05x02 - Canoeing, Nets and Crutches

[bunniefuu]

[Dallas off-screen]
This is the Science of Stupid.

Yes, this is the show
where courage meets calamity.

Watch as our fearless fanatics walk the
line between scientific discovery

and sudden disaster,
so you don't have to.

Then we'll reveal what went
wrong, and why,

with the help of such
scientific principles

as bending stress,

conservation
of linear momentum

and arboreal locomotion.

So, open your minds and prepare for a
large serving of knowledge.

Watch out, it's the
Science of Stupid.

In this show we'll be
looking at angular momentum,

unstable oscillation
and thermal conductivity.

But first this.

When I was first told about off road
uni-cycling, I thought this sounds

like a tricky mix of balance,
control and nerves of steel.

Maybe I finally
found my sport.

I imagined I'd look
something like this.

But I'm sad to admit that
it was a lot more like this.

I'm still finding
twigs every time I shower.

And that is because off roading is hard
at the best of times.

On a uni-cycle it's nearly impossible,
and science tells us why.

On a uni-cycle he has to maintain both
front to back

and side to side
stability.

He needs to counter steer to move the
wheel's

point of contact with the
ground.

He anticipates obstacles when off road
by shifting his center of mass to avoid

unwanted torque.

And once moving,
it helps to keep moving.

So, you have to be careful of
torque, side to side stability

and front to back stability.

That sounds tricky.

Maybe we should just start
with a few dos and don'ts.

Do remember its
easier when moving.

See what I mean?

His lack of movement made it difficult
for him to counter steer,

and easy for him to
embarrass himself.

Do try to avoid obstacles.

[man] [bleep].

[Dallas off-screen]
Like large rocks, for example.

The impact needed to flip a uni-cycle is
a lot less than it would be on a bike.

[man] [bleep].

[Dallas off-screen] See?

[man] Why didn't I commit?

[Dallas off-screen] I'm pretty
sure that wouldn't have helped.

And if you're
thinking of doing this.

[man] Ooh!

[Dallas off-screen] Don't.

Because it looks
like it really hurts.

This guy forgot that unlike a bicycle,
front to back stability is an issue.

[man] Ooh.

[man] Don't worry,
I got it on film.

[Dallas off-screen] Which I'm
sure is a great comfort to him.

Remember to
anticipate obstacles.

Or that could happen.

For uni-cycles, front to back
stability is always an issue.

So if you miss
even a small divot,

you could find out what
your friend's shins smell like.

How about we try a trick?

But make sure you've
mastered the basics first.

[man] Come back!

[Dallas off-screen] When you're really
good, you can attempt jumps like this.

But you really shouldn't.

I think he's lost his uni-cycle, which
is probably for the best.

I love swimming, but after decades of
always using the ladder,

I've decided to live a little and extend
my repertoire of ways to enter the pool.

I tried diving and bombing,
and they were okay,

but now I'm searching
for the next big thing.

Such as the soaring eagle,

the stop, drop and roll,

or the face flop.

As you can see,
they were all rubbish.

But if like me you long to perfect a
front flip into the pool,

then you'd be wise to
listen up to the science.

The diver needs to generate enough
horizontal and vertical velocity

to safely clear the poolside.

She throws her arms out to
generate angular momentum,

and by tucking she exploits this

angular momentum,
increasing her rotation speed,

allowing perfect
timing for her water entry.

So there we have it.

It's all about dialing up the power,
because maximum height means

more air time for your flip.

Well, that's the height sorted, let's
see how he gets on with the flip.

Ah, not very well.

With a good arm swing in extra air time,
he manages a full flip

and then a bit more,

so he over rotates and flops
at more than 20 miles an hour.

Boy, he must be
red in the face.

Okay, let's try again with slightly less
angular momentum.

I said slightly less.

This time the guy's feet slip and he
can't get enough push, so his attempt at

angular momentum was
thwarted and his holiday spoilt.

Let's see if this young swimmer has
better luck with her tuck and flip.

[woman] [bleep].

[man] She's OK.

[Dallas off-screen]
Great tuck.

She decreases her moment of inertia and
she makes a full flip.

If I had a tip though, it would be

you need to work on your horizontal
velocity.

It hurts less if
you hit the water.

[woman] Yes.

[Dallas off-screen] No.

He stood on a table to give
himself more height,

but pushing down to launch put too

much pressure on his makeshift
diving board and once again,

that's not enough
horizontal velocity.

You need to jump from something solid,
like the ground.

