05x16 - Roof Snow, Skateboards and Vehicles

[bunniefuu]

[Dallas off-screen] This
is the Science of Stupid.

Yes, this is the show where buffoons
and brain power are fused

in a festival of foolishness.

You'll see our rash researchers push
science and themselves

to the limits and beyond.

Often with
excruciating consequences.

We'll reveal what
went wrong and why.

With the help of some key
scientific principles such as

distribution of force,

rotation and traction.

So buckle up and hold
on tight, because this

is the
Science of Stupid.

In this show
we'll be looking at.

Ricochet.

Resilience and
relative motion.

But first this.

I went to the Torino Winter Olympics
to watch the curling.

I am a massive fan of any
type of competitive brushing.

But while I was there I caught some of
the men's giant slalom, wow.

And now there is nothing I love more
than watching competitive skiing.

But get a poor start and everything can
go downhill very fast.

Like this.

[man] Damn!

[Dallas off-screen]
Or indeed this.

[woman] Owwww!

[Dallas off-screen] Skiing is really
only fun to watch

when people are bad at
it so if you

want to spare yourself the blushes of a
blooper reel, pay attention to this.

Skis are very long levers
attached to the feet,

this reduces the racers ability
to withstand perturbations

as any force applied to the tip
of the ski will produce a large

torque that the ankles
will struggle to canter.

Racing makes staying
in control harder.

Competition affects the level of mental
arousal

and if this is excessive it can
lead to

increased muscular tension,
poor decision making,

loss of concentration
and disrupted co-ordination.

Perturbations,
levers and torque.

I thought it was all about bending your
knees and pointing in the direction you

wanted to head but after that run down
on racing,

our researchers are raring to go,

so let the games commence.

This racer is pushing himself to the
limit in pursuit of a competitive edge.

[man] That's not cool.

[Dallas off-screen] No it's not cool and
it's also quite painful.

It seems his level of arousal
is too high

causing him to push himself
to the point

where he loses coordination
and control

and because of the
low friction between skis and

snow, stopping quickly is.

A little tricky.

Don't worry he
was fine, eventually.

This downhill dare devil seems to have
nailed it and those are some nice turns.

I think we could be looking
at a potential champion.

[man] That's neat.

[Dallas off-screen]
Neat he may be.

But that's not tidy.

As he speeds down the course,

he fails to produce enough downward
force on his right

side so his legs separate.

And when his ski gets snagged

it experiences a strong torque that
makes it rotate,

meaning this turn.

Was slightly more memorable
than he'd have hoped.

Ski cross competitions can create
colossal collisions causing.

Carnage.

The competitors race harder when up
against one another

as a opposed to a clock.

When the guy in blue leans too far
right,

he loses most of his friction and
gravity

pulls him down.

As he falls he takes out
the legs of the red guy.

And they go from
skiing to dominoes.

Despite all the risks involved
in a downhill ski race,

when the weather is fair and your

form is good, there
really is nothing better.

Sadly her form wasn't good.

[man] Stop start.

Yellow flag!

[Dallas] Jumping into vehicles should be
reserved for action heroes in

Hollywood blockbusters.

Because when mere mortals try to do it,

well, firstly it's really dangerous
without a

team of trained professionals behind
you, and secondly the results

tend not to
be that impressive.

Although they can
be quite funny.

And a moving vehicle will tend to make
things more embarrassing.

[man] Run Forrest, run!

[Dallas] Jumping onto a moving vehicle
is incredibly dangerous,

but if you want to know how the stunt
people in Tinseltown do it,

here's the science.

Our man needs to match the position and
velocity of the vehicle as he comes into

contact with it.

As soon as he makes contact

he needs to be at the velocity of the
vehicle or his body needs

to accommodate the relative
difference in velocity.

Stepping one foot onto the moving
platform

while the other is on a static
surface

results in limb separation and a lack of
momentum to complete the move.

If movement and direction are
perpendicular to the vehicles

his velocity in the vehicle's

direction is zero so
success is near impossible.

Now clearly jumping onto a moving
vehicle is never a good idea.

Let's see just how bad
an idea it really is.

[woman] Destiny, hurry get on!

[Dallas off-screen] Yes hurry indeed,
it's time for Destiny to seize the day.

Yeah less Destiny,
more body at restiny.

To increase her chances of success,

she should leap onto the moving platform
but she

chooses to step onto it.

So her ground foot gets left behind as
it's on a static surface.

And that.

Is never a good idea.

Now that it is a
beautiful Mustang.

