04x04 - Skateboarding and Motorbiking

[bunniefuu]

[Dallas] This is the Science of Stupid.

[Campbell reading]

Yes, this is the show where
intelligence and idiocy are merged...

in a cornucopia of carnage...

as our trusty team of testers...

explore key scientific principles...

so you don't have to.

With their expert assistance,
we'll scrutinize the science behind

muscular strength,

sliding force,

and torque.

So pay attention
and prepare to be schooled,

because this is the Science of Stupid.

[electricity crackling]

In this show,

we'll be looking at turning force...

Ahh!

[Dallas] Traction...

and range of motion.

Augh!

[Dallas] But first, this.

[glass shattering]

[electricity crackling]

[glass shattering]

It's often said
that the way to conquer your fears

is to meet them head-on.

So when it comes to riding a bike,

it's all about putting the pedal
to the metal

and launching yourself into the unknown.

[rock music]

But not like that.

[upbeat music]

Ahh!

[Dallas] Not like that either.

Yes, jumping is quite hard.

Augh!

[Dallas] But not as hard as landing.

That's really difficult.

In the daredevil world of cycling,

you're never that far
from stunts going wrong,

which is great news
for this show's producer.

So to execute a successful dirt jump
without breaking any bones,

it's important to understand the science.

After launching from a jump,

he follows a curved parabolic trajectory,

which is a function of his horizontal
and vertical velocity.

A launch angle of 45 degrees

perfectly balances horizontal
and vertical velocity

to achieve maximum horizontal range.

On landing, he flexes his hips and knees
to help absorb the impact.

Now, it's all well and good
being able to jump,

but on a dirt track
that parabolic trajectory is key

to making sure your wheels can clear
multiple bumps along the course.

Let's see how our ever-reliable
researchers get on.

He seems to have got this.

Let's see, up and down,

up and down,

up and...down.

His launch angle is too steep,

meaning too much vertical
and not enough horizontal velocity,

causing a collision with the ramp
that arrests the bike's momentum...

while he continues.

Nothing better than the great outdoors
and some fresh air, but too much air...

Augh!

[Dallas] And you might get a bit winded.

In spite of his run-up, the rider's
parabolic trajectory is too short,

and his bike collides with a ramp,
making his front wheel a pivot...

[man] Oh!

[Dallas] ...and spoiling his afternoon.

The higher the ramp...

Ahh!

[Dallas]
...the further you have to fall.

With too steep a launch angle,

there's too much vertical
and not enough horizontal velocity,

meaning this helmet-less hero's
front wheel...

impacts with the top of the ramp,
and he impacts with the ground.

Ahh!

And one last thing,
if you must jump on a bike,

don't land on your head.

[electricity crackling]

[engine revving]

I love golf.

For me, there's nothing better
than spending a morning

playing a quick nine holes.

Well, I say that, but sometimes
it does take me the afternoon too.

The amount of shots I take, though,
I certainly get my money's worth.

But it's not really the golf
I like if I'm honest.

[softly] It's driving the golf carts.

Here I am with my brother-in-law
on the golf course only last week.

[man] See you guys.

See you later!

[beep]

[Dallas] To be honest,
he was a rubbish caddy anyway.

[man laughing hysterically]

I think this guy might be showing off.

Ahh!

[Dallas] Well, at least
his girlfriend's having fun.

-Ex-girlfriend.
-[woman groaning]

And this is not going to end well.

[man] Tell her to
keep her foot on the brake.

[girl] That's a good idea.

[man] What the... [beep]

Brake, brake, brake, brake!

[Dallas] It ended well for us at least.

Traveling in an open-sided vehicle can be
as dangerous as riding a rhinoceros,

so it's very important
to be aware of the risks,

and Newton's first law
is a really good place to start.

It tells us that objects
will continue moving

at the same velocity in the same direction

unless acted on
by a sufficient external force,

like a rhinoceros.

This open-sided golf cart can't supply
a centripetal force to the passengers

when it turns a corner,

and static friction is unlikely
to be large enough to compensate,

so when he speeds up or down
or changes direction,

his inertia could separate him
from the cart.

The tighter and faster he turns the cart,

the larger the centripetal force required
to take him with it

and the higher the chances
of him coming unstuck.

So don't drive too fast,
don't turn too tightly,

and definitely no sudden braking,

and you should be fine.

[upbeat music]

Has this guy been paying attention?

Argh!

[Dallas] Uh, that'll be a no.

The driver manages to overcome his inertia
and stay on board during the turns.

But as the cart rapidly decelerates
on impact with the cage,

it all proves too much,

and static friction from the seat
isn't up to the job.

[man] Hold on, I hear the G1.

I hear the Yamaha G1.

[Dallas] Now, remember,
these are leisure vehicles,

and they're not designed...

Ohh!

[Dallas] ...for muddy terrain.

As the wheels dig in, its high speed
is brought to an abrupt halt,

and the driver's inertia launches him...

