07x10 - Dance, Rapids and Medicine ba*ls

[bunniefuu]

[Dallas Campbell]
This is the Science of Stupid.

[electricity crackling]

[klaxon blaring]

Yes, this is the show that
pits science against stupidity.

[screams]

Watch as everyday people
attempt the frankly perilous,

astounding and unbelievable,

and endure the consequences.

Then we reveal what went wrong

and why with the help of some
fundamental laws of science.

[man] Whoa-h*-h*-hoo.

[Dallas] Such as angular momentum,

hydrodynamic drag and Pascal's law.

These are the people that suffered

so that you don't have to,

so watch out it's the Science of Stupid.

[electricity crackling]

In this show, we'll be discussing
sliding and spinning with low traction,

[men shout]

tickling your taste buds
with gustatory perception

[whines]

and how to make a spectacle of yourself

with planes of rotation, but first this.

[glass shattering]

[electricity crackling]

[shattering]

There is nothing in this world
I find more relaxing

than gently floating down
a meandering river.

Oh, yeah, this looks a bit less
relaxing than I had in mind.

[people shouting]

[man off-screen] Lean left! Lean left!

[Dallas] I don't
think leaning's gonna help.

-[man screams]
-[woman gasps]

[man off-screen] Look at how
much fun they're having!

[Dallas] Well, not so much fun
by my standards

but the crowd seems to be loving it.

[screaming]

Well, one of them anyway.

[man off-screen] Lean right!
Lean right! Lean right!

[Dallas] If it turns out that
traveling down raging rapids

is your cup of tea,
and each to their own,

then an understanding of
kinetic energy and turbulence

would help keep your head above water.

River rapids are created

as fast flowing water,
under the force of gravity,

travels down a steep gradient

gaining lots of kinetic energy.

This energy leads to erosion

and tight river channels with
boulders breaking the surface.

The fast moving river combined
with this uneven topography

creates turbulence and forms
eddies and holes

where water flowing over the boulders
folds back on itself

recirculating the flow.

Rocks, fast flowing
water, potential drowning,

it could all be, well, a death trap.

Luckily these rapid rafters
have all got guides to,

you know, guide them around the danger.

Or in this case, straight into it.

[people shouting]

Ah, well. At least the raft got away.

This guide appears to be paddling
the raft straight back into the hole.

As the water drops over a rock,
it recirculates back in on itself,

pulling the boat backwards.

But at least this
chap listened to the science

and he bailed
before they got into trouble.

Genius.

Once you get sucked into those
holes, it's very hard to get out.

While they work that out

let's have a look at our checklist,

fast flowing water, check.

Uneven topography, oh yes.

Turbulence, absolutely.

No, lightening the load
won't work, I'm afraid.

What you need is some help.

A little shove?

There you go, that's better.

The water flowing fast over
the uneven river bed

has created a hole where the
river folds back on itself,

sucking rafts...

and pretty much anything else into it

until something else gives you
a little nudge of kinetic energy.

Thank you.

I'm sure there'll be somebody
else along in a minute.

Now, this river does seem to have
rather a lot more kinetic energy.

How are they gonna cope
with all that turbulence?

[man off-screen] Dig it in! Dig it in!

[Dallas] Fortunately,
the reassuring guide at the back

sound like he knows exactly what to do.

[man off-screen] Right guys, dig hard!

Dig hard!

[screams]

[Dallas] Right. Unfortunately, he's no
longer in the boat.

The speed of the water
combined with the uneven river bed

meant that when they went over a wave

it transferred a lot
of kinetic energy to the boat,

which acts a bit like a catapult...

[slow motion screaming]

sending him into the drink.

[indistinct chatter]

Ah, thank goodness, the captain
is back in the driving seat.

Do rafts have driving seats?

[man off-screen]
Yeah, thanks. We're good.

[electricity crackling]

-[creaking]
-[clattering]

[Dallas] We may be the Science of Stupid

but we've never shied away
from a little high culture.

