01x04 - Karate Flops

[bunniefuu]

RICHARD: Standby.
It's the Science of Stupid.

- [electricity crackling]
- [glass shattering]

[alarm blares]

[reading]

[lively folk music playing]

Yes, this is the show that fuses
science and stupid.

Over the next half hour,
we present amateur scientists,

self-selecting for
the right stuff of stupidity.

They'll show us exactly
how they veered off path.

As they tested scientific principles
like torque,

gravity,

and Newton's laws.

MAN: Oh, you okay, bro?

RICHARD: They found out the hard way.

WOMAN: Oh, my God!

RICHARD:
Try and break the laws of science,

and they'll break you.

[engine revving]

Listen up, people.

If you're thinking of trying out
any of this stuff yourself,

remember, it could be fatal.

Oh!

RICHARD: Or might just hurt.

[glass shatters]

It's the Science of Stupid.

Coming up, we'll see how
the first law of motion

can affect your drift.

When throwing the hammer
can knock you down.

MAN: Oh!

RICHARD: And when electricity gives
the ultimate shock to the system.

- [electricity crackling]
- [all yelling]

[glass shatters]

But first, this.

- [electricity crackling]
- [glass shatters]

Ice.

It sank the Titanic,

and can cause all manner
of mishaps and accidents,

and that is why it needs to be
treated with respect.

[upbeat music playing]

- [man yelling]
- [woman yelling]

WOMAN: Now you don't need to shower.

The problem with ice

is you don't know how thick it is
until it's too late.

Falling through ice is potentially deadly,

but what exactly is ice?

Here's what you need to know.

When water temperature falls below zero,

tiny ice crystals form and grow.

They then fuse,
making even bigger crystals,

thickening and strengthening
the layer of ice.

There's always a thin layer
of water on top,

which makes it slippery.

Ice needs to be at least
three inches thick to walk on,

but the weakest points
will be in the middle,

and at the margins.

- [cracking]
- [man laughing]

In areas where the temperature
remains below freezing

for long periods of time,

ice becomes incredibly thick and strong.

To land this hundred ton
Ilyushin in Antarctica,

the ice has to be at least
three feet thick.

So, you get the picture.

Ice can be incredibly strong,

if the temperature is low enough

for the ice to grow sufficiently thick.

Well, most of us don't live in Antarctica,

so the brave climatic researchers
we're about to meet

have had to conduct their experiments

with slightly less predictable ice.

- [bleep]
- RICHARD: He's a confident looking chap.

But how cool is he?

- [crashing]
- [man yelling]

Not as cool as the ice,
it seems, but arguably as thick.

You need almost 1,000 pounds of force

to break three inches of ice.

He's probably just experienced
a bit less than that,

all on his bottom.

And sometimes that layer of water
can be a bit deeper,

and disguise the ice below.

All he's managed to break is his skull.

[man laughing]

Many people die every year,

accidentally falling through ice.

This chap is planning to jump
into the center of the pond,

where the ice is weakest.

- [splashing]
- WOMAN: Ooh! Aah!

RICHARD: As many as 20 percent
of people can die from shock,

after being in frozen water
for just five minutes.

Most people would be
unconscious after 15 minutes.

A two degree loss of
core body temperature,

and hypothermia sets in.

Time for a nice, hot drink.

[bleeps] scary as hell!

[woman whimpering]

- [electricity crackles]
- [creaks]

How much electricity can k*ll you?

The electric chair carries around
two and a half thousand volts.

That's more than ten times
the electric supply in your home,

but never mess
with that domestic 230 volts,

because it's still highly dangerous.

MAN: Hey, let's fix this.

You just plug it right
into the electrical--

- [electricity crackling]
- [clattering]

RICHARD:
Oh, did he just get a little shock?

The electrical current causes muscles
to contract involuntarily.

It's known as the grabbing effect.

Maybe we won't plug it
into the electrical outlet.

Yes, touching live wires can end badly.

Unfortunately, human beings
and electricity go together

dangerously well.

To flow continuously,

electricity needs a complete path,
or circuit.

A circuit can be created by anything
that conducts electricity.

