05x08 - Sand, Wedding Cake and High Fives

[bunniefuu]

[Dallas] This
is the Science of Stupid.

Yes this is the show where intelligence
and idiocy are combined.

[man] I can't get out!

[Dallas] You'll see the scientifically
under-educated push themselves,

our science to the extreme, often with
rather painful results.

Then we'll reveal what went wrong and why
with the help of some fundamental laws

of science such as gravity,

phases of matter and ricochets.

So buckle up and pay
attention because this

is the Science of Stupid.

In this show we'll be looking
at arboreal locomotion.

The conversation
of linear momentum.

And class one levers.

But first this.

Last weekend I was hanging
out with my leather clad

biker buddies at the clubhouse and

as usual and we got on to
one of our favorite topics,

is anything cooler
than a wheelie?

And in the end, the only thing we could
think of was an even bigger wheelie.

The 12:00 wheelie is just one of
those tricks that ladies love.

Which is one of the reasons
why we're all still single.

You can only achieve it if you're in total
control of your bike.

So not him.

And for goodness sake remember to
always wear a helmet, unlike this bozo.

That could have
been a lot worse.

Luckily all those guys were fine,

but it does rather prove the point that


are stupidly foolish,
incredibly dangerous

and should only be
attempted by professionals.

And if that hasn't put you off trying one,
then maybe the science will.

A wheelie involves raising the
front wheel off the ground

which requires continual
acceleration to counter gravity.

But once he has the bike vertical,

the combined center of mass
is over the back wheel

so only small
corrections are needed.

He does this by carefully
modulating the throttle

and rear brake to generate small
torques about the rear axle.

The fastest motorcycle wheelie
ever was nearly 200 mph

which goes to show that some
people just can't help showing

off when they get
on a motorbike.

Like this guy.
Textbook.

Or is that joke book?

But at least his fans
adore him either way.

This guy has a 12
bar on his bike.

This helps him to balance by creating a
second point of contact.

But showing off to the crowd as he slows
down creates instability and despite

a successful dismount, the rider forgets
to release his grip from the handlebars

and ends up mounting
his machine.

Practicing in more private
setting is probably best.

Especially if you're
not very good.

He tries to get his center of mass

directly over his back wheel
but overshoots

and there's a massive jolt caused by the
bike's rear end touching down.

This throws the bike forwards with such a
force that the handlebars are ripped from

his hands and he's left behind
wondering why he spent

all that money on
the custom paint job.

Finally, someone who
knows what they're doing.

But performing a stunt like
this on a public road

in amongst traffic
is incredibly stupid.

And that's why.

This guy does a great job of modulating
the torque using his throttle,

but as he comes to the traffic
light and has to land,

he accidentally
opens the throttle,

firing himself through a
red light and into trouble.

Another reminder not
to do this on the road.

And I'm not so sure it's such a good idea
on the race track either.

Well the good news is that
your bike came in second.

The bad news is you didn't
even cross the line.

I think that it goes without saying that I
like to take care of myself,

physically that is.

[whistle].

Thank you very much.

And when it comes to my workouts, I like
to make sure I'm challenged.

Because you should
always aim high.

I reckon a big higher than that.

And remember practice makes.

[man] Ouch!

[Dallas]
Perfect-ish!

Done well, this can show off
your skills and strength.

Yeah but that wasn't
done very well.

For me, my go-to exercise
is the clap pushup.

But to pull it off successfully
requires an understanding

of momentum and gravity,

so I suggest you pay
attention as we jump right in.

He applies an impulse with
his arms, chest, and shoulders,

propelling his center
of gravity upwards.

By keeping his hands
close together,

he's able to generate a larger impulse
achieving more upwards momentum.

This spacing also reduces the distance his
hands need to travel for the clap.

This needs to be quick

because gravity will immediately begin
accelerating him towards the floor.

So you need to push hard to
get air, move quickly to get

your arms back underneath
you and stay focused.

And all that is easier to do if you keep
your hands closer together.

Like this kid.

I love it when people
listen to the science.

Don't get over-confident
and widen your grip.

Ah, you were doing so well.

By moving his hands further
apart they had to move faster,

and he only managed 40%
of the original impulse.

And that wasn't enough.

Just remember guys without
enough upward momentum,

you're gonna have a bad time.

This guy is sensibly starting
by mastering the basics.

You need to perfect the pushup
before you can add the clap.

Exercise should make you
ache, but not in the face.

Still that's a freak occurrence.

Don't let it put
you off getting fit.

