08x07 - Snowboarding, Boats and Walking the Plank

[bunniefuu]

DALLAS (off-screen): This

is the Science of Stupid.

Yes, this is the

show that extracts cold,

hard science from

hot headed stupidity.

Witness the act of misguided

human guinea pigs treating the

world like their lab, and

suffering the consequences.

We'll analyze what went wrong

and why with the help of

scientific principles

like angular momentum,

terminal velocity

and trajectory.

So, look and learn

but don't copy.

Watch out, it's

the Science of Stupid.

In this episode we'll be

getting our heads around

access of rotation,

discovering a high friction

approach to skiing and

enjoying the upward force of

buoyancy, with any

luck, but first this.

Drag and lift, not moves from

one of my acclaimed dancercise

videos but the basic

components of aerodynamics,

drag force and lift force.

You've got lift and drag.

I think he wanted more lift.

As you can see, understanding

aerodynamics can be the

difference between

success and failure.

Thankfully aerodynamics follows

some pretty simple rules.

You've just gotta make

sure you've learnt them,

so pay attention.

Drag is produced by trillions

of tiny air particles hitting

an object as it moves

through the air.

The larger the frontal area of

an object the greater the drag.

By making an object

streamlined you can reduce

turbulence, which lowers drag.

A wing generates lift as it

redirects the flow of air

passing around it, so by

turning air flow downwards you

create an upwards force, lift.

Which is lucky because

that is exactly what Newton's Third Law states,

for every action there is an

equal and opposite reaction.

Thank you, Newton, but more

importantly it's the science

we use to fly.

Airplanes are

obviously very aerodynamic,

they're both streamlined

and use their wings to create

lift, unlike those square

baggage containers with large

frontal areas

relative to their weight.

The resulting drag from the

wind overcomes the friction

with the ground, which saves

a trip on the baggage truck.

Come on guys, it's not

rocket science or is it?

There's one.

Whilst a rocket's aerodynamic

shape minimizes drag going

forwards, their fins

increase drag for stability,

unless you get the

fins wrong and then, well,

it's even better.

So, what about lift?

This glider is designed to

continuously use lift and drag

to perform loop to loops and

it would have kept going if it

hadn't hit her in the face.

Now, these speed boats are

designed to have very little

drag and they use streamlining

to slice through the air

particles about the water but

hit a wave like that one and

that same streamline design

will just as efficiently

create lift turning

it into a plane,

before it turns

back into a boat.

Incredibly our

boat pilot was okay.

And now we briefly shun the

failures of the many to shine

a spotlight on the

extraordinary success of one

singular human being, a ballet

dancer's pirouette is widely

considered a thing of beauty

but personally I prefer my

pirouettes in a car.

MAN: Go.

DALLAS (off-screen): This is

Ronnie C'Rock attempting a

Guinness World Record title

for the tightest 360 degree

turn in a car.

To succeed he needs to

spin between two trucks,

a gap just over eight feet wider

than the length of his car.

Mr. C'Rock,

that is a world record.

So, spinning a car through a

tight gap is scientifically

possible, possible

but not advisable.

Because attempt to rotate

your car in any kind of gap

and you'll be lucky

to lose just your wheel.

This is an incredibly

dangerous stunt,

which you should

never attempt.

Now, you may have seen race

drivers use drift turns to

take corners

tighter and faster.

It's a similar principle

to Ronnie's 360 but with a

critical difference,

that being the axis of rotation

and who better to demonstrate

both than the man who's since

beaten Ronnie's record,

stunt driver Alistair Moffatt.

To perform a drift turn in

a car Alistair turns sharply

allowing centrifugal force to

overcome traction at the back

wheels but with the access of

rotation towards the front of

the car its path will be

wide, however during the 360,

traction is lost at

both the back wheels and the front wheels,

causing the access of rotation

to move closer to the center,

allowing the car to spin

through a long narrow gap.

The longest continuous drift

was an incredibly 232 miles,

which couldn't have

been achieved without a little centrifugal force.

This is the force acting

outwards on an object when

it's rotated.

And it's something our first

wannabe record breaker is keen

to demonstrate.

Good one.

Centrifugal force overcomes

friction at the rear,

car rotates around this

axis this way, then that way,

then we lose traction at the

front so the access finally

moves towards the middle but

well it all gets a bit messy.

So, how do we

get a tighter spin?

That's right, fella.

We lose traction at the front

wheel sooner so we quickly get

that access towards the middle

and the car does its thing.

Although you really

couldn't have found a more dangerous location.

Or maybe you could.

Really nailed that

central axis though, well done.

But it was assisted by the

low coefficient of friction of

ice, making it easier to lose

traction but not so easy to

control your car.

So, I'm afraid that

attempt won't count.

