08x06 - Downhill Cycling, Eggs and Surfing

[bunniefuu]

DALLAS (off-screen): This

is the Science of Stupid.

DALLAS (off-screen):

Yes, this is the show that explores scientific

theory through

practical stupidity.

Witness as people around

the world push the boundaries of science and fall flat

on their faces, or rather worse.

We'll reveal what went wrong

and why with the help of scientific principles such

as impact force,

thrust,

and that cold-hearted

little terror gravity.

This is the school of hard

knocks, so watch out for the Science of Stupid.

DALLAS (off-screen): In this

episode we'll be exploring how linear momentum becomes

angular, revealing the

power of hydrodynamic drag

and we'll be getting

our claws into ornithology.

MAN: Back off, bird.

DALLAS (off-screen):

But first this.

DALLAS: We'll never know

exactly where the game of tug of w*r originated.

It's evident in millennia

old rituals across the world, from the Middle East to

South East Asia but what I'm

fairly sure of is that they didn't do it like this.

DALLAS (off-screen): Yup, that

is two monster trucks playing tug of w*r and you know what?

That's a terrible idea.

DALLAS: Alas, vehicle

tug of w*r is more common than you might expect.

It's also dangerous,

not to be copied but scientifically informative.

Torque is a twisting force

often referred to as the pulling power of a car but

the secret weapon in this

w*r isn't grunt, it's grip.

DALLAS (off-screen):

A powerful engine can generate a large amount of

torque giving a vehicle a lot of

pulling power from the get go

but he won't be getting

anywhere without friction.

The greater the coefficient

of friction, or grippiness

between wheels and ground,

and the greater the weight of

his vehicle the more friction

he has to push against.

Exceed the friction

force of his opponent and

static friction becomes

kinetic friction.

Wheels spin and

it's game over.

DALLAS: Okay, let's

start by selecting some suitable vehicles.

DALLAS (off-screen): Oh.

MAN: We've got lots

of weight up here

for extra traction

for both vehicles.

DALLAS (off-screen):

Okay, well that is a start.

(laughing).

MAN: Nice!

DALLAS (off-screen): But no

one is going anywhere because your cable is attached at

different heights, your

seating modifications have messed up weight distribution

and thus your vehicle's torque

and friction forces cannot be effectively harnessed.

Result, engines

rev, cars bounce.

MAN: That's hilarious!

DALLAS (off-screen): Well,

whatever makes you happy.

Okay, these trucks do look

relatively better suited, so who's gonna win?

White or silver?

Very good, silver.

Can we have our

white truck back now?

DALLAS (off-screen): No?

Okay, well, it was a foregone

conclusion anyway because since the coefficient of

kinetic friction is

less than the coefficient of static friction,

once our white truck

wheel's slip it's game over.

And finally, he's

brought it back, and almost in one piece.

Right, let's mix it up.

Snowmobile versus ATV.

Tracks versus chunky tires.

Round one to chunky and that's

because his big grippy tires were designed for providing

friction on soil, so it too is

a foregone, oh, he's pulled the momentum card.

Okay, let's up

the weight class.

It's dump truck versus

children's school bus.

MAN: The bus mightno,

no, the truck is gonna win it.

DALLAS (off-screen): Well,

the bus's overhang adds more weight over the rear wheels,

increasing the friction and

the truck is empty so it has less weight over the back

wheels and less friction and,

as we all know, grunt's no good without grip.

MAN: It broke the bumper!

DALLAS (off-screen):

Yes, it did.

Can we please go

to school now?

DALLAS: And now we go from

poking the finger at the ridiculous to clapping

our hands at the extraordinary.

A trip to the Portuguese

fishing village of Nazaré brings many delights visiting

the historic fought,

riding the vernacular or simply going for a paddle.

DALLAS (off-screen):

In some of the biggest breaking waves in the world.

This monster is 80 feet

tall, no surfer had ever ridden anything so big

until Rodrigo Koxa came along.

That's him there.

It's like being chased

by a seven-story building and that is a world record.

The biggest

wave ever surfed.

DALLAS: Thinking of packing

your board and mounting your own record attempt?

Well, think again

because massive waves

(screams).

DALLAS (off-screen):

Aren't the only things that can hit you.

DALLAS: Big wave surfing is

dangerous but particularly so at Nazaré whose

epic waves are formed over

a long journey across the Atlantic before being funneled

into supersize giants

by a vast undersea canyon.

To ride those requires a

mastery of velocity and hydrodynamic drag.

DALLAS (off-screen): To catch

a wave a surfer paddles to closely match its velocity.

The bigger the wave the faster

it travels, which for an 80 footer could be 35 miles an

hour, so jet skis

are used at Nazaré.

Once up our surfer keeps his

board carefully balanced because if the nose digs into

the water the sudden

increase in hydrodynamic drag will slow his board

but not his body.

DALLAS: It's also worth

considering that the density of water gives it a colossal

weight of over 8 pounds

per gallon, not something you want smashing into you

but these troubles can be eased

by minimizing hydrodynamic drag, for example.

DALLAS (off-screen): Heading

out our wannabe record breaker will duck dive cleanly

through the wave

or do the opposite.