Like I said completely freakish.

And once you manage to master
a pushup clap,

then you're reading for the next level,

a pushup with the
clap behind your back.

Now this is much harder because your
hands need to travel further for the clap

so you either need a bigger
push or quicker hands.

Think hands of lightning.

Face of thunder.

Without sufficient momentum he didn't
achieve enough air time

to complete his clap,

so his face got slapped.

Look at this guy.

It's almost like the rules of
gravity don't apply to him.

But they do.

Good arm speed for the front claps but not
enough push to give his hands

the air time needed to
travel the longer distance.

[man, off-screen] I caught that.

[Dallas] And as you
know it's hard to look cool

when you've just
squashed your own nose.

We all enjoy an afternoon
at the skate park,

but can you guess what
key scientific principle

this skater is about
to demonstrate?

[Dallas] Did you
guess what science our

skateboarding friend
is about to show us?

Yes it's bending stress.

As the skater jumps on the board he
creates a downward force on both ends

but the concrete exerts an
upward force in the middle.

Together these produce
a bending stress,

which is too much for the
tensile strength of the board.

I think he understands now.

[man] Oh!

I like to think of
science as the secret glue that

holds the fabric of the
universe together.

And even in the small things,
if you just scratch the surface

you'll find a beautiful tapestry of often
painful science beneath.

Now this might look like a
couple of workmen messing around

but it's a delicate ballet of fulcrums,
pivots and parabolic trajectories.

[man, off-screen] You've
got to get it higher, man.

[Dallas]
All working together.

[man, off-screen] Now!

[Dallas]
To make him look stupid.

The whole idea of a hard hat
catch is to make the hat arc

through the air before it lands
beautifully on your head.

But you've got little chance
unless you know your science.

When our man stamps on his
shovel it acts

as a class one lever which
uses the downward

driving force at one end to launch the hat
into the air at the other end.

To catch it, he needs to predict
its parabolic trajectory.

Angular velocity will cause
his hat to spin in the air.

He wants to catch it with the
convex side up or it'll hurt.

So that all sounds fairly simple but has
anyone been paying attention.

[man] It's all about
that fulcrum point.

[Dallas]
Sounds like he has.

[man, off-screen] Come on.

[man] Ooh!

[Dallas] But
he definitely has not.

Too much driving force and the
far end of the lever rotates

too fast right off
the fulcrum point.

And that is why you should
pay attention to the science.

Let's see if this
chap does any better.

[man] Ouch!

[Dallas]
Nah, not really.

It's just bad but
in a different way.

By getting his friend to stamp
on the plank,

he achieves a much better driving force

and a much better aim,

but the hat has either too little or too
much angular velocity.

[man] Ouch!

[Dallas] And that's
why they call it a hard hat.

So that's catching hats.

And why you shouldn't
really bother.

[bell rings].

Alright settle down, it's your
own time that you're wasting.

Yes it's time for today's science lesson,
the part of the show where we focus on

a key scientific principle and if you want
to know what we'll be studying,

you'll have to tell me what
the following have in common.

This ridiculous
goal celebration.

These chest bumping champs.

And this ping pong pelter.

If you said that they were all examples of
the conservation of linear momentum,

move to the top of the class.

It tells us that during a
collision the overall momentum

in straight lines
must stay the same.

In order words,
linear momentum is transferred

between objects but never lost.

While falling these ba*ls
have momentum and experience

an impulse when they land.

The basketball transfers momentum to the
smaller ball which has less mass

and so it experiences a
greater change in velocity.

Momentum is a vector quantity which
means it has both magnitude and direction.

So even though these two ba*ls
go off in new directions,

the new sideways components

cancel each other out meaning the total
momentum remains the same.

Now let's see if you've
been paying attention.

Question one: we know that
in any collision overall

momentum is always conserved,

so how do we make an
object lose its momentum?

These amateur gymnasts
are about to demonstrate.

Ah that's smashing.

The catchers have greater
combined mass than the jumper,

so they absorb her momentum
by bending their arms.

This enables them to throw her back
upwards, transferring momentum again.

Unfortunately, they don't
bother to catch her,

which means you
need better friends.

Right, question two: does a
collision always result

in an object
losing its momentum?

This gym ball prankster
is about to find out.

The exercise ball has much less mass than
the man, so he easily withstands

the collision enough to
redirect the ball's momentum,

and that's called karma.

And now we come to our third and final
question, when two things collide,

is it only their velocity
that's conserved?

