04x07 - Slides, Horses and Twerking

[bunniefuu]

[Dallas]
This is the Science of Stupid.

[reading onscreen text]

[military drumming]

Yes, this is the show where knowledge

and foolhardiness combine.

-Aah!
-As our trusty team

-of testers...
-Aah!

...learn their science the hard way,

so you don't have to.

With their help, we'll demonstrate

scientific principles such as friction...

[woman laughing]

centrifugal force...

and center of gravity.

There can only be one winner

in the battle between
science and stupidity.

-So don't be a loser.
-Aah!

Pay attention.

It's the Science of Stupid.

[electricity crackling]

In this show, we'll be looking at

horizontal velocity...

rotational work...

[woman laughing]

...and elastic potential energy.

-[all] Whoa!
-[Dallas] But first, this.

[electricity crackling]

Being a grown-up
is not all it's cracked up to be.

There are the aches and the pains,
and then your hearing starts to go.

And don't get me started
on the regular toilet breaks.

But I'm joining
the ever-growing band of adults

rallying against the ravages of time.

And how do I turn back the clock?

I ride a child's scooter.

[energetic music]

[Dallas] It's fun...

Oh, [bleep]!

[boy] Mum, you're good to go!

A bit edgy...

[woman grunting]

...and it gives me the street cred

I so desperately crave.

[child laughing]

All right, calm down.

A child's scooter is perfectly
proportioned-- for a child,

but it can become dangerously
unstable when ridden by adults.

To master this skill--
dare I say art form?--

it is worth availing yourself
of several key facts.

The combination of a short wheel base

and a high center of mass
are problematic.

It only takes a small
angle of lean from vertical

to move the center of mass
outside the base of support.

Dangers are amplified by handlebars

which act as a lever arm

when a pull or push force is applied,

creating a turning effect.

Additionally, the wheels
are small and hard,

meaning a larger angle of attack

for small bumps
which can cause them to stop dead

while the rider's momentum continues.

If all this science has yet
to convince the dope dads,

mean mums, and grisly grandparents

of the perils of riding
these contraptions,

then perhaps this will help.

[man] On your mark, get set,
go, go, go, go!

[Dallas] Ah, a competitive mum
getting ready

to show her kid who's boss.

-Aah!
-[Dallas] Ouch.

This leaning lady's poor positioning

and high center of mass
make the handlebar tilt,

creating a turning effect

that leads
to a less than graceful dismount.

Aah!

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

-Aah!
-Or maybe not.

Here the rider has accounted
for his higher center of mass

with a good crouch.

Unfortunately, the water
is hiding a pothole...

which has too large an angle of attack

for the small wheel of the scooter.

Nice belly flop.

This dad is breaking all the rules.

Come on! No scooters in the house.

Check out my scooter!

[Dallas] Even worse,
he's ignored the science.

The short wheel base
and his high center of mass

combine to make him unstable...

leading him to pull back
on those handlebars,

creating a turning effect...

-[clattering]
-Oof!

And a very sore bottom.

Now, if we throw a bit more
momentum into the mix,

does that help?

-Ohh--
-[all gasp]

No.

The rapid deceleration of the scooter

as it catches the ramp

combines with her momentum
to rotate her forwards.

-Ahh!
-[all gasp]

At least now she's got a firm grip
on the law of gravity.

Most importantly,

when riding
any child's scooter, remember...

-[gasps]
-you're not a child.

[electricity crackling]

[rumbling]

Most people think tires are just something

to put on your car or your bike,

but here at the Science of Stupid

we like to think outside of the box.

We've rounded up some
of the finest scientific minds

to explore other uses for them.

Swings...

[woman laughing]

human hooplas...

Aah!

...and now this has become
rather popular.

Uhh!

Maybe not quite that!

Yes, a tire's natural bounciness

makes it an ideal impromptu springboard,

and with the right application,
it should be no more dangerous

than a blindfolded battle with a bear.

The key is in the science.

First, he needs lots
of horizontal velocity.

A fast run-up should help with this.

He plants his feet to deform the tire,

storing elastic potential energy...

[dynamic music]

...which then boost
s his vertical velocity.

After take-off, he tucks tight
to increase his spin.

He must remember to untuck
to slow his spin

for a smooth landing.

Sounds perfectly simple,

so let's start with more of a challenge--

the upturned tire.

Same science rules apply,

but in order to maximize
that vertical velocity,

it's all about planting your foot
on the apex of the tire.

Got it?

This guy means business.

-[grunts]
-Funny business.

He's got everything wrong,

starting with a slow approach

then poor foot placement,

and he tops it off with a loose tuck,

meaning he under rotates.

Pay attention to the basics, please.

Pneumatic tires were invented in 1845

by Robert William Thompson.

[all] Oh!

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

There's no problem with the run-up,

but he's missed the apex of the tire,

and then he forgets to untuck,

causing over-rotation.

[all] Oh!

Nice hair, though.

Now, we've got the basics covered,

so let's up the jeopardy
with multiple rotations.

