01x07 - Rooftop Drops

[bunniefuu]

RICHARD:
This is the Science of Stupid.

- [electricity crackling]
- [glass shatters]

- [alarm blares]
- [reading]

This is the show that combines
stupidity and science

in a mix so volatile,
it'll take your breath away.

Over the next half hour,

we'll see acts of hair-brained hilarity

and then explain the science
behind what went wrong.

Consider this a guide
to what you should never do.

If you ignore the laws of science,

they'll pay you back...
with painful dividends.

So observe our intrepid investigators
from all around the world

and learn why physics can be
fly by the seat of your pants stuff.

Never try anything you see
in this show at home,

or anywhere.

Yes, science will slap you
wherever you are.

Welcome...

to the Science of Stupid.

- [electricity crackling]
- [glass shatters]

On this show, we'll see
the effects of expanding gases.

[expl*si*n]

And the effects of kinetic energy.

But first, this.

[glass shatters]

[electricity crackling]

Scientists and engineers
have spent decades

developing accessible safety technology

for the masses.

But there's always
a joker who comes along

and puts all that hard work
to a different use.

If you don't believe me,
check out what these pranksters did

with the humble airbag.

At Christmas.

"May your holidays
be full of surprises and joy."

- [screams]
- MAN: Oh, God! Oh, my God!

ALL: ♪ Happy birthday... ♪

RICHARD: At a birthday party...

and even a wedding.

[expl*si*n]

WOMAN: Are you [bleep] kidding me?

Jason! God damn it!

RICHARD:
At least she saw the funny side.

- [indistinct chatter]
- [laughter]

Despite what you've seen,

the airbag is an extremely complex
piece of engineering.

When compared to cars
with just seat-belts,

they've reduced deaths
in head-on crashes by 30%

since their introduction.

Here's how.

Most people know airbags inflate quickly,

as fast as 30 milliseconds.

But the really clever part of the airbag

is that it's fully inflated

before the passenger hits it
and then slowly deflates,

absorbing force.

Were it not to do this,
it would cause serious injury.

Inflating at up to 250 miles an hour,

it packs the same punch
as a professional boxer.

[bell ringing]

So here's a demonstration
of that expl*sive force

as two airbags
are put inside a dryer.

Why they've been put there,
I don't know.

MAN: We are ready to blow.

[laughing]

RICHARD: Over 20 gallons of gas
in an enclosed space.

MAN: Holy [bleep]!

RICHARD: Well, I guess if you live
in the country

you need to make
your own entertainment.

MAN: Wow.

But remember, that expl*sive power
is not what saves you.

It's the cushioning effect
of the deflation.

An inflating airbag
and a person don't mix.

If you don't believe me, check this out.

Our next demonstration suggests

that the weight of an armchair
and a fully-grown man

is no match for an airbag.

And what about a 400-pound mower?

MAN: Oh, my God!

RICHARD: It's not God, it's physics.

An inflation force
of 750 pounds to be precise.

- [indistinct chatter]
- [laughter]

And don't forget, it's the deflation


that saves you.

It's definitely not the initial expansion,

as these backroom scientists will testify.

Remember, the airbag should be deflating
when you make contact.

- MAN: Oh! [groans]
- [laughter]

RICHARD: Otherwise the only thing
being absorbed...

is the sound of your beach bum.

MAN 1: Are you OK?

MAN 2: We are not doing that again.

- [laughter]
- RICHARD: A good decision, I think.

[groaning]

And check out this pair
of budget thrill seekers.

I love cigarettes.

- [expl*si*n]
- [both groan]

They're looking into the big bang theory.

Sitting an inch or two away
from the inflation

before it deflates

means you'll feel
all that expl*sive force

right up inside you.

MAN: That, like, ruptured my stomach.

- [electricity crackles]
- [creaks]

Despite first appearances,

the humble seesaw
is actually one of the most dangerous

of playground activities.

Especially when
you don't utilize it correctly.

- [groans]
- RICHARD: Ouch.

If you want to avoid
a trip to the hospital,

you might want to differentiate
your pivots from pain.

Here's the science.

When stripped down to the basics,

a seesaw is a lever
balanced on a central pivot.

When two people of the same weight

are sitting equal distance from the pivot,

they'll be evenly balanced

and they'll experience
an equilibrium position.

A small input of force from the legs

moves you up and down.

An increase in weight on one side

will disturb that equilibrium.

Counteract this problem by moving
the heavier weight closer to the pivot,

as this has the effect of decreasing
the leverage applied to the lighter side.

Get it right, you can do this.

Both girls are of the same weight

and equal distance from the pivot.

It's poetry in motion.

