06x13 - Ice Bergs, Piers, and Teeter Totters.

[bunniefuu]

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

Yes...

this is the show where we X-ray
extraordinary stupidity...

to get to the bare
bones of science.

We examine scientific
misadventures

that end in catastrophe

then consider the causes
and reveal the reasons.

Maybe they haven't understood
angular momentum.

Or they didn't realize the negative side
of positive feedback.

Or maybe they didn't fully grasp the
principles of material strength.

But we have.

Don't try any of
this yourself.

Watch out.

It's the Science of Stupid.

In this show, we'll explore the force of
sudden deceleration...

how pier diving connects
to impact force.

and the way turning effect
can really spoil your day.

But first this.

Of all of nature's wonders,
icebergs get a lot of bad press,

mostly thanks to sinking
that unsinkable ship.

But that wasn't really
the iceberg's fault.

After all, they're just massive
chunks of floating ice

and they really can be
astoundingly large.

The biggest ever recorded

weighed a gargantuan


and covered over


That's larger than Lebanon.

[woman off-screen] It
is, it's going over.

[Dallas off-screen] And it contained
enough water

to provide more than 1,000
tons for each and every person on Earth.

[onlookers] Whoa!

[Dallas] But if you want
to know about icebergs,

first you need to
know about glaciers.

Now, these form on land
over thousands of years

when snow gets
compressed into ice.

Over time, gravity pulls
this mass of ice downhill.

When a glacier extends
over open water,

it no longer has solid
ground to support it.

Gravity exerts
a downward force,

creating a torque which
eventually overcomes

the ice's flexural strength.

And a chunk of the
glacier falls away.

This is called calving.

Archimedes' principle
of buoyancy

states that as long as
the total weight of the object

doesn't exceed the weight
of the water being displaced,

it will float.

And because ice has 90%
the density of water,

about 90% of the iceberg
will be submerged,

with only 10%
above the surface.

[man off-screen] How much of
the iceberg was underwater?

[Dallas off-screen] And that is
literally the tip of the iceberg.

At the bottom of an iceberg,

the ice can be
thousands of years old.

Mammoths and
saber-toothed cats

could have still been
walking the earth

when the first snow
that formed it fell.

So, if you see the bottom
of a newly formed iceberg today,

you could conceivably be

the first human ever
to lay eyes on it.

Of course, you aren't always
in the frame of mind

to wonder at such things.

[man off-screen] Dude.

[Dallas off-screen] Particularly when
dozens of tons of ice

are falling in your direction.

As this windsurfer
approaches the glacier,

its flexural strength can
no longer resist the torque,

and a large chunk
carves off.

The birth of a new iceberg.

But will our surfer be beaten
by this oversized ice cube?

No.

But he still ends up
in the drink.

This seal is chilling out,

taking advantage of Archimedes'
principle of buoyancy.

As long as her weight, plus
the weight of the iceberg,

still doesn't exceed the weight
of the water it's displacing,

then they'll
bob along gently.

The perfect place
to relax.

[man off-screen] Hey!

Hey!

-[seal barks]
-[man laughs]

[Dallas off-screen] But even in
Alaska,

you can't get away from
camera phones.

So there you have it:

icebergs, one of
nature's wonders.

[man] Whooo!

[Dallas off-screen] Although
not as mysterious as his reasons

for wanting to do this.

[man] Aaah!

[man off-screen] Come
and get me, it's cold!

[Dallas] Now, I'm
not a bad swimmer.

And I love nothing more than
jumping into some water,

but thanks to my
understanding of science,

I always err on the
side of caution.

Of course, some people aren't
nearly as sensible as me.

And it's people like that
who jump off piers.

[man] Whoo-hoo!

[Dallas off-screen] That was incredibly
dangerous and should not be repeated.

If you must jump off a pier,
I'd recommend something...

a little less challenging.

-[woman off-screen gasps]
-[girl off-screen] Ohh!

[woman off-screen]
The board came out.

[Dallas off-screen]
Yes, we saw it.

Jumping off a pier has
the potential to be

about as harmful as hugging
an irritated hippo.