Salt water is very good
at conducting electricity,

and because the human body
is 70 percent water

and contains lots of salt,
we make great conductors.

So if you touch an exposed wire,
you will complete the circuit,

getting a shock as the current
flows into the ground.

An insulator, like rubber soled shoes,
can break the circuit,

stopping electricity flowing
through your body

and into the ground.

But remove the shoes,

and the current will go
straight through you,

causing an electric shock.

[electricity buzzing]

[rock music playing]

An 8,000 volt electric fence
has a very low current.

120,000th of an amp is probably not enough

even to k*ll a squirrel.

- [electricity crackling]
- MAN: Aah!

RICHARD: But quite enough
to tickle a man in shorts.

His bare knees touching the ground
have completed the circuit,

sending the current from the fence
through his body,

and into the ground.

- [electricity crackling]
- MAN: Aah!

RICHARD: Touching a friend
adds them to the circuit.

And because he's got bare feet,
he's not insulated.

- [electricity crackling]
- MAN: Aah!

RICHARD: Which completes the circuit.

Does electricity still flow through
several people holding hands?

WOMAN: All right! Yep!

- [electricity crackling]
- ALL: Aah!

RICHARD: Yes. Yes it does,

if the person on the end
goes all hippie and barefoot.

What if they insulate themselves
with wooden and plastic furniture?

- [electricity crackling]
- ALL: Aah!

RICHARD:
They get a shock, and we get a laugh,

because the chap on the end
has removed his shoe,

completing the circuit.

[electricity crackling]

Electric fences are really
for containing animals safely.

- [electricity jolting]
- [pigs squealing]

If they were both wearing rubber shoes,

only one of them would have had
a surprise encounter from behind.

- [electricity jolting]
- [pigs squealing]

- [glass shatters]
- [electricity crackling]

[lively folk music playing]

DIY removals can
sometimes end in scientific disaster.

Can you guess what scientific principle

these fellows have overlooked

as they try to tip their couch
over the balcony?

- [glass shatters]
- [electricity crackling]

The scientific principle
these fellows have overlooked

is the principle of pendulums.

Our two strong men are trying to do
a bit of furniture moving.

Hold on. Are they trying
to get it in or out?

[glass shattering]

They think they're being clever,

balancing their couch
on the banister like a seesaw.

But when the couch gets stuck,

instead of gravity just pulling it down
like a seesaw,

it swings back 'round on itself,

more like a pendulum.

[glass shattering]

- [electricity crackling]
- [metallic squeak]

Did you know that in the US alone,

over 20,000 kids a year

go to hospital with
shopping cart related injuries?

Here's a demonstration of why.

We're the street bobsled team.

MAN [imitating Jamaican accent]:
Yeah, man, bobsled. Here we go.

- Here we go, baby.
- Bobsled.

[both yelling and laughing]

- [crashing]
- [groaning]

Science tells us
that was almost inevitable.

Unlike some things in life,
when it comes to wheels,

size matters.

The wheels on a monster truck
are big and fat,

for going over bumps.

But the wheels on a shopping cart
are small and narrow,

to reduce friction during steering
on a smooth, flat surface.

But when they encounter an obstacle,

more of the impact force will
push backwards on a small wheel

than on a bigger wheel.

And carts with people in them
have a high center of mass,

making a vehicle that's
just asking to topple over.

Don't worry, he's not real.

But she is.

[man laughing]

Having no engine
isn't necessarily a bar to acceleration.

All you need is a hill start and gravity.

Remember, little wheels,
plus high center of mass equals...

[crashing]

Face-plant.

That steep slope might be smooth...

[crashing]

But the sudden change of pitch

where it meets the ground
becomes a solid obstacle.

If you hit a big enough obstacle,

those little wheels will stop altogether.

MAN: Aah!

RICHARD: Becoming a handy pivot.

[crashing]

But watch where you fling your passenger.

Small wheels, high center of mass,
big obstacle...

It's the perfect recipe
for an express checkout.

MAN 1: Where are you?

MAN 2: Argh!

- MAN: What are you doing here?
- RICHARD: No big fat wheels

means that a cart can't absorb
any bumps in the ride.