Up.

Down.

Up.

Down.

Up.

Mesmerizing, isn't it?

But it doesn't take a lot
to upset that equilibrium.

- WOMAN 1: Ready, ready, ready.
- WOMAN 2: Ready?

- [screams]
- [laughter]

RICHARD: Oh, dear.

Let's just see that again
but with arrows.

One of the riders is heavier
than the other.

Sorry, but that's you on the left.

It just is.

If she'd sat nearer the pivot,

the seesaw would have
regained equilibrium

and she wouldn't have had to rely
on such a big push off.

WOMAN: Ready?

- [screams]
- [laughter]

RICHARD: A push off
that proved to be her undoing.

If you add height to that extra weight,

the equilibrium can be thrown sky high.

No prizes for spotting
that this isn't a seesaw.

That said, this air bed
can be used to similar effect.

A greater mass landing on one side

results in higher velocity on the other.

Lucky the window was closed.

- [electricity crackles]
- [metallic thud]

Can you guess what scientific principle

this human cannonball
is about to experience?

[glass shatters]

[electricity crackling]

Who guessed the fate
of this flying physicist?

The scientific principle
behind this clanger is momentum.

Momentum is mass times velocity,

and at 50 miles an hour,

our cannon fodder has a lot.

The net's job is to
slowly reduce that momentum

and lower the impact of force.

Unfortunately the poles holding the net

haven't been tethered well enough
for such a force.

No broken bones,
but the same can't be said for his pride.

[glass shatters]

[electricity crackling]

My favorite time of year is winter.

The first snow has fallen,
and in a scene played out across the land,

children wrapped up in hats and scarves

rush to their nearest hill,
dragging sledges.

But it's not too long
until the virgin white snow

is stained with blood and tears.

MAN: Ohh!

I'm afraid those smashes
were pretty much inevitable.

You see, the problem with most sledges

is that they're bad at stopping.

The reason for that lies in the science.

Like ice, snow is covered
with a very thin layer of water

that provides a fluid barrier

between the sledge
and the surface of the snow.

And it can be as thin
as eight millionths of an inch.

This film acts like a lubricant,

minimizing friction,
allowing the sledge to slide.

Newton's first law of motion
means you'll keep going

until something stops you.

Have you got that?

You need a thin layer of water
to minimize friction.

So it's best to wait until winter.

Once the snow comes,
there's a lack of friction.

So the steeper the hill,

the greater the force of gravity

and the faster you'll go.

So even the smallest bump
will send you flying.

Oh, my God. My face.

RICHARD: It is amazing

what eight millionths
of an inch of water can do.

The fastest speed ever recorded
on a gravity-driven sledge

was 62 miles per hour.

So it is pertinent to remember
Sir Isaac Newton's first law of motion,

you'll always keep going...

until something stops you.

So you might need a helping hand.

Or a helping paw.

Here they come down the hill.

It looks like Ruben is in the lead.

And here comes...

RICHARD: Typical news reporter,
giving every story plenty of spin.

That was a bad idea.

- [electricity crackles]
- [creaks]

Parkour is that crazy sport
invented by the French,

where they jump with cat-like agility
through an urban environment.

There are loads
of different moves to master

amidst the concrete jungle.

But some are harder than others.

MAN: [bleep]!

RICHARD: So maybe
we should start with the basics.

One of the nuts and bolts tricks
is the gainer.

A backwards somersault
whilst still moving forward.

When done correctly,
it can be pretty impressive.

MAN: Oh-h*-h*!

RICHARD: When done badly,
it's very painful.

MAN: Right on the snoz!

RICHARD: To help him
and other parkour enthusiasts,

here's some science.

The key is to turn
that horizontal speed into rotation.

Our expert does this
by swinging his arms

and kicking up.

He then spins by tucking in his legs.

The laws of angular momentum will dictate
how quickly he spins.

If he halves his length,
he'll quadruple his spin speed.

Got that?

[laughter]

Anyone can have the occasional slip up.

Go on, have another go.

Now, that's--that's more like park-floor.

When the insanely brave get bored,

they mix things up a bit,
taking a standard gainer

and throwing in an object to vault over.

It's known as a "Kong gainer."

It's also one of the hardest moves
in parkour to master.

Here's why.

It involves the practitioner
approaching the wall

with plenty of speed.

Instead of using their legs for leverage,
they use their arms,

pushing themselves
into a full rotation.

But just like the gainer,

the same rules of science
and common sense still apply.

Like actually beginning the rotation.

MAN: Ow!

RICHARD: Pay attention.

When length doubles,
spin speed is quartered,

whilst neck length can also be reduced.

