairly heavy...

and prone to flipping.

[all shouting]

Now, while those trendsetters
were all fine,

what we've just learnt is that

when jumping on an ATV,
you can really get hurt,

so let's check out some science, shall we?

Our off-roader makes sure

he builds up sufficient
velocity on approach.

If he leaves the ramp too slowly,

he'll generate angular momentum
as gravity pulls down

the ATV's heavy front end.

If the landing zone is lower
than the take-off zone,

he's in the air for longer,
so will rotate further.

He lands on the back wheels
before the front,

flexes his knees
to distribute the impact force.

OK, let's start with the launch.

Now, remember, those ATVs
are seriously heavy,

so although excessive speed
can be dangerous,

it is essential you hit
any jump with enough velocity.

[man 1] Oh, geez.

[Dallas] And that wasn't enough.

But getting his ATV to stand
like that is pretty clever.

Hitting the jump
with insufficient velocity

meant that as soon as it left the ramp,

that heavy front end
was pulled into a nose dive.

[man 1] Oh, geez.

-Hey. Are you all right?
-[man 2] Yeah.

-[man 1] Are you sure?
-[man 2] Yep.

[man 1] All right.

[Dallas]
I think that means he's all right.

Maybe a bigger ramp would help?

Or maybe not.

I admire your spirit,
but with that steep ramp,

you'd no chance of building
much velocity for anything.

He seems pleased, though.

And his dog's happy.

[laughs]

OK, remember,
if your take-off area is higher

than your landing area,
you have longer to fall

and therefore longer to rotate
into a nose dive,

so it's even more important
to avoid that angular momentum

by launching as quickly as possible.

Let's hope this sand dune jumper
remembers that.

[indistinct shouting]

[Dallas] No, he hasn't.

Maybe his mate will learn
from his mistake.

[man groans]

Or maybe not.

[school bell rings]

[liquid bubbling]

Right, pay attention, please, class.

It is time for the science lesson,

that part of the show
where we probe the inner workings

of a particular scientific principle.

So who can tell me
what the following have in common?

This karate chop flop...

Hai-yah! Ohh!

This topless tumbler...

[laughter and shouting]

And this punch drunk pugilist.

[groaning]

The answer is, of course,
the coefficient of restitution,

or just how bouncy something is,

and that all comes down to that
indisputable pillar of physics,

the conservation of energy.

Let's see an example.

[dynamic music]

As these two objects accelerate,

they gain velocity and kinetic energy.

This rigid billiard ball
has a high coefficient of restitution,

meaning that it retains
most of its kinetic energy

during the collision,

for a large bounce.

With a low coefficient of restitution,

this pliable lump of putty
permanently deforms

as its kinetic energy is converted
to other forms such as frictional heat.

And since energy must be conserved,

it has no kinetic energy left...

and no bounce.

Now, to retain that
kinetic energy for a big bounce,

an object can be either perfectly rigid,

like a billiard ball,

or it can be soft and elastic,

deforming as it stores
the energy and releases it.

OK, question one,
who can give me an example

of something soft
with a high coefficient of restitution?

Oh, that looks fun.

[screaming]

That, not so much.

That's right, trampolines
give you a soft landing

and have a high coefficient
of restitution.

In fact, her bounce stored and returned

enough kinetic energy to launch her

into an impressive front flip.

-[clank]
-[screaming]

Yeah,
that metal part, not so soft.

[onlookers exclaim]

Right, on to question two.

Do humans have a high
or low coefficient of restitution?

-One, two, three...
-[Dallas] The classic trust fall.

...go!

[screaming and crying]

[girl 1] You're meant to fall backwards!

[girl 2] It's not funny!

[girl 1] It's hilarious.

[Dallas]
Uh, it's kinda funny.

That's right, humans have
a low coefficient of restitution...

which means they don't bounce very well.

These gentlemen know the science,

so they're using bouncy gym ba*ls

to increase the coefficient
of restitution.

[groaning]

Remember, humans don't bounce.

And if you're gonna
try and outsmart the laws of physics,

you gotta try better than that...

because science is better than you.

So we've learnt that
when you mix collisions and people,

it's less about bouncing
and more about smashing.

My third and final question is:

When something permanently deforms,

what happens to the kinetic energy?

[boy grunts]

[laughter]

[Dallas]
Exactly right, it's dissipated.

By starting high,
he generated kinetic energy

equivalent to a mouse travelling

at almost the speed of sound...

which was all used up
in permanently deforming

that metal frame.

All right, class dismissed!

[electricity crackling]

When I was a little boy,
my dad used to tuck me in at night,

and I'd tell him
I'd dreamt of being able to fly.

