03x14 - Skateboards, Food Fight and Springboards

[bunniefuu]

[Richard]
This is the Science of Stupid.

-[electricity crackles]
-[glass shatters]

[alarm blares]

Yes, this is the show
that applies scientific hindsight...

-[all scream]
-...to brazen stupidity.

Watch as everyday people
attempt ill-advised stunts.

Resulting in limited gain.

[laughter]

And limitless pain.

[groans]

We'll reveal what went wrong and why

through key scientific principles,
such as...

-[yells]
-...rotations,

oscillation,

and torque.

So sit down and prepare to wince.

It's the Science of Stupid.

[glass shatters]

[electricity crackling]

In this show, we'll be exploring

the joys of impact force...

[yells]

...the conservation of momentum...

[man] Ohh!

[Richard] ...and we'll be explaining
the dos and don'ts

of atomization.

That's a don't.

But first, this.

[glass shatters]

[electricity crackling]

[glass shatters]

As a species, we've evolved to develop

coping mechanisms
to deal with sudden dangers,

such as being chased by wild animals.

As saber-toothed tiger attacks
have declined,

we've found new ways of testing
our defense mechanisms.

There's the classic surprise.

[gasps, screams]

[woman] Oh, my God!

[Richard] The wake-up call.

-[people yelling]
-[screaming]

And of course the old pot trick.

[yells]

[laughter]

Works every time.

It appears that scaring other people

has become something of a hobby
for folk of all ages.

All it takes is a sudden shock

for us to lose all self-control.

But what is the science
behind our reaction

to people shouting "boo"?

[ghost cackling]

When he receives a fright,

his nervous system
sends a signal to the brain,

triggering involuntary actions,
like jumping.

Next, his heart beat
and respiratory rates increase.

[thumping]

And adrenaline is released,

enabling him to run faster,

or, if in a fight, hit harder.

It would seem that sudden shocks,

whether we like it or not,

make us jump, good at running away,

or sometimes a bit fighty.

Now let's see how people make use

of these essential biological responses
in the field.

Is anyone home?

[woman screaming]

Only her brother disguised
as an evil freak.

Messages from the brain
made her involuntarily jump

and scream and most likely
increased her heart rate.

[woman, off-screen] Get out! I can't
have you doing this anymore!

That was too much.
That was too much.

[Richard] So I'm sure she'll see
the funny side in about a month.

Of course, that scaredy-cat jump

is only our nervous system
trying to protect us.

[man] Oh, God!

[Richard] And occasionally embarrass us.

[man] Are you crying?

[Richard] It's not his fault.
He's just got a really nervous system.

[man] Oh, God!

[Richard]
Sometimes adrenaline is described

as the fight-or-flight hormone.

This chap has very little adrenaline
in his system at the moment.

[screaming]

And now he has quite a lot.

Here's the fright.

[screaming]

Here's the fight.

And here's the flight.

See ya.

I think that went well.

It's the family fishing trip,

and Dad has brought
a rubber snake along.

What a joker.

But will it trigger
a fight or a flight response?

[woman, off-screen] What is that?

[both screaming]

[Richard] Yep, it's definitely not fight.

[screaming]

Oh, Dad, you must be so proud.

[laughter]

[electricity crackles]

[creaking]

If there's an activity
guaranteed to result

in monumental pain,
then BMX biking is it.

Want to enhance that pain and anguish?

Well, simply take your BMX
and try a back flip or a front flip.

But you can't just peddle up
to a ramp and start flipping.

You need to get to grips
with the basics, like...

holding on.

[man laughing]

[man, off-screen]
You all right?

[Richard] He's been better.

Understanding that
a soft landing surface...

[yells]

...isn't always a good thing.

Although they seem
quite pleased with it.

And above all else...

[crowd, off-screen] Ohh!

[Richard] ...wearing a helmet.

[crowd, off-screen] Ohh!

[Richard] But if all that
seems rather obvious,

well, rest assured,
there's also a bit of science

in the shape of horizontal velocity,

moments of inertia and impact.

And if you're not too keen on
an unhealthy dose of the latter,

listen up.

