05x09 - Unicycle, Segway and Arm Wrestling

[bunniefuu]

[Dallas] This
is the Science of Stupid.

Yes, this is the show where complex
science collides with complete stupidity.

[man] Whey...there it goes.

[Dallas] While we step back
and watch the fall out.

You'll see backyard experimenters push
themselves and science to the extreme,

often with painful results.

Then we reveal what
went wrong and why,

with the help of such scientific
principles as vertical velocity.

Friction. And amplitude.

[screaming]

[Dallas] So strap yourselves in, and
hold on tight because this

is the "Science of Stupid".

In this show we'll be
looking at inertia.

Paper arousal.

And perturbing forces.

But first this.

It's typical isn't it?

I've been looking around for a while for a
way to enliven my commute to work and

as soon as I come up with a good one,
everybody else has the same idea.

[Dallas] Yes the big wheel really is
an excellent way to travel.

They're so good, I really can't think of
any reason you wouldn't use it.

Except perhaps that reason.

A lot of groundbreaking things
came out of the 1960s,

the moon landings,
bell bottoms,

the civil rights movement,

but maybe the most important one was the
big wheel trike.

The big wheels outsize front wheel gives
it a higher gear ratio

and a smaller angle of attack, meaning
that it can cope with bumpier terrain

and reach higher speeds than
tricycles with a smaller wheel.

But its chassis design with
bucket seat

means there's not much to
hold onto during jumps.

Add to that, three wheels are
intrinsically less stable than four,

so on corners centrifugal force
is more likely to tip you over.

Well that all sounds fairly simple as long
you corner slowly and gradually,

and don't try to jump, and keep
your center of mass as low as possible,

you should be fine.

Let's see if this lot have
been paying attention.

Has this kid remembered the golden rule

that three wheels are less
stable than four?

Eh, no.

When he turns too sharply,

centrifugal force pulls him far enough
sideways that he topples

over, crushing his
stuntman dreams forever.

Will this grown up have better luck trying
a jump on a small child's trike?

Not really.

The small angle of attack means the wheel
easily surmounts the slope,

but the lack of structural elements to
hold him onto the trike

means he becomes
separated in the air.

Yes, Evil Knievel's got
nothing to worry about here.

And of course, it goes
without saying that

you really shouldn't be using
these things on the road.

Or that might happen.

-[man] [bleep] [bleep]
-[man 2] Are you okay dude?

[man] I'm good, I promise.

[Dallas] Well you're more lucky than good,
next time stay off the road.

Maybe we'll have better
luck with less speed.

Uh, maybe not.

[Dallas] Hands eh?
What are they good for?

The odd bit of scratching,
maybe a text or two,

but nowadays when I wanna carry
something I use my head, literally.

I can't believe that I didn't
think of it before,

it just lets you do so
much more stuff.

[woman] Can you find one,
four one, five back?

[Dallas] Like solving that
last-minute puzzle before

heading back to the library.

Busting out some dance moves.

Or just emptying the shed.

[woman] Isn't it easier
just to take a few trips?

-[man] No.
-[woman] No, that's not easier?

[man] No, two
trips are for losers.

[woman] Yeah?

[Dallas]
I couldn't agree more,

it's a matter of personal
pride that I only ever

make one trip when
carrying things.

Moving house last
week almost k*lled me.

[woman] You OK?

[woman] You OK?

[man] Yeah.

[man] You were distracting me.

[Dallas] Let's face it,
we've all been there,

but do it right and the head balance can
open up a world

of hands free
possibilities.

So what is the science
behind this skill?

[Dallas] As he throws the
ball up onto his head,

he needs to ensure that its center of mass
is within the base of support,

which because both the top of his head
and the ball are curved is very small.

Amazingly a taller object is easier to
balance because it tips over more slowly,

giving him more time to correct.

Either way, the balancer has to
make continuous fine adjustments

to keep the object in a
state of dynamic stability.

And he needs to watch out for any external
forces like a breeze

which could move
its center of mass.

A taller object is
easier to keep balanced,

as its mass is distributed further from
your head for a larger moment of inertia.

So it will rotate slower but fall more
dramatically should anything go wrong.

[Dallas] Yes that's all very impressive,
but has he remembered to watch

out for any
external forces?

No, he hasn't.

Even balancing on his hoverboard,

he manages to make small
adjustments to keep his

tablet's center of mass above
the base of support

formed by its corner
and his forehead.

But this little chap, like myself, has a
very low tolerance for show offs.

Yeah, not so clever, now are we?

With its wide flat top this
table looks good for balancing,

but it's always best to check how heavy
something is before giving it a go.

My point exactly.

That table has a large moment of inertia,
meaning it should fall more slowly,

but it's also very heavy, in
this case a little too heavy.

Ah, the old wine bucket
on a pole routine.

This guy looks like he
knows what he's doing.

But looks can be deceptive.

