08x11 - Scooters, Roofs and Snowmobiles

[bunniefuu]

DALLAS (off-screen): This

is the Science of Stupid.

DALLAS (off-screen): Yes,

this is the show that tips a beaker full of stupidity

over a filter of science.

Relax as amateur researchers

and wannabe pros

test the laws of the universe

so you don't have to.

We'll reveal what went wrong

and why with the help of

scientific principles such as

lift, or lack thereof.

Flexural strength

and our

old favorite angular momentum.

So, watch and learn but

never copy because this is

the Science of Stupid.

DALLAS (off-screen):

In this episode we'll be studying how science can

improve your log press.

The material strength

of rooves

and we'll be getting

to grips with reaction force,

but first, this.

DALLAS: Back in the 1930s

Joseph-Armand Bombardier invented the snowmobile in the

hope of opening up the frozen

wastelands of the world but he could scarcely have imagined

that that would

merely be the start.

DALLAS (off-screen): As

extreme winter sports fans saw other opportunities for

racing, jumping

and, of course, crashing.

DALLAS: As the name suggests,

snowmobiles are great at traversing snow but when

there's a gap in the snow,

like a riverbed or ditch, it seems some people are also

using them for

traversing thin air.

That is not a good idea,

even if it is scientifically possible.

DALLAS (off-screen): A

snowmobile's trajectory will be determined by its speed on

take-off and the

angle of the launch area.

Once airborne its trajectory

is fixed, however by hitting the throttle,

or brake, they can

alter their pitch mid-air.

This is because of

conservation of angular momentum,

which dictates there must

be a rotation in the opposite direction to the track's

angular acceleration to keep

the total angular momentum the same but under or overcook it

and you're eating snow.

DALLAS: Okay, it is possible

to jump a gap on a snowmobile but with all that science to

go wrong it's also

unequivocally dangerous and therefore utterly inadvisable.

We can only hope our intrepid

researchers have at least done their homework.

DALLAS (off-screen): The

biggest gap ever jumped was a staggering 412 feet.

This guy is setting

his sights a little lower

but not low enough.

Starting so close to the

drop he doesn't have enough time to build up speed and

with no ramp his trajectory

intersects with the steep slope of the bank.

Thankfully he was wearing

a helmet and then he wasn't.

Maybe it's safer to keep

the gap over dry land.

Hmm, maybe not.

This time there's enough

velocity and there's a ramp but don't forget that due to

the conservation of

angular momentum, hitting the throttle mid-air

pitches the

snowmobile backwards.

I think he might have

overcooked it a little.

Will it be third time lucky?

Success, until he

hits his friend.

His trajectory is just

sufficient to clear the gap and by hitting the throttle

he's carried up the bank

and straight into his friend.

I mean, former friend.

But if you still can't

get the science right there is another option,

simply hide.

Sh, I think you

got away with it.

DALLAS: We've learnt

all manner of science from people getting it wrong but

occasionally some of

us do get it right, so right in fact that they

set new world records.

DALLAS (off-screen):

Like China's Hou Kai.

He's attempting the most

handsprings in a confined space in one minute and,

no, this footage

hasn't been sped up.

I couldn't even do a

single handspring but who can?

Hou Kai can.

That's 50 and a

new world record.

DALLAS: Now then, attempting

any gymnastic move without proper training is not a good

idea but don't

take my word for it.

DALLAS (off-screen):

Take hers.

(laughter).

DALLAS: As all professional

gymnasts know, the handspring is all about angular velocity

and the vestibular system.

DALLAS (off-screen): A

handspring requires a decent base of support and a strong

push off to

generate angular velocity.

It requires an intermediate

hand support and then a fully extended body flip with enough

angular velocity to

complete the rotation.

The vestibular system is also

important, liquid in our inner ear sloshes around which the

brain uses to monitor balance.

Continuously spinning means

the fluid builds up momentum and can lead to dizziness.

DALLAS: So, breaking this

record requires not only the mastery of physics to achieve

the correct amount of

rotation but also a brain accustomed to dealing with

the vestibular system's

dizziness inducing signals.

Something you'd probably want

to master in private before committing to an audience.

DALLAS (off-screen):

Our first wannabe record breaker does like to make

a big entrance though.

(laughter).

DALLAS (off-screen): And

possible a speedy exit.

She loses her base of support

as her left foot slips, meaning she's not able to

generate enough

angular velocity.

(laughter).

DALLAS (off-screen):

Which I assume is what her friend was pointing out.

Now, he looks more the part.

WOMAN: Come on, Joey!

DALLAS (off-screen):

Yeah, come on Joey. Go for the record.

WOMAN: Yeah, come on.

DALLAS (off-screen): Or just

do that. It's up to you, Joey.

Joey completes the

handspring okay but he didn't have enough

angular velocity to

complete the flip.

WOMAN: Yeah, come on.

WOMAN: I told him not to do it.

DALLAS (off-screen):

Well, he didn't listen, did he?

It's the rodeo

and time for the traditional handspring act.

(screams).

DALLAS (off-screen):

Maybe best done before the horses had been out.

She's lost her balance,

most likely due to information from her vestibular system.

