08x10 - Donuts, Pouring and Handstands

[bunniefuu]

DALLAS (off-screen): This

is the Science of Stupid.

DALLAS (off-screen): Yes,

this is the show that extracts science from stupidity.

DALLAS (off-screen): Prepare

your eyeballs for acts of absurd risk taking

and toxic levels of

scientific ignorance.

We'll explore what went wrong.

DALLAS (off-screen): And why,

with the help of some curious scientific principles.

Such as angular momentum,

flexural strength,

and that sneaky critter,

wave speed.

Bend the laws of physics

(screams).

DALLAS (off-screen):

And they'll snap back in your face.

So watch out, it's

the Science of Stupid.

DALLAS (off-screen): In this

episode we'll be learning about bridge strength,

exploring the most effective

way to steer an air foil wing, not like that,

and we'll be examining

how towing induces torque, but first this.

DALLAS: There are three

kinds of doughnuts, sugary ring doughnuts,

sugary jam doughnuts, and then

there are the ones that are really bad for your health.

DALLAS (off-screen):

These ones.

Well I can see why people

pay money to watch this.

But take any friction fighting

high jinks to the roads and

it's a serious

hazard for motorists.

And for trees.

DALLAS: They were okay, but

extremely lucky, so you should never attempt this,

but off the road and in the

hands of an expert doughnuts are a masterclass in static

and kinetic friction.

DALLAS (off-screen):

Our driver hits the gas hard and turns sharply.

The excessive torque at the

rear wheels overcomes static friction between the tires and

the ground, so they become

subject to kinetic friction, which offers less resistance.

The reduced grip allows

centrifugal force to slide the wheels in a circular path like

the ring of a doughnut.

DALLAS: So not just risky,

but scientifically tricky to pull off,

although not

everyone seems to think so.

DALLAS (off-screen): I mean,

this guy reckons he's got the science nailed,

but in fact he hasn't

lost traction at his back tires at all,

he's just using rollers, see.

Which does reduce the

risk of kinetic friction burning up the tires

(scream).

DALLAS (off-screen):

But doesn't make it less dangerous.

MAN: Woah! Watch out, man!

DALLAS (off-screen):

It's a bit late for that.

Ah, the parking lot doughnut.

Using kinetic friction and

centrifugal force to drift into a space.

DALLAS (off-screen):

Like a glove.

Having successfully turned

static friction to kinetic at the rear wheels,

he then momentarily let up the

power on those wheels and went back to static.

So he stopped

circling and went straight.

There are better

ways to park a car.

DALLAS: And now we take a

break from the misadventures of the scientifically ignorant

to drop our jaws in awe at

one extraordinary act, one extraordinarily dangerous act.

DALLAS (off-screen):

The French Alps.

A cable car crosses

12,000 feet above sea level.

So far, so ordinary.

But nearby pro speed flyer,

Arnott Longabardi, takes off.

Approaching at almost 50 miles

an hour, he's aiming to land inside the moving cable car.

DALLAS: Now if you're under

any illusion that Arnott's feat was not incredibly risky,

consider he was travelling at

up to 50 miles per hour towards a moving doorway

roughly eight feet

wide, whereas

DALLAS (off-screen): This chap

is going a whole lot slower,

and aiming for the top

of a massive hill

MAN: Otherwise you're

gonna end up in the bushes.

Ah.

DALLAS (off-screen):

And yet he still missed.

MAN: Well

MAN: I don't think that

was supposed to happen.

DALLAS: Besides years

of training and meticulous planning,

the key to Arnott's success

comes down to three points.

Trajectory, acceleration,

and deceleration.

DALLAS (off-screen): To

achieve more lift he increases the wings angle of attack,

deflecting more air downwards.

To turn he pulls the break on

one side, pulling down its training edge,

increasing drag there.

As the wing recovers he

accelerates, increasing the airspeed over and under it,

generating more lift.

To decelerate he tugs on the

breaks, which pulls down the trailing edge of the wing,

thereby increasing drag.

But this can eventually stall

the wing, where he loses lift and plummets.

DALLAS: Arnott had to

deliberately induce a stall just a few feet before

reaching the cable car

so he didn't end up like a fly on a windscreen.

But any wannabe stunt flyer

hoping to top his feat would

first need to work on

their trajectories.

DALLAS (off-screen):

Here we are pulling one side of the wing,

using drag to sweep side

to side, increasing air speed as it recovers.

So in theory we could

line up with a cable car,

or a tree.

Remember, increasing

airspeed over and under the wing increases lift,

but he could've

done with a bit more.

This handglider's

trajectory is inline with our paragliders,

but fortunately he spotted

this and is tilting his wing to increase lift.

It was just a little too late.

Luckily he did have

a reserve parachute.

DALLAS (off-screen):

Okay, let's look at breaking.