So, a bit of science
should shine a light

on the do's and don'ts
of this hazardous hobby.

Our man needs to be
careful because the pier

is frequently
exposed to water,

which can combine
with seaweed and algae

to lubricate the surface
and reduce friction.

Jumping off requires our man
to create a reaction force

with both horizontal
and vertical components.

Once airborne, he follows
a parabolic trajectory

and can make use of any
angular momentum for a flip.

When entering the water,
a streamlined profile

will minimize hydrodynamic
drag and impact force,

while a flat profile
will do the opposite.

[man gurgling]

Well, that addresses
the how you do this

but not really the why
you'd want to do this.

Personally, I'd still recommend
giving this one a miss,

but obviously not everyone has
my legendary level of restraint.

This pier is nice and low so it should
be ideal for a simple jump,

but I wonder if they've
noticed how slippery it looks.

[girl screams]

[Dallas off-screen]
Wonder no more.

[laughing]

The wet wood at the end
of the pier has low friction

and offers little resistance

to the forward component
of her step.

So her foot keeps
moving forward

and her body rotates back

before her momentum treats
her to a surprise swim.

[laughing]

At least this guy is
taking the time needed

to consider the science
before undertaking

his stupid stunt.

Either that or he's
a bit nervous.

Okay, yeah,
he's a bit nervous.

But with any luck, that will give him
the edge he needs.

[jumper] Ooh!

[friend laughing]

[Dallas off-screen] This is
almost the perfect pier jump.

His run-up gives him
good horizontal velocity

and a trajectory long enough
to make it over to the beam.

But on landing, his body
still has some momentum

and rotates forwards
and a little sideways.

So, his sneakers
get a soaking.

This guy has added
a level of jeopardy

that I'm not
comfortable with.

[man] ****!

[Dallas off-screen] I don't think he's
that comfortable with it either.

[man] Oh ****, that hurt!

[Dallas off-screen] As he
throws his body back for a flip,

he fails to let go
of the poles

so he gets no
horizontal velocity

and rotates straight
down onto the pier.

[groans]

[Dallas off-screen] Can you guess what
science this impatient trucker

is about to unwittingly
demonstrate?

[Dallas off-screen] Did you
guess what scientific lesson

this trucker is about
to be reminded of?

Well, "patience is a virtue,"
but also turning effect.

The turning effect of a force depends on
the size of the applied force

and the distance
to the pivot.

When the end of the
train-towed crane

catches the
tractor-toting truck,

it applies an
incredibly large force

at quite a distance from
the pivot at the wheels,

so the truck...

takes a tumble.

In a letter to his son, Albert
Einstein famously compared life

to riding a bicycle,
when he wrote,

"Only when moving can one comfortably
maintain one's balance."

And he was relatively clever.

But I'm not sure he was
expecting that bicycle

to be ridden over
a gigantic teeter-totter.

[man off-screen] Oh!

Oh!

[Dallas off-screen] Although, to be fair
to him, just like life,

a teeter-totter certainly
has its ups...

[women scream]

...and its downs.

Some call them teeter-totters,
others say seesaws,

but scientists prefer
to call them

a lever consisting of a
beam and fulcrum point.

Well, however you want
to describe them,

they are dangerously
difficult to bike over,

for some very good reasons.

A teeter-totter starts
as an upward ramp,

which reduces his momentum,
then becomes a downward ramp,

which increases momentum.

These changes in momentum
are caused by impulses.

The rider needs
to compensate for them

by carefully controlling
their cycle speed and balance.

When it shifts, the bridge
experiences a turning moment.

The farther the rider
from the pivot,

the greater the
rate of rotation.

Now, remember, it is important
to try and maintain

a constant velocity when
riding over a teeter-totter

to keep the bicycle stable.

[woman off-screen]
Faster, Kate, faster.

[Dallas off-screen]
She seems very quick.

[screams]

Maybe a bit too quick.

Despite Kate's confident
high-velocity approach,

she steered off the
edge of the ramp,

which resulted in a turning
effect on her bike...

