08x13 - Beach Driving, Running and Freediving

[bunniefuu]

DALLAS (off-screen): This

is the Science of Stupid.

DALLAS (off-screen):

Yes, this is the show that draws samples of science

from the veins of stupidity.

Watch as ordinary people

take extraordinary risks

for the sake of

who knows what.

We'll explain what went wrong

and why with the help of

some of sciences best

loved principles,

such as impact force,

velocity

and, my friend

and yours, momentum.

Physics has a mean

streak, so watch out it's the Science of Stupid.

DALLAS (off-screen): In this

show we'll be analyzing the material strength of concrete,

pondering the limits

of automated response.

(laughter).

DALLAS (off-screen):

And ruminating on the parabolas of chair jumpers

but first this.

DALLAS: Sunbathing, oh,

sunscreen stinging your eyes, sweat drenching the pages of

your copy of Galileo

Galilei's Sidereus Nuncius.

There are way more exciting

things to do on a beach.

DALLAS (off-screen): These

guys don't read, they ride.

The endless horizon, the

sea breeze whipping past,

surf lapping at the wheels.

(screams).

DALLAS (off-screen): The

delicious taste of sea water.

DALLAS: Whether on two wheels

or four driving on a beach is alas rather more hazardous

than lounging on one

thanks largely to the potential for low traction

and high ground pressure.

DALLAS (off-screen): Ground

pressure is a vehicle's weight divided by the surface area

supporting that weight, so a

rider and lightweight bike with skinny tires may actually

exert more ground pressure

than a heavy truck with wide

tires and run more risk

of sinking in the sand.

Below the high tide mark the

sand tends to be wetter,

firmer and relatively better

suited to driving on but the

looser dry sand further up the

beach can more easily shift

under the tires, resulting

in a loss of traction.

DALLAS: Experienced sand

drivers often deflate their tires for more contact with

the surface and

less ground pressure.

You can even get purpose

built sand bicycles with huge fat tires.

DALLAS (off-screen):

And this isn't one of them.

His bike may be lightweight

but narrow bicycle tires exert a lot of ground pressure and

so sink in, as does his face.

Okay, let's try something

heavier like over twenty times heavier,

luckily those wide tires

keep the ground pressure low and the wet sand is firm

and less likely to cause

a loss of traction, unless of course you do that.

And from one truly awful idea

to a man in a plastic box.

Light weighted design,

a relatively high surface area in contact with

the firm wet sand.

Has this young genius

discovered the future of beach transport?

MAN: Oh.

DALLAS (off-screen):

No, of course he hasn't, which was evident as he swung

out and sped up, tilted

to one side, applied more ground pressure here,

dug in and then got to spend

a few moments contemplating why

no one else had put their

hand up to sit in the box.

So, what if we take

our vehicles a little further inland?

Like 100 miles inland

where the sand is dryer

and somewhat bumpier.

MAN: Are you ok?

MAN 2: Yeah.

DALLAS (off-screen): And that

is a flipping miracle because this was not the look of

someone who would be okay.

So, don't try any

of this yourself.

DALLAS: And now we briefly

interrupt our critique of the extra silly to

salute someone extra special.

Now, if I suggested a sport

that literally drained your body of life-sustaining

oxygen, edging you to the

very brink of existence, you'd probably say,

'No, thanks.'

DALLAS (off-screen):

But then you're not Alessia Zecchini aiming to

dive deeper on one breath than

any female free diver has before in her category.

Even at the surface the

average person runs out of breath after little more than

a minute but Alessia

is far from average

and down at 351 feet,

almost the length of

a football field, she breaks the record.

Surfacing after a

single breath hold of 3 and a half minutes.

DALLAS: It's easy to

forget how dangerous swimming under water can be.

DALLAS (off-screen):

It can feel tranquil, almost womb-like

until you hit a problem.

DALLAS: Which in

freediving can result in oxygen starvation,

nitrogen narcosis,

decompression sickness, black out,

all the bad stuff but whilst

I wouldn't advise trying to beat Aleccia's record

I would recommend learning

the science behind the feat.