I'd hate to see anything
bad happen to it.

[man off-screen]
Oh no, no, no, no, no.

[Dallas off-screen] And I think that guy
is in agreement with me.

Thankfully he challenged his inner
action hero and save the day.

Phew!

[man] Oh no, no, no, no, no.

[Dallas off-screen] He matches his speed
to the vehicle and uses the car as a

support making it
easier to jump into.

And his Mustang emerged unscathed so
he didn't even need to pony up

for a new paint job.

If you can't resist the lure of
Hollywood,

one option is to become a
stunt man.

An option I think
he should avoid.

The foolish fall guy's direction of
movement

is perpendicular to the vehicle's

and there is no way for
him to match its velocity.

So when his feet land on the roof,

they stick to it due to friction and the
movement of

the car generates
a torque, which leads him

to rethink his
career path, on the path.

Can you guess what key scientific
principle this man

and this giant doughnut are

about to demonstrate?

[Dallas off-screen] We asked you what
key scientific principle

this tube-throwing
teacher was about to show us.

Did you guess kinetic energy?

The man manages to get
the tube to move very fast.

When the tube hit, it transfers some of
its considerable kinetic energy,

it also deforms which compresses the air
inside, storing energy and then

releasing it on the rebound.

As an extra kick
of kinetic energy.

Best gym class ever.

I'll be honest, I have pretty limited
success when it comes to playing golf.

The last time I was on the course I only
managed to strike two ba*ls and that's

because I stood on the rake.

For some people it all
comes a bit too easily.

And for others it doesn't.

And that's why golf
is best played outside.

Deliberately hitting a golf ball off a
wall

is dangerous and foolish and that's

because when a golf ball rebounds off
another surface

there's a lot of science going on and if
you can understand it

you can impress your friends with
a cheeky ricochet shot.

Striking the ball
gives it kinetic energy.

When the ball impacts another surface,
it deforms reversibly.

When it ricochets off a flat
surface its angle of approach

will equal the
angle of rebound.

And the collision
is largely elastic,

meaning it retains much of its
kinetic energy and momentum.

Hang on just
taking some notes.

You see, I love golf

but I've always found it to be an
endless series of tragedies,

obscured by the
occasional miracle.

And that was both
tragic and miraculous.

[man] Oh my
******* God, kid!

[Dallas off-screen] The ball rebounds at
an angle

that puts it on a collision
course with his leg,

and it retains most of its kinetic
energy

during the largely elastic
collision

with the pole causing
him to get grass stains

on those lovely
white trousers.

[woman] Duck and cover!

[Dallas off-screen] If you're gonna try
a trick shot you need to strike the ball

cleanly and know your angles.

[woman] Oh!

[Dallas off-screen]
Wait, was that the trick?

She tries to undercut the ball so that
it clears the rocks

but she doesn't manage to do it

and the angle of rebound
equals the angle of approach

and the elastic collision
means that the ball

still has most
of its kinetic energy.

[woman] Oh!

[Dallas off-screen]
On impact.

Something worth considering,

especially if you like hitting ba*ls
with a lot of power.

[woman] Oh my God!

[Dallas off-screen] Okay settle down
everyone because it is time for today's

science lesson, that part of the show
where we dissect a particular principle.

So, who can tell me what
the following are showing?

This idiotic ice breaker?

[man] Yo.

[Dallas off-screen]
This wall breaking Wally?

And these bungee
corded bouncers?

Is that your shoe?

Yes it is.

If you said material resilience
and toughness, well done.

Now don't let your minds wonder as there
will be a test afterwards.

Okay let's delve
a little deeper.

This tire is made from rubber,

a resilient material that can absorb a
lot of

energy elastically, allowing
it to deform and bounce back.

This metal paint can is non resilient,
so can't observe much energy

before it deforms permanently.

But it's tough so absorbs the
energy without fracturing.

This ceramic teapot is fragile, so can't
absorb much energy.

Before it fractures.

So there you have it, but how resilient
and tough are you

when your knowledge is thrust
into the spotlight?

Let's find out.

Question one, can you give me an example
of a fragile material?

This climber might
give you a hint.

Yes that's right, ice can
be a fragile material.

The climber is using his pick to work
his way up the giant icicle.

But the ice is fragile and so can't
absorb much energy without fracturing.

[man] Holy moly!

[Dallas off-screen] This researcher is
keen to validate our findings.

[man] Final words.

This is gonna be ******* cold!

[Dallas off-screen] Don't worry this is
a controlled experiment.