Do that and you'll find that

as you offer the wave literally the largest surface

area possible, like this,

it'll gladly reciprocate with all the drag it can.

Like that.

Our next potential record

breaker is learning to closely match the velocity

of oncoming waves.

WOMAN: Oh my God.

DALLAS (off-screen):

And still learning.

Here she's happily padding and

needs to speed up a bit but here she stops paddling.

Oh, look, the sun's gone in.

Once up our hopefuls

must avoid digging their noses into the water.

Or that might happen.

That's more like it.

Good balance,

not too much drag.

Keeping that nose

out of the, duck.

Never mind.

His board was

well-balanced, decreasing drag but his head got in

the way and increased it.

I don't think we'll be

breaking any records today.

MAN: This should be fun!

DALLAS (off-screen): If it's

sitting in a puddle probably not but can you guess which

scientific principle

he's about to demonstrate?

MAN: This should be fun!

DALLAS (off-screen): Now then,

did you work out the science he's about to show us?

Oh dear.

That didn't look

fun but the scientific principle was acceleration

and oh so much more.

The slope is not only steep

but lubricated with water which allows gravity to

accelerate into a high

velocity until he experiences impact force,

then angular velocity and

then a bit more impact.

Too much science for one man.

MAN: That hurt!

DALLAS (off-screen):

Don't try that yourselves.

DALLAS: And now for a

biological seminar on toes of the avian kind.

Now, to you and I, toes

are predominantly for aiding balance and thrust while

walking but to the

arm-lacking bird they are multi-tools designed

for just about everything.

DALLAS (off-screen):

From defending the realm.

MAN: I'm a vegan man, back off!

DALLAS (off-screen): To

simply making good friends.

Who's a pretty Polly?

DALLAS: And bird's toes are

not only handy, so to speak, but surprisingly diverse.

DALLAS (off-screen):

Anisodactyl feet as modeled by our lightweight songbird

friend have three spindly

toes pointing forwards and one back,

designed simply for perching.

The zygodactyl feet of parrots

with two toes forwards and two back are adapted for

dexterous work like climbing.

Whilst the powerful claws of

such as raptors, have special ratchet-like tendons that lock

in place to grip

struggling prey.

DALLAS: So, you see

bird toes are highly specialized to lifestyle,

whatever you fancy

there's a set of toes evolved just for you.

DALLAS (off-screen):

Take Clive, connoisseur for the fruit and insect salad,

he's no need for

gripping large prey.

His Anisodactyl feet

have evolved to grip branches,

not laptops.

Considering

rescuing that osprey?

Well, bear in mind that

not only do they have curved hook-like talons

designed for catching fish

WOMAN: Ow! Ow!

MAN: It's on your fingers.

DALLAS (off-screen):

But they're raptors too, so they have that

tendon locking mechanism.

MAN: Are you okay?

There you go.

DALLAS (off-screen):

But don't worry, a minute later off he goes.

Hopefully

without Mum's finger.

These burrowing owls use

their raptor claws to dig howls and catch mice.

Yeah, pretty clever but

what else can you do?

Oh, one leg.

Yeah, it is quite good.

So, with bird toes

it's not all about grip.

WOMAN: Dan, what do I do?

DALLAS (off-screen):

Excellent question.

You see, that is a cassowary,

mainly a fruit eater so no locking death grip to worry

about but it does have a

5 inch inner claw of bone sheathed in keratin designed

to stab anything that might

pass as a threat, so

WOMAN: Help!

DALLAS (off-screen):

Quite but when it comes to sharp claws even a cassowary

comes second best to our

zygodactyl friend, Buddy.

WOMAN: Good job Buddy,

file your nails.

DALLAS (off-screen): Oh, Buddy.

You've changed.

DALLAS: People often say

to me, 'Dallas, I do like a pedal around town but is

there any way of making

it more scientific?' Well, there's good news.

In three words.

DALLAS (off-screen):

Urban downhill cycling.

Bombing down specially

made urban courses often through hillside towns,

it's a gravity assisted crash

course in weight distribution, velocity and momentum

and the people are

ever so friendly.

Hiya. Hiya.

Ola, hello. Hi.

See ya later, see ya later.

But there is one minor issue.

It really hurts

when you fall off.

Oh, stupid gravity.

DALLAS: Urban downhill

cycling is a dangerous sport, best left to the experts

but of all the terrifying

obstacles to be encountered,

perhaps the most troublesome

are the steps and the jumps.

Thankfully no obstacle is

a match for a comprehensive understanding of physics.

As our cyclist rides down the

steps the center of mass is closer to the front wheel so

he leans back to keep it

safely inside the base of support and stay balanced.

Too far forward and any abrupt

change in angle can cause his

linear momentum to become

angular momentum.

Then come the jumps where

he'll need all the velocity gained from the slope to

overcome gravity and make

it to the landing ramp, unlike his friend.

DALLAS: Okay, let's break

down our analysis, starting

DALLAS (off-screen): With

the steps and a beautiful demonstration of weight

distribution, keeping

their centers of mass well back on those stairs

and now for an example

of how to do the opposite.