...off the fairway and into the rough.

[man laughing]

[rock music]

These beanie-wearing blokes
are burning rubber.

Now, remember, lads, keep it gentle,
nice and stable, no sharp turns.

I said no sharp...

-Ow.
-[Dallas] Oh, forget it.

Yes, we all saw what you did.

When he over-steers the cart,
it's thrown into a skid,

culminating in a rapid turn
and deceleration.

Meanwhile, the passenger and driver
are victims of their own inertia,

with the driver coming off worst.

[electricity crackling]

Can you guess which scientific principle
this balancing buffoon is demonstrating?

[glass shattering]

[electricity crackling]

[glass shattering]

We asked you what science this
ladder-climbing lemon was showing us.

Did you say dynamic stability?

Well done.

Ugh!

[Dallas] Sort of.

As the balance board
tries to move and tilt,

he makes continuous fine adjustments
to get back to his equilibrium point

to stay balanced.

He's in a state of dynamic stability.

However, the higher
the combined center of gravity,

the harder it is
to stay close to that equilibrium point...

Ugh!

[Dallas] And that's not so dynamic,
just painful.

[electricity crackling]

Inline skates, caster boards, hoverboards,

all modern-wheeled transport
for the supposedly cool kids.

But for me, the original
is still the best.

Yes, I like to kick it old-school.

It's just how I roll-er skate.

[upbeat music]

It's just so groovy.

And you can do it anywhere.

Well, he can't, obviously.

Yeah, unfortunately,
not all roller skaters

are blessed with
my superior ankle mobility.

But what is that, and why is it important?

Let's have a look at some science.

[rock music]

When roller skating, her center of gravity
must remain above her base of support,

so to stop the wheels
rolling out from under her,

she crouches down and keeps her weight
above her supporting leg.

The two-by-two wheel configuration

makes it harder to tilt the roller skate
when pushing off or turning.

As a result, her ankle will supinate
or turn outwards dramatically,

increasing the risk of injury
and compromising her base of support.

So remember to move
your center of gravity as you go,

and you can try
crossing over your feet when turning

to avoid excessive supination.

But most importantly,
make sure you look the part.

[funky music]

Yes, that's the look I'm talking about.

The fastest recorded time to roller skate
one kilometer backwards

is just over two minutes.

And this guy wasn't involved in any way.

He's expertly
keeping his skates underneath

his boogieing center of gravity,

but when his right skate
jams against his left skate,

his center of gravity continues backwards

wrecking that street cool vibe.

[upbeat music]

Is anywhere safe
from the scourge of the selfie stick?

Ahh!

I got that! I got that!

[Dallas] It doesn't bring out
the best in people.

This disco diva
is using the crossover method

to avoid excess ankle supination.

But her center of gravity moves
too far backwards relative to her skates

and they roll out from under her.

Ah, the Kansas City roller derby.

But I can't see
roller derby star Patti Wackin.

Oh, there she is.

Patti uses her practiced ramming technique

to manually remove her
competitor's center of gravity

from above her base of support.

Tough but fair.

[bell rings]

All right, class, it is time
for today's science lesson.

Jones, stop picking your nose.

OK, now, who can tell me
what key scientific principle

the following are all demonstrating?

[upbeat music]

This bodybuilding bozo...

[man] One. Two.

[Dallas] This bizarre biscuit breaker
or cookie cr*cker...

and this backyard beater.

Ahh!

If you said range of motion, well done.

You've earned yourself a gold star
and an extra scoop of ice cream at lunch.

But what does it mean
in a scientific context?

[electronic music]

For a jab, our friend here extends
his elbow and flexes his shoulder,

rotating it through a full 90 degrees.

For a high kick, he simultaneously
flexes and abducts his hip before

explosively extending his knee
just before impact.

By moving both joints in
complementary directions at the same time,

he combines their individual speeds
for a faster jab or kick.

All clear? I hope so.

Because nobody wants to end up
looking stupid.

Right, question one.

What range of motion is required
to successfully hula a hoop?

Let's see if she's got it.

She flexes and extends her hips
to produce a series of pelvic tilts,

demonstrating excellent hula skills.

[glass shattering]

But very poor spatial awareness.

Due to her proficiency,
the hoop is spinning very fast

so flies off at high speed,
and this diva loses her spotlight.

Question two.

How can we use the range of motion
in multiple joints to our advantage?

Throwing something
combines movement in many joints

forming a kinetic chain,
which gives the throw more power.

Ugh!

[Dallas] Things don't always go to plan.

Now your third
and final question for today.

Why does the hip joint
have such a large range of motion?

Hips are ball and socket joints,
making them perfect for kicking.

This guy's practicing on some pads
that his foolhardy friends are holding.

-Augh!
-[laughs]

[Dallas] That's gonna hurt.

[laughing] Did you record that?

[Dallas] Luckily we did, yes.