With a lot of mass at the end of a long
pole he's maximized the moment of inertia,

so he has more time to react, but the wine
bottle hits from the side.

The center of mass moves quickly outside
of the base of support,

and it's hard to make adjustments with a
wine bottle falling towards your face.

[man] This is Jeff...

...with the egg
balancing competition.

[man] [bleep] statue.

[Dallas] Jeff
here looks like an expert.

That egg's not tall and its curved shell

means that the base of support
is even smaller,

making this an impressive
bit of balancing.

[man] Bend over Jeff,
let it roll off.

[man 2] Go on, I'll catch it.

[man 2] Go on, into my hands.

[Jeff] **** it's stuck on!

[Jeff] You *******!

[Dallas]
Jeff, that's cheating.

Can you guess what scientific principle

this Russian forklift driver
is about to demonstrate?

[Dallas] I asked what scientific principle
we were about to see

in action in this alcohol
filled warehouse.

It's Newton's Second Law, which goes to
show that alcohol isn't always the answer,

but usually worth a shot.

The driver hits the racking
at a fairly high speed,

and Newton tells us that the
faster something crashes,

the more force
it will produce.

This causes the column to buckle

to the extent that it can no
longer take the weight above it,

which causes a domino effect.

The driver was okay,

but the five million rubles worth of vodka
and cognac was a little worse for wear.

[Dallas] You know what gives
me the heebie-jeebies?

Specters, spirits
and apparitions.

In short, spooks.

So I was alarmed when I heard about
people ghost riding the whip.

[Dallas] It turns out it just means
getting off a moving vehicle

and letting it keep going,

as if it's being driven by a ghost, which
is obviously dangerous.

But some people are foolish
enough to try it with tractors.

Bicycles,

or even motorcycles.

[Dallas] Anytime you get out of a moving
vehicle whether on purpose or not,

you are putting
your life in danger.

But it got me wondering about
the science behind

the ludicrous past time
of ghost riding.

[Dallas] In order for his motorbike to
ghost after a man jumps from it,

it needs directional
and side to side stability.

At sufficient speeds,

motorbikes are good at staying straight
and upright for three reasons,

a backward angle steering axis
creates a positive caster angle

which helps the front
wheel stay straight.

The heavy wheels provide
gyroscopic stability,

and if it does start
to lean over,

camber thrust steers the bike to bring the
wheels back under its center of mass.

But the bike's inertia can turn
this into an oscillation

which grows as
the bike slows down,

until it eventually
topples over.

[Dallas] It's all about
stability and speed,

and you need to make sure you can reach
your bike again before it falls.

Maybe it's easier
than it sounds?

[Dallas]
Or maybe not.

At speed, the
self-steering effect

of the bike's positive caster
angle keeps it going straight.

But as the bike loses
speed and leans over,

it's steered into a growing
oscillation by camber thrust.

Which is one of the reasons
speed's so important.

[man] [bleep]

[Dallas] Although
not as important as aim.

Positive caster angle combined

with gyroscopic stability
of the bike's heavy wheels

means it just keeps going, which in this
case was a bit of a shame.

[man] Oh!

[Dallas] Maybe it
would be easier to have someone

there to collect
the bike for you?

I think that worked real well.

[man] That worked real well.

[Dallas]
Go on, give us a whoop.

[man] Woo-hoo!

[Dallas] Thank you.

For these guys speed was the issue, two
little and a small wobble

grew into a large enough oscillation to
make the bikes fall over.

[man] Oh!

[Dallas] And
to make them look foolish.

Oh, him again.

But has he been
paying attention?

No, not even a little bit.

[Dallas] Alright everyone,
settle down please.

Harmsworth, see me after class.

Yes, it's time for
the Science Lesson,

that part of the show where we take a long
hard look at one specific principle.

So who can tell me what the
following have in common?

[Dallas]
This careless swinger.

[man] Oh my God!

[Dallas] This
unfortunate little brother.

And this careless boater trying to
cool down on a hot day.

[man] He needs a beer!

[man] Throw him a beer!

[man] Oh!

[Dallas] Good idea, nothing's
more refreshing than a dip.

Did you guess gravity?

Well as every good
schoolchild knows,

gravity is the natural phenomenon

by which all things are pulled
towards each other.

When this stretched slinky is released, it
undergoes a restoring force

that pulls the top and bottom
ends towards the center.

Although this makes the bottom
appear to hang in the air,

the Slinky's
center of mass

is actually accelerating towards the
center of the earth, due to gravity.

But gravity doesn't always mean
things move directly downwards.

After the dart is thrown,

it follows a curved parabolic trajectory
as its horizontal

velocity combines with gravitation
acceleration before hitting the balloon,

when gravity once again, accelerates the
water directly downwards.

Basic stuff, right?

Well let's see who's
been paying attention.

Question One, what happens to
an object with smaller mass

when it comes close to an
object with a much larger mass?

[Dallas] This
gentleman is about to show us.