First, he approaches with
plenty of horizontal velocity.

Then shifts his weight
over the back wheel

and leans back
to generate angular velocity.

Tucking in reduces his moment of inertia,

enabling him to rotate faster.

And leaning back,
then landing rear wheel first

helps reduce
the average impact force.

Whether you're going for
a back flip or a front flip,

the key principles are the same,

and the first thing you're going to need
is horizontal velocity.

It's all in the approach.

A long approach is good
for building velocity.

-[groans]
-[laughter]

Slowing down and letting go
of your bike is not.

Bigger jump now,

but this gravity-assisted
downhill approach

is all about velocity.

[yelling]

[crowd] Ohh!

[Richard] The landing
was more about friction.

He built up lots of horizontal velocity

but not nearly enough
to give him the angular velocity

he needed to complete the flip.

[crowd] Ohh!

[Richard] Don't worry,
a perfect, painless flip

is more than possible.

In fact, in 2011 Jed Mildon completed

the first triple BMX back flip.

You see, he knew just how important
it is to tuck in tight.

Here's an example.

Okay, that's the complete opposite.

[groans]

Here it comes,
looking for that perfect rotation.

[yells]

Oh, I have seen better.

Immediate abort of flip,

complete lack of tuck,

resulting in a large moment of inertia

and an even larger moment of regret.

It's the big one.

[crowd gasps]

[man] Ahh!

[Richard] And a big opportunity to show

how landing on one wheel
at the wrong angle

can result in the kind of rotation
you could really do without.

[electricity crackling]

[clattering]

This talented young lady
is going to demonstrate

a key scientific principle

through the medium
of contemporary dance.

Can you guess what it is?

[glass shatters]

[electricity crackling]

[glass shatters]

So have you guessed
what scientific principle

our little dancing queen
is going to demonstrate?

Well, take your pick.

Linear momentum takes her back.

Gravity takes her down.

And her kinetic energy is transferred
to the mirror and the shelf.

You're like a little science machine.

Well done, you.

[electricity crackling]

[creaking]

For me, the perfect holiday
is a horizontal one.

If I'm not snoozing in my room,

you'll find me reclining
on the sun lounger.

If not there, you'll catch me relaxing
on a beach towel.

And if I want to dip
my toes in the pool or the sea,

I can do just that
still perfectly horizontal,

all thanks to my inflatable.

I simply pick up my raft

and saunter down to the water's edge.

[laughter]

Oh, I did say saunter.

Okay, but in their natural home,
the swimming pool,

inflatables are relaxation epitomized.

[woman, off-screen] Ahh!

[laughter]

[Richard] Providing you can get on one.

Now, doing that hinges on
Archimedes' principle of buoyancy,

and if inflatable rafts and rubber rings

had been more of a thing
in Ancient Greece,

this is how Archimedes
might have explained them.

The larger the volume of raft underwater,

the greater the buoyant force.

Provided that force
can equal the weight

of you and your raft, you'll float.

But whilst the base of support is wide,

the raft is very light,

making for a precariously
high center of mass.

Also, the air inside can be compressed

when you apply force,
which can distort the base.

Worse still, there is no friction

between the raft and the water.

Meaning it can easily
slip out from under you.

You see, all Archimedes was trying to say

was that you want to keep
nice and low on your raft

and make sure your weight
is evenly distributed.

So simple, you'd be forgiven
for wondering

who'd get a thing like that wrong?

Here's Stewart.

[man, off-screen] No, no, let him.

He knows his weight distribution
in this situation now.

[Richard] He's got supportive friends.

[man, off-screen]
Yeah, he's got the technique.

[Richard]
But not a particularly supportive raft.

[man, off-screen] Ohh!

[Richard] Oh, Stewart,
you really haven't grasped

the weight distribution thing.

This looks more promising.

[woman screams]

Nah, just kidding.

The nightmare combination
of high center of mass,

low friction, not to mention
almost no base of support

allows the ball to rotate.

Was that ever going to work?

There is, however, another technique
for launching onto your raft.

It's high-velocity and high-risk,

but done correctly it will elevate you

to near godlike status
amongst the pool community.

It's called jumping.

