03x16 - Ski Lift, Doors and Bubble Wrap

[bunniefuu]

[Richard]
This is the Science of Stupid.

-[electricity crackling]
-[glass shatters]

[alarm blares]

[man screams]

Yes, this is the show
where science meets stupidity.

[yells]

A half hour of ill-advised stunts

performed by people with too much time

and too little sense.

[yells]

We'll explain what went wrong and why

through some key scientific principles,

such as combustion,

elasticity,

and that old devil called friction.

[yelling]

So don't be a statistic, be a scientist,

and take notes on the Science of Stupid.

-[glass shatters]
-[electricity crackling]

In this show,

we'll see how angular momentum
can bring the house down,

the impact force of a m*ssile...

[groans]

...and the surprising side
of a turning effect.

[tires screeching]

Nice cushions.

But first, this.

[glass shatters]

[electricity crackling]

[glass shatters]

The boffins here
at the Science of Stupid Laboratories

have been searching long and hard

to find a device that can cause
more pain and discomfort

than the skateboard.

Well, they've finally cracked it,

and it's called the caster board.

Instead of four regular wheels,

you get two swiveling casters.

And if that wasn't wobbly enough...

[groans]

...caster boards are all swivelly
in the middle as well.

[moans]

That wasn't a very scientific explanation
of caster boards,

but this is.

Whilst a skateboard
has corner wheels fixed to axles,

caster boards have two pivoting casters

mounted on an articulated board.

To move forwards, the rider uses his feet

to twist the board sections
in smooth oscillations.

Because of their inclined axis,

this sideways force translates
to a component of force

that acts forwards.

To steer, the rider must
lean into the corner

whilst ensuring he doesn't move too far

beyond the small base of support.

When it comes to getting from A to B,

caster boarders have two options.

They can rely on good old gravity.

[man] Oh, my God!

-[yells]
-[man laughing]

[Richard] Or option two,

by moving her feet back and forth,

she's creating oscillations,

[screams]

and now she's not.

[man, off-screen] Oh, no, I feel so bad!

[Richard] Yeah, but you sound so happy.

[man laughs]

Keeping your center of mass
above your base of support

is vital for balance.

[screams]

[woman, off-screen] Oh, my God!

-[Richard] See what I mean?
-[woman, off-screen] Are you okay?

[Richard] Oscillating on a small base
of support is hard enough,

bounce a ball off your face,

-[woman, off-screen] Oh, my God.
-[Richard] ...and it's really tricky.

[woman, off-screen]
Are you okay? [laughing]

[Richard] Having mastered
balance and propulsion,

you'll inevitably come across an obstacle.

This is usually a good time
to learn how to steer.

Even at speed,
caster boards are extremely agile...

[groans]

...in the right hands, of course.

Had he angled his front wheel
into the turn

and his rear wheel away,

the wheels would have
redirected his momentum,

and he would have made the turn.

But he didn't.

[electricity crackling]

[creaks]

[clatters]

If you've got a whopping load to transport

and it's simply too big for your car,

all you need is a trailer
and these easy to follow tips.

Before setting off, ensure your load
is secured to your trailer.

[people screaming]

They didn't.

When turning,
give yourself plenty of space...

[tires screeching]

...but not that much.

[bleeping]

And when passing slower vehicles,

make allowances for your trailer.

-[horn blaring]
-[tires screeching]

You'll need more room than you think.

The biggest issue with towing trailers

is a phenomenon known as fishtailing.

If you're not familiar with fishtailing,

it's when you look in your wing mirror

and you see your trailer doing this.

It's not good.

Left unchecked,
this side-to-side swaying

can become an issue.

[tires screeching]

[indistinct chatter]

See what I mean?

So if you want to avoid
dumping your precious cargo

on the hard shoulder,
you'd better listen up.

A fishtail can very easily
escalate into a jackknife.

Confused?

Well, here comes the science.

If a sideways force pushes a trailer,

it will twist about its tow point.