It's time to tuck.

An athlete. He should be good.

-[screams]
-Yes.

Good horizontal velocity
and a nice launch,

but his tuck is not tight enough

to achieve two full rotations.

[screams]

At least the sand broke his fall.

Remember, tuck...

-[screams]
-Untuck.

Flipping off a tire is difficult,

it's dangerous, and,
if you ignore the science...

[screams]

...incredibly stupid.

But not as stupid as this.

Ooh!

[blows]

[electricity crackling]

[metal creaking]

[Dallas] Which scientific theory

is this fish delivery driver
about to demonstrate?

[lively fiddle music]

[glass tinkling]

[electricity crackling]

[Dallas] We asked you
what scientific principle

this fish forklifter
was going to encounter.

A gold star if you said
turning force and gravity.

As the crate collides with the truck,

there's a reaction force

which combines with the push
from the forklift

to create a turning force on the crate.

Once the crate's center
of mass passes its zenith,

gravity takes over.

At least he'll have
his own table at lunch.

I was never the biggest boy
in the playground

or the strongest or the most handsome.

Although, I should mention

I did go to a school for gifted children

and super models.

But if I ever feel a bit
insecure nowadays,

I just go out for a drive in one of these.

This is me driving
Dream Catcher last weekend.

[energetic music]

That was cool. There's nothing better

than taking Dream Catcher
out on a Sunday afternoon,

jumping over a few cars,

and then pulling
some donuts in front of a crowd.

[engine revving]

Oh, yeah, I forgot that happened.

[crowd screaming]

My advice in these situations
is to keep calm,

run for it, and hope nobody was looking.

Monster trucks are monstrous
because of their high clearance,

huge wheels, and grippy tires,

which makes them good
at clearing large obstacles.

But their greatest strength
can also be their greatest weakness.

[rock music]

On reaching a tall obstacle,

the truck has to climb at a steep angle.

This can force its center of gravity

outside of its base of support,

causing it to tip over.

With sufficient momentum,

a monster truck
can jump over the obstacle.

But build too much momentum,

and the large tires
and soft suspension...

could compress too much on impact...

bouncing the truck up and over.

So those are the basics.

They seem fairly straightforward,

but have our experts got
their heads around the science?

[man] Come on!

[man] Yeah-ha!

[Dallas] I'm guessing
that's gonna be a "no" from this guy.

[man] Fail!

[Dallas] Due to the height
of the obstacle,

he doesn't have enough
momentum to mount the car

with front and back wheels,
so gravity takes over.

[light music]

[crowd yelling]

[banjo music]

This chap has chosen to up
his horizontal velocity...

Which didn't help.

You see, he's failed to take
the terrain into account

and launched himself into a near-fatal
somersault of doom.

Luckily, he walked away from this crash

with only a dented ego.

[bell rings]

[objects clattering]

[liquid bubbling]

It's time for today's science lesson,

and there will be a test
at the end of this,

so pay attention, please.

Right, who can tell me
what scientific concept

the following are all demonstrating?

This sleepy table leaner...

[man laughing]

This bedroom acrobat...

-[man laughing]
-Oh, [bleep]!

[men] Oh!

And this overenthusiastic
pole dancer.

Nice moves.

He really brought
the house down that night.

Did you guess work and power?

Well, if, like me,
you're a big fan of aerobics,

then they're words you hear
shouted at you every day.

But what do they mean
in a scientific context?

In its simplest form,

work's done when a force moves an object.

Lifting this heavy barbell takes effort,

and work is done.

Holding it still requires
quite a lot of effort,

but no work is done as it isn't moving.

As it's lowered, he's doing negative work

as the object's moving
in the opposite direction

to the force he's applying.

And when he drops it,
gravity does work over less time,

generating more power.

So work is done
when a force moves an object,

and power is how quickly
that work is done.

Got it? Let's see. Question one.

Does a large amount of force
always result in a lot of work?

Diggers are capable of delivering a force

of nearly 400,000 newtons
which is equivalent to

the weight of more
than six African elephants.

But far more convenient...

[light music]

...whilst the digger
was exerting force on the silo,

it was only doing work
once the silo started moving.

That was a stupid place to park anyway.

[car alarm blaring]

Let's see if these girls
have got the hang of it.

[girl laughing]

Yep. It might take a second

for the force to get her
to start to move,

but that is rotational work... done.

Question two. Does work only occur

when the object is moved
in the same direction

as the force is pushing?

A-ma-zing. That is a new world record.

That's the longest
anyone who does CrossFit

has gone without mentioning it.

[man grunts]

This guy is doing negative work,

slowing the rate
of gravitational acceleration.

While the women,
despite the strength it takes

to hold themselves up,
aren't doing any work at all.

[man grunts]

And now we come to our third
and final question.

What do we call the rates
at which work is done?

[overlapping chatter]

-[snap]
-[screams]

-[Dallas] That's right. It's power.
-Oh [bleep]!