By extending the knee
as the hip moves forwards,

he makes his foot travel very fast,

and considerable momentum
is transferred to the pad

causing a painful surprise.

-Augh!
-[laughs]

[Dallas] So there we have it,
there ends our lesson on range of motion.

Ahh!

Augh!

[Dallas] Class dismissed.

[glass shattering]

[electricity crackling]

[glass shattering]

When I was a boy, not so long ago,

I dreamt of having a boat
and sailing the open seas.

But on my last vacation,
I spent 20 minutes on a pedalo,

and it completely changed my mind.

Some things are just best left
to the experts.

After all, there's nothing better
than a ride on the open water.

But that's not open.

These people seem to know
what they're doing.

Ahh!

[Dallas] Apart from that guy.

What's important
is to always keep a lookout.

[man] Ohh! [bleep]

This boat business
is clearly not that easy,

and even the basics can catch you out,

like steering,
where the most simple mechanism

means that when
I turn the steery thing left

the boat goes right.

"But it's not that complicated,"
I hear you say,

but that's just where the science begins.

[upbeat percussive music]

Most small boats are steered
using a tiller

with power provided by the sails.

When the sails are full of wind,
they can be pushed sideways.

This creates a turning effect
that tilts the deck, risking a capsize.

By placing his weight on the other side,

he can counterbalance the turning effect
by gravity acting on his mass.

Care should also be taken
to avoid the boom

as it swings 'round to take advantage
of the wind's direction.

Now that we're down with sailing science,

let's put some of that theory
into practice in the real world.

[light guitar music]

Catamarans are great fun to sail
with their twin hull design,

but it can reduce hydrodynamic drag.

Augh!

[Dallas] But it won't eliminate
the chance of getting wet.

Standing up on the narrow hull
as they turn,

he's become a victim
of his own turning effect...

Augh!

[Dallas] And his higher drag
mean he's quickly left behind.

[upbeat guitar music]

Another catamaran,
and this one is going really fast.

Well, he made a splash.

This unexpected plunge is caused

because too much wind
hits his sail as he turns,

and he can't counterbalance the force
using his weight,

which means the boat tilts even more,

and because he's not attached,
he gets a surprise swim.

[rock music]

When steering a powerboat like this,

there are lots of factors
to take into account.

Ignore science,
and you'll end up looking stupid.

-Augh!
-[Dallas] Exactly like him.

[upbeat horn music]

The passenger acts as ballast
and moves around

to stop the boat tilting or lifting.

But when they hit the wake
of the other boat,

it causes them to tilt

and to toss the passenger out
into the sea.

[electricity crackling]

In my previous career as a top stuntman,
I had this motto,

it's not the falling that hurts you.
It's the ground.

And I proved that right
time and time and time again.

You only need to do it badly once
to learn that landing is pretty important.

[man] Three, two, one!

Oh!

[Dallas] He knows what I mean.

[upbeat guitar music]

Hee-ya!

[Dallas] And this guy.

Maybe animals would be better at this.

Yeah, told you.

[yelps]

Ow, spoke too soon.

Yes, landing is vital,

and some animals are better-suited
for doing it than others.

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

they should at least have the edge when
it comes to understanding the science.

When an animal falls from a height,

gravity accelerates them
towards the ground

by 22 miles per hour every second.

Animals can avoid damage to their bodies
on landing by having certain adaptations

that reduce the impact force
or lessen its effects,

like gradually flexing their limbs
on landing,

which increases the impact time
for a lower impact force.

Small animals can survive longer drops

thanks to higher strength
relative to their weight,

as well as more drag,
so they build less momentum.

And some animals have another advantage

as landing on all four feet
reduces the impact on each leg.

So it all seems to work in theory,
but how does it stack up in practice?

[upbeat music]

[horse sneezes]

Bless you.

This baby horse
surprises himself with a sneeze

and falls over unexpectedly.

Well, we've all been there.

As a result, its limbs are
poorly positioned for landing.

But fortunately,
with such a short distance,

no damage was done.

[light upbeat music]

What about Harry the hamster?

Interesting dismount.

He didn't run fast enough
to keep up with the wheel.

But, thankfully, Harry didn't fall far,
and he's very small,

so he can't build up much momentum,
and no damage is done.

He even managed a little bounce there.

Classy.

Will hounds do any better?

I guess not.

As the dog fails to catch the Frisbee,
he slightly overshoots with his rotation,

and with his feet out of position,

he lands on his face.

Ah, now, cats are famous
for always landing on their feet.

[meows]

Or is it face?

[meows]

[glass shattering]

[electricity crackling]

[glass shattering]

"Bad times have a scientific value.

These are occasions
a good learner would not miss."

Not my words,
the words of Ralph Waldo Emerson.

And who'd have thought that
these guys were so well read?

[lively fiddle music]

[man] Oh!

Ahh!

Ahh! Augh!

Ahh!

Ugh!

Ahh!

Ahh!

Ugh!

-[man groaning]
-[man 2 laughing]