02x06 - Flip Flops and Power Purges

[bunniefuu]

[Richard, off-screen]
It's The Science of Stupid.

[man] Aah!

[Richard, off-screen]
Yes, this is the show that

combines science and stupidity.

Over the next half hour,
you'll see some astoundingly

daft behavior from people who
ignore the rules of science.

We'll reveal what
went wrong and why

by exploring such scientific
principles as reaction force.

[man] Aah!

[Richard, off-screen] Friction.

Center of gravity.

And my own personal
favorite, momentum.

It's simple, bite off
more than you can chew,

and science will
have you for breakfast.

So behave, it's
The Science of Stupid.

On this show, we'll reveal

what happens when elastic potential
energy releases its potential.

[man, off-screen] Oh, h* h*!

[Richard, off-screen] A method
for applying force to turn.

That wasn't it.

[man, off-screen]
What the hell?

[Richard, off-screen] And how not to
balance a moving center of mass.

[woman] Oh, aahh!

[Richard, off-screen]
Like that, for example.

But first, this.

The staircase,
it's a pretty ancient invention.

Even the escalator's
over a century old,

and yet not everyone
seems to be familiar

with how they work.

Yes, rail sliding
is generally unwise.

On your standard rail,
were it not for friction,

you could be
accelerating from naught

to 60 in less
than four seconds,

but a clear route
and good exit strategy

might offer a little
damage limitation at least.

An obstacle-free
rail is essential,

because velocity increases,
so will impact force,

and any solid obstacle

will exert an equal
and opposite force on it,

which really hurts.

For a safer exit, he
reduces his velocity gradually

by landing, running on his
feet and slowing down gently.

If he doesn't, his feet
will stop too suddenly,

and his momentum will
rotate him forwards.

When it comes to rail sliding,
it seems age is no barrier.

But that is.

And so's that.

Remember what I said
about solid objects?

Escalator signage
can slow you down,

but not without
pain or embarrassment.

I wonder what
his friends think?

[laughing]

[Richard, off-screen]
Yeah, he agrees. Charming.

Here's a man with too
much time on his hands,

and a nice, smooth banister.

[man] [bleep]

[Richard, off-screen] Well,
apart from that bottom bit.

Now, escalators have a
smooth curve at the bottom.

It should slow
him down gently.

Or drop him like a brick.

Velocity in one direction
means his mass will want to

keep going in that direction.

It is surprising, isn't it?

So if velocity's the problem,
why not bail out

before you reach top speed?

[man, subtitled]
Ah, that's a bad idea.

Ah, that's a very bad idea.

[Richard, off-screen]
Yeah. You think?

Okay, yeah,
that was a bad idea.

When he bailed out, he'd already
built up far too much speed

for his legs to keep up.

You see, just a little
goes a long way.

Oh, and that's the
up escalator, matey.

Read the signs, please.

Look, remember the science.

Your feet can slow
you down gradually.

[man] That's quite sexy like.

[Richard, off-screen]
No, doesn't do it for me.

But the point is, he can
run out all that velocity

when he reaches the bottom.

Well, right idea, not
quite the right time to do it.

[man] Are you
actually all right?

[man] No.

[Richard, off-screen]
Well, not surprising, really.

When I first
heard of tumbling,

I thought, sounds
a bit like falling over.

Turns out it is.

Okay, but when
ex*cuted correctly,

it looks more like this,

a proper gymnastic discipline

that involves
linking somersaults,

flips and twists.

Even the best gymnasts
have to start somewhere,

so here's some
flipping science.

The gymnast starts
with a powerful take-off.

Leaning in the direction
he wants to rotate.

Once airborne,
the more he tucks in,

the more he will rotate.

It's the conservation
of angular momentum,

and means he can
increase his spin speed

by as much as three times.

Finally, he lands
with his center of mass

slightly in front of his feet,

so that his momentum brings
him to a stable position.

So, it's about
getting your spin spot-on,

but of course,
every good tumble

starts with a powerful takeoff.

This does seem to lack
a professional feel,

but let's give him a go.

Go on, lad!

[boy] Oh!

[Richard, off-screen]
Oh! He may be young,

but if you want
to make it in tumble,

you've got to give
it more than that.

Never mind, son.

[man] Come on Joe.

[Richard, off-screen] Joe's built of
sturdier stuff,

but is power all you need?

[man] Ohh!

[Richard, off-screen] No, you also need
a bit more rotation than this.

Come on, lean into it.

And this, well,
it's just a bit flat.

By not bringing
his mass, the result is,

once again,
too little rotation.

Tuck in, mate.

But can you do too much?

Yeah, you can.

That's over rotation.

[man] And from Mexico,
this is Nick Rodriguez!