Maybe an inflatable ring will fix that.

[clangs]

Then again, maybe it won't.

- [men off screen laughing]
- MAN: Ow!

RICHARD: On flat ground,
all you have to worry about is balance.

Which, with a high center of gravity,
is easier said than done.

Two mistakes here.

[crashing]

Shopping trolleys work best
in a supermarket,

and remember what your mum said
about riding on the back?

It still stands.

And with two in the cart...

- [woman screams]
- [crashing]

Come on, it's obvious.
Even more top heavy.

MAN: And we're done.

RICHARD: Would bigger wheels
help make our trolleys safer?

In this case, no.

Like an overloaded truck,
its high center of mass

means it's still very likely
to topple over.

- [electricity crackling]
- [creaks]

You should always drive
with due care and attention.

Car related stunts like drifting
should always be left

to the experts and kept off
the public highway.

Sadly though, there are many
amateur enthusiasts

only too eager to prove themselves
by putting the pedal to the metal.

[tires screeching]

Or in this case...

[crashing]

Metal to the metal.

[crashing]

Despite appearances,

and many of the practitioners,

it's not just a mindless activity.

There really is a lot of
physics involved in drifting.

Unlike normal cornering,

when the driver wants the car
to stick to the road,

when drifting,
he wants it to slide around.

Drifting is a way of
using the car's inertia,

its tendency to go in a straight line,

following Newton's first law of motion.

First, he deliberately
reduces the friction

between the rear tires and the road

by spinning the tires very fast.

This loses the traction,
and makes the back end spin out.

At the end of the turn,
steering out of the corner

decreases torque,
making the back wheels regain grip.

Get my drift?

Question a man's driving skills

and you attack the very
foundation of his masculinity.

So I won't be quizzing any of these
hot wheeled heroes anytime soon.

This low budget dr*fter has mastered

the art of reducing friction on
those spinning back wheels.

[crashing]

But when it comes to regaining
friction and control,

that wet surface prevents
the tires from gripping.

[crashing]

The open road is no place for drifting,

and this guy's way off track.

[crashing]

Actually, he does start on the road.

But then he goes off it and onto the grass

and loses traction.

Before he can regain grip
and recover steering,

the wall brings him to a smashing stop.

On a closed course, here's what
a professional would have done.

Steering out of the drift reduces torque

and stops the car
spinning round completely.

Sometimes drifting isn't even planned.

[tires skidding]

[crashing]

MAN: I got that on video.

RICHARD: Thanks to our eagle-eyed,
giggling cameraman,

we're able to see how flooring it
in a powerful supercar

causes those wheels to spin
and lose friction,

creating an impromptu drift.

MAN: No way!

RICHARD: Yes way.

But look on the bright side.
Great parallel parking there.

Has this guy got it?

Well, he's got the muscle.

Now just look at his wheels spin,
reducing the friction.

And there it is,
nice steering out of the drift.

Ah, look,
steering into the drift for torque

can give the car a 360 degree spin.

Yow, if only he had the road
all to himself,

it would have been better.

MAN: Woo!

- [glass shatters]
- [electricity crackling]

As a man reaches out to his inner Tarzan

to swing in a circle,

he must beware the hidden forces at work

that can end in unexpected collisions.

Like this.

MAN: I got you baby!

- [yelling]
- [snaps]

Did you do that on purpose?

[bleeps]

Swinging into solid objects,

might at first glance,
be simple buffoonery,

but it's actually the result
of failure to grasp

some rudimentary science.

When you jump onto a rope,

inertia would carry you straight ahead.

But if the attachment
is not directly ahead,

centripetal force will
pull you in a circle.

The faster you go, the larger the circle,

and rope tension increases

as centripetal force
keeps you from flying away.

So if you want to jump off,

you've got to let go
at just the right moment.

And then gravity will bring you
back down to Earth...

with a bump.

MAN: One, two, three, go.

RICHARD:
This would-be pirate of the Caribbean,

hopes to jump off the boat
and swing into the water.

But the centripetal force
keeps him flying in an arc

back onto the boat around
the rope's fixed point.