Pulling down the trailing edge

of the wing increases drag, which can lead to a stall,

which does slow you down,

but can also

cause a sudden drop.

All of our flyers were okay,

but it seems none of them has quite the mastery of

trajectory to nail the

target, or have they.

MAN: Cheers!

DALLAS (off-screen): And to

you sir, but I'm not sure we're quite ready for

cable cars just yet.

DALLAS (off-screen): We're

abut to see a scientific principle in action at this

drive-through, but can

you work out which one?

DALLAS (off-screen):

Did you guess the science that's about to liven

up this drive-through?

It's parabolic trajectory.

This is dictated by take

off velocity and launch act.

So when our driver

inadvertently hits the gas, accelerates to a high velocity

and launches up a slope, he

would've followed a complete parabolic trajectory over the

other car if he hadn't

caught it with its wheels.

People train for years

to be able to do that.

DALLAS: Sometimes the

coming together of two different activities

brings inspired results.

Water pole,

equestrian vaulting, chess boxing, joggling.

Other times less

inspired, more, hmm, insane.

DALLAS (off-screen):

This is Jamie, he's a snowboarder, and this chap,

he's a pilot of an airplane.

Mix them up and you get

up to 77.7 miles per hour.

I'm glad he didn't take off,

because you don't have to be towed by a plane for the

landing to hurt.

MAN: Yeah, that felt.

DALLAS: Yep, some snowboarders

and skiers are shunning the traditional gravity assisted

method of building and

turning instead to snow mobiles, ATVs and even cars,

and that is a terrible and

dangerous idea, as you may

notice from the

following physics.

DALLAS (off-screen): As our

snowboarder is towed the rope exerts a pulling force,

whilst friction at the

ground acts to slow him down.

The distance between them

produces a torque or turning effect on his body.

By leaning back he produces

torque in the opposite

direction and maintains balance.

But as he swings out on a

turn he experiences torque rotating him sideways,

so he must lean

in to counter it.

Get the balance right and he

can build plenty of velocity to go airborne.

Not that it's recommended.

DALLAS: Let's

consider that velocity.

A skier on a twenty degree

slope can be accelerated by gravity to 60 miles an hour

in around eight seconds.

An ATV can accelerate to 60

miles an hour in five seconds.

DALLAS (off-screen): All

the more reason to lean back.

DALLAS (off-screen): Okay,

not exactly 0-60 in five, but combine a lack of backwards

lean with a big pulling

force and big friction and you get big torque.

So what if we try this

on a surface with a lower coefficient

friction, like a frozen lake.

See how just a little

backwards lean produces the counter-torque needed

to keep him perfectly balanced.

Until he caught the

front of his ski.

Actually I'd forget about

the skis and just get a boat.

Snow, solid ground, much

better, and look at this, crouching low brings the

pulling force and frictional

force closer, reducing torque, and leaning back easily

produces enough

torque to counter this.

But will he remember

to lean in as he turns?

Yes he will, but

only for a little bit.

Don't worry, he was fine.

And now we've got torque

under control, ish, let's try a jump.

We just need plenty of

velocity and a clear landing area.

DALLAS: Surviving evidence of

bridge building dates back at least 3,000 years,

and in that time we've gone

from piles of stones to the 102.4 mile Danyang-Kunshan

bridge in China, and yet some

of us still don't seem to get how to use them.

DALLAS (off-screen):

Bridges are for walking along, not climbing down.

Bridges are not practical

launches for kayaks,

and you're supposed to

cross the wide bit in the middle, not that bit.

It's okay, he made it to the

other side, but don't ever try anything like that,

or that.

DALLAS: Yep, a bridge is more

in the realm of common sense, but how they're made is

without doubt a science.

DALLAS (off-screen): A beam

bridge consists of a rigid horizontal structure anchored

at either end, often

supported by piers.

In these bridges the beam

experiences both tension and compression,

making them the

weakest design.

Truss bridges and suspension

bridges solve this by separating compressive

and tensile forces.

Material choice is

also significant.

While concrete has high

compressive strength,

steel is flexible

with high tensile and compressive strength.

DALLAS: In Neolithic times

our primitive ancestors are believed to have built simple

beam bridges out of

anything they could find.

DALLAS (off-screen): Luckily

Aluminum ladders

hadn't been invented.

Anyway, early engineers

would've concluded that an unsupported

twelve-foot-ish long hollow

beam of aluminum construction

is incapable of bearing

a roughly 200 pound load.

They were Neolithic,

not nincompoops.

Some of the earliest known

timber bridges date back to the Roman empire

and had supporting piers

like this one.

The pier easily bears

the force of his weight pushing down,

but not the force as

he pushes sideways.

Oh, we've got a lot to

thank the Romans for.

Much later the ability of

trusses to separate compressive

and tensile forces enable

engineers to build bridges with

wider unsupported spans

and long moveable bridges.