[laughter]

...a lot sooner
than she expected.

Ah, nice to see someone
taking safety seriously

and wearing a helmet.

[biker] Oh! [bleep]

[Dallas off-screen]
And a good job, too.

As this mountain biker
reaches the pivot point,

he's lost all
his original speed,

and as the teeter-totter
becomes a downward ramp,

the impulse takes him
down and forwards...

[man] [Bleep]

[Dallas off-screen] And
then a bit more down.

[man off-screen] [bleep].

[Dallas off-screen]
Her again, eh?

Let's see if it's
second time lucky.

[biker screams]

-[woman off-screen] Oh Jesus!
-[Dallas off-screen] You might want to

see someone about those impulse control
issues.

[Dallas] It's time to
limber up your lobes,

stimulate your synopses, and get ready
for today's science lesson.

It's the part of the show
where we place

one particular scientific
principle under our microscopes,

and as always there will
be a quiz at the end.

So try to stay awake.

All right, what do the
following have in common?

This sloppy skier...

[both laughing]

[woman off-screen]
Ooo! Helen...

...pull, ***** pull!

[Dallas off-screen] This
energetic exerciser...

[equipment clangs]

And this terrible
bit of towing.

[crowd cheering]

[man off-screen] Oooh!

[cars collide]

[car alarm blaring]

[Dallas] Did you guess
Newton's second law?

Well, way back in 1686,

Isaac Newton determined
three laws of motion.

The second one states that force equals
mass times acceleration.

But what does that mean
in the real world?

Let's have a look.

A roller skater
moving at speed

delivers an impact force
to her partner

proportional to her mass
and how far she decelerates.

That force is able
to accelerate her partner,

but since she's
a similar mass,

the acceleration
is quite low.

But when that impact is delivered to the
lightweight ball,

its acceleration
is much greater,

sending it flying.

Got it? I hope so because
it's time for the quiz.

What happens when
a relatively large force

is applied to a
relatively small mass?

Maybe this bantamweight
has the answer.

Did you see that coming?
He certainly didn't.

Even the force from
Dad's careful jab

is enough to accelerate
his son's small mass.

[father chuckles]

[Dallas off-screen]
Don't worry, he's fine.

Ah, Ping-Pong.

[man off-screen] Oh!

[Dallas off-screen]
And Ping-Pain.

A table tennis ball
has very low mass,

so even a small force
is enough to accelerate

it quite significantly.

[man] Oh!

[Dallas] Time for question two.

Does Newton's second law only
mean force makes acceleration?

Some days, there's nothing
more relaxing than a drive.

[driver yells]

Oh, how tiresome.

[woman shouting]

The law works both ways.

The tire's sudden deceleration
creates an impact force,

and a very interesting
insurance claim.

[man] This is how we play Pong!

[Dallas off-screen] Here's
another smashing example.

[man] Oh!

[laughing]

[Dallas off-screen] Her
hand decelerating

creates a force on his face.

[man off-screen] This
is how we play Pong!

[Dallas off-screen] Then
you're doing it wrong.

Here's the final question.

What happens when a small force
is applied to a large mass?

What's this poolside
prankster up to?

Looks like the
joke's on her.

[child screaming]

She's small, and so is
the force she applies,

but it's enough to accelerate
dad into the pool,

closely followed by her.

Let's see what these
guys have learned.

Ah, very little.

I wonder if Newton
ever came up

with any health
and safety laws.

[Dallas] Now, you may not know
this, but I once had a job

as a human cannonball
in the circus.

I don't like to brag,
but when I left,

they didn't replace me.

Apparently they couldn't find
anyone of my caliber.

But I still go back,
and of all the circus acts,

I always enjoy trapeze most.

That's gonna make
your head spin.

If you have trapeze skills,
you need never be bored.

I mean, reading the paper
on the way to work

is just so passé.

You've probably already guessed,
but today we're looking

at the art of static trapeze,
so let's not hang around

and swing straight
into the science.

Our trapeze artist
is balanced

while her center of mass
is well positioned

over her base of support.

