05x11 - Bench Press, Beer Keg and Snow

[bunniefuu]

[Dallas] This is the Science of Stupid.

Yes, this is the show where
physics meets foolhardiness

as our trustee
team of testers

learn their science the hard
way, so you don't have to.

With their help, we'll get to grips with
some serious principles, such as torque,

arboreal locomotion,
and transfer of momentum.

[man] Yes!

[Dallas] In the battle between
science and stupidity,

there can only
be one winner.

So don't be a loser.

Pay attention.

It's the Science of Stupid.

In this show, we'll
be looking at friction,

Hooke's Law,

and range of motion.

But first, this.

We all know that
terrible feeling.

You're halfway through the school run

when you suddenly remember
that that show you

like is on in five minutes and
you've forgotten to record it.

It happened to
me just last week.

And my friends do spoilers.

I only just made
it back in time.

Actually this, of
course, is rallying.

And not my idea of fun.

But, if you do choose to drive a rally
car, you might want to equip yourself

with some basic knowledge.

Because, while going fast in a straight
line is relatively easy,

throwing a bend into the equation can
make it a little less straightforward.

When driving a rally car at speed over
bumpy terrain,

changes in the surface angle

are likely to give him air
and take away his steering.

But that's not the only way
our man can lose control.

On a loose surface like dirt, the wheels
can easily lose traction.

On corners, this is called
a power slide,

but only if he can stay in control.

And, if he veers off course, natural
obstacles can generate a turning effect,

flipping him over.

The longest ever power slide in a car
was timed at two hours,


point the driver must have been really,

really dizzy.

Stewie thinks he's found
the perfect location

to capture some action snaps of the

rally cars power sliding past.

[man] I'll tell you what, Stewie.

You get a lot of ****
flying over here.

[Stewie] Try coming
over here bud.

[Dallas] Well, let's action snaps
and more face full of mud.

As the car slides around the bend, the
rear wheels go into the loose dirt.

So, instead of pushing the car forwards,
the tires displace the surface they've

come into contact with.

[Stewie] Wow!

Literally just
after I said that.

[Dallas] As you can see, being a
spectator at a rally comes with risks,

so it's best to
stay off the track.

Unlike this marauding mutt

who can thank his lucky
stars for that very near miss.

The car hits a bump
and the changing angle of

the surface converts
some of its forward velocity

into upwards velocity and it glides over
the head of the confused canine.

Funny, it's normally the
dogs that chase the cars.

Safety is always important,

which is why rally drivers wear helmets
and their cars

are built around a cage designed to
withstand heavy collisions.

[man] [bleep]. My God.

[Dallas] Which is a good thing.

When the driver over steers, he loses
traction on his rear wheels,

goes up on the bank and
creates angular momentum.

The car goes into a spiral
dropping it's camera on impact,

before bouncing
away like a ballerina.

Amazingly, the crew, just like everyone
we've seen, walked away unharmed.

I once saw a man squeeze himself into a
tiny box at the circus.

It's amazing the lengths some people
will go to to avoid clowns.

Things then went from bad to worse, as
he also had sever claustrophobia.

After all, there is nothing
worse than getting stuck.

[woman] You might have
to grease his ears.

[man] Wait, have
him crawl out, Papa.

Maybe he can crawl out.

[Dallas] Ah, that's a relief, as my
personal phobia is greased ears.

This looks like an emergency.

[girl] OK we need to call 911.

[woman] No!

[girl] What's the emergency.

My Mom's butt is
stuck underneath the bed.

OMG, I think we're gonna need the
police, ambulance and the fire

department for this one.

[woman] What were
you even doing in it?

[man] I was standing on
it to clean the roof ****.

[Dallas] And, if
you're gonna stand on anything,

make sure it
can take your weight.

It's important to remember that when

going through a small gap,
friction between

our body and the enclosed sides acts
against the propulsive force that's

pushing you forwards, so
it resists your movement.

In other words, you get
stuck and this is never good.

But a bit of science might
help you out of a tight spot.

To start moving forward,

our man needs to generate propulsive
force that exceeds

the frictional force
holding him there.

The widest points on a human body are
the hip girdle and shoulder girdle,

so these are the points he is
most like to be pinned at.

One strategy is to use the flexibility
of your legs,

hips and spine to manipulate where

your body makes contact with the edges,
thus changing the

distribution of
the frictional forces.

This way, you can
wriggle yourself free.

But, as anyone who's ever found
themselves stuck in a bin will tell you,

every situation is different.

So we've got our trusty team of testers
to do some further research,

so you don't have to.