[Richard, off-screen]
Yeah, yeah, Nick from Mexico.

But what's your
angular momentum like, Nick?

[gasps]

[Richard, off-screen]
Sort of a mixed bag then.

Nick landed with his center
of mass ahead of his feet.

Yeah, he over-rotated.

Oh, hang on,
he's turned it around,

and himself,
about three times.

Well done, Nick.
You've done your country proud.

Remember, if you do
land on your feet,

make sure they're in
front of your face,

not the other way round.

It's not gonna win
any tumbling trophies,

but it is my
favorite reading position,

interestingly.

Good job the floors
are covered with soft mats.

The walls, not so much.

These guys are trying
to get into a watermelon

using the most
convoluted method possible,

but what science will this
culinary exercise reveal?

[Richard, off-screen] Now, did you guess
what science we are about to witness?

[man] Aah!

[Richard, off-screen]
Yep, it's compressive force.

The watermelon's tough
skin and rounded shape

allows huge compressive forces

to build up
from the rubber bands

as they're added,

so when it finally gives way,

the pressure is so great that
they top fires into the air

at around 13 miles an hour.

Who says fast food
can't be healthy?

As social media challenges go,

tipping a bucket of
icy water over your head

seems pretty safe,

but there are some dos and don'ts when
it comes to a hazard-free pour.

[man] Oh, God.

[Richard, off-screen] If
you're not feeling confident,

don't do it on your own.

[man] Somebody should
be doing this for me.

[Richard, off-screen]
Yeah, I just told you that.

[man] Oh, God.

[Richard, off-screen]
Do throw the water.

[man] Oh!

[Richard, off-screen]
Don't throw the bucket.

And of course,
don't use a dumper truck.

It's elementary, really.

And now we've
covered the basics,

onto the nitty gritty,
and by that I mean science.

A bucket of sloshy water's
moving center of mass

makes it difficult to control.

By holding the bucket
with both hands at the bottom,

that center of mass is
above the pivot point formed

by your hands,

which would make it difficult to
balance the bucket as you pour.

For more control,
you can grip the bucket

with one hand
at the top of the rim,

supporting it at
the bottom with the other.

Better still, you can
support the side of the bucket

on a solid object
so that it pivots around it.

So, the science is telling us

that the perfect pour
is down to a well-placed hold.

It's a technique that
not everyone seems to have

got to grips with.

[man] You have 24 hours.

[Richard, off-screen] Ah, the
classic ice bucket challenge.

[man] Or donate $100.

[Richard, off-screen] Let's
see if he was paying attention.

[man] Okay, here we go.

[laughs]

[Richard, off-screen] No,
your hands were a bit close

at the bottom there, son.

But don't worry,
you're not the only one.

Here's a family scenario.

One of these three is about
to face the same problem,

but can you guess which one?

[clock ticking]

Not her, it's her.

And in this family,

the punishment
for failing science is swift.

Other than
standing on one leg,

she briefly removed her
second hand from the top

of the bucket and was
too late correcting it.

And whilst he had
a bigger bucket,

it wasn't a problem, because
his technique was spot on.

But he's a grown-up, sort of.

Now, to get a bit of height.

A balcony is perfect,
and remember,

you want to pivot
that bucket on its side.

But where do you
not want to pivot it?

Oh, yeah, the bottom.

[woman] Aah!

[Richard, off-screen] Oh, and did you
know water is extremely heavy?

About 800 pounds
per 100 US gallons.

Yeah, it's heavy, yeah.

This bucket of water

is around the weight
of 63 bags of sugar.

But not as sweet.

So surely it wouldn't be sensible
to try anything heavier.

But then this show isn't
called The Science of Sensible,

is it?

Does he realize that that isn't
just moving center of mass,

it's also an extremely big mass.

Well, he does now.

If you read a kayaking manual,

the first chapter is likely

to be about launching
it into the water,

and there is
the keyword, water.

But as we all know,
real men don't read manuals.

Yes. Unfortunately,
land kayaking is a real thing

people actually do for real.

So if you insist on
joining their ranks,

it wouldn't hurt to
learn a bit of self-control.

Cue the science.

A big challenge in
land kayaking is steering.

One method is to drag your
paddle against the ground.

This creates a friction force
away from the center of mass,

slowing you down more on
one side than the other,

and making you turn.

Another solution is
to prod your paddle

against the ground.

The force you exert on
the ground turns the kayak,

this time in
the opposite direction.

Just to show you
it can be done,

here's some guys who seem
to know what they're doing.

Nice!

And to address the balance,
here's someone who doesn't.

Hang on, where's your paddle?

[man] Ooh-hoo-hoo!

[man] Not too good?

[Richard, off-screen]
Well, what do you reckon?