That's right, the object with less mass

is pulled more towards the one with the
greater mass.

In this case that's the
center of the planet.

He's old enough to know that both climbing

over banisters and carrying ba*ls
in your mouth,

can be deadly.

Don't try this at home.

Okay, question two.

What happens when an object is acted
upon by gravity,

and has horizontal velocity?

That's right, it curves through the air in
a predictable parabolic trajectory,

which if you can work it out correctly,
you can use to your advantage, like this.

Or this.

By anticipating this arc, the concert goer
gets himself a free drink.

Let's hope that is beer
and not something else.

And the final question, what happens when
a force countering gravity is removed?

This lady is going to be
thrown in the air,

presumably for
forgetting her costume.

[Dallas] But the force needed to overcome
the pull of gravity is quite large,

and her friends aren't well positioned.
Class dismissed.

[Dallas] I think we can all agree that the
animal kingdom is a terrifying place,

filled with frankly
disturbing animals,

and I'm not just talking about great white
sharks and scorpions.

But tiny lizards.

[screams]

[Dallas]
Fluffy bunnies.

[girl] Ta da dah! Oh!

[Dallas]
And charming frogs.

[screams]

[Dallas] Just like us, when animals
get scared

it triggers a fight or flight
response,

also called, hyper arousal.

This natural reaction is designed to
temporarily improve an animal's ability

to fight their way out
of danger or flee.

In humans it causes over 1400 different
physiological and biochemical changes,

including pupil dilation.

In all animals, adrenalin helps raise
blood sugar,

increases the heart rate and diverts

blood from the digestive
system to the muscles,

so they can work more efficiently.

All this is almost instantaneous

and involuntary controlled by the
primitive brain.

Of course, there is a third
reaction to perceived threat,

and that is to
freeze on the spot.

It's so a predator won't
be drawn to movement,

so it works a lot better on
lions than on, oncoming cars.

[Dallas] The most appropriate response
varies from animal to animal,

often depending on the situation
and who you're up against.

A moose is a prey animal conditioned to be
wary of bears, wolves and cougars,

but not it turns
out, lawn mowers.

This cat's reactions have been fine-tuned
over time by evolution.

But his ancestors never
had to deal with toast.

Thus, cats may know all about kitchen
appliances,

but hyper arousal is
involuntary.

So will this goat fight
or fly when spooked?

Or just fall over?

When scared, this goat's muscles tense up
and it appears to faint.

In a few seconds
it's fine again.

My daughter loves balloons, but I probably
should have listened to my wife

when she told me
not to spoil her.

Don't worry, I'm sure she'll
be absolutely fine,

after all what goes up, must come down.

[Dallas] Ah, that's more like it,
a proper hot air balloon.

Time for them to
go up, up and away.

Into a waist high fence.

Still, if at first you don't
succeed, try and try again.

And then hope someone has
a ladder for your rescue.

Heated to over 200 degrees Fahrenheit,

the air inside the envelope weighs
about 20% less

than the surrounding air, but there's a
lot more to it than that.

A balloon is made up of a
basket, envelope, and burners.

Force from the weight of the balloon is
balanced by the buoyant force

from warm air inside
the envelope.

When these two vertical
forces are unbalanced,

the balloon accelerates upwards

or downwards, but you are
at the mercy of the wind.

The balloon's envelope has a
high surface area so experiences

a large horizontal drag force,

and due to the large volume
of air inside the envelope,

it's difficult to increase
the buoyant force quickly.

So a balloon will often move faster
horizontally than vertically,

making it hard to
avoid obstacles.

Very much like a man trying to swim in a
dress, it's all about buoyancy and drag.

[Dallas] Ah, nothing
better than a peaceful drive

and spotting a hot air balloon
floating through the sky.

Eh yeah, that one doesn't
look quite so good.

I think he's stuck.

I always find it's best not
to panic in these situations.

[woman] Oh no! My God!

[Dallas]
Having snagged on the tower,

the balloon loses buoyant force
from the envelope of hot air.

In an attempt to arrest the fall
the pilot blasts his burner,

but without the envelope above
it this only makes things worse.

The people on board
escaped with cuts and bruises,

but balloons can be dangerous,

which is why health and safety is usually
so stringent at large displays.

Hang on a minute, no barrier for the large
crowd, using wood for the burner,

envelope made of paper.

I predict bad things.

The only thing that could make
this worse, is if, I dunno,

it was packed with
homemade fireworks.

Yeah, that's worse.

The bottom of the envelope
detaches, and the buoyant force

is no longer balanced by the weight of the
basket, so it accelerates upwards.

The fire continues to burn below,

leading to an impressive low level
pyrotechnic display.

In the wacky world of accidents waiting to
happen, this just happened.

Famous rocket engineer, Wernher Von
Braun said, "Research is what I'm doing,

when I don't know
what I'm doing".

So, let's all sit back and
enjoy some research in action.

[music plays through credits]