The force from the towing vehicle
will swing it back,

but its inertia can also lead
to an overshoot,

causing an oscillation.

If the driver's corrective steering

is out of phase with the trailer,

it can increase that snaking motion.

This can cause a loss of traction,

exerting a turning force
on the back of the car,

jackknifing it out of control.

The right way to control
a fishtailing trailer

is to ease off the gas

as soon as you become aware
of the wobble,

bringing the trailer safely back
behind your car.

But we don't always do
the right thing, do we?

Oops.

The force from the passing truck
started an oscillation,

and as the heavy trailer
had more inertia than the car,

when the driver slammed on the brakes,

the trailer continued...

which was unfortunate.

Driving through Australia's vast outback,

you can go for hours
without passing another vehicle.

-[horn blaring]
-[tires screeching]

Well, what were the chances, eh?

To help reduce fishtailing,

most trailers are designed
to be low to the ground

with a low center of gravity,

increasing stability
and reducing the chances

of being blown across the road.

But there's an exception to every rule.

In this case it's called a caravan.

This driver's in a bit of a hurry
to start his holiday,

but he needs to take care.

A caravan's high center of gravity
and un-aerodynamic shape

make them more susceptible to...

Oh.

Well, that, really.

The fastest recorded caravan
clocked 142 miles an hour.

These ones are going a little slower.

Oh, dear, holiday ruined.

A cheeky nudge from behind
increased the turning effect

at this van's pivot.

It became unbalanced...

and it went.

The owners will be heartbroken.

[man 1] That was excellent mate, that was.

Enjoyable!

[man 2] Very enjoyable!

Worth half a lap.

[man 1] Yes.

[Richard] The makers of Science of Stupid
would like it to be known

that many caravans were hurt
in the making of this program.

I mean many.

[electricity crackles]

[clatters]

Can you guess what scientific principle
these workmen are about to demonstrate?

Mull it over.

[glass shatters]

[electricity crackling]

[glass shatters]

Did you guess the science
we're about to see?

[man screams]

He certainly didn't.

But it was sheer strength.

The roof is built to withstand
a load spread over a wide area,

but since the cement
was poured onto a small area,

the load exceeded the sheer strength
of the single beam.

And...

-[yodeling]
-[man screams]

...it gave way.

Yeah, you might be a bit stiff
in the morning.

[electricity crackles]

[creaks]

I'm really surprised by the diversity
of the subjects

we cover on Science of Stupid,

but when they told me we were
looking at air fares, even I was...

What's that?

"Air flares"?

Nope, not a clue.

Oh, I see.

You take the classic break
dance move, the windmill,

and give it lift.

Perfecting the air flare needs practice,

dedication,

and support.

[woman] Are you going to keep going
until you break something, Alex?

[Richard] Did you know that break dancing
is thought to get its name

from the '70s DJs
who played the instrumental breaks

in dance music?

Nope, well, if you think
that's interesting,

listen up whilst I rap
about the science of air flares.

Leaping onto his hands,

he starts to spin
with relatively low angular velocity.

He keeps his legs stretched out,

creating a large moment of inertia

and generating plenty
of angular momentum.

Pushing down on the floor
then creates a reaction force,

lifting him off the ground.

Spinning on one hand
leaves you seriously unstable,

lose friction and you could be
facing a major slip-up,

so I suggest you put
in some practice first.

Let's start off gently.

Ah, promising.

Not bad.

Is your neck supposed
to be that bendy?

When his hand lost friction
and slipped away,

it left his center of mass unbalanced,

which is a real pain in the neck.

[man, off-screen] That was sick.

[Richard] Yeah, you'd better check
it's still on, mate.

An air flare requires
an expl*si*n of angular momentum

to create the energy
required for lift off.

Just do make sure all of that energy
is going where you want it to.

This dancer has moved
all of his furniture,

giving him plenty of space to practice.

[glass shatters]

Ah, well, it is cool break dancing.