Let's hope she's lost

her sense of smell as well, and taste.

So, are we ready to

beat Hou Kai's record?

MAN: Oh.

DALLAS (off-screen): No.

DALLAS (off-screen): Well,

this kid's got all the moves.

The floss, err, that

one but can he guess the scientific principle

he's about to demonstrate?

DALLAS (off-screen): Did you

guess the science this kid's dance demo would lead to?

Yeah, that's right.

It's impact force.

When he lands he applies the

force of his weight plus his downwards momentum,

which produces a large impact

force exceeding the material strength of the barrel.

There are easier ways

to tap a barrel, kid.

DALLAS: The aquatic ape

theory proposes that our ancestors lived in water

at least part of the time.

It is contentious and many

dismiss it but one thing I think we can all agree on is

that some modern day humans

are more aquatic that others.

WOMAN: Where is it?

WOMAN: Arggghhh!

WOMAN: Oh my God.

DALLAS

(off-screen): But what is it?

(screams).

WOMAN: I see it.

WOMAN: I see it,

it's right next to me.

DALLAS (off-screen): Is

it a Great White Shark?

An alligator?

Nope.

In fact it's a humble manatee.

(screams).

WOMAN: Look at that!

WOMAN: Look at it!

WOMAN: It's huge!

DALLAS (off-screen): Yes,

huge but completely harmless.

Herbivorous and rather

sensitive, so please if you do meet a manatee keep your

distance and avoid

being shouty, splashy or annoying in anyway.

WOMAN: It's like 40ft long.

DALLAS: Some animals are

simply more adapted to cutting it through the water

than us h*m* sapiens.

DALLAS (off-screen): Fish have

smooth streamline bodies which reduce hydrodynamic drag

through the water.

They swish their tails from

left to right to propel themselves forward.

Whales and dolphins have

horizontal tail fins as they evolved from four-legged

animals with limbs underneath

their bodies, so their backbones naturally

bend up and down.

While most creatures have

their thrust at the back, sea lions use their front flippers

to push themselves forward

with their back flippers used for steering.

DALLAS: Yes, marine creatures

move in all manner of ways and their ability to glide through

the water is often a

matter of life and death.

DALLAS (off-screen): This sea

lion is after a fishy snack but will the fish's rear tail

propulsion be enough to

out-swim the sea lion's front flipper power.

MAN: He's missed it.

DALLAS (off-screen): Yes,

it will but he's still hungry.

(screams).

(laughter).

DALLAS (off-screen): By

rotating their hind flippers underneath their bodies sea

lions can also walk on land,

which is unfortunate for this fisherman.

(laughter).

DALLAS (off-screen): Here's

a family hoping to get a closer look at the silver

carp's marine movement.

MAN: Oh, sh*t.

MAN: He got you in the face.

DALLAS (off-screen):

Close enough for you, madam?

The streamlined body of the

silver carp reduces hydrodynamic drag,

helping it to build

up enough propulsive force to hit granny.

MAN: In the face!

DALLAS (off-screen): But

if it's propulsive force you're after imagine having

to breach 40 tons of bodyweight

through the surface.

That's a lot of work for

a mouthful of plankton.

DALLAS: Roofing is the

trade of constructing and repairing rooves,

it's the fourth most dangerous

profession in the US and a job that takes balance,

a head for heights

and years to master.

MAN: We have a roof.

MAN: Where did it go?

MAN: We have a roof

that we built

on the ground

that's got to go

up here.

MAN: Let's see if we

can get it up there.

MAN: Wish us luck.

DALLAS (off-screen):

Um, good luck.

And we're all set.

MAN: I'm losing it!

MAN: Everybody OK?

MAN: Yes, good.

DALLAS (off-screen):

Never been better.

DALLAS: A prime example

of why you don't need luck in the roofing business.

You need knowledge of

the scientific principles.

DALLAS (off-screen): Flat

rooves are less expensive and quicker to build but are less

durable than pitched rooves

and there is more risk of water pooling,

which can weaken

them overtime.

Pitched rooves are built uses

trusses, their triangular shape gives them high strength

and rigidity by

distributing the load throughout the structure.

The slope allows water to

drain off more easily, however it also reduces friction as

less of the force of

your weight is acting perpendicular to the slope,

increasing the

likelihood of a fall.

DALLAS: Given that rooves are

usually high up and generally made from materials not

designed for walking on

it's easy to see the dangers.

Best left to the

professionals.

MAN: Today I'm

setting trusses up.

DALLAS

(off-screen): Lesson one.

A strong roof needs strong

trusses, in this case made from dense wood.

MAN: Just gently

lift it up there.

DALLAS (off-screen):

Lesson two.

Erect your trusses with care.

MAN: Yeah, just like that.

MAN: And that's

all there is to it.

MAN: You know.

DALLAS (off-screen):

And lesson three, don't speak too soon.

BOY: Just got home from school.

DALLAS (off-screen): This

wannabe future roofer wants to get some practice in.

BOY: So now I'm going

to go jump off my roof.

BOY: Normal.

DALLAS (off-screen): It

sounds like a terrible idea.