DALLAS (off-screen): As our

free diver dives his body consumes his oxygen supply,

which can lead to a

potentially lethal blackout.

In his favor is an

evolutionary response, called the mammalian dive reflex,

which diverts oxygen rich

blood to the vital organs

and reduces the heart rate,

lowering

oxygen consumption.

Efficient monofin technique

also helps, its large surface

area displaces a lot

of water, propelling him

forwards with minimal effort

thereby conserving oxygen.

DALLAS: Okay.

Nearly ready to break some records?

It's time for a

quick kit check.

Flippers work on the same

principle as monofins,

displacing water to

generate propulsion.

WOMAN: Honey!

DALLAS (off-screen):

Not so good on land though.

Alright, let's dive

down where the mammalian dive reflex kicks in,

even at shallow depths.

Not exactly what I meant by

mammalian dive reflex and whilst they'll still be

experiencing the reflex

they're rather wasting its oxygen conserving effects.

That's better, making the most

of the propulsion generated by his flippers with gentle

rhythmic kicks, conserving

precious oxygen for the swim back up or for riding a bike.

Okay, let's head up but calmly

and oxygen efficiently so as to avoid that thing all free

divers fear, I was actually

thinking of blacking out

but on that

evidence I think we

should leave

Aleccia's record well alone.

DALLAS (off-screen): Soaring

the skies like the majestic eagle but can you predict the

scientific principle this sky

diver is about to encounter?

DALLAS (off-screen): Now, did

you guess the science this sky diver is going to demonstrate?

No? How about now?

(screams).

DALLAS (off-screen):

Yes, that's right.

It's aerodynamic drag.

Our skydiver pulls hard on the

brakes increasing aerodynamic drag on his parachute which

decelerates him, but

not soon enough, so he overshoots his landing area

and finds another

way to slow down.

Is he okay?

MAN: Wooo!

DALLAS (off-screen):

Well, sounds like it and it'll be a fun surprise for

the house owner too.

DALLAS: What am I?

I was pioneered by the

Romans over 2,000 years ago, I'm now the most commonly

used manmade material on Earth.

I might be responsible for

as much as 8% of the world's carbon dioxide emissions

and I can also be

DALLAS (off-screen):

Quite heavy.

DALLAS: Oh, yes.

I am, of course, concrete made

of a simple mix of aggregate, like gravel and sand,

cement and water and science.

DALLAS (off-screen): As

water is added to concrete mix a chemical reaction,

known as hydration, causes

crystals to grow in the cement as it hardens locking together

the aggregate particles.

Its ability to be poured makes

concrete highly moldable and once its set it has a high

compressive strength so it can

withstand enormous forces applied directly through the

concrete but its

tensile strength

is only about a tenth

of its compressive strength,

so it's weak against

forces trying to pull it apart or bend it.

DALLAS: Moldable when wet,

strong when dry, these are qualities that made it

popular amongst trade

professionals and amateur enthusiasts.

MAN: He's plowing, he's plowing.

MAN: He's going to go for it.

DALLAS (off-screen): These

concrete fans are hoping to see if that recently

laid mix has cured.

MAN: He's going to go for it.

MAN: Oh yes!

MAN: Jeez!

DALLAS (off-screen):

It hasn't cured.

MAN 2: Did you get that?

Did you get that?

MAN: I sure did!

DALLAS (off-screen):

Handy because now we see how the tires sink in,

so the chemical reaction

is still happening but when it hardens those cement

crystals will bind the

aggregate together with a lovely new tire pattern

and not everyone likes patterns.

He hates them.

Oh, he hates them.

MAN: He's thrown the hat.

MAN: Throw that hat, yes!

DALLAS (off-screen):

Maybe they should have blocked it off,

like with a concrete barrier.

You see, that would have

worked because while the car applies a large force to the

barrier this is strongly

resisted by inertia due to its heavy weight,

resulting in a large amount

of compressive stress, which as we all know

concrete can handle.

Cars, meh, not so much.