She swings back and uses
her strong leg muscles

to form a hook
around the trapeze.

Hanging below the bar,

her weight acts
to increase friction

between her clothing
and the trapeze,

keeping her
securely in place.

Then she uses the grip strength
from her hands and arms

to give her body
momentum and rotate it,

to end the move in style.

So, it's all about
a graceful combination

of strength, friction,
balance and momentum.

Now we've seen
the fancy stuff,

we should probably go back
and look at the basics.

[woman off-screen] Monkey roll.

[Dallas off-screen] The names
are so evocative, aren't they?

[woman off-screen]
Split-knee back flop?

[woman laughing]

[Dallas off-screen] Never
heard of that one.

[woman laughing]

And it's for exactly
the same reason

that I am wearing
two pairs of shorts

under my trousers
right now.

You really can't
be too careful.

His grip is good,
providing enough friction

to keep him attached
to the trapeze

as he swings around.

Unfortunately, he's also
trapped his trousers

in that iron grip, too,

which means they stay
attached to the swing

even when he doesn't.

These two are also
learning the ropes,

and the best way
to operate a crash mat.

She has enough grip strength
to hang from his feet

with a little helping
hand on her legs.

But when she swings round,
her motion means

it's difficult for him
to tighten his grip in time

for enough friction
to capture.

So the only question
remaining is...

why the large pause?

[orchestral fanfare playing]

Swinging trapeze this time.

That takes nerves of steel

and complete trust
in your partner,

just like a marriage.

[man off-screen] Ooh!

[Dallas off-screen] Might
need a bit of counseling.

She aims to complete
the hand-over

at the static point
of the swing,

but waits too long
and misses.

She's left holding on
with one hand,

and her grip strength
and friction lets her down.

Straight down.

[woman] Oh! Oh, sh**t!

[Dallas] Some records are
beaten by tiny margins

as incremental advances
mean minute improvements.

So you can never be sure that
you'll be the champion for long.

Unless you are Mikhail Tyurin.

He holds the record for
the longest-ever golf shot,

a massive 1.26 million miles,

but he did have
the unusual advantage

of teeing off from the
International Space Station.

We'll be covering slightly
less ground today,

as we look at mini
golf and putting.

It takes patience and persistence to
perfect your putting.

[cheering]

Timing and precision
are also crucial.

[cheering]

It's a great pastime
to enjoy with your friends.

Unless of course one
of your friends is him.

But if you want
to perfect your putt

and master the short game,

you'll need to understand
the science.

A successful golf putt
requires a small force

applied to the ball that
accelerates it just enough

that it doesn't stop
before the hole

and low enough that it
doesn't jump over it.

The exact right amount
to accelerate the ball

is hard to achieve,

which is maybe why golfers
are paid such a lot.

When a ball is putted a little too fast
to land straight in the hole,

it can ride the inner edge

and roll around the inside of the hole
as it descends.

If the resulting velocity
is sufficient,

then the centripetal force won't be
enough to keep it on its

circular trajectory and it'll
fly back out.

[man groans]

Armed with this handy advice,

we should be able to sink a few
ba*ls with minimum frustration.

Let's see.

Blindfolded?

If he pulls this off,
I'll eat my hat.

And by "hat,"
I mean sandwich.

He gets exactly the
right amount of force

behind the ball to achieve
the required velocity,

and the, let's be honest, luck
to hit the hole straight on.

[cheering]

[man off-screen speaking Japanese]

[Dallas off-screen] Could
this pint-size putter

be the next golfing
superstar?

[crying]

Well, he's certainly got
the right temperament.

This tantrum was
due to the ball

moving slightly faster
than the ideal velocity.

This meant that its
momentum was greater

than the centripetal force
offered by the hole,

resulting in the
ball popping out

and the kid losing his cool.

[crying]

So, that's mini golf.

[boy] Ow!

[Dallas off-screen] Not
as fun as it sounds.

Aristotle is supposed
to have once said,

"There is no great genius
without some touch of madness."

And going by that logic,

this lot must be
seriously intelligent.

[music plays through credits].