A more suitable location

but can we get a tighter 360?

Eee, no,

or yes but is it a record?

Perfect central axis and

that turn is on a dime but

there's a slight problem

using the barrier.

It's kind of cheating, no?

So, the only thing we're

gonna be breaking today is cars.

Oh, it's just a regular

morning but can you guess

which scientific principle

we're about to see?

DALLAS (off-screen):

Did you work out the science we're about to see?

Eyes on the feet.

Yes, it's fight or

flight but, let's be honest,

mainly flight.

When she tripped on the snake

the shock triggered a release

of energy boosting chemicals

into the blood stream.

That prepared the body

to fight back or flea.

Poor thing.

WOMAN: It touched

me, it touched me!

DALLAS (off-screen): No,

I'm not talking about her.

I'm talking about him.

He must have got

the fright of his life.

The main problem with

skiing is it's really expensive.

Now, there are

cheaper options.

Like going out of season

or test running a more local

slope but it can be, well, err,

a bit friction-y.

If I still haven't convinced

you that skiing on snowless

slopes is a dangerous

and appalling idea,

allow science to have a go.

Snow tends to smooth over

rough terrain and offer

consistently low friction

thanks to a slick watery film

formed when the

skis slide over it,

which helps them

accelerate smoothly.

Few surfaces

offer the same result.

For instance, even a grassy

hill may have patches of

higher friction that cause

them to suddenly decelerate.

Furthermore, there are likely

to be bumps that are bigger

than the skis were

designed to handle.

Thought provoking but

let's not just rely on pretty

pictures, let's run

some practical tests.

Everyone on this snowy

slope is enjoying consistent

low friction,

now let's experiment.

Yup, as predicted.

Snow smooths out an uneven

surface and its wetness

lubricates, allowing

his skis to slide.

Snowless ground slows down his

skis allowing him to stretch

and be laughed at.

Okay, what if we

reduce friction?

Say by using wetted mats.

It's not a complete solution.

The lubricated mats did help

him gain speed until he ran

out of mat and hit

a bump in the dirt.

Still, there's bumps and then

there's this kind of thing.

He did find the snow

eventually but first he had to

go through

high friction, uneven ground,

big log,

if not for snow's impact

absorbing embrace that could

have been a lot worse.

MAN: Rock skiing the Big Sky!

DALLAS (off-screen):

You will be if you try that again, my friend.

But if you really can't wait

for the seasons to change.

Why not change your skis?

Wheel skis offer

rolling friction,

a lower form of friction for

gliding along a sidewalk as if

it was smooth snow.

Some people have water in

their blood and that's because

they've sunk and

didn't use a proper boat.

His boat has a few holes.

And very little else.

So, it's just

not worth the risk

trying to patch up or cobble

together your own makeshift

boat, that's because engineers

follow a set of complex rules

commandeered, of

course, by science.

Buoyancy is the upward force

that keeps a boat afloat.

It's created by pushing away

water and receiving in turn a

force equal to the weight

of the water it's displaced.

The center of buoyancy is

in the middle of a boat's

submerged volume and the

boat's center of mass should

be directly in line

with this for stability.

The boat also needs to be

waterproof and strong enough

to withstand the force of the

water pushing in on it and the

weight of the load above.

As long as we follow those

simple rules we should be fine.

Isn't that right, team?

This boat-ress is obviously

very buoyant thanks to the air

bubbles contained

in the mattress,

however it's not waterproof

so it's taking on water fast,

making it too heavy for

the trapped air to cope with.

MAN: I made it.

DALLAS (off-screen):

And you almost sank, so maybe don't make another one.

That's more like it.

You can always trust the

scouts to do a job properly.

MAN: Head, shoulders,

knees and toes

DALLAS (off-screen):

And to sing at the most inappropriate of times.

MAN: shoulders,

knees and toes

DALLAS (off-screen):

Serves you right,

the guy in the left

was out of tune.

The barrels are both

waterproof and buoyant but it

turns out the scouts didn't

do a very good job of lashing

them all together.

Dib, dib, dib.

Okay, this chap

has worked it out.

He's using an old foam board

which was clearly designed

with the help of real

engineers to float.

(screams)

DALLAS (off-screen):

Unfortunately there's nothing

the engineers can

do about user error.

MAN: That's cold.

DALLAS (off-screen): By

leaning to his right his

center of mass moves too

far away from his center of

buoyancy, so the one time we

had a viable boat we didn't

have a viable captain.

The same principle applies

to a pontoon as a boat,

a buoyant force is created

equal to the weight of the

water it displace and it's

just about coping with these

cars but not

that massive truck.

MAN (off-screen) : No. Whoa.

DALLAS (off-screen): Well,

that's just inconsiderate.