He'd lean over and ruffle my hair and say,

"Don't be ridiculous.
It's physically impossible."

So to prove him wrong,
I decided to give hang gliding a go.

-[groaning]
-[Dallas] And it didn't go well.

But it isn't just me
who dreams of flight.

I feel your pain, my penguin brother.

Luckily, dogs have got nine lives--

No, wait, that's something else.

Do you see what I mean?

Even animals seem to want to fly.

That said,
it doesn't take a genius to know

the one thing that we have in common

is that we're lacking
the essential equipment

required for flight.

But while it's true that only birds,

insects, and bats can really fly,

other members of the animal kingdom
have still managed

to take to the air using a simple trick:

gliding.

Now let's take a look at the science.

[dynamic music]

Effective gliding is all about

maximizing the glide ratio,

which is the horizontal distance traveled
over the vertical distance fallen.

This sugar glider has short membranes
between its limbs

which give it a low
glide ratio of about 1.8...

meaning they can't glide all that far.

Birds have gone one step further,

evolving long, thin wings
that generate less drag and more lift.

With a higher glide ratio of about 19,

this albatross is well adapted
for gliding long distances,

using little energy.

So when it comes to mastering the skies,

gliding is very, very useful.

It can keep you safe should you fall,

and it can help you travel long distances
without getting tired.

Just spread your wings,

feel the wind in your feathers, and...

[bird squeaking]

...look where you're going.

Ah, ha-ha, the graceful parrot.

The largest species have a wingspan
of more than four feet,

so they should be really good at gliding.

-[parrot squawks]
-[thud]

[Dallas] Moving on...

Ever heard of indoor sky diving?

Well, this is the sugar glider
equivalent.

[squeaks]

With a low glide ratio, she's using drag

to effectively slow her fall...

right into the camera.

Ah, the cat, man's best friend,

and not normally associated with gliding.

[man] He won't make it.

[Dallas] Ah, scientist, eh?

[meows]

Ah, he's absolutely right.

A big jump, but without wings,

he didn't have much hope of gliding.

-[man] Oop.
-[cat meows]

Maybe stick to chasing birds
instead of trying to be one.

Don't worry, none of the animals
were seriously hurt

during the course of their research.

Embarrassed, yes,
but not hurt.

[electricity crackling]

Now, as a modern man,
I like to get my hands dirty

in the kitchen,
and nothing is guaranteed

to get your hands dirty
quite like combining

those two great art forms
of cooking and acrobatics.

It takes concentration, a bit of skill...

but it can be done.

Very nice, but I ordered an omelet.

Wear appropriate eye protection...

and try to avoid...

whatever that is.

Yes, we're talking about the pancake flip,

where batter meets velocity.

But to avoid a hefty clean-up job,

best take heed of the science.

[dynamic music]

With a sharp forwards push
to loosen the pancake,

she kicks the pan upwards...

generating vertical velocity
for height...

and flicks the front backwards,

generating angular velocity for the spin.

Whilst centrifugal force keeps
the pancake stretched flat...

the cooked batter offers
enough structural integrity

to stop it from being pulled apart.

Finally, she brings the pan back

underneath the pancake
for a perfect landing.

Now the largest pancake
ever made

had a diameter
of nearly 50 feet.

We might need to start a little smaller,

but regardless of size,

to get that crucial half a rotation
needed for an evenly cooked pancake,

you need a perfect combination
of height and spin.

Right, let's start with the height.

So big flip, right?

[Dallas] This looks promising.

[laughing]

OK, you didn't need
that much vertical velocity.

Let's give angular velocity a go.

Is that even a pancake?

[laughter]

No, that's a lumpy omelet.

And it lacked the structural integrity

to withstand the centrifugal force
of the flip.

Exactly. Walk away.

Now back to pancakes.

[shrieking]

The structural integrity
of the pancake was good...

the pan, less good.

Now he's just showing off.

[all laughing]

Another backwards trajectory,
but this time a bigger flip

so the pancake went flying into the sink.

[laughter]

I don't know why you're laughing.
That was your breakfast.

[electricity crackling]

And that sadly brings us to the end

of yet another crash course
in misadventure.

A clever person once said
that the greatest discoveries

begin not with "Eureka!"
but with "That's funny."

But as we've learnt, they can also begin
with excruciating pain,

so don't, repeat don't,
do anything you've just seen.

I'll see you next time.

Hai-yah! Ow!

[country music playing]

[shouting]

[groaning]

-Whoo!
-[man] Yeehaw!

[grunts] Oof.

[meows]

-[all gasp]
-[groans]