01x03 - Poolside Fails

[bunniefuu]

It's the Science of Stupid.

- This is the Science of Stupid...

...the television program filled
with stupid stuff

and smart science.

- The show with the crazy stunts...

...along with the hard scientific facts

- behind the smashes and smacks.

We'll tell you about centripetal force

and momentum.

Be astounded as these brave
buffoons discover...

...expl*sives

and the laws of rotation,

without the slightest idea
of what they're doing.

- If you upset science...
-Oh,!

...it'll crush you like a worm.

Come on in to the Science of Stupid.

On this show, we'll see
what happens when momentum

is converted into impact.

We discover Hooke's law from 1660.

And light up the night sky with gunpowder.

But first, this.

I always thought golf carts were made

for trundling, exercise-adverse

Tiger Woods wannabes from hole to hole.

But fail to observe some basic science
and it's a very different story.

I got it, I got it!

Oh,! Dude!

I'm good! I'm good!

Well, other than being stuck
under a golf buggy.

So why are golf carts best driven
on even ground, at sensible speeds?

The answer lies in the science.

Axle width compared
with a low profile

gives an unladen golf cart
a low center of gravity.

That makes it as stable as a car.

As soon as people and loads are added,

the center of gravity rises
by up to 50 percent,

which makes it much less stable.

So when turning or on a slope,
it doesn't take much force to tip it.

Once the center of gravity
moves outside the wheelbase,

over the golf cart goes.

This enthusiastic researcher
has decided to conduct his experiment

by taking the cart
off the golf course altogether.

You don't need a crystal ball
to guess this one.

Whoa!

Holy! Holy!

That steep hill shifts
the cart's center of gravity

relative to the wheelbase and induces
some automotive acrobatics.

Holy!
Dude, are you okay?

These chaps clearly
aren't convinced by the science

and are seeking further proof.

Yee-hoo!

Yeah, that's pretty conclusive.

This guy has got the right idea--
a golf buggy on the golf course.

What could possibly go wrong?

Remember, turn a fully laden
golf buggy too quickly or sharply,

and the force involved will tip
the unstable buggy over.

You'll find yourself
with some explaining to do

when you get back to the clubhouse.

This charitable couple have been
good enough to offer a lift

to these two well-fed gentlemen.

But they're going to learn about shifting
the center of gravity the hard way.

That shifted, definitely.

Golfers, take note,

the center of gravity can shift
backwards as well as sideways.

And that's why
I never pick up hitchhikers,

and you should take care in golf carts.

Trees. Don't you just love them?

They're the lungs of the Earth
and homes for birds.

You won't catch me chopping down a tree,

and it's not just an environmental thing.

Tree felling can be
a very costly business.

That hasn't gone
strictly according to plan.

So, tree felling is
clearly best left to the pros.

But can science help stop trees becoming
weapons of mass destruction?

You bet she can.

A tree's center of mass is the point
at which its weight is balanced.

Our old friend gravity
will always want to pull a falling tree

to the side at which its
center of mass sits,

in other words, its heavier side.

To control the fall, lumberjacks
shift the center of gravity

by removing weight
from the tree's heavy side...

or change the direction of fall
by applying force via a rope or chain.

They cut a notch at the base
to control the fall direction,

but however well you cut the notch,

trees will always tend to fall
in the direction of the center of mass.

If the science hasn't convinced you

that tree felling is
best left to professionals,

this probably will.

This would-be woodsman
has cut an expert notch,

believing that he'll control
the fall of the tree

away from his house.

We just took out half the house.

RICHARD: You did.
That could have gone better.

Let's rewind to see why.

If we freeze the clip here,
it's clear to see that branch growth

has made the tree heavier on one side,

pushing its center of mass
towards the house.

However neat the notch,
it'll always struggle to counteract

- the center of mass.
-Going the wrong way!

Oh, my gosh!

That was not good at all.

Mm-hmm.
Thanks for clearing that up for us.

Of course, in a built up area, getting
the science right is even more vital.

You wouldn't want
that tree falling in the road.

Oh, my God!

That's not cool, that's dangerous!

Not a resounding success, but rewind

and we'll see that failure
was always the most likely outcome.

Freeze here, and we can see
the tree clearly leaning to the left,

with the center of mass over the road.

Cutting a notch was never
going to change the outcome.

Oh, my God!

Still not convinced by the evidence?

Meet Brad.