Winding up for an air flare,

this king of spin
has lots of angular velocity...

-[screams]
-[people shouting]

...but not for long.

He should learn to watch where he's going.

So what have we learned?

Well, I don't know about you,

but what he's learned
is that if you're going to generate

all that angular momentum
with your legs,

make sure your arms can keep up.

[groans]

[bell rings]

[beaker shatters]

[gurgling]

And now it's time
for today's science lesson.

This is where we take a serious look

at one of science's
fundamental principles.

See if you can guess
what today's star principle is

from the following.

This guy...

[man, off-screen] He's coming at me!

[Richard] ...these people...

[all gasp]

...and this cat.

[cat meows]

[items clatter]

Okay, the last one may have thrown you,

but we're talking about waves.

More than just a way of saying hello,

waves can also be a tad destructive,

so here are three crucial things
you need to know

about the science of wave power.

As waves pass through,

the particles of a substance oscillate,

giving energy to nearby particles,

and allowing the wave
to move forwards or propagate.

Amplitude is a measure
of a wave's height from rest to peak.

Wavelength is the distance
between consecutive waves.

The two main types of waves
are longitudinal,

whose particles move back and forth,

and transverse,
whose particles move up and down,

or side to side.

Waves in the sea, however, are orbital,

combining a bit of both.

Right, I hope you've got
your thinking caps on,

because it's time for a test.

Question one,
transverse and longitudinal waves

oscillate in different ways,

but which different ways?

Here's a clue.

He's demonstrating
how a transverse wave can behave,

up and down,
transferring energy along his body.

And he's demonstrating
that it might be time to go home.

Sound waves are longitudinal,

vibrating air particles back and forth.

[bass scratching]

In this case, a bit too much.

[man] I knew that was a bad idea!

[Richard] Hmm, so did I.
Try using your hands next time.

But what of those combination waves?

Well, those often come
in the form of orbital waves

which have a circular motion,

and question two is,
where do we find them?

Hey, would you mind showing us?

[yells]

Thanks.

[yells]

That ripple of water is an orbital wave,

radiating out in a circle.

Okay.

There's another,
see, an almost perfect orbit.

[yells]

Not particularly perfect for him.

And now for our third and final question,

can you remember
how amplitude is defined?

It's height,
and the bigger the amplitude of wave,

the more energy it can carry.

Hope he's good at holding his breath.

Of course, as a wave hits the shore,

the bottom of the orbital breaks

and some energy is dissipated.

So, I wouldn't taunt it.

[screams]

And here ends our lesson on waves.

See ya later, much later.

[screaming]

[glass shatters]

[electricity crackling]

[glass shatters]

Street trials riding
is like parkour on two wheels,

riders go to extreme lengths
to ride their bikes

over the highest
and narrowest obstacles.

Why stay on terra firma
when you can do this?

[grunts]

[man, off-screen] Are you okay?

[Richard] I doubt it.

But practice makes perfect,

and soon you'll be turning heads
with smooth moves like this.

[biker yells]

Ooh, pebbly beach, I prefer sand.

Narrow tires and top heavy riders
make bikes unstable

at the best of times,

but if you're determined
to take a ride on the wild side,

then you'd better know the science.

A rider and bike
have a narrow base of support

and a high center of mass,

which can easily create
a turning effect around the tires.

Riding slowly,
he can move his center of mass

to counterbalance the tilt of the bike,

or adjust the position
of his base of support by steering.

But at slow speeds,
larger moves are required,

with little room for maneuver.

So the key to staying balanced
is to find that equilibrium

between your center of mass
and your base of support.

Even the smallest of movements

can be the difference
between the success...

[yells]

...and that.

His sideways momentum
pushed his center of mass

too far left.

[yells]

Look on the bright side, your bike's
gonna be really clean now,

and so are you.

Riding on a rail this narrow
leaves zero room for maneuver,

but as long as he maintains
his balance and his momentum,

he should be...