So, lads, you've seen

how high concrete's compressive strength is,

what about its

tensile strength?

Yep, it's about

ten times weaker.

As it hits the ground part

of it is compressed and part of it is stretched.

That's the tensile

stress, which concrete doesn't like at all.

DALLAS: The high jumper,

the long jump, hurdles.

There are a number of official

athletics disciplines that cater for those with a talent

for leaping and not one

of them involves chairs.

DALLAS (off-screen): Not that

he cares because when it comes to the distinctly unofficial

sport of chair jumping this

guy is in a league of his own,

and this student

of chair Olympics,

he's in a

different league.

A rubbish one.

DALLAS: Leaping over chairs is

highly unsafe, unwise but not in the least unscientific,

as our expert free runner

will kindly demonstrate.

DALLAS (off-screen):

The faster he runs the more horizontal velocity he

generates and the more

downwards force he applies with his launching foot the

more of that horizontal

velocity he converts into vertical velocity.

The perfect balance results in

a parabolic trajectory with his apex in the middle of the

chairs so he can

make the distance.

By extending his legs forwards

he lands with his center of mass just behind his base of

support, which helps

him control his momentum.

DALLAS: My favorite chair

technique is the one with no parabolic trajectory

whatsoever, or as

I call it, sitting.

But for those who can't help

but leap it all starts with horizontal velocity, i.e.

DALLAS (off-screen): A run up.

(laughter).

DALLAS (off-screen):

Typically followed by vertical velocity, i.e. a jump.

Onto two chairs now and I'll

be interested to know how this piece of cardboard

is going to help.

Yup, I'm still interested.

Because he was messing around

with that cardboard rather than extending his legs

forward he landed with his

center of mass in front of his base of support,

so his momentum

carried him into the table.

MAN: You missed everything.

DALLAS (off-screen):

He didn't miss the table.

Three chairs with desks

and a new approach but will jumping from a height mean

he won't need as much

vertical velocity?

Who knows but he did need

more horizontal velocity.

We now have four chairs.

(laughter).

DALLAS (off-screen):

And now back to three.

Parabolas are symmetrical so

if the apex of the trajectory is here and not here in the

middle the end will be there.

(laughter).

DALLAS: As our lives become

ever more robotic, automated

and arguably less humanized

should we be worried?

It's a subject that inspired

science fiction writer, Isaac Asimov,

over half a century ago

as he set out his three laws for robotics.

DALLAS (off-screen): First, a

robot may not injure a human being or through inaction

allow one to come to harm.

DALLAS (off-screen):

Oh, broke that law.

Next, a robot must obey orders

given to it by human beings.

Or at least try.

And finally a robot must

protect its own existence as long as such protection does

not conflict with the

first or second law.

Yeah, we're not

doing very well, are we?

DALLAS: Maybe the problem

is those robots were largely controlled by human beings,

so prone to user error but

advances in automation and artificial intelligence mean

we could be moving towards

a future where human control is obsolete.

Way more comforting, right?

DALLAS (off-screen):

Teleoperated robots are controlled directly by humans,

automated technology brings

various levels of decision making with some machines

programmed to

react to stimuli.

Whilst artificial intelligence

allows machines to mimic functions we associate with

learning, ranging from

cognitive intelligence using past experience to make future

decisions to emotional

intelligence using a recognition of human emotion

to inform decision.

The gateway possibly

to self-awareness.

DALLAS: The term 'robot'

emerged in the 1920s from the Czech word 'robota' meaning

'forced labor', describing

beings that would unquestionably do our bidding

to carry out essential tasks.

MAN: It's midnight and we are

cooking an egg with a robot.

DALLAS (off-screen): Not

particularly essential but will his teleoperated robot

improve

efficiency in the kitchen?

No but that's not its fault.

MAN: Robots are as

smart as the user.

DALLAS (off-screen): Yeah,

teleoperated robots maybe but not automated robots,

like this vacuum, which makes

navigation decisions as it bumps into stuff but without

cognitive intelligence it

can't learn from experience.

So, whilst these cats

(laughter).