WOMAN: What are you doing?

WOMAN: Stop!

DALLAS (off-screen):

Not quite movable enough.

WOMAN: Oh my God, oh my God.

DALLAS (off-screen):

Doll, I know what you're thinking, but don't worry.

We haven't forgotten about

the mighty suspension bridge.

WOMAN: Holy cow, look at that!

DALLAS (off-screen): Well I

did say steel was flexible,

but I think I'd rather take my

chances on a pile of stones.

DALLAS: And now, gentle

viewers, we explore the science behind a truly

underappreciated

life skill, pouring.

DALLAS (off-screen): It can

be key to a future career.

Sommelier.

It can be critical for

surviving natures torment.

Well in his mind at least.

MAN: Shhh.

DALLAS (off-screen): Okay,

and it can be brilliant for pulling pranks

on your friends.

MAN: Oh.

DALLAS (off-screen):

See, everyone loved that.

DALLAS: People are really

struggling with the fundamentals of pouring.

Maybe they underestimate the

complex chemistry and physics at play as a liquid flows.

DALLAS (off-screen): Waters

density makes it heavy and its center of mass can slosh

around, making it

difficult to carry.

This is because liquids

are made up of loosely bonded molecules,

strong enough to keep the

molecules close together, but weak enough to let

them move around each other.

With one hand at the bottom

and the other at the top you can easily apply torque to

safely tip the bucket and

control the flow, ideally.

DALLAS: Now as an parent will

testify, that sloshing center of mass can take time for

young hands to

get to grips with.

BOY: Grab those.

BOY: This one is for me.

BOY: Uh oh!

DALLAS (off-screen):

Don't worry, little clean up, and let's try a pour.

Good control of that

moving center of mass.

It's precocious start.

BOY: Uh oh, I spilled!

DALLAS (off-screen): Never

mind little man, those naughty loosely bonded molecules are

hard to handle.

Not to mention

BOY: Slippery!

DALLAS (off-screen):

You got it.

Some pourers are so highly

skilled they can do it in near total darkness.

(screams)

DALLAS (off-screen): Bravo.

Even in the dark she performed

a precision pour by sticking to the classic technique,

one hand at the bottom,

one at the top, allowing her to easily generate

the torque needed to

safely tip the bucket.

DALLAS (off-screen):

Okay, so that's close range.

Let's make this a

little harder and go higher.

MAN: When I say OK, alright.

DALLAS (off-screen):

Yeah, not perfect.

The evidence points to a

poorly managed flow, and underestimation of weight,

and terrible balance.

DALLAS: You may have seen

acrobats elevating their handstands using specialized

stilts to make an

extraordinary feat of muscular control more precarious and

more impressive, but some

people don't have the stilts.

They have other things

which makes the results mixed.

A set of dumbbells, yes.

Basketballs on

dumbbells, double yes.

A tower of dumbbell

weights, it's a no.

DALLAS: In a handstand you are

effectively standing up using muscles like the triceps,

deltoids, which weren't

designed to do the job.

Add another object between

you and the ground and you're adding more places

where it can go wrong.

Here's your science.

First he kicks up,

giving himself just enough angular momentum to rotate

into the handstand.

He must ensure his center

of mass is over his base

of support and his

hands for stability.

And if the object he's on

isn't fixed down his hands must be positioned well within

its base of support to avoid

a turning effect causing the object to pivot.

DALLAS: As you can see,

an elevated handstand should only ever be performed by

a trained expert using

a good solid platform.

DALLAS (off-screen):

Here we have a picnicker and a cooler box.

It does have a large

base, but it also has wheels.

What if we try something fixed

to the ground, like this bin, but without the hinges.

If he'd been directly

over the pivot here it might've been possible,

but he wasn't, so

it wasn't possible.

How about

something less pivoty.

Well actually Sugarlump has

twelve potential pivot points, but those muscular legs

are forming a solid base.

Shame about him.

Sugarlump's sturdy work was

ruined by the excessive angular momentum of his human.

And besides, it's kinder to

stick to inanimate objects,

but maybe not your

mum's kitchen sides.

They might form

a sturdy base

DALLAS (off-screen):

But you might not.

WOMAN: What was that?

DALLAS (off-screen): Uh oh.

Quick analysis.

Moving one hand

reduces his base of support,

meaning he

couldn't counter the turning

effect, so it's a no

for kitchen sides too.

They're simply too

expensive to replace.

WOMAN: What have you done now?

DALLAS (off-screen):

And keep replacing.

DALLAS: The American

poet and philosopher, Ralph Waldo Emerson,

once remarked, 'Bad

times have scientific value.

These are occasions a

good learner would not miss.' It makes sense.

I mean, who'd want

to miss this lot.

(music plays through credits)

♪

BOY: Slippery.