He's just too far forward so

when he hits the flat linear momentum becomes angular

momentum and then back

to linear before gravity finishes the job.

Luckily these courses

actually do have devices to reduce momentum.

MAN: Ah.

DALLAS (off-screen):

They're called walls.

Make a sudden change of

direction, end up at too tight of an angle and even that

padded wall isn't going to

take all of your momentum,

which is why he ended up there.

Now, onto ramps, harnessing

gravity to build plenty of velocity for a perfect launch.

Alright, not much of

a slope here but still just enough velocity.

I miscalculated.

You see, on a shallow gradient

with little help from gravity you need to pedal harder for

velocity otherwise gravity

will kind of get you down.

DALLAS: True strength is

not so much about brute force as control,

which is why you don't have to

be big to master the ab wheel.

Regard.

DALLAS (off-screen):

One, two, three, come on.

Four, nice work kid.

Now you, sir.

WOMAN: Oh.

MAN: I did it twice!

DALLAS (off-screen):

Oh, congratulations.

DALLAS: To be

fair, this isn't easy.

I mean, there's a lot

of muscle contractions and extensions,

center of mass stuff

and an annoying turning effect to deal with.

To maintain control of the

wheel he must move slowly, extending and contracting

his core muscles as a group.

This gets harder as he pushes

out as gravity acting on his center of mass generates more

of a turning effect

pulling him down.

As he slowly pulls the wheel

back under him his base of support gets smaller,

meaning his muscles

have to work even harder to

keep his center of mass

within it and remain stable.

DALLAS: Tricky stuff and to

pull it off safely you need strong back muscles,

powerful hip

flexes, steel abs

DALLAS (off-screen):

And an iron face.

Remember push out and you

have a large base of support,

pull back under not so large

and don't forget thanks to that

toning effect your abs work

just as hard pushing out.

Still too easy?

Just add a bit

of extra weight.

MAN: You don't want

to keep your head up.

MAN: Keep your head down.

MAN 2: Alright,

keep my head down?

DALLAS (off-screen): Yeah,

not that far down but you've nailed the turning effect.

So, let's go next level

with the standing ab roll.

MAN: Stand up

and all the way up.

(laughter).

DALLAS (off-screen):

Steady on.

Yeah, if you're still

struggling to go easy on that reduced base of support,

like he is, there are

other ways of toning your abs without hitting

your head on the floor.

See, didn't hit the floor.

DALLAS: Allow me to

introduce to you my good friend, the egg.

Simple, mundane even or the

astonishing work of millions of years of evolution.

DALLAS (off-screen):

Surprisingly strong in some ways,

unsurprisingly weak in others,

which makes them fascinating to scientists.

(laughter).

DALLAS

(off-screen): And to him.

DALLAS: A chicken egg shell is

predominantly a layer of calcium carbonate,

less than a hundredth

of an inch thick.

It doesn't stream strength

until you take a closer look at that shape.

DALLAS (off-screen):

The curvature of an arch gives its strength,

so whilst the shell's

flatter sides are relatively easy to squish

the more curved top and bottom

are much better at

distributing compressive force

so it takes a lot

to squish it.

But the thin shell is brittle,

so tap an egg with a spoon

and the impact force

will easily crack it.

Delicious if you'd

bothered to cook it.

DALLAS: So, that

curvature gives our egg a surprising amount

of compressive strength.

DALLAS (off-screen): Which

means it takes a lot of force to squeeze the top and bottom

but not the sides and since he

applied that compressive force to this side of the egg,

well, where else

was it gonna go?

That's why we tend to tap them

more typically with a spoon.

Her egg strikes Dad

with a stronger more curved top and doesn't break,

on his forehead at least.

Okay, let's do a test.

MAN: So you have an egg in here?

GIRL: Yes.

MAN: It's supposed to

not break when you drop it?

GIRL: Yes.

DALLAS (off-screen):

But which is better?

Human ingenuity

or hen-gineering.

That's a joke.

Yes, it's hen.

Her contraption offered some

protection from compression but it was overcomplicated

and weakly held together.

The egg, however, survived

the fall but while the shape may be strong

MAN: Dutch!

DALLAS (off-screen): The shell

needs to be brittle enough for birds to peck out of.

MAN: Is it broken?

(screams).

DALLAS (off-screen):

For dogs to peck into.

MAN: Very large egg.

DALLAS (off-screen): Oh, look

at the curvature and yet a little impact force is all it

takes to reveal, what the?

Wha?

MAN: Wow.

MAN 2: (laughs). Wow.

MAN: An egg inside an egg.

DALLAS (off-screen): You see,

eggs, so simple, so remarkable,

we really should celebrate

the geniuses behind them

but maybe just stick to

laying eggs, ladies.

DALLAS: In 1915 when Einstein

published his theory on general relativity his

notion that massive objects in

space cause a warping of space

time encouraged us all to ponder

the possibility of time travel

but could we go back to the

past to right previous wrongs?

Well, unfortunately

for this lot not yet.

(music plays through credits)

MAN: I'm a vegan man,

back off.