[crashing]

He needs to know when to hold on,
and when to let go,

which is about now.

[crashing]

Well, he will know, for next time.

[crashing]

This young chap
doesn't want to go into the water,

but over it and back again.

There goes the centripetal force
pulling him right around

in a circle.

That happens to contain a tree.

[man laughs]

Who said playing in
the fresh air was good for kids?

[man laughs]

[crashing]

Imagine a giant tetherball,

with the tree as the post to pivot around.

His speed has made
his swing circle bigger,

making it too big for the clearing.

I think he's another one who
couldn't see the wood for the trees.

Hmm. Felt them, though.

Argh!

RICHARD: Here, the rope is fixed,

but the crane arm is moving,

because the aim is to flick him out.

[crashing]

MAN: Oh, dear!

RICHARD: Remember,
the body's inertia means

it will move in a straight line,

without centripetal force
keeping it moving in a circle.

When the crane arm
suddenly stops for a flick,

it throws a spanner in the works.

[splashing]

MAN: That's probably a broken leg.

Probably!

Could be a hospital. Oh, dear, oh, dear!

RICHARD: Thank you, doctor.

- [electricity crackles]
- [metallic thud]

The athletic discipline of discus

hasn't changed much
for two and a half thousand years,

since the Ancient Greeks
would toss discs made from stone,

bronze, iron or lead.

That's a cone made of plastic.

Not a carefully weighted discus.

Oh!

The only disc
you'll find me tossing is a compact disc.

I got an MP3 player for my birthday.

But to throw a discus well,
you also need good spin speed

and the right angle.

The rotational force of your body
as you spin 'round is torque.

The more torque you have,
the faster you speed up,

increasing the velocity of the discus.

Then, because Newton's first law
states that an object

will continue to move in a straight line,

you let go.

The optimum release angle is 35 degrees.

When you release the discus,
it'll fly off in a tangent

to the circle, like a stone from a sling.

But the more you spin,
the more likely you are to fall over.

When you get the timing right,

you can use your torque
to achieve amazing feats.

[crashing]

He's got good torque,
but he doesn't say much.

Yeah.

RICHARD: All the torque
in the world won't be any good...

if you drop the discus.

Or if you haven't got a discus at all.

[crashing]

When you are trying to throw
an actual discus,

plenty of torque and no grip
are not happy bedfellows.

The Hammer is a younger sport than discus

by over 1,000 years,

but the basic principles at work here
are just the same.

Unlike the discus,

the hammer thrower stays
in the center of a bigger circle

created by the hammer

going around at up to 65 miles an hour.

- [crashing]
- MAN: Oh.

RICHARD: All objects go straight,

unless a force acts on them,

so the hammer will fly off,
unless you hold onto it.

But you have to let go at the right time.

[crashing]

Every pound in additional weight

increases the force
that you need to control.

[crashing]

Combine that weight with a lot of speed,

and the slightest slip
can end in catastrophe.

The world record distance
for the hammer throw is 285 feet.

That's not it there.

Nor is this.

[crashing]

Remember, the hammer
is traveling bigger distances

at the outside of the circle
than at the center,

but with the same number of turns.

So whilst his body is only
spinning at five miles an hour,

the hammer is going at
over 50 miles an hour.

Doubling the spin speed
quadruples the force you need

to keep the hammer going in a circle.

Make sure you're strong enough.

[crashing]

That's why exercise
isn't always good for you.

[crashing]

- [glass shatters]
- [electricity crackling]

You might have had your bellyful

of bone breaking, face-planting
and mayhem for now,

but if you ever find yourself
tearing the soggy envelope

of scientific exploration,

it won't be the science of the classroom

that stops you getting
your head smashed in,

but your newfound knowledge
of the Science of Stupid.

[crashing]

- [electricity crackling]
- [pigs squealing]

- [crashing]
- MAN: Oh!

- [tires skidding]
- [crashing]

[crashing]

- [tires skidding]
- [crashing]

MAN: I got that on video.

MAN: Argh!

- [electricity crackles]
- [screaming]

[dog whining]

[splashing]