Do it right, and you'll win friends
and make Archimedes proud.

Just like that.

[all cheering]

Do it wrong... and you won't.

Another thing about inflatables,
they are a bit bouncy,

which is why he's going for a foam raft.

[man, off-screen] Go!

Oh, [bleep].

[Richard] Oh, that's regrettable.

[man, off-screen]
We're filming someone's death.

[Richard]
Oh, not quite, but foam rafts

have as rubbish a coefficient of friction

with water as inflatable rafts do.

So any sideways force,
and they are a bit slidey.

[yelling]

And not at all in a fun way.

[bell rings]

[beaker shatters]

[gurgling]

It's that time in the show
to sit up a little straighter,

pay a little more attention,

and become a little better educated,

because it's the science lesson,

where we examine a key
scientific principle.

Today's principle is shared
by the following two things:

a campfire you wouldn't want
to toast marshmallows on...

-[man] Oh!
-[laughs]

...and a birthday party
which turns the notion

of blowing out the candle on its head.

[screaming]

Or rather, his head.

Incredibly, he suffered no major injuries,

but please, don't even think
about messing with fire.

It is, without question,
extremely dangerous.

Okay, on with the lesson,
and today's theme is atomization,

the process by a which a substance
is split into fine particles.

Here's what you need to know.

With flammable liquids,

what burns is the vapor they give off

at certain temperatures,

not the liquid itself.

But by spraying paraffin into a fine mist,

this fire-breather is atomizing it.

Dispersing it into smaller droplets.

Increasing its surface area,

allowing it to vaporize more easily

and mix with oxygen, and so burn.

It's basically
what a car's fuel injector does

by spraying fuel into tiny particles.

But taken out of the safe confines
of your car's engine,

this atomization thing
can be very dangerous.

To ensure you fully understand why,
here's a little test.

Question one,
how can you atomize something?

[man] Hey!

[Richard] Yes, by spraying.

Go on, have another go.

[people yell]

Okay, I'd stop now.

Don't worry, he's fine.

[laughter]

Question two, particles in a liquid

tend to be quite tightly packed

and do not mix so easily with oxygen.

So how can a liquid fuel burn?

Let's have a demonstration.

Looks like nice weather for a barbecue.

[man] Initiation sequence.

[Richard] Uh, I think you mean "ignition."

[man] Three.

Two.

One.

[coughing]

[man 2, off-screen] You okay?

[Richard] It doesn't sound like it,

but let's take a look
at what happened.

First, he sloshed a load of fuel
onto the wood heap.

It was a lovely hot day,

hotter in fact
than the fuel needed to vaporize

into a large and highly flammable
cloud of tiny particles.

Then he blew up.

And his day got even hotter.

And now, question three.

Can you think of any alternative ways

of creating really tiny,
spread-out particles?

This would-be chef
is going to deep-fry a turkey.

[woman, off-screen] Whoa!

[Richard] And also give
a perfect demonstration of atomization.

The water in the turkey
is rapidly turned to steam,

which blows the oil away
in a fine mist or vapor,

which ignites when it comes into contact
with the flames.

[woman, off-screen]
It's going to be delicious now.

[Richard]
I'm fine with a bowl of cereal, thanks.

[man] Ahh!

[Richard] So that concludes our lesson
on atomization

and things you really
shouldn't try at home.

-[man] Whoa!
-[laughter]

[Richard] Like this.

[man] Do I have a beard anymore?

[Richard] Count yourself lucky
you still have a face, man.

[glass shatters]

[electricity crackling]

If, like me, you were always the last

to be picked for
the football team, always,

you'll be familiar
with the position of goalkeeper,

and it's not just the feeling of rejection

that makes it such an unappealing role.

For starters, it's humiliating.

And if that wasn't enough,
it can really hurt.

[man]
You all right, buddy?

[Richard]
But if you have drawn the short straw

and been stuck in goal,
you'll be pleased to know

that science can offer some clues

to being better at saving,
and here they are.

Angles are all-important.

The closer a goalkeeper
is to his opponent,

the smaller the available
sh**ting angle either side.