Brad's not getting bogged down
with details like science.

He's not interested in the tree being
clearly heavier on the right.

What if that lands on you, Brad?

It won't,
it's going to land on you.

How do you know?

I'm angling it,
it's gonna come like this, then like that,

- then it's gonna fall that way.
-Okay.

The center of mass suggests
that it'll fall to the right, Brad.

But don't worry about that.

Oh no.

Oh, yeah.

This young man's done his homework.

He's attached a rope that he'll pull on
to control the direction of the fall.

It's a technique used
by professionals, you know.

It's just that professionals
tend to use a truck,

not a slightly built college kid
for the pulling part of the operation.

Here's a little scientific teaser for you,

an airport next to the beach.

How convenient.

But why are those people running away?

Who guessed why these
holidaymakers are making a run for it?

These twin engines generate
a total take-off thrust

of up to 64,000 pounds.

Some people think it's fun
to hold onto the fence.

That wind speed is
almost 90 miles per hour,

hurricane speed.

- Should have fastened your seat belt.

Breaking down.

It's so embarrassing.

I mean, one minute you're king of the road

and the next, you're a damsel in distress.

You need a tow.

Like this.

Okay, so it isn't as simple
as it first appears.

Towing is all about tension and stress.

Sounds like marriage.

Tension is the force exerted on a body

when it's pulled
in one or more directions.

The effect of tension is stress
on the part of the body being pulled.

Tensile strength refers to the amount
of stress that will make a material fail.



For towing success,
make sure that your towing point

has enough tensile strength to cope
with the stress placed upon it.

Secure towing point
with sufficient strength.

Got that?

Yee-hee!

Well, he hasn't.

The strength of the Jeep's
front wing is far from equal

to the tension and stress
created by the towing vehicle.

It was a bit like anchoring
a charging elephant to a block of cheese.

Here's a question for you,

will hooking up three trucks
in a series create

enough pulling power to shift
this massive yacht?

- I think that's a no.

A better method would have been to attach
each truck to the boat in parallel.

The pulling power would
have been the same,

but without the other trucks
pulling at the front,

the stress exerted on each truck
would have been reduced.

Once you've got the science cracked,

there are a few practical
guidelines to follow.

Oopla.

Ooh! Ooh!

Like making sure
there's someone in the towed vehicle

to steer it and apply
the brakes when necessary.

But these lads have put the science
and technique together.

Good strong towing point
and someone in the car to control it.

What could possibly go wrong?

A little tip, keep the ignition on.

If you don't, the steering lock is
liable to engage when you turn a corner.

We just had a bad accident!

He's perceptive, I'll give him that.

If ever there was a leisure product
designed to cause pain and humiliation,

it's the pogo stick.

It all starts as innocent fun.

To prevent your pogo stick
from becoming a no-go stick,

you'll need to get your head
round some basic physics,

stored energy and angle of landing.

This is gonna hurt, isn't it?

Pogo sticks can be powered by springs,

compressed air or elastic,

all of which store energy from one bounce
and release it on the next.

Hooke's law states
that the force you apply to a spring

is proportional to its compression.

That means the harder
you push down on the spring,

the harder you'll be pushed back up.

The aim is to land
at 90 degrees to the floor,

with your weight centered over the stick.

Too acute an angle on landing

and all that thrust sends
you the wrong way.

If you master the basics
of powerful jump and landing angle,

you can start thinking about tricks.

Really?

These experts
fully understand the physics,

using the energy of each successive bounce

to gain enough air
for them to show off their stunts.

You can even use all that energy
to execute a spectacular dismount.

Here's another spectacular dismount.

Spectacularly painful I suspect.

With so much potential energy stored
and then released,

correct landing angle is vital.

Remember, the magic number is 90 degrees.

You don't need to jump that high
for your landing angle to cause problems.

Hooke's law states that weight
also affects the spring's compression.



Can this suburban pogo-er
show us how it's done?

-
- No. No, he can't.

The landing was near
the magical 90 degrees

but his weight wasn't over the stick.

Ah, a seasoned street performer.

At last a professional to demonstrate

the science and technique.

There he goes.
A full understanding of Hooke's law

as he uses the energy from each bounce
to gain impressive air.

And if he keeps landing at 90 degrees,

all that energy will send him
straight back up.

Don't worry, it's part of the show.

I've never been to a pole dancing club.

That's why I need to pay
particular attention to the next item.