[man, off-screen] Oh!

[Richard] Oh, dear.

Using short pedal strokes
to carefully shift center of mass,

this was looking great until he stopped,

and it was time to say, goodbye balance,

hello gravity.

As well as changing your riding position,

on wider obstacles
you can move your handle bars

to adjust your base of support.

This contraption
is called a teeter-totter,

it's a lot like a see-saw...

[grunts]

...only more painful.

Running out of momentum
meant this rider

had to adjust his base of support

on the narrow platform to stay balanced...

-[biker grunts]
-...but only briefly.

Momentum isn't a problem here.

His speed means he doesn't
have to make big adjustments

to stay upright.

But will a bold approach work
on the narrow bar?

Well, that'll be an eye-watering no then.

The curved bar didn't offer
enough frictional resistance

and the wheel slipped.

He was lucky, if he'd landed on his elbow,

he could have got a nasty graze.

[screams]

[electricity crackles]

[creaks]

When I was lad, if I wanted to
torment my family, and I did,

I'd resort to using crude devices
like pea shooters,

water pistols, and cap g*ns.

But the modern delinquent has discovered

a more sophisticated type of projectile.

-[darts popping]
-[child laughing]

Isn't that right, Granddad?

But as you can see,
foam darts are relatively painless.

But just in case you're thinking
that taking a pot shot

at your grandparents is fine
as long as you firing foam,

I think we should at least consider
the science behind foam darts.

A projectile's trajectory

is affected by air resistance
slowing it down,

and gravity pulling it downwards.

The greater the distance,
the more time air resistance

and gravity have to act
on the projectile.

And when hitting a soft target,

the impact occurs
over a longer period of time,

reducing the force
and potentially the pain.

If you're going to pop Grandpops,

pop him the belly, not the eye,

and take a few steps back first,
it's kinder.

Right, let's start
with the distance factor.

[man, off-screen]
Abbie, come check this out.

[Richard] Yeah, the long range shot,

not long enough for her.

Still more air time for gravity and drag
to divert those darts,

so low accuracy and low impact force.

[yelling]

Okay, that's a bit closer,

but I wouldn't wanna be you
when you've run out of a*mo.

No idea why,

but this chap's trying to sh**t
his camera point blank,

and yet he's missed.

Another go?

[screams]

Bull's-eye!

Traveling just a few feet,

his dart retained
plenty of energy to bounce back

in a large, elastic collision,

followed by a fractionally
less large eye collision.

It's okay, the camera was fine,

although his aim
is now even worse actually.

Okay, remember, it's not just how hard
those little foam darts hit,

it's where they hit
that can be the problem.

Example please.

There is a reason why some toys
come with age restrictions...

[boy screams]

...and that's it.

[boy screams]

Granddad accidentally hits
the lad's head which is hard,

so it will not absorb so much impact.

I'd put that down if I were you.

Remember, not the head
because that's quite hard.

The long range and a tiny g*n
will also help reduce impact,

so you should be fine.

Nope, my mistake, you're in trouble,

-big trouble.
-[man 1, off-screen] Stop asking.

[man 2] Three.

[Richard] Oh, no.

[man 2] Two.

[Richard]
Oh, the things people do for science.

[man 2] one.

-[screams]
-[laughter]

[Richard] Yeah, brings a tear to your eye.

Although the soft target area
was able to absorb more force,

a bigger g*n and closer range

still equated to
a painful amount of impact.

With friends like these,
what did you expect?

[glass shatters]

[electricity crackling]

[glass shatters]

That's all for now.

I hope you've been paying
close attention to the science,

because you've witnessed
what can happen if you don't.

So please do not attempt
any of the stunts you've just seen,

if you need a reminder why, here it is.

[yells]

-[cat meows]
-[groans]

[screams]

[yells]

[woman screams]

-[horn blaring]
-[tires screeching]

[screaming]

[screams]

-[horn blaring]
-[tires screeching]