Here's one of our top
scientists attempting to fit

through a tiny resistance band.

[screams]

[Dallas] No one
ever said science was easy.

The band is compliant, so it stretches
around him and he manages to create a

propulsive force larger
than the frictional force.

But it's elastic, so stores energy and
when it gets past his widest point

it releases that energy in quite a
painful, yet humorous way.

This guy is experimenting at the
children's trampoline park.

Test complete.

The extra height from his bounce

increases his downward velocity enough
to force his

head into a much smaller gap than
friction would normally allow.

I can smell the
Nobel Prize already.

Test number three.

Well, he seems bowled
over with the result.

The bowler's fingers are wedged too
tightly into the ball,

so the frictional force
equals the propulsive force,

meaning the ball stays
attached to the human.

And he gets a
bill for the damage.

[man] My chubby arse is stuck.

My arse is stuck.

I'm not joking.

[Dallas] Not again.

[man] I can't get out.

[Dallas] So, when it comes to
small spaces, my advice is.

[man] Dad, help us.

[Dallas]
Stay out of them.

Traffic is annoying, but can you guess

what key scientific principle
we're about to see,

courtesy of this
impatient driver?

[Dallas] We asked what science
were we about to witness.

Did you guess inclined planes?

You don't need to be an expert
in physics

to know that two objects
can't occupy the same

physical space.

So when the car tries to
overtake the bus,

it's forced to take
the less desired path,

which sadly also contained
a concrete side wall.

As it's shaped like an inclined plane,
it easily lifted the side of the car off

the ground and gave the driver a gentle
reminder that patience is a virtue.

Yes, I've always
dreamt of being a pirate.

Why, you ask?
Well, three main reasons.

I love parrots, I can pull off
an eye patch

and I've always wanted to
sleep in a hammock.

It just looks so relaxing.

-See what I mean?
-[woman] Oh my God.

[Dallas] Ah, the double hammock,
meaning double risk.

And that is why.

At least this one
looks a bit sturdier.

But looks can be deceiving.

Don't worry,
she was absolutely fine.

But those hammocks don't look quite as
relaxing as I'd first imagined.

There's clearly a bit of an art to
getting into one and staying there.

Perhaps a bit of
science might help.

A hammock gives our man a large base of
support, distributing his weight,

which means he's less likely to overcome
it's strength or fall off.

Tension in the cord supplies the force
that keeps the hammock suspended.

But getting on can be tricky.

The force of his weight on either side
won't be aligned with the upward force

from the hammock.

These combine to create a force couple
which generates an unwanted rotation.

Tension, rotation, force couples,

there's a lot more to the world of
hammock than

first meets the eye.

Let's see how our testers are getting on
with their own experiments.

Technically speaking,
hammocks are for relaxing in

and shouldn't be used as swings.

I think that might be why.

As my friend here swings,
his weight falls too far backwards

and its force is no longer

aligned with the upward component of
tension from the hammock,

so the forces combine to
create a force couple.

[man] Just sit in it. Just sit in it.

[Dallas] Almost 2,000 people a year
are injured in hammock-related

incidents in America alone.

So, suspending your hammock beneath a
bridge over water is asking for trouble.

And when you ask for
trouble, you get trouble.

[man] Just let go.
One, two, three, go.

[Dallas] Our tester lowers himself
into the hammock gently,

but the knot on one side fails
and the hammock

can no longer supply the
tension force at

one end, so it
becomes a pendulum,

and he becomes
another statistic.

Ah, dry land.

Always a good start.

Here we go.

Now, let the relaxation begin.

Right, break's over.

Back to work.

When his friend pushes him too much, the
hammock swings a long way from that

center line and his weight is no longer
aligned with the support,

so there's nothing to stop him from
finding out how the floor tastes.

My guess, a little bit earthy.

Okay, everybody
settle down please.

Morley, stop mucking about.

Yes, it's time for today's
science lesson,

that part of the show
where we dissect one

specific scientific principle and have a
good old rummage around inside

to see its workings.

So, who can tell me what the
following have in common?

This backyard acrobat.

[man] Go!

[Dallas]
This big bouncer.

And this father and
son workout routine.

[boy] Dad!

[Dallas] Years from now, his
psychologist will pinpoint this moment

as the source of the issues.

If you said Young's
modulus, then well done.

Because, as we all know,
it's the measure of the stiffness

of a material under tensile or

compressive stress.

A cord's Young's modulus determines how
much it'll stretch once all the slack

is taken up.

A falling weight
applies stress to the cord.

This metal cord has a high Young's
modulus and hardly stretches at all.