Of course, it's not foolproof.

He builds sufficient
horizontal velocity,

but is unable to convert any of that

into vertical velocity due to
a lack of friction under foot.

That didn't go so well.

This trainee Jedi looks
ready for action,

but can you guess what key scientific

principle he's about
to demonstrate?

[Dallas off-screen]
We ask you what science

this light saber wielding swinger
was about to show us.

Yes, it's the
co-efficient of friction.

With their swings out of synch, they
easily pull each other off balance,

but the high co-efficient of
friction between the rubber seat

and his shorts means that

they stay put
while he doesn't.

Looks like the Force wasn't
strong enough this time.

I've mastered everything,

from BMX and skateboards to pogo
sticks and micro scooters,

but even I'm slightly nervous about
jumping on board with the latest craze.

Mounting a hover board is tricky for the
more mature amongst us and getting help

from a child is
nothing to be ashamed of.

But that is.

Maybe it's best if we
leave them to the kids.

Ooh, mum's gonna k*ll
you when she gets home.

A hover board is a self balancing
vehicles that's best used outside.

They're great because they've got the
potential to make you look stupid

before you've even gone anywhere.

When he steps onto the board, both feet
must be placed centrally

to avoid instability

as the board tilts
backwards of forwards.

Any correction he makes can grow into an
unstable oscillation and he'll become

shaky and will fall.

Using another person as a stabilizer can
backfire if you're holding onto someone

who's standing on the floor,

as this will stop your center of mass
moving as the board

wants you to, interfering
with its control system.

As is so often the case, it's about
keeping your center of mass over your

base of support, so due to their height,
most grown ups are at a disadvantage.

But when has that ever
stopped them from trying?

This lady is taking her first tentative
steps onto a hover board.

And despite her timid nature, I think
she might just have succeeded.

Oh, I hope I
haven't jinxed her.

Oh, I have.

Her constant corrections means she sets
off an unstable oscillation

which increases in magnitude until she

remembers why these
are best used outside.

[woman off-screen]
Pushing down.

[woman] You gotta
get on it fast!

[Dallas off-screen] Another beginner.
Will he fare any better?

I guess not.

This guy uses the fridge
as a stabilizer,

but this affects his balance
and control of the board,

setting off an unstable oscillation
which quickly moves his center of mass

too far outside
his base of support.

That looks both
painful and humiliating.

[man] Can you just
stand in front of me...

...and hold my
hands for a second?

[Dallas off-screen] The main problem
with hover boards is that

they're inherently unstable.

Getting help from his son backfires

because it stops his center of mass
moving as the

board wants him to.

So his son works as a de-stabilizer
rather than a stabilizer.

And suffers the consequences.

Sit down Jenkins
and stop crying.

Your mother only
left an hour ago.

Yes, it's time for today's
science lesson,

that part of the show where
we examine one

particular scientific principle, and
this one is full of dangers,

so please don't try
anything you're about to see.

Now, who can tell me what
the following have in common?

[man] That's kind of a lot.

[Dallas off-screen]
This foolish fire starter,

[man off-screen] Oh [bleep].

[Dallas off-screen]
This culinary master

and this cool dude.

Did you guess
thermal conductivity?

This describes how easily a material

transfers heat via conduction or
direct contact.

This flame is comprised of a gas mixture
which has low thermal conductivity.

As the sparkler passes through, not
enough heat is transferred

to start it burning.

However, the source of the flame, wood
fuel, has a higher thermal conductivity

transferring enough heat to start the
sparkler's combustion reaction.

And liquid water conducts heat
even more efficiently,

so is able to cool the wood quickly

enough to extinguish the fire.

Sounds simple enough, but it's
worth remembering that

heat continues to be conducted as

long as two objects at different
temperatures remain in contact.

Right, let's go
straight to question one.

Which part of a fire
conducts heat most quickly?

Well, this looks exactly
the sort of thing that should

only be attempted by
trained professionals.

That guy jumped through the flames which
have a low thermal conductivity.

Let's see if his
friend does as well.

[woman] Jump!

[Dallas off-screen] I
think she meant "jump higher".

He hits the barbecue, which is
full of coals,

and they have a
higher thermal conductivity.

Lucky for him, that barbecue
is right next to the pool.

Question two, can you name a common
substance with low thermal conductivity?

Everyone loves a barbecue, but lighting
them can be a problem.

But not as big a
problem as that.

[man] Water, water, water!

