04x11 - Snowmobile, Skateboard and Long Robes

[bunniefuu]

[Dallas] This is the Science of Stupid.

[reading]

Yes, this is the show where science

meets stupidity.

[man 2] Ahhh!

[Dallas]
Watch and learn as everyday people

attempt acts of jaw-dropping lunacy...

[yells]

...with eye-watering results.

We'll clarify where
they went wrong and why

with the help of scientific curiosity,

such as...

torque...

slowing force...

and traction.

So sick back and prepare for the pain.

Watch out.

It's the Science of Stupid.

[electricity crackling]

[man 2] Yeah!

[Dallas] In this show,

we'll be looking at turning effect...

[man 2] Whoa-oh.

[Dallas] ...translation...

[laughter]

...and good old impact force.

But first, this...

[electricity crackling]

Some people like classical music
to help them unwind,

others need a massage to relax,

but for me, at the end of a hard day

there's only one thing
that really works...

grabbing my pogo stick
and bouncing my cares away.

Do it right, and the only way is up.

[man 2] Whoa!

[Dallas] That wasn't right.

Do it wrong,
and you'll soon know about it.

At least he was wearing a helmet.

Ignoring the science on a silly stick
is clearly stupid,

but if you'd prefer
to land without a crash bang

or a wallop, you better pay attention

to this pogo slow-mo.

Our pogoist knows
that he needs to continue bouncing

to remain upright,
because his pogo stick

is an inverted pendulum
in unstable equilibrium.

To remain dynamically balanced,

he continually moves and angles his stick

for each landing, relying on the friction

between the stick and the ground

to resist any sliding force

from his weight and horizontal momentum.

And he must keep a firm grip
with his hands and feet

to maintain control.

For success, you need the delicate trinity

of rider, pogo stick, and the ground.

Get the balance right, and you'll feel

like you are floating on air.

Like this guy, who is enjoying

showing off his skills.

He's certainly flying high.

And the bigger the bounce...

the bigger the impact.

Lots of momentum,

too much lean, and a sliding force.

Make that a really big sliding force.

And a smack on the face.

Stick placement is paramount.

And poorly done,
it can affect impact force.

That's not exactly
where he wanted to place it.

Oh, [bleep].

Ohh.

[Dallas] Taking his hands
and feet off the stick

meant this guy couldn't
control its positioning.

And on impact, the stick's effort to apply

a gradual slowing force to our pogo jumper

acted in the wrong place.

The painful place.

This guy looks confident and ambitious.

I'm sure he's on top of the science.

[yells, groans]

[Dallas] Or maybe at the bottom of it.

He tried to convert
the stick's upward velocity

into forward bounce,

but because he angled the stick
after it was already compressed

and angled it considerably more

than the mere ten degrees from vertical
needed to clear the stairs...

[yells, groans]

...it kicked up
and turned into a rotation.

Ah, some festive family fun.

And everyone has an uncle
who gets a bit carried away.

[kid] Do it.

Do it!

[Dallas] That's got the party started.

The fun uncle, or funcle's, demise

was overbalancing on a smooth floor.

The floor's low friction
offered barely any resistance

to his large sliding force.

And meant, for him,
the pogo ended with a low blow.

[laughter]

[electricity crackling]

[engine revs]

Paradiddle pata fla fla flammadiddle.

These are not the words to a magic spell.

They are in fact my favorite
drumming rhythms.

I used to imagine myself
in front of a stadium full of people,

hitting them with a "pata fla fla,"

all of them chanting my name in unison.

But in reality,
I was more like these guys.

Ow.

This military drummer...

this serenity seeker...

[woman] Louder!

...and this rebellious rocker.

-[groans]
-[crowd oohs]

[Dallas] Yeah, I bet
you're feeling a bit silly now.

[cheers and applause]

In a perfect world,

drumming can make you
look like a rock star.

But just how do you master the skills

to unleash your inner drumming demon?

Here comes the science.

Our drummer creates an elastic collision

when he strikes the drum stick
on the skin.

Most of the drum stick's kinetic energy

is stored and transferred
back to the stick

during the impact.

A loose grip decouples
the stick from his hand,

allowing it to pivot,

producing the rapid strike rate

needed for a rolling drum beat.

When he pivots the drum stick,

he gives it angular momentum.

This means that even when he releases it,

it'll continue rotating,

allowing him to do twirling tricks.

If linear momentum
is applied to the stick,

it can up the ante on the tricks possible.

But with extra momentum,
it's a little harder to control.

Just ask this underdressed drummer,

who needs more control

and more clothes.

I think I can see a pattern emerging.

Let's see how this guy does.

Maybe a pair of safety goggles?

The angular momentum
keeps the stick spinning,

but the fumbled catch adds
linear momentum into the mix.

Resulting in a stick in the eye.

This looks better.

Well, at least he missed his face.