Take contemporary dance,

a fusion of ballet, modern and jazz.

It's a melting pot of moves,

not to mention science

and this is a lyrical kick,

a dynamic high flying kick

as demonstrated by an expert
in contemporary dance...

and here by an expert in something else.

Yeah, it's not all that easy

and in layman's terms

the key is getting one foot high

whilst keeping the other firmly planted.

In strictly scientific
terms however, it is this.

To perform a lyrical kick,

she first accelerates
one leg smoothly upwards.

She must not generate
too much upward force

that she almost leaves the ground

as this would reduce
the friction at the foot

which remains on the floor,

and she might slip.

Despite her base of support
being reduced,

she keeps her center of mass over it
and finishes gracefully.

So, that's your science

and now, I proudly present our line-up

of elegant dancing queens and kings,

and their beautiful lyrical kicks.

Oh, sorry. I missed
that one. Can we get another?

[screams]

No, first one was better.

Large upward force of
kick reduces friction,

horizontal force overcomes friction...

-girl hits floor.
-[screams]

Absolutely classic.

[screams]

Out of the bedroom now and
into the hall with serious stuff.

Just remember to go easy
on that upwards force.

-[screams]
-And the horizontal one too.

In contemporary dance, every
move has profound meaning,

"Thou has stabbed
my heart, but I care not.

I rise like a kite."

[man] Ow.

[Dallas] Then fall a bit
like a wet towel.

A critic might say that
it was sheer commitment,

an attack that undermined his footing

but we know it was horizontal force
and a lack of friction.

In summary, it was a
profoundly moving performance,

-marred only...
-[man] Ow.

[Dallas] by the paucity of
scientific understanding.

[electricity crackling]

-[squeaking]
-[clattering]

Now it's time for a vertigo
inducing challenge,

but which scientific principle

is about to flash before
this biker's eyes?

[glass shattering]

[electricity crackling]

[shattering]

Did you get to the bottom of the science

this cyclist is going to show us?

No? Well, he's about to.

Whoa, that was extremely close.

It's all about inertia.

As the ridge stops his front wheel,

his inertia means his mass
wants to continue in a straight line.

Something else wants to
travel in a straight line, too.

Oh, I quite liked that bike.

[glass shattering]

[electricity crackling]

[shatters]

What is it about snow that brings out
the inner child in us all?

Most people see snow and
they start chucking it,

sliding in it or jumping into the stuff

but throw an ATV into the equation

and the potential for danger
is amplified.

[screams]

You see? It's amplified.

Especially if you do what he did,

a 360-degree plus turn,

known to some as a donut

because it's, yep.

It seems ATVs with their
short wheel base

are rather adept at
it and here's how it works.

Our driver accelerates and turns hard,

as the rear wheels lose traction

they begin to slide on the snow
and the ATV rotates.

Because traction on snow is so low,

soon both front and back
wheels are sliding

and the access of rotation gets closer
and closer to the center of the ATV

until it's spinning on the spot.

This can lead to the driver experiencing
a large amount of centrifugal force

which can result in flight.

I prefer my donuts rather less dangerous

and with a lot more jam

but not everyone is like me,

so let's start by seeing

how that low traction works
on a regular corner.

Yup, that's how it works.

The snow is compacted

providing low traction
and making it good for sliding

but as soon as their wheels touch

a turning effect is created,
which sends him out of control.

Okay, let's tighten
up that axis of rotation...

with a midnight snack, a tasty donut.

Using a run up, he suddenly
turns the handle bars,

and begins to slide.

By turning hard, he's able to spin
in tight circles as he slides.

Much like eating donuts,

with doing donuts it's hard
to know when to stop.

[laughter]

[screams]

It looks like the laws of
physics decided that for him.

[man off-screen] Awesome.

[Dallas] He uses the low traction
to his advantage

but his increasing angular velocity

pulls his center of mass further away
from the access of rotation until...