BOY: It's much

higher than it looks.

DALLAS

(off-screen): And much weaker.

Don't try this at home,

or anyone else's home.

Unfortunately for him flat

rooves are generally less durable than pitched rooves.

This one looks rotten so its

material strength is unable to support his weight.

BOY: I had a feeling

that was going to happen.

DALLAS (off-screen):

Ah, so you were just demonstrating structural

integrity for us, were you?

Oh, thank you.

Pitch rooves are

typically more durable.

MAN: Ah.

(laughter).

DALLAS

(off-screen): And slippier.

Pitched rooves might

allow rain to run off but not always snow.

An icy covering combined with

the angle makes for very little friction and now we

re-join our roofer

friend at the final stage of construction.

MAN: We have a window

that we wanted to put up

on the second

floor as we're doing this.

MAN: Just want

to see how it goes.

DALLAS (off-screen): This

guy has got all the kit.

He just hasn't got a window.

DALLAS: There's no better

place to start with scooter tricks than the bunny hop.

50. See?

It's easy but then I do

know an awful lot of science.

Thanks.

DALLAS (off-screen):

Let's see how much our first researcher knows.

Great bunny hoop but you

need to work on your ledge grind 360,

yeah and buy me a new camera.

DALLAS: The bunny hop looks

simple enough but there's an awful lot of complex science

packed in, so let's get

the basics right, shall we?

DALLAS (off-screen):

The rider rolls to build up linear momentum,

then crouches and pushes

down hard with his feet.

This produces an equal and

opposite reaction force, launching him upwards.

At the same time he pulls up

with his arms to lift the scooter.

On landing he must flex his

knees to reduce the impact force and keep his center of

mass over his base of support

to ride away successfully.

DALLAS: It's a lot of science

to get wrong, so best to practice somewhere with plenty

of space like, I

don't know, a skate park?

DALLAS (off-screen):

Okay then.

GIRL: I'm a bunny, duh.

DALLAS (off-screen):

She vaguely knows the name of the trick.

DALLAS (off-screen):

Just not how to do it.

Failing to pull up on the

handlebars enough means the front wheel hits the object to

be jumped, resulting in

her hitting the floor.

DALLAS (off-screen): Maybe

it's best to keep the scooter party tricks outside.

Like Dad showing his

daughter he's still got it.

All that just to teach his

daughter a science lesson.

What Dad was clearly showing

her was that if you pull

up the handlebars but don't

generate a reaction force with

your feet you'll put the handle

bars under too much stress.

Lesson learnt.

Let's try with

someone less middle-aged.

A bunny hop with a slick rail

grind and he's not even finished yet.

MAN: Oh.

DALLAS (off-screen):

Yeah, he is now.

The rider generates a reaction

force and pulls up on the handlebars at the same time,

placing him on the rail.

He controls the grind by

making sure his center of mass remains over his base of

support but when he

then tries a tail whip

he misses the

scooter and is now possibly missing some teeth.

MAN: Oh.

DALLAS: The pillars of

Hercules, the key toss, the fridge carry.

They're all impressive enough

but when it comes to peculiar weightlifting challenges

I like a log press.

DALLAS (off-screen): This

particular log is 33 feet long and weighs over 1,400 pounds.

It's basically a tree.

DALLAS: But as impressive

as that was it wasn't technically a log press.

For one of those you'd need

to grab a special piece of equipment called a log bar

and get to grips with some

heavy lifting science.

DALLAS (off-screen): Log bars

have a much larger radius than a traditional barbell,

so the lifted is forced

to hold the log further away from the body.

This moves their combined

center of mass further forward meaning the lifter needs to

lean back to keep his

center of mass above their base of support.

Once pressed the log will

transfer momentum to whatever it lands on.

DALLAS: It's all about

keeping that center of mass above the base of support

by leaning back.

We've sent a few of our more

muscular researchers out to put the science into practice.

DALLAS (off-screen):

Great start.

Shame about the finish.

He didn't even manage to get

it above his head before leaning the combined center of

mass too far outside

of his base of support.

Trying to compensate he

introduces horizontal momentum,

which he's unable to stop.

This guy looks like a pro and

he's got it above his head.

MAN: Oh.

DALLAS (off-screen): For

all the good it did him.

After an initial good start he

lets the log move too far backwards taking the combined

center of mass outside

his base of support.

Luckily his friend is

there to check that he's okay using his own special

form of sign language.

MAN: Are you OK?

DALLAS

(off-screen): Yes, I'm fine.

But let's not forget that with

the log press the lift is only half the battle.

You still need to put it

down when you're finished.

Gently does it.

DALLAS (off-screen):

Due to its large radius the lip on the wrack wasn't big

enough to stop it rolling off.

He was okay but do bear in

mind the log press may be good for your arms but not always

great for your tum tum.

DALLAS: No matter how

foolish they might seem, it's important to recognize

how much we learn through

the deeds of others.

Sir Isaac Newton once said,

'If I had seen further it is by standing on the shoulders

of giants.' Of course, the

problem withstanding on giant shoulders is that it does

rather hurt when you fall off.

(music plays through credits)

♪