The work involved
in stretching and contracting

this giant elastic band is the same,

but as it contracts more quickly...

[screams]

...we would say that it had more power,

as he'll testify.

[electricity crackling]

Ah, there's nothing
that I love more than a birthday.

Admittedly, it's often
just me alone in a room

with only a cake to keep me company.

But you can't eat the cake

until you've blown out those candles,

and the options
on how you do that are limitless.

[energetic music]

Radical...

biological...

[farting]

and traditional.

[glass shatters]

Just don't invite your cousin Kevin.

OK. A question.

Why do we put candles
on top of a birthday cake?

Because it's too hard to put
them on the bottom.

Let's get on with the science.

[dynamic music]

To light a candle,
you need three things--

heat provided by this match,

oxygen from the surrounding air,
and fuel.

Here it's the wax vapor
coming off the wick.

Together, these are known
as the fire triangle.

To extinguish the candle,

cold air must pass over the flame quickly

in order to remove the heat component.

We can achieve this

by following the continuity principle

and pursing our lips.

This decreases the size of the opening
that air is forced out of,

thus increasing the velocity
of the air stream.

You should also try
not to be too far away.

[blows hard]

More distance means more turbulence

affecting the velocity
and accuracy of the air stream.

Being closer to the candle
limits the effects of turbulent flow

and allows me to get on
with eating this cake.

♪ Happy birthday to you ♪

[Dallas] Ah, so cute--

one of our youngest researchers

blowing out a birthday candle.

Pffft!

[dad] Try again.

Blow up, blow up here.

-Pfft!
-[Dallas] Cute, he may be,

a scientist he is not.

Blow it up here.

-Pfft!
-Whoa, dude.

Of course, smaller lung capacity
can be a problem for infants.

What did you--

[Dallas] Ah. He should
have more experience.

But a lot less dignity.

[laughter]

The falling dentures
manage to divert the air stream

in multiple directions,

extinguishing all but one candle.

He couldn't wait to sink
his teeth into that cake.

[laughter]

How's our little researcher
getting on with that candle?

Here. Ready?

Blow.

-There ya go! Yay!
-Whoa!

[Dallas] Blowing through the straw,
he's managed to channel the air stream,

defeating the effects of turbulence.

-There ya go! Yay!
-Whoa!

♪ Dear Megan, happy birthday... ♪

[Dallas] A Mexican-themed
birthday party.

Sombreros... check.

Ponchos... check.

-And... a human piñata.
-[woman] Megan?

Nice blowing.

Megan really knows her fire triangle.

[woman] Megan?

-What she doesn't know...
-[woman] Megan, stop!

...is that her friends are idiots.

Megan, come on.

Don't worry. Megan was fine.

But she doesn't want a cake next year.

Funny, that.

[electricity crackling]

Since the dawn of time,

a battle of the Titans has raged on.

For millennia,
mankind has been locked in conflict

with the sneakiest of foes--

trees.

-What? Oh.
-[man] Commit.

I just--

Ohh!

[Dallas]
See what I mean? Sneaky.

[upbeat music]

He didn't even see that one coming.

[cracking]

Well, that one is your fault.

[man laughs]

If only we could be

a bit more like
some of our furry friends,

like the sure-footed goat.

[bleating]

Not that one, though.

Grip is absolutely essential
when climbing trees

due to their curved branches and trunks

which require plenty
of frictional resistance to stay on.

Annoyingly, many creatures
have the edge over us,

but don't blame me,
blame science.

Opposable thumbs and toes
can allow hands and feet

to clamp around branches and trunks,

providing a large normal force

which increases frictional resistance.

Additionally, some monkeys
have a prehensile tail

that can act as a fifth hand.

Another adaptation
is seen in many arboreal animals

with sharp, rigid claws
at the ends of their hands and feet

creating extra grip.

Another piece of science
to consider when climbing a tree

is whether it has the material
strength to support you.

If it doesn't, our old friend gravity

will have the upper hand.

Kurt the koala demonstrates
his outstanding grip...

-[people gasp]
-and his poor grasp of physics.

Kurt's opposable thumbs and sharp claws

generate a strong grip,

giving him a solid base
from which to launch into a jump.

Unfortunately, the branch
lacked the material strength

to support him.

-[cracks]
-[crowd gasps]

Maybe Kurt should go easy
on the eucalyptus in future.

This squirrel is an expert tree climber.

But this isn't a tree.

[man]
There he goes! There he goes!

[Dallas] And his claws
won't dig into the smooth metal pole.

[man] I'm going! No! I can't...

Ah!

[Dallas] Of course,
if you can't find a tree,

use a ladder.

But not like that.

[electricity crackling]

And that's all for now.

I hope you've been paying
close attention to the science,

because you've seen
what can happen if you don't.

[lively fiddle music]

[girl laughing]

-[snap]
-[screams]

[screams]

Ohhh!

-[man 2] Oh!
-[man 3] Aah!

[laughter]

Uh-aah! Aah!

Unhh!

[squeaks]

Oof!