He had me
worried for a second.

[man] ******* scary as hell!

[Dallas off-screen] I think it goes
without saying

that that is a really stupid idea.

Question two.

When might you need a
material to be resilient?

A bungee cord is very
stretchy and resilient.

But that connection
point, is not.

As she starts her decent,

we can see the resilience of the bungee
cord as it stretches,

all the time absorbing
energy elastically.

However the connection point is not as
tough as the cord

and fails completely when

too much energy
is transferred to it.

Thankfully despite plunging into a
crocodile infested river,

she was
miraculously uninjured.

Time for our third
and final question.

How do you find out
how tough a material is?

The answer of course is
to give it more energy.

But ideally not like that.

He needed the backboard to absorb the
energy from his descent and support him.

But it lacked the toughness
to do that and fractured.

That's the end of our lesson on material
resilience and toughness.

Class dismissed.

[Dallas] When I was younger
I broke a girl's heart.

She told me she wanted to walk down the
aisle so I took her grocery shopping.

It was never gonna work out but
fortunately

she did take a shine to a
shelf stacker and

lived happily ever after.

If you are going to walk down the aisle,
make sure you haven't overstocked the

flower girl's petal basket.

Or she could end up as the
highlight of the wedding.

That is unless you
forgot to wear a belt.

Yes nice legs, no wonder he's keen to
show them off before the reception.

Walking down the aisle is a big part of
any wedding day

so if you want to avoid
a marital

meltdown on day one,
perhaps this will help.

Our man's dress shoes generate a low
co-efficient to friction

so he's more likely to slip

during two key points
in his gate cycle.

The heel impact phase relies on a
backwards, frictional force to stop

his foot sliding forwards.

While the propulsion phase
relies on a forwards,

frictional force to stop
his foot sliding backwards.

When he slips his center of mass is
unsupported by his feet,

and gravity generates a turning force
that rotates him to the ground.

Now that we're armed with a
little science

let's check how
our researchers are getting on

with their investigations.

A what a cute little chap,
has he been paying attention?

No.

The little boy is less coordinated than
grownups

and runs too fast for his
little legs, meaning his center of mass

is not supported by his feet and he
experiences

a turning force
and a face plant.

This couple should have
a bit more experience.

Ah.

The smooth soles on the ladies
fancy footwear

have a small
co-efficient of friction with

the ground and during the heel
impact phase of her walk,

when her applied horizontal force

is largest, she
overcomes the maximum.

Frictional force.

One last nugget of wisdom I
can offer is that piggy backs.

Are a nuptial no, no.

When he mounts her back,

their combined center of mass is
unsupported by her feet.

Gravity generates a turning force

that rotates them embarrassingly to the
ground.

And into the annals
of wedding history.

I'm not sure, but I think the reason we
carve pumpkins on Halloween

is to prove our dominance over nature.
And I assume we display them

on our porches as a warning to other
vegetables.

Which is probably wise as fruit and veg
can be scary, just ask this dog.

If you can catch him.

Bobcats on the other hand are
highly territorial

and will assert their dominance if they

think their territory
is being invaded.

[man] He got it!

[Dallas off-screen] Whether
a species is solitary

or forms hierarchical groups,

there are various factors that determine
if an animal is subordinate or dominant.

An animal's place will be determined by
sex, age and seniority,

but size is probably the most common
contributing factor

to dominance dynamics.

Animals establish dominance over one
another in a number of ways.

Individuals may dominate or
control access to various resources

including potential and actual mates,
food, territory and sleeping areas.

They may also attempt to control the
movements of others

or demand their attention.

When animals live in stable groups, the
superior competitor should consistently

win each contest and the inferior
competitor should retreat.

This is called a
dominance relationship.

But it sounds remarkably
similar to married life.

As we have learned,

size is the most common contributing
factor to dominance dynamics.

However despite being much bigger,
stronger and more dangerous,

this German Shepherd doesn't
have enough confidence

and the plucky duck dominates him.

Dominance relationships essentially
exist due to competition over resources.

[woman] I told you
that wasn't yours.

[Dallas off-screen] The iguana has
stacked his claim for the soft toy

and while the cat's intervention is
not legitimate competition,

the male iguana
competes aggressively.

The most important thing
to know when you're in

a well-established
dominance relationship.

Is know your place.

That's all for now, but I will
leave you with this thought.

Success is a science, if you have the
conditions you get the results.

But I'm not sure these guys
wanted the result they got.

[music plays through credits]