This bungee cord is exactly
the same length,

but has a low Young's
modulus and stretches

easily, so the
weight keeps moving.

And most elastic object
obey Hooke's law,

so the further you
stretch something,

the more force you need
to keep it stretching.

Let's see how much
of that has sunk in.

Right, question one, when
doesn't Young's modulus apply?

I think this guy is
about to show us.

The branch he's using
is a stiff material,

so it has a high
Young's modulus.

But, once stress is applied,

the tensile strength of the branch is
exceeded and it

snaps, meaning Young's
modulus no longer applies.

Question two,
which famous scientist's law

is Young's modulus closely related to?

My grandmother always used to say,
"Never ride a bike into a bungee cord."

And now I know why.

The bungee cord has a low Young's
modulus and is very stretchy but,

as Hooke's law tells us, the more it's
stretched, the more force it'll need

to keep stretching.

Eventually, the force trying
to recoil the rope

is greater than the
stress he can apply

which equals pain.

And now we come to our
third and final question.

What behavior can we expect from a
material with a low Young's modulus?

Ah, this look's fun.

Of course, unlike science,
fun is subjective.

The space hopper's material

has a low Young's modulus, so it's
flexible and will deform

a lot when stress is applied.

Which in this case is a good thing,

because it increases the time
of impact and thus

decreased the
average impact force.

So there we have
it, Young's modulus.

Class dismissed.

When I was a lot younger,
I was a big fan of kickboxing.

I don't mean doing it myself,
obviously,

I mean I watched a
lot of Jean-Claude Van Damme

movies while wearing my karate pajamas,
which is probably

what this lot should have done.

Mind you, it's heard not to show off
when the opportunity presents itself.

Purple hair.

Surely there's no need
to show off anymore.

Purple hair,
red face. Clashes a bit.

This guy seems relaxed,
he must know what he's doing.

Where nonchalant
meets incompetence.

High kicking is a high risk
business and,

if you wanna
flex your muscles like that

bloke from Brussels, you should really
pay attention to the science.

He starts by pushing against
the ground with his kicking leg,

generating momentum.

The large range of motion in
his hip joint

allows him to lift his
kicking leg high,

while his planted leg acts as a pivot,
around which he rotates.

The coefficient of friction
between his foot and the ground

is low enough to allow

rotation, but high enough
to stop him from slipping.

Now, obviously that was done
in a controlled environment,

something we'd always recommend when
experimenting in the name of science.

Sadly, the laboratory isn't where you'd
usually find arcade punch bags.

Instead, they end up in places where
people are prone to improvements.

Phew, I thought that
was gonna end badly.

I wonder how her male
companion will do.

Eh.

The lady has flexible enough
hips to achieve

the range of motion
needed to reach the bag

without lifting her supporting foot,
allowing her to pivot safely.

While her gentleman friend attempts an
ambitious flying scissor kick,

misses and then his legs aren't where
he needs them to be.

Friends at the fairground.

Is this a safe setting?

No.

He gets a good push off from his kicking
leg, generating plenty of momentum,

but the coefficient of
friction on his supporting leg

isn't high enough to stop it
from slipping out from under him.

I think one of his friends
needs to throw in the towel.

People often tell me I am the perfect
catch, which is ironic.

But imagine how much harder catching is
for an animal without hands.

Surprisingly,
it's much harder.

Dogs love to fetch, but can you love
something without being good at it?

You're probably
better not to even try.

That's the spirit.

I know exactly how
those dogs feel.

The only thing I
can catch is a cold.

But maybe some science will
help improve my motor skills.

Linear optical trajectory theory

states that the catcher should
move in a way that

makes a thrown object follow a straight
line through their field of vision.

They should also keep the object rising
and falling at a constant speed

above the ground.

This means the faster
the object gains height,

the further back
the catcher needs to move.

However, trajectory prediction and
position aren't everything.

The grip a catcher can generate and the
ability to adjust their type of catch to

the object will also
decide success or failure.

So let's see an expert in linear optical
trajectory theory in action.

Yeah, not him.

But dogs should
be good at this.

This lady has a
frisbee and three dogs.

[woman] Oliver, wrong way!

[Dallas] But it looks like only two
of them were paying attention

to the science.

When the frisbee is thrown, two of the
dogs predict it's trajectory.

[woman] Oliver, wrong way!

[Dallas] While Oliver decided science
isn't really for him.

And remember, playing catch
indoors is never a good idea.

As my late grandmother
constantly reminded me,

if at first you
don't succeed, give up.

If only this lot had
listened to that sage advice.

[music plays through credits]