His loose grip allowed the stick
to slip from his hand,

and its angular momentum kept it spinning.

[whistles]

Luckily, he's better at catching

than keeping hold of it.

Now this guy seems to have
got the hang of it.

And...

I spoke too soon.

It's beside you. No there.

On--on--on-- not-- yeah, there.

You got it.

Now, there's nothing like
the skill, talent and pizzazz

of an elite marching band.

And that lot is nothing like
an elite marching band.

This guy only has a small slip,

but due to the turning effect
being amplified

by the weight of the drums,

he's soon flipping like a cheerleader.

[man 2] Ohh.

[Dallas]
Maybe they shouldn't have put the band

back together after all.

[electricity crackling]

This couple are having
a lovely day out in the woods.

But what science are our two hikers
about to demonstrate?

[electricity crackling]

[Dallas] We asked what science
these two ramblers

were about to show us.

Whoa!

Aah!

[Dallas] Yes, it's stability.

Bipedal locomotion is inherently unstable,

and on the narrow, cylindrical log

his ability to reposition
his feet to maintain stability

is reduced and he loses his balance.

And when he applies a large force

to his friend as he falls,

she can't resist
and takes a tumble as well.

[indistinct shouting]

Still, it's all just water
under the bridge now.

[electricity crackling]

I'm a big fan of winter sports,

but for some people the lure
of skiing and snowboarding

just isn't enough.

Instead, they've found
an altogether more...

ridiculous pursuit.

He seems to be enjoying it.

[yells]

Her, not so much.

And that, that is just stupid.

[yells]

And completely unnecessary.

Snowdrift diving can be
incredibly dangerous

and could end with injury or even death.

It's also unlikely to become
an Olympic sport anytime soon,

which is not surprising
when you look a bit closer at the science.

As our man falls,
his velocity will increase.

And the faster he's moving,
the harder his impact

with the ground is likely to be.

To reduce this, he dives
into fresh, deep, soft snow,

which compresses to absorb his momentum

over a longer period.

By spreading his body,
he creates a larger area,

distributing the force.

He'd do best to avoid
older, hard and icy snow,

as it could result
in a shorter impact time

and higher impact force.

I was gonna say that
this is the sort of thing

that should only be
attempted by professionals,

but actually I don't think
anyone should be doing this,

even when the snow does
seem soft and deep enough.

His height seems good,

snow seems fresh,

but he does realize that
snow is cold, right?

[laughter]

Ahhh!

[Dallas] He does now.

With his arms outstretched,

this snowdrift jumper
is able to maximize the area

impacting the fresh, soft snow,

landing a textbook jump.

-Ahhhh!
-[laughter]

[Dallas] Though next time,
I'd recommend something

a little warmer than boxer shorts.

This guy looks like
he knows what he's doing.

I'm not sure that's
exactly what he had in mind.

[man 2] Oh!

[Dallas] Jumping into a snowdrift

requires certain basics to be adhered to.

-[man 2] Ahhh!
-[laughter]

[Dallas] Like actually hitting the drift.

As this guy is about to leap, he trips,

reducing his horizontal
velocity and displacement.

And because his takeoff angle
was close to zero,

he rotates straight down onto the fence.

-[laughter]
-[indistinct chatter]

And even when you hit the snow...

[laughter]

Things don't always go to plan.

The wannabe snowdrift diver
got everything wrong here.

A rapid deceleration into hard snow,

and diving headfirst
instead of distributing

the impact force across his whole body.

[woman] Are you stuck?

I wonder what makes you think that.

[woman laughs]

My sentiments exactly.

[school bell dings]

[crash]

[liquid bubbling]

Settle down, class.

Close your desks, stop talking.

Yes, it's that time again
where we dig deep

into our pile of scientific principles

and pick out an interesting one.

So who can tell me what
the following are demonstrating?

These swirling swingers...

Ahhh!

[whooping]

[Dallas] ...this spinning skydiver...

[skydiver] Whoa!

[Dallas] ...and this silly stair jumper.

[groans]

That's right,
today's lesson is forced couples.

So we'll be exploring what happens
when two opposing and non-aligned forces

are applied to an object.

As they spin our cheerleader,

they apply forces
at her shoulders and legs.

The vertical components of the force
accelerate her upwards,

resulting in a vertical translation.

But the horizontal components
of the two forces

act in opposite directions
and are not aligned.

They act together
to produce a force couple,

which makes her rotate on the spot.

To spin properly,
she needs to remain rigid

to allow the forces to work evenly on her.

And because force couples create rotation,

they can give an object angular momentum,

which can keep it spinning
even after the force

is no longer being applied.

Now for the quiz. Question one.

How do you create a force couple?

Mostly used for up and down,

escalators can also
take you round and round.

[groans]

[Dallas]
The two opposing escalator hand rails

moving in opposite directions

were applying a force
to our French escalator surfer,

creating a force couple.