DALLAS: Are you bored of your

daily skipping fitness routine?

Keen to add the threat

of serious injury to your

gymnastic display?

Then the skipping backflip

might just be for you.

It's performing a full

backflip whilst skipping but

before you get any ideas,

be aware some people still

struggle with the

concept of regular skipping.

MAN: It's heavy and it's wet.

DALLAS (off-screen):

That's because it's a towel.

Aside from the use of

appropriate equipment,

i.e. a rope, a successful

skipping backflip relies on

mastering a lot of complex

physics as our precocious

young gymnast

knows all too well.

For the backflip he pushes off

to generate angular momentum.

Using the rope just long

enough to give his head and

feet sufficient clearance,

he uses angular velocity to

create sufficient centrifugal

force to keep the rope taut as

it spins.

Tucking in reduces

his moment of inertia,

an object's resistance to

rotational acceleration,

enabling him to spin faster

and complete the flip.

There's a lot to take in

so let's just start with the

skipping bit and selecting

a rope of sufficient length.

It's a little short,

don't you think?

Then again, with enough

centrifugal force to keep the

rope taut he's cleared it.

Oh, for goodness sake.

No matter how big the swing

you do still have to time your

jump right or the only angular

velocity you'll get will be

the roly-poly kind.

Although it does

look quite fun.

Okay, I think we're ready to

move on to the backflip part.

MAN: Oh.

DALLAS (off-screen):

We're ready, he's not.

He had friends swinging the

rope for him so it should have

been easier but halfway

round he untucked his legs,

increasing his moment of

inertia slowing down his

rotation and making it all

the more fun for his friends.

Sometimes it's

best to go it alone.

MAN: Ah.

DALLAS (off-screen): And then

share the fun with millions.

His foot caught the rope,

slowing his rotation which

slowed even more

when he untucked.

He was okay but my advice if

you're thinking of trying the

skipping backflip is don't.

MAN: Ah.

DALLAS (off-screen): In 1769 a

group of mutineers allegedly

confessed to bumping off

their commanding officers by

literally bumping them off

a plank of wood attached to

their ship.

Now, if true this could be the

first recorded instance of

walking the plank and walking

the plank is now an experience

we can all enjoy.

WOMAN (off-screen): Don't fall.

DALLAS (off-screen): Thanks to

a virtual reality headset and

the plank laid

harmlessly on the ground.

MAN: Go back out

on the plank and jump.

Just jump right off.

MAN: Yeah, forward though.

WOMAN (off-screen): Oh.

DALLAS (off-screen): Okay,

maybe not totally harmlessly.

MAN: You alright?

DALLAS: Simply stepping off a

plank in virtual reality can

be surprisingly

tricky but why?

Well, science, that's why.

Balancing on a narrow plank

our man relies on visual input

from his eyes, vestibular

input from his inner ears and

proprioceptive input from

his muscles and joints.

The inputs feed into his brain

which send messages to muscles

which adjust body

position and maintain balance.

A VR headset provides a visual

input that when stepping off

the plank contradicts the

vestibular and proprioceptive

inputs from his body.

This can stop him from

making the automatic postural

adjustments that

help him balance.

We've provided some

of our top researchers with state of the art

VR headsets and told them

to learn all they could about

visual, vestibular and

proprioceptive inputs.

Here's Josh, normally

perfectly capable of walking

in a straight line,

he's struggling.

JOSH: Oh, this ain't fun at all!

DALLAS (off-screen): No,

Josh and that's because the

VR headset is showing your

eyes that you're teetering

over a long, scary drop.

JOSH: I'm not jumping.

DALLAS (off-screen):

Unfortunately even though his inner ear's muscles

are telling him

he's still on the plank.

MAN: I'm falling.

DALLAS (off-screen): His VR

headset has miscalculated and

is showing him that he's

plummeting to his death.

Well, Josh, if you

think that's too real

spare a thought for Jeanine

testing out joysticks that

add haptic feedback,

a virtual sense of touch.

She's doing okay, just needs

some real world encouragement.

MAN: Don't fall,

you're gonna die.

DALLAS (off-screen):

It's a little bleak.

MAN: Oy!

DALLAS (off-screen):

And factually incorrect.

MAN: Are you OK?

DALLAS (off-screen): Yes,

Jeanine is alive and well,

even if her visual input

is telling her otherwise.

Back on the plank that input

caused her brain to think her

base of support, the plank,

was high off the ground and

her sense of

balance couldn't cope.

So, that's

walking the plank in VR,

where real world pain

is virtually guaranteed.

There's an old saying in

the scientific community,

experiment, fail, learn,

repeat and this next lot have

certainly taken that to heart.

Minus the learn-y bit.

♪