-[screams]
-donuts.

A moment on the lips, pain on the hips.

[man off-screen] Woo. Awesome.

-[sizzling]
-[burbling]

[Dallas] Okay class, sit up
straight and pay attention.

It's time for today's science lesson.

Here, we'll examine a
scientific principle in detail

and then dive straight into a pop quiz.

Let's see if you can guess today's theme
with the help of these clues.

It can be joy.

[laughter]

It can be...

[screams]

-[woman off-screen] Is it hot?
-[boy] No.

-[groaning]
-[Dallas] Not joy.

[woman off-screen]
You want to try wasabi?

[Dallas] Or it can be a plea for...

[child] Help.

[Dallas] Yeah, don't try that yourself.

Did you guess the answer?

Yes, of course you did.

It's taste, also known as
gustatory perception,

but what's actually happening
on a scientific level

when we put food into our mouths?

When food enters our mouth,

and makes contact with our tongue,

it reacts chemically
with taste receptor cells.

Taste buds are made up of
around 100 of these cells

and thousands of taste buds
are found on every tongue.

The cells then transmit messages
via nerves to the brain,

which produces the sensation of taste.

For example, there's sweet,

sour, mostly caused by acids,

salt, savory and the
potentially fatal bitter taste.

The sensation of something
being spicy isn't a taste,

it's a pain signal sent by the nerves

caused by substances such as capsaicin,
which is found in chilies.

Our brain has evolved to
recognize these tastes

to enable us to distinguish the
delicious from the deadly.

Okay, class. Attention.

It's time for your test.

What taste does an acid produce

when it interacts
with a taste receptor cell?

This ten-month-old baby doesn't have
a care in the world until...

[screams]

Her mother passes her a lemon.

-[screams]
-Did you guess it?

Yes, the answer is a sour taste.

As she puts the lemon in her mouth,

her taste receptors
send signals via nerves

to her brain that results in that face.

If you're not sure about something

the best thing is to try it again.

[screams]

Yup, there's the proof.

[screams]

Okay. Time for question number two.

What is the purpose of
recognizing a bitter taste?

Haha, little ones.

They're so trusting, aren't they?

But what happens when Mum swaps
yogurt for vegetable mash?

Will baby notice?

[cries]

Absolutely. She's small but not stupid.

You see, these responses are
hardwired into our brains

and the evolutionary reasons for
us disliking bitter tastes

was to help us avoid poisonous plants.

[cries]

And that's why most kids
don't like vegetables

that have a bitter taste,

through experience
they can learn to like them.

[cries]

Yep, I still look like that
when I eat Brussel sprouts.

Now it's time for your
third and final question.

What sensation isn't detected
by our taste receptor cells?

[man] Without further ado,
ladies and gentlemen,

this is a Habanero pepper.

[Dallas] Yup, you've guessed it.

The answer is spiciness.

[man] Habanero pepper
dipped in ghost pepper hot sauce...

and we're about to eat this.

Down the hatch we go.

[Dallas] This is a really
dangerous idea.

It causes pain.

[man] I can't see.

[Dallas] And can make it hard to...

[man] I can't hear.

I can't talk.

[Dallas] But luckily it hasn't
affected his common sense

because he never had
any in the first place.

[man] I'm going to go
and get some ice cream.

[Dallas] Class dismissed.

[glass shattering]

[electricity crackling]

[Dallas] It's believed that
the term "medicine ball"

was coined in the late 19th Century

when our ancestors cottoned
onto the medicinal benefits

of chucking heavy ba*ls about.

And today we're still reaping
the rewards and then some.

It's all about momentum,

trajectory and timing.

[laughter]

Medicinal or not mess
up your throw or catch

and medicine is what you're gonna need

and the best remedy of all,
well, let me prescribe some science.

When throwing the medicine ball,

he needs a large amount
of force to get it going,

weighted medicine ba*ls
have a large mass,

therefore large inertia,

which is an object's resistance
to changes in its motion.