Look, don't worry if
you're on a tight budget,

even a plank will do.

By applying a little pressure
to the road on one side,

he generates enough
friction to keep him moving

to the left.

Beautifully done, sir!

A quick note, though.

Even if you do
bother trying to steer,

you won't get
much friction on ice.

But you will get speed!

So don't forget, the
prodding technique also works.

Providing you use your eyes.

[man] Ughh!

[Richard, off-screen]
That's more like it.

A couple of quick prods
and you're safely past the tree.

That could have been nasty.

Oh, and here comes your mate.

[man] Aah!

[man] What the hell?

[Richard, off-screen] I know,
all that field to aim for.

Never mind.

[Richard] Now you've
heard of slack lining.

No? Well, it's this.

Acrobatics on a kind
of giant elastic band.

It's a bit like a
cross between a tightrope

and a trampoline.

Trouble is,
they're not that slack.

It's all about
something called

elastic potential energy.

"What's that, Richard?"
I hear you cry.

Well, you're
about to find out.

When an elastic object deforms,

it stores up
elastic potential energy.

The greater the force of
his weights on a slack line,

the greater the
energy it stores.

When he bounces
on a slack line,

it can deform to
such an extent,

and store so much energy,
that when released,

it launches him into the air.

The key is to keep
his center of gravity

directly over the line

so that released energy launches
him in the right direction.

Ever accidentally flicked
yourself with an elastic band?

No, I don't know
how you would.

But if you did,
you'll find it stings.

Now what if that
elastic band was a lot bigger?

[screams]

[Richard, off-screen]
It'd be a bit like that.

Just by standing on it,
the slack line stores up

loads of potential energy,
which remains stored

as long as he's
in perfect balance.

So much energy was released
that the line flicked up

before he even
had time to fall.

[man] You caught the line!

[Richard, off-screen] Yeah, it's called
a nut shot, but I can't think why.

Nothing like a helping hand
to keep that center of gravity

directly above the line.

It's even more helpful
if you don't let go.

Now, it's all very well
walking in a straight line,

but slack lines
are made for bouncing,

although there is a little
fact you should bear in mind.

Energy stored is proportional
to stretch squared.

But what does
that actually mean?

Just twice the stretch
equals four times the energy.

And four times
the pain, roughly.

This is ambitious,

but at least there's
a lake to break his fall.

Looks a bit cold, though.

[shivers]

Now, when he jumped, the slack
line stored loads of energy,

and once his center
of gravity was off,

the energy that was
released sent him flying.

Chill out, fella!

So, remember,
center of gravity.

Elastic potential energy.

[laughs]

[Richard, off-screen]
Oh, and the nut shot.

[man] Ow!

[Richard, off-screen]
There it goes.

Leaping from an
aircraft with a parachute

is probably quite scary.

But you don't need
a plane or a parachute

when you've got a giant
fish bowl and a big fan.

Behold, the joys of
indoor sky diving!

Yeah!
You can fly like a bird

and perform tricks
that are really impressive!

Whoa! Oh!

Anyone else get
motion sickness?

I can feel myself going.

It takes real skill and lots
of air time to be that good.

But if you're
too busy for that,

here's half a minute of
science to get you started.

Sky diving is largely about

controlling
your center of pressure

where drag acts relative
to your center of gravity.

For stability, make a
downwards arch with your body.

This keeps
your center of pressure

above your center of gravity.

Keep your body shape
symmetrical to stay still,

and maneuver by changing
your shape to get more drag

or less drag
on one part of your body.

Just don't overdo it.

So the basic idea is
to use your body shape

to control drag.

Well, not quite
the perfect arch,

but at least he's stable.

[man] Whoa!

[Richard, off-screen]
Did I speak too soon?

By moving one
arm down, then up,

he created more
drag on one side,

flipping him over.

Oh, the indignity.

That's better, big man!

Take that, gravity! Ha!

Don't be too smug, though.
We did see the first bit.

[man] Whoa!

[Richard, off-screen]
If you're an expert,

you can move those
limbs to control drag

and steer yourself about,
out to increase drag,

in to reduce drag.

It you're rubbish, you can just make
yourself violently ill.

I don't think she's an expert!

He's got the right idea!

Then once he's had his face
pulled out of the cushions,

he's gonna show us
what happens when you

dramatically reduce drag.

Yep, you dramatically plummet.

The fastest outdoor skydive
was over 830 miles an hour.

The indoor one.

[man] Yee-haw!

[Richard, off-screen]
Probably a lot slower.

He does like those cushions.

Right. I hope you've learned
something from all this,

half an hour
listening to me rant on

is surely better
than six months in traction.

So be safe,
and we'll see you next time

on TheScience of Stupid.

[man] Oh! [bleep]