But he wasn't rigid,

so one force produced a translation,

so he mange la terre,

if you pardon my French.

[groans]

Question two.

What happens if the forces
being applied to an object

are not equal?

[man 2] Do it!

[Dallas] Well, you won't
get a pure rotation,

but could perhaps get a face plant.

Here, his forward velocity

doesn't match the treadmill's
backwards movement,

which means he's unable
to achieve a pure rotation

on the spot.

The resulting translation
made for a slightly more

acrobatic workout than he planned.

[groans]

And our final question.

When a force couple creates rotation,

what else do you get?

[groans]

[Dallas] It's angular momentum.

By twisting the handle bars
in opposite directions,

he creates the force couple.

But when he lets go,

angular momentum keeps
the wheels spinning as it hits the ground.

[groans]

Which is his downfall.

Quite literally.

And that concludes our lesson
on forced couples.

[laughter]

Class dismissed.

[electricity crackling]

My wife always insists
on a tractor to do our gardening,

which is odd, as we live in a flat
and only have one window box.

It just seems more trouble
than it's worth.

But there we are,
where there's a will, there's a way.

And this guy has found a way.

The wrong way.

It's important to wear high-viz...

[man 2] Ahhh!

[Dallas] So we can always see you
make a fool of yourself.

And try not to over-rev your engine,

or that can happen.

Tractors can be tremendously problematic,

especially if you ignore the science,
so pay attention.

Tractor engines produce a lot of torque.

Now with wide tires to maximize traction,

they're perfect for pulling heavy loads.

But they're often large in size
and are very heavy,

which can make it harder
for them to get up hills.

And if they hit something,
their large mass

contributes to a large
momentum and impact force,

often inflicting more damage
than they sustain.

[horse neighs]

So there you go.

On one hand tractors have
the power and size

to revolutionize modern agriculture,

but on the other hand,
they can be very annoying.

Everyone knows the pain of getting stuck

behind a slow-moving tractor on the road.

There really is nothing worse.

Except perhaps maybe that.

It's a struggle to get
the tractor up the hill.

And when something gives
and it starts to roll,

its very large mass means the car
comes off second best when they collide.

Luckily, the lady inside
knows trouble when she sees it

and remembers her handbag.

My favorite way to spend a Sunday
is to watch a bit of sport,

and my favorite sport
is tractor hill climbing.

[upbeat rock music]

Although that doesn't usually happen.

Even with its large wheels
and plenty of torque,

maintaining traction on this steep hill

was always going to be
a struggle for the tractor.

But a sudden increase in traction,

meant that torque
could generate a rotation,

and on the hill, a 15-degree lift

was enough to make a tumble...
unavoidable.

[electricity crackling]

Yesterday I lost my house keys,

and I was forced to resort
to desperate measures.

[laughter]

Keys or no keys,

I was not about to miss
my favorite soap opera.

-[man 1] Yeah!
-[man 2] Ow!

[Dallas] I still haven't seen it,
so no spoilers, please.

I wouldn't have had that issue
if I had the climbing prowess

of the humble house cat.

Could you check the guttering
while you're up there?

-Thanks.
-[cat meows]

Clearly some animals are better
suited to climbing than others,

and while a person might not have
the physical advantages of a pussycat,

they should at least have the edge

when it comes to
understanding the science.

To scale vertical surfaces,

animals will seek out
small ridges or handholds

to help them resist
the constant pull of gravity.

The force of their weight
pressing down on these holds

produces a normal force
that creates friction

to help them stay attached.

Hooked claws with narrow tips

can exploit these tiny ridges
without much muscular exertion

and allow the animal to keep their body

closer to the wall to minimize
the turning effect from gravity.

And if the high pressure
beneath an animal's sharp claws

is able to overcome the material strength

of whatever they're climbing,

they'll be able to pierce it,
creating their own handholds.

Very handy indeed.

Cats are natural-born climbers.

[cat mews]

But it takes some practice.

This silly kitten has got
just about everything wrong.

He's jumped straight at a smooth wall

with no ridges, and it's too hard

for his claws to grab onto.

[mews]

So they don't.

This bearded dragon, Izzy,

would normally be climbing trees
in the wild.

But perhaps she'd be better off
being a ground dweller.

Izzy used her claws on the bars,

but the smooth steel was too hard
for her claws to dig into.

Her persistence pays off,

but she forgot that
when you're on an unstable surface,

you really need to dig your claws in.

This kitten, however, didn't forget.

Hello.

Aah. Aah!

[Dallas]
And I don't think his owner will either.

-Oww! Ow.
-[meows]

Ah.

[electricity crackling]

That's it for another demonstration
of how not to mix science and stupidity.

Please do not attempt to copy
any of the stunts you've seen at home,

and here is a quick reminder of why.

[lively fiddle music]

Ahhh!

[yells]

[laughter]

Ahhh!

[groans]

[man 2] Watch it!

Aah!