[Dallas off-screen] He flaps around
trying to put out the flames but air,

as well as being a
good source of oxygen,

has low thermal conductivity so can't
remove heat from the fire quickly

enough to extinguish it.

Luckily, water has high
thermal conductivity, so it can.

Maybe you're better off
just having the salad.

And now our final question.

Does water have a high or
low thermal conductivity?

Getting iced water tipped over you is a
good way to get cold fast.

[man] Just go.

[Dallas off-screen] See?

They both understand that now.

Water has thermal conductivity 25 times
higher than air, so it'll cool you down


worse when it's a surprise.

Okay, class dismissed.

[Dallas] I can't really talk about it,

but I did spend some time in the Secret
Service.

Along with learning the proper way to
wear a tuxedo

and a class in witty
one-liners,

we did all sorts of training.

I'm now an expert, for example,

at crawling over walls and barriers
undetected.

This is us now.

We based our methods on animals
with superior skills in jumping,

balance and stealth.

The animal kingdom is full of
animals

and they've devised plenty of ways to
surmount obstacles,

and some are more effective than others.

But the real innovation was hurdling,

which allows an animal to clear an
obstacle

without touching it and with
a minimal decrease in speed.

When hurdling, an animal needs
to raise its center of mass

just enough for its body and limbs to
clear the obstacle

without losing
too much forward momentum.

A biped's center of mass is on
top of a single pair of legs,

so clearing the obstacle benefits from a
splitting or tucking motion.

But a quadruped's center of mass is
between two pairs of legs,

so to clear the obstacle it raises its
fore limbs and pushes off with its

hind limbs, curving its body.

When it comes to hurdling,
four-legged quadrupeds have an

anatomical advantage
over two-legged bipeds.

So let's see an
expert at work.

Ah, such grace, such beauty.

Such a disappointment.

The pooch in front raises its
center of mass

just enough to
get it over the hedge,

while his friend does not.

But you can't keep a good dog down and
he soon finds his own way through.

This rider wants to
make it over the jumps.

And she does,
just without the horse.

Horses have been bred
for their jumping abilities.

Those are short jumps

so the horse only needs to raise its
center of mass slightly to

clear the obstacles.

But he still doesn't.

This goat is making
the most of his run up.

Very clever.

Yes, genius.

He jumps way too early and loses his
horizontal momentum rather suddenly.

The best film ever made is Sylvester
Stallone's moving drama Over The Top.

It's the incredibly affecting story of a
trucker who goes to Vegas

and wins the world arm
wrestling championship.

It's been widely acknowledged
to have inspired a generation.

It certainly inspired me!

Aaarrrghh!

Oooh!

This girl certainly
seems inspired.

But if she keeps straining like that
she'll have an accident.

It's not just youthful exuberance that
makes a champion either.

Experience and technique
are just as important.

If you want to avoid being beaten by the
grip of a granddad,

I suggest you pay
attention to this.

Our man's elbow acts as the pivot point
and his forearm as a lever.

He needs to apply as much torque as
possible to his opponent's lever,

and the person that can
apply the most torque wins.

Arm wrestling also requires a strong
base of support

to provide a solid pivot
point for the elbow.

If the material strength of the support
is exceeded by forces from the arms

and the weight of the wrestlers leaning
on the table, it will break.

Now that we're equipped with a
bit more knowledge,

let's see how our trusty testers are

getting on with their research.

It's all about
location, location, location,

and this is
the wrong location.

As they wrestle, the base of support
wobbles and their pivot points move,

decreasing stability, and a lack of
friction means his feet slip and he

hits the deck.

Now, were these
guys paying attention?

No, not even a bit.

Choosing a glass surface for their base
of support

is a mistake because it's
brittle,

and when too much force
is applied, it breaks.

I don't want you to look stupid, but it
has come to my attention that

an arm wrestling variant
exists that's potentially

even more bruising
to your ego, so beware.

[man] Ready?

Three.

Two.

One.

[Dallas off-screen]
I did warn you.

When the guy on the right pulls down on
his friend's arm,

he stretches the muscle and
soft tissue around the joints,

storing elastic
potential energy.

When he lets go,
elastic recoil occurs

and the fist springs
back to where it came from.

[woman] Oh my God,
you guys are so mean!

[Dallas off-screen] So the next time
your friend asks you to do this,

find another friend.

Ralph Waldo Emerson is
thought to have once said,

"Science does not know
its debt to imagination."

In that case, these pioneers are the
greatest scientists of all time.

[music plays through credits]