08x02 - Fishing Net, Luge and Diving

[bunniefuu]

DALLAS (off-screen): This

is the Science of Stupid.

DALLAS (off-screen): Yes,

this is the show that subtracts the science from the stupid.

Observe as amateur researchers

fight the laws of physics

head on and

invariably lose.

We'll explain what went

wrong and why with the help of scientific principles

such as traction,

terminal velocity

and our old friend gravity.

Watch it but don't

copy it because this is the Science of Stupid.

DALLAS (off-screen): In this

episode we'll be studying how physics can improve your

catch, how a smaller

surface area improves entry

and we learn that humans

aren't the only animals

(screams).

DALLAS (off-screen):

With chemical weapons.

But first this.

DALLAS: The unofficial

motto of Speedway racing is go fast, turn left

and you can see why.

DALLAS (off-screen):

Left, left, left, left, left, not left enough.

DALLAS: Really it should

be "Go fast, turn left and try not to crash",

a feat made trickier because

Speedway bikes have absolutely no brakes.

For the purpose of

self-preservation that is not at all helpful but for the

study of centrifugal

force it's fantastic.

DALLAS (off-screen): The key

to Speedway is power sliding.

When riders approach a corner

they increase the torque at

the back wheel until it loses

traction and slides sideways.

This allows some of the

propulsive force from the

rear wheel to counteract

centrifugal force but if

a bike collides with another

bike it'll transfer some of

that momentum onto that

bike with potentially dirt-eating consequences.

DALLAS: And with these bikes

capable of hitting 60 miles an hour in three seconds,

as fast as some Formula 1

cars, that's a lot of transferred momentum.

Fortunately all of our

racers have carefully studied the science.

DALLAS (off-screen):

That rider could write a book on centrifugal force.

That rider needs to read one.

Back wheel hits wall, slows

bike, jolted rider succumb to centrifugal force.

At least the bike

hasn't given up.

Thankfully these riders are

keeping well away from the wall

but not each other.

Bikes touch, bike at the

back transfers some of its momentum to the other bike,

other bike goes airborne

but not quite as far as this guy thought.

I've no idea why this

rider fell off but even without him his bike

generates plenty of

momentum to transfer.

You know, maybe brakes

would have been a good idea.

DALLAS: And now we briefly

turn our attention from people getting it spectacularly wrong

to someone getting it

extraordinarily right.

Now, the science of falling

dictates that the quicker you stop the harder the landing,

so if I were to jump from

a height I'd be better off landing on something that

brings me to a slow

gradual stop, like deep water but probably not

a child's paddling

pool, if I'm honest.

DALLAS (off-screen):

Meet Professor Splash.

He's aiming to break

the world record for the highest shallow dive,

by leaping from this 37.4

foot high platform into this

tiny pool which has about

a foot of water in it.

Professor, are you okay?

You little trickster.

You just got yourself

a new world record.

DALLAS: Now, did I mention

how dangerous that was?

Seriously do not try this

at home or anywhere else.

DALLAS (off-screen):

And that includes here.

Oh, there'll be sore

heads in the morning.

DALLAS: There's just too much

science to get wrong, stuff

like hydrodynamic drag

and angular momentum, all of which luckily

can be demonstrated with

objects that don't feel pain.

DALLAS (off-screen): Our diver

must gain just enough angular momentum to land horizontally

because the larger the

surface area that hits the water the more hydrodynamic

drag he experiences,

and the quicker he stops.

Too much angular momentum

and he will over rotate,

meaning less surface

area hitting the water,

so less hydrodynamic

drag and he won't slow down

fast enough to avoid

hitting the bottom.

DALLAS: Alright, so knowing

the science we now understand

why Professor Splash chose to

use the belly flop technique,

but as we all know the belly

flop has a serious flaw.

It really hurts, which makes

it odd that some people

appear intent on trying

to break the Prof's record.

DALLAS (off-screen):

This chap is starting with a low level approach,

just as well really.

His initial jump gives him too

much angular momentum and he enters at too steep an angle,

giving him limited

hydrodynamic drag.

He was okay but that could

have ended up a lot worse.

DALLAS: Alright, let's put the

shallow water to one side and focus on those fast stops,

AKA belly flops.

Now, just bearing in mind the

larger your surface area the more water molecules that are

to catch you and so

the more drag there is.

DALLAS (off-screen):

And the quicker.

You stop, which feels

a bit more like that.

MAN: Oh.

DALLAS (off-screen): You see,

liquid water, solid ground.

It's all just

bunched up molecules.

MAN: Don't dive,

just do it with a twist.

DALLAS (off-screen): You mean

angular momentum but watch out because the higher

you fall the more

ground like it feels.

And did you know that some

of the energy you transfer to the water becomes sound?

The slap and some

of it becomes heat.

The sting.

DALLAS: Which is another

reason why this dangerous stunt should only be attempted

by an experience expert

with iron clad abdominals, like Professor Splash.

DALLAS (off-screen):

And not her.

Or anyone else.

I think the Professor's

record is safe for now.

WOMAN: Keep it down.

1-2-3.

Keep it on the ground.

DALLAS (off-screen): Can you

guess which scientific principle these revolving

friends are demonstrating?

WOMAN: Keep it down.

1-2-3. Keep it on the ground.

DALLAS (off-screen): Did you

guess the science this spinny game would lead to?