It's important he gives the
ball an appropriate trajectory

to ensure it doesn't
collide with anything.

Inertia tries to keep it moving
with a certain velocity,

meaning it also requires
a large force to stop it.

Easier said than done when
you're working hard

building muscles with sweat
running into your eyes.

This lady is altering
the ball's trajectory

with a bounce, that's hard...

-[woman yelping]
-on your face.

Plenty of force but that
trajectory misses the target

and then hits the weights,
and then her face.

[woman yelping]

Well, they say no pain, no gain.

This guy is throwing
a burpee into the mix.

Not bad.

But his friend is upping the ante
and adding a catch.

[man off-screen] Quick, come on. Oh.
[laughter]

[Dallas] With his back.

Timing was close enough.

Good catching hands, but the
trajectory was less than ideal.

[man] Oh. [laughter]

[Dallas] And definitely not medicinal.

Perfect trajectories and lots of force

but remember just as it takes
a large force to move a big mass,

it also takes a large force...

[grunts]

[groans]

to stop one.

Stupid inertia.

[electricity crackling]

Everyone loves a show off, don't they?

Don't they?

While I was at parties in the 1980s

showing everyone how cool
my microscopic bacteria slides were,

Danny Bannister was doing yo-yo tricks
to unbridled adulation.

Well, not anymore. I mean, he's 46.

And frankly, yo-yos
are yesterday's news.

This is poi,

originating from the Maori
of New Zealand.

Swing tethered weights in
rhythmical geometric patterns

and you'll be the most
popular act on the beach,

apart from him.

-Everyone loves watching that guy.
-[man] Ow.

[Dallas] If you're keen to
explore the traditional art of poi,

you first need to wrap your head
around scientific principles

such as centripetal force
and planes of rotation.

The circular motion of her
hands keeps the poi moving,

the weighted end wants to
travel in a straight line,

but the string creates
a centripetal force

making the poi take a circular path
around her hand.

She needs to be aware of
the poi's plain of rotation

because one small miscalculation

and the poi could hit her,

so she carefully manages the rotation

with the rhythmic circular
motion of her hands.

To be a poi show-off, you need
to develop actual skills

that you can then show-off.

For people starting out,

I would suggest a private
location for your first performance...

as opposed to being in full
view in your front garden.

Oh, close one.

Those pois were traveling
at around 50 miles an hour

so that could have been nasty.

[screams]

Yeah, a bit like that.

Classic rookie error,

his poi gets tangled and adopts
a new plain of rotation.

Oh, poi. What have you done to us?

Ah, the living room,

less opportunity for humiliation here,

but still plenty of scope for pain.

He's made a spectacle of himself.

He went wrong when he stopped
moving his arms

creating a new plain of rotation

that caused the heavy poi's progress
to be impeded by his face.

Who put that there?

Ah, a proper poi here,

in fact, he's gone next level
and onto fire poi.

I wouldn't recommend this

but he does seem to have the skills...

[cheering]

...to set the place on fire.

[cheers]

When the poi comes off the chain,

it loses the centripetal force required
to keep it traveling in a circular path

and takes its own path instead.

[cheering]

Okay, crisis averted.

Carry on, it's still
impressive just with one.

Thank you all for coming,

and really pay no attention to
what's going on behind me,

it's all part of the show.

I never liked that tree anyway.

Hated it.

[electricity crackling]

[clattering]

And there ends our journey
watching people hurt themselves

all in the name of science,

but please don't take
their pain in vain,

take a lesson from them
and do not attempt any of this at home.

Reminding you that
stupid is as stupid does,

here are the highlights.

[man shouting]

[man off-screen] Awesome!

♪♪

[whines]

-[yelps]
-[clattering]

[screams]

[yelps]

[man off-screen] Dig hard! [screams]

[grunts]

[grunts]

[girl] Help!