But the more susceptible
he is to being passed

by the parabolic trajectory
of an overhead lob.

Whilst it's moving,
the ball has momentum.

So if the goalie touches
the ball but doesn't catch it,

the ball will be redirected
and its momentum conserved.

[crowd, off-screen] Ohh!

[Richard] And being 6'5" with hands
the size of dinner plates

doesn't go amiss either.

So remember, the closer
you are to a striker,

the smaller the angle he has to sh**t.

[indistinct shouting]

[whistle blows]

But that was a bit too close.

[whistle blows]

Free kicks are a perfect time for a goalie
to get into position.

Or enjoy a drink. It's up to you, mate.

A less-than-ideal starting position
for the goalie

gave the striker
a larger potential sh**ting angle.

[crowd cheering]

Yeah, it-it went in.

So that's angles. Now momentum.

-[man] Ohh!
-[Richard] Good save.

Although he didn't have much choice.

His hard forehead
meant the ball was able

to retain its kinetic energy,

flying safely away from goal,

or rather the up-turned trampoline.

Let's see if he can get a hand to it.

[man groans]

Nope, but he did manage a header.

Goalie misses ball,

so momentum of ball
is transferred to goal.

And momentum of goal
is transferred to him.

[man groans]

[electricity crackles]

Getting stuck
behind someone driving slower

than a tired tortoise can be frustrating.

But knowing when and how to get around
another vehicle safely is a precise art.

So whatever and wherever you're driving,

the rules of the road are to be obeyed.

For example, keep an eye on your speed.

Keep an eye on your friends.

And always, but always,
keep an eye on your mirrors.

Or if you're on a bicycle...

[man groans]

...other people's mirrors.

But aside from the obvious,

there is also some serious science at play

when weaving around other vehicles.

It involves principles
you don't want to mess with.

I'm talking centrifugal force, traction,

and something known as the optimal line.

Accelerating to a higher velocity,
he pulls out.

As he turns, he experiences
centrifugal force,

pushing him to the outside.

He steers in a wide, smooth arc
to minimize this force

and to avoid the rear wheels
losing too much traction,

taking him on a path known
as the optimal racing line.

It's also worth bearing in mind

that you need to cover
a lot of distance rapidly.

For example, if you
were doing 60 miles an hour,

and the car you were overtaking
was doing 50 miles an hour,

you would need a clear
half a mile to get past.

So the first step is getting
just enough acceleration.

Overtaking in a race
is an essential skill,

but this chap is struggling
to accelerate past his competitor.

[man cackles]

He's not, though.

The sudden burst of speed

caused him to lose traction
on the front wheels,

causing an understeer.

But what happens if someone tries
to overtake you on the inside?

I think it's what's known
as increasing his drag.

Or in lay terms, cheating.

[man] Huh?

[Richard] Ah, we're with the big boys now.

Good control of acceleration.

Nice smooth arcs to keep traction.

He's got it.

[horn blares]

Him, not quite so much.

[man, off-screen]
Whoa! Didn't we do well?

[Richard] Yeah, you did. But he didn't.

Finally, don't forget,
whatever you're driving,

that optimal line is essential.

[groans]

Yeah, that's...
that wasn't exactly optimal.

Good acceleration.

First arc, nice and smooth.

Second arc, unnecessary,

sending him arcing...

[yells]

...into the fence.

[man 1, off-screen] What happened?

[man 2, off-screen] He rode straight
into the barbed wire fence.

[Richard] Correction,
arcing into the barbed wire fence.

Hey, keep them up.
This is a family show.

[laughter]

[glass shatters]

[electricity crackling]

[glass shatters]

There you have it, lots of reasons
not to do lots of things.

I used to wonder if they
all knew what we know now,

would they still do it?

The conclusion I've reached is:
quite probably.

After all, it's why we call
it the Science of Stupid.

Goodbye.

[screams]

[woman, off-screen] Ahh!

[man screams]

[woman screaming]

[boy groans]

-[man laughs]
-[woman screams]

[man, off-screen] Ohh-oh-oh-oh!

-[man] Ohh!
-[screaming]

[woman, off-screen] Whoa!

[onlookers scream]