It's a tough one as you

may have been looking at the wrong spinner,

so not him but him.

WOMAN: Oh.

DALLAS (off-screen): And it's

the vestibular system which tells our brain about motion.

When we spin a liquid in our

inner ear sloshes around that the brain uses to aid balance.

Stop spinning and the liquid

temporarily keeps sloshing,

so the brain thinks

we're still spinning.

WOMAN: Oh.

DALLAS (off-screen): And

that is terribly confusing.

DALLAS: Long-time friend of

the show Charles Darwin knows a thing or two when it comes

to natural selection and

survival of the fittest, like the need to be able to defend

yourself from a

physical attack.

(screams).

DALLAS (off-screen):

Or a verbal as*ault.

MAN: He's got me.

DALLAS (off-screen):

Still going.

DALLAS: Animals have three

main forms of adaptation to help them defend themselves,

physiological,

structural and behavioral.

DALLAS (off-screen):

Physiological are internal features,

like an octopus's ability

to change color and help him turn himself into something

less tasty, like a rock.

Other animals use structural

defenses, like armor or teeth and claws,

and the final technique is

behavioral defense where the animal reacts in a special way

to protect itself

from a perceived threat.

Tabby take down.

(cat meows)

DALLAS: Right, physiological,

structural and behavioral.

With so many weapons to choose

from it is amazing anything gets eaten at all,

although it's not just

about fending off predators.

DALLAS (off-screen): Take this

guy, minding his own business, enjoying nature's beauty,

though not the

guy on the bike.

The bull

guarding his territory.

This is both a structural

defense, his horns and heavy skull and a behavioral

defense, charging the threat,

but you don't have to be that

big when you can

make yourself big.

(screams).

DALLAS (off-screen): Spreading

his frills out our tiny annoyed frilled neck

lizard displays his

structural defense.

Sure, he's not velociraptor

but he's more than a match for h*m*-flip-flopias.

A useful physiological

defense is the good old fashion stinger where animal

bodies create a chemical

c*ck which is painful,

as our friend here finds

out whilst trying to

remove a wasp's nest.

DALLAS (off-screen): Some wasp

species use their stingers for defense and for hunting prey

but hopefully he's

not on the menu.

WOMAN: I'm sorry.

DALLAS (off-screen):

Yeah, you don't sound sorry.

Ah, now this fella's copied my

own personal defense strategy.

(screams).

DALLAS (off-screen):

Nope, not the rooster.

WOMAN: No, don't run, don't run.

DALLAS (off-screen): The kid.

We h*m* sapiens wouldn't be

where we are today without running away from stuff.

DALLAS:

Bobsleigh, luge, skeleton.

Without doubt some

of the scariest events at the Winter Olympics.

DALLAS (off-screen):

These sleds can hurtle down frozen tracks at speeds

in excess of 80 miles an hour,

so should only be done

by trained athletes and even

then still quite dodgy.

DALLAS: Knowing the high

velocity risks it would seem an unwise decision

to attempt to carve out

your own homespun track, well it would to me anyway.

MAN: Go, go, go.

GIRL: Oh.

DALLAS (off-screen):

But not to Dad.

DALLAS: As you can see gentle

viewers, this is dangerous stuff but a little scientific

learning might help

with damage limitation, emphasis on 'might'.

DALLAS (off-screen): The

ultimate DIY track needs a lot of compacted snow for a smooth

low friction surface and a

slope with banked sides keeps him on track whilst gravity

does its stuff and

pulls the sled down, gaining linear momentum.

Large bumps are not

ideal because if he ends up airborne any angular momentum

gained on take-off will

cause him to rotate.

DALLAS: A proper Olympic

track will be meticulously engineered with just the right

gradient to ensure good

gravity assisted momentum, plus a uniformly smooth

surface for

consistently low friction.

DALLAS (off-screen):

This snowy gulley has got gravity covered

but it's not so

snowy at the bottom.

So, when a bump throws

him off his linear momentum is quickly reduced by the

high friction of the dirt.

Well, at least he's

got a free lunch.

Okay, this kid's

remembered the snow, shame about the bump.

(laughter).

DALLAS (off-screen): The

linear momentum was good but he then overly minimized

friction through air flight

and used his face to add unnecessary angular momentum.

(screams).

DALLAS (off-screen):

This could be it.

Prepare to be ama

DALLAS (off-screen):

Zingly disappointed, yeah.

Once again a bump has sent our

researcher airborne but this time she has picked up angular

momentum,

rotating her in the air.

Luckily Dad is here with

some soothing laughter.

But every now and then our

science dads get it right, but let's be honest,

no one likes a show-off.

That counts for you too kids.

DALLAS: There's nothing

I like more than getting away from the hustle

and bustle of city life, jumping

on a boat and going net fishing,

but then of course I am an

expert, much like this guy.

DALLAS (off-screen):

Err, actually I was thinking of someone else.

DALLAS: The thing about

casting a net is it looks much easier than it is.

There's actually a large

amount of science involved, like our old friend

conservation of momentum and

its touchy acquaintance, friction.

DALLAS (off-screen): She

rotates her body to give the

net plenty of momentum and so

time to spread out in the air

but conservation of momentum

means that as the net

gains forward momentum

she gains backwards momentum

and so applies a backward

force to the boat via her feet,

therefore she must also ensure

that there is good friction

between her feet and the

boat to