DALLAS (off-screen): Can learn

to hate vacuum cleaners, this automated lawnmower will

always be

indifferent to moose.

What's that?

ROBOT: I see a carton

of matcha green tea, a refreshing beverage.

DALLAS (off-screen):

Sounds delicious.

A sophisticated array of

recognition sensors give him more points of reference to

make more complex decisions.

MAN: Your matcha

green tea drink, Tony.

DALLAS (off-screen): It's

Dallas, actually, but it's not quite emotional intelligence

or self-awareness.

ALEXA: What makes

you think I not you?

ALEXA 2: Do you believe

it is normal to be not me?

ALEXA: Does someone else

believe I believe it is normal to be not you?

DALLAS (off-screen): These AI

PAs aren't self-aware either,

they're just having an

algorithmic moment.

ALEXA 2: We were

discussing you, not me.

DALLAS (off-screen): Charming

but with robot intelligence still in its infancy.

GIRL: Hi robot. Hi robot.

DALLAS (off-screen):

Should we be worried?

GIRL: Hi robot.

DALLAS (off-screen): Or should

we embrace our brave new world of automated efficiency.

GIRL: Ahh.

GIRL: I love you robot.

DALLAS (off-screen):

Unfortunately discarded water heaters can't love back.

DALLAS: Fight or flight,

the biological survival response to a threat common

throughout the animal kingdom.

Now, when it comes to the

flight element we h*m* sapiens don't quite have the

acceleration of, say,

the cheetah at 0 to 60 in three seconds.

We're more about distance.

DALLAS (off-screen): Where

it pays to carefully moderate your pace and to

look where you're going.

DALLAS: Distance running

is largely aerobic rather than anaerobic,

and that means our body

uses the oxygen we breathe in to release the energy

stored in glucose.

It's more fuel

efficient than the mostly anaerobic sprinting,

which helps you go the

distance but to win the race you also need

an efficient technique.

DALLAS (off-screen):

An energy efficient stride favors horizontal

motion over vertical.

Our runner maintains

a high cadence, almost 180 steps per minute,

and strikes with

the ball of her foot.

This reduces contact time

with the ground and impact force running up through

her knees and hips.

She's also keeps an upright

trunk and strikes the ground almost directly beneath her

center of mass, which utilizes

more of the force from pushing off to propel her forwards.

DALLAS: Ostriches can run over

distance at 31 miles an hour, an impressive 15 minute marathon

pace, but when it comes to

ultra-long distances it's actually we h*m* sapiens who

are believed to set

the gold standard.

DALLAS (off-screen): But even

an ostrich would tell you it's vital to get into that

efficient stride

right from the start.

WOMAN: Come on, Hannah.

Go Hannah.

DALLAS (off-screen): Let's

move on to some good, efficient strides.

Trunk upright, foot strikes

just ahead of center of mass, high cadence,

pretty efficient.

CROWD: Oh, oh. Oh.

DALLAS (off-screen):

Yep, that was less efficient but sometimes we do need

to change it up.

Here's the 400 meters where

poor Alison is floundering at the back.

Well, perhaps she's just

trying to economize her pace initially,

maintaining energy

levels before

MAN: Turn on the jets Alison,

turn it on!

DALLAS (off-screen): That's

right and now Alison swiftly moves from a more aerobic pace

to a more anaerobic pace, less

fuel efficient but it gives her the boost she needs to

annihilate the

opposition with her jets.

Still, there are races where

it's quite hard to adopt an efficient stride.

I mean, trunk, the opposite of

upright, far too much contact time with the ground

and that arm cadence is awful.

You can't get worse than that.

DALLAS (off-screen):

Oh, maybe you can.

DALLAS: For years it was

widely believed that the dramatic rise and fall of

Norwegian lemming populations

was due to the creatures willfully flinging themselves

over cliff edges but thanks to

proper scientific analysis we now know this to be hokum.

I mean, what kind of species

would do something so stupid?

WOMAN: Honey!

(music plays through credits)

♪

GIRL: I love you robot.