And make sure you get enough height,

because you don't want your spin...

unspun by your face.

I just tried a Kong gainer.

- Right there.
- MAN 2: Mm!

MAN 1: Yeah.

[glass shatters]

[electricity crackling]

Men, let's be honest,

building a house
is a pipe dream for most of us.

But when it comes
to knocking something down,

there's no need
to call the professionals.

How hard can it possibly be?

MAN: Make one more here,
see what happens.

MAN 2: Oh, no.

RICHARD: Perhaps it is best
to call the professionals.

MAN 2: Fail.

Most of us won't ever
actually need to take down

a 60-foot-tall tower,

but we might have a wall
or shed that needs demolishing.

First up, here's some
basic common sense rules.

Make sure you wear protective gear.

Familiarize yourself with the tools.

WOMAN: The other way.

[woman yells]

RICHARD: And always
clear your surroundings.

MAN: Oh, my God, this is so stupid.

Somebody needs to call the police.

RICHARD: So stop filming it
and phone them.

MAN: This is bad.
That could've k*lled someone.

In 2012, there were 775 deaths
in the US construction industry,

so if you want to avoid becoming
just another statistic, watch this.

Buildings are designed
to withstand severe loads

with a very low chance of collapsing.

But even when unloaded,
removing load-bearing walls

is a dangerous road to catastrophe.

Remove too much
and you'll literally bring the house down.

So instead, start from the top
and work down

to prevent accidental collapse
of the whole structure.

Put even more simply,
take the roof off first.

These guys look like
they know what they're doing.

The shirts say it all.

Oh, you're supposed to take the roof off.

MAN 1: That's the way to do it.

WOMAN: No, it's not.

Mark, I'm gonna kick your [bleep] a*s.

RICHARD:
One raw bottom later...

WOMAN: Beautiful.

Now that's the way you do it.

Yeah, it moved.

RICHARD: You have to take the roof off.

Just ask Jacob Weir.

MAN: That dropped an inch.

RICHARD: Where do you think
Jacob's gone wrong here?

Let's rewind.

By removing all this,

the roof is now
dangerously unsupported,

which means one little prod...

and Jacob nearly lost his leg.

Don't worry, he's OK now.

- [electricity crackles]
- [creaks]

Now, I do love a beach holiday,

that feeling of soft sand
between your toes,

the sound of the ocean.

The water lapping away at your ankles.

And then...

MAN: Oh, [bleep]!

RICHARD: ...sometimes Mother Nature
can be mischievous.

[screams]

So if you want to avoid a soaking,

here's some swell science
to help you deal with life at sea.

At sea, a wave is not the result
of water moving to shore

but actually created
by the wind moving across it.

It's this that we see
as ripples on the surface,

moving across the sea.

It's a bit like how a Mexican wave works.

It's not the people that are
moving around the stadium.

It's their combined staggered movement

that gives the impression of the wave.

The key to not being engulfed
by that approaching wave

is to reduce the surface area
in contact with the wave.

And it means
that in the harshest of sea conditions,

you can do this.

By reducing surface area
in contact with the waves,

this boat remains afloat
in massive seas.

Of course, most of us will rarely
find ourselves at sea in a storm

but even the waves on a beach
can pack a punch.

Waves break
when they reach a shallow shore,

like this rocky one.

The top of the wave
overtakes the bottom,

creating a huge breaker.

With one cubic yard of water
weighing over a ton,

it really pays to avoid Neptune's wrath.

These boys think they're safe
with no rock for the waves to break on.

[laughter]

But that wall's a pretty good substitute.

You can run from science,

but you can't hide.

[laughter]

One of the biggest waves ever recorded

was 32 meters tall during Typhoon Krosa.

That's as tall as a ten-story building.

So it's obvious, the bigger the wave,

the more energy is carried.

Double the height,
it's quadruple the energy.

And that is why it's so important
to respect the science of waves.

Ignore it at your peril.

Especially close to shore,
where the waves are breaking.

These young hipsters
look like they're having fun

in their power boat.

All they've got to do when
meeting those pesky waves

is hit them at the right angle.

I guess that wasn't the right angle.

At least the captain
went down with his ship.

Literally.

Fancy another day out tomorrow, girls?

[glass shatters]

[electricity crackling]

[glass shatters]

That's enough trials and tribulation
in the traumatic world of physics.

Science can really ruin your day,

so please don't try
any of this at home.

But if you do, I don't know,

make sure you've got
good health insurance?

No, just-- just don't do it.

There's always somebody else who will.
Trust me.

MAN: Oh, my God!

MAN: Oh!

MAN: Oh!

- Right there.
- MAN: Mm!