This guy is gonna find out with
his self-designed safety ball,

but I think the only discovery he's gonna
make is that he's a buffoon.

They've forgotten that
momentum is a vector quantity,

which means it has both
magnitude and direction,

so they bounce off in
different directions

and the momentum of the
system is conserved.

Class dismissed.

A wise man once said that life is like
a rollercoaster

and I can see exactly
what he meant.

It's full of ups and downs, it's a bit
expensive and generally overrated,

and if the person in front of you is sick
you're in for a bad time.

Yes be you young,

or slightly less young.

[screams].

[man] I thought you
weren't going to scream.

[Dallas] Rollercoasters have us
all acting the same way.

[girl] Mummy, what's happening?

What's happening?

[Dallas] And asking ourselves the same
basic fundamental questions.

[woman] Why?

Why?

Why?

At its most basic level the rollercoaster
is a machine that moves through cycles

of converting gravitational potential
energy to kinetic energy and back again.

So it's energy that makes
rollercoasters work.

But it's the sensation of acceleration
that makes them fun.

The fluctuation in acceleration is what
makes the rollercoaster exciting.

Because he feels many forces
acting on him in unusual ways.

When the car pulls him to one side he
feels a centrifugal force

that tries to accelerate
him to the opposite side.

As he travels round the loop, his inertia
generates acceleration

towards the outside of the loop, which
pins him to his seat, even though when

he's upside down gravity is accelerating
him downwards and out of his seat.

Acceleration fluctuation can also make
people do some silly things,

from uncontrollable screaming
to unusual facial expressions.

[girl] Oh my god,
oh my god!

[Dallas] This girl is not a fan of
acceleration fluctuation,

but she stupidly got on this incredibly
high rollercoaster anyway.

[screams].

[Dallas] Because of her inertia every time
she experiences acceleration

like that, she reacts by
screaming her head off,

[screams].

like that.

[girl] I'm
not doing that again.

DALLAS [off-screen] They
all seem to be having fun.

Except for that guy.

Low friction between the rider's phone and
pocket means it slips out.

And while he carries on moving,

the phone's inertia is overcome by air
resistance,

so it slows down and
then gravity takes over.

Let's hope he did buy insurance
when he took out his contract.

We all like a gentle
walk in the woods.

But when it's really
muddy don't you look up

and think maybe it would just be a lot
easier to swing through the trees.

After all, I spent my youth
practicing on the monkey bars.

Ah, halcyon days.

Maybe this sort of thing is
best left to the monkeys.

The issue here is
that that's an ape.

And when you do get the hang
of moving through branches,

you can use those same skills
for all sorts of things.

[man] Come on. Let go!

[Dallas] Like not
coming inside for a bath.

[man, off-screen] I give up.

Scientists like to call traveling through
trees arboreal locomotion.

It makes them appear smart without all the
bother of having to wear glasses

or actually learning anything.

But what does it actually mean?

Arboreal mammals have adapted to their
environment in a number of ways,

like having strong
gripping paws or claws,

taking longer steps and adopting a more

crouched posture to lower
their center of mass.

They also tend to have
longer forelimbs,

allowing them to cross gaps and
reach from branch to branch.

And there's one important
thing you need to remember.

Make sure that any branch you climb
on has enough material strength

to hold your weight.

So it's best to
proceed gingerly.

Like this sloth, who's been
adapted by evolution

to have long reach
and strong grip.

But that doesn't matter if
you pick the wrong branch.

Don't worry, he was fine.

This squirrel's claws are curved and sharp
enough to grip into the bark,

whereas the dogs are not,
so he can bark all he likes.

We call robbers who clamber in
through inaccessible windows

cat burglars because of
their climbing prowess.

So it follows that cats should
be naturals in the trees.

But maybe some of them
didn't get the memo.

This lioness has sharp claws
allowing the paws to grasp

so she should be
equipped for climbing.

But she's also relatively heavy,

she won't mind me saying that, and that's
a very thin branch.

I thought cats always
landed on their feet.

Yeah whether you're hanging from a real
tree or a modern metal approximation,

you need to always ask
yourself the same thing,

will it hold my weight?

The branch he's swinging
on is made of metal,

but its material strength is unable to
cope with the stress he applies.

We're probably best to leave all this
arboreal locomotion to the experts.

Albert Einstein apparently once said,

"anyone who has never made a mistake
has never tried anything new".

So it looks like these guys have
got the seal of approval

from the mustachioed
physics botherer himself.

[music plays through credits].