Ah!

Oh, that wasn't
what I was hoping for to be honest.

So it appears that pole dancing
isn't all about sensuality and seduction,

but it is all about science.

Most pole dancing involves the dancer
spinning around the pole,

which acts as a central pivot.

Gravity is always pulling
the dancer's body down,

so they need to counter
that gravitational pull with friction.

Dancers do this by keeping
as many points of contact as possible

on the pole at any one time.

Minimal clothing maximizes
skin contact with the pole,

helping to increase friction.

Has this amateur enthusiast
been consulting the textbooks?

Oh, I'm afraid not. No, she hasn't.

It was a good start.

Bare feet for extra skin on the pole

and three points of contact.

But to rotate that leg
she has to move her hand,

reducing a point of contact.

To avoid accident and humiliation,
the budding pole dancer

needs to understand
not only the science of technique,

but also the science of levers.

Pole dancers position themselves
at right angles to the pole

by using their limbs like levers.

By pushing up on one lever
and pulling up with the other,

they support their weight.

Although their center of gravity
is away from the pole.

This increases the force on the pole

by 60 percent more
than the dancer's weight.

So a strong, well-anchored pole is vital.

This young scientist knows her friction,
but she's forgotten her levers.

If only she wasn't using
a bargain-basement pole.

By pushing with her thighs
and pulling with her arms

either side of a join in the pole,

she's subjected a natural
weak point to unbearable strain.

Perhaps it's just
that science is a man thing.

- May-- maybe not, no.

Even with a strong pole,
it must be anchored top...

...and bottom.

Nobody wants seven years' bad luck.

Ooh! Ah!

Don't worry, I haven't gone mad.

I'm portraying a child
at a firework display.

Fireworks have been around
for over 2,000 years,

and to this day, they are
potentially very dangerous

and should be treated with respect.

Unlike this guy.

Guy Fawkes...

- you get it?

All fireworks rely on gunpowder

for the expl*sive energy
that sends them high into the sky

or excites the metals
that produce pretty colors.

To understand the danger of fireworks,

you need to understand
the science of gunpowder.

Gunpowder can burn very quickly

because it contains
most of the oxygen it needs to burn.

In just 0.2 seconds,
the gunpowder in a firework

can reach a temperature
that's hot enough to melt steel.

When lighting a rocket,
the exhaust gases produced

by the burning gunpowder
propel the firework into the sky.

In stationary fireworks,
like Roman candles,

those exhaust gases travel
in the opposite direction,

spraying colored sparks.

In firecrackers, those gases move
air extremely quickly

to produce those trademark crackles
that can be as loud as 170 decibels.

So, let's recap.

Gunpowder burns very fast,

which is why you're advised to retire
to a safe distance after lighting.

In a rocket, the exhaust gases
from the fast-burning gunpowder

provide thrust for launching,

provided the rocket's upward
trajectory is not impeded.

He may not be experiencing
the thrust, but he is getting

a very good demonstration of exhaust gases

that can reach over
500 degrees Fahrenheit.

Do I need to remind you
not to follow in his footsteps?

A Roman candle held horizontally
allows this young chap

to give his friend a very personal insight

into the fast burn and intense heat
of a gunpowder expl*si*n.

Oh!

It's also something
you should never do yourself, ever.

I can't even class this as an experiment.

Remember, those exhaust gases can reach

500 degrees Fahrenheit.

"Why" is the only,
the only word in my head.

Just why?

In firecrackers that gunpowder
expl*si*n moves air so violently

that the crackles can be as loud
as military-grade weapons fire.

That was around 170 decibels.

I said it was 170 decibel--
Oh, never mind.

So, let's recap.

Gunpowder burns very fast...

...and very hot...

Aah! Oh, no! Dude!

Oh, dude!

...producing lots of noise.

Come on...

Oh, Lord Jesus! Jesus!

Of course if you do find
yourself in a firework calamity,

it's vital that you stay calm.

Who lit fireworks?

Holy! Oh,!

Whoo!

At least that one worked.

That was awesome!

There's just time to remind you

not to try any of the experiments
you've just seen.

If you choose to ignore my advice,

don't come crawling to me
for a cuddle when you get hurt.

You've been warned.
Don't try this at home.

No, not this, I'm just sitting here,

but any of the things we saw
people doing that were dangerous.

Bye!

-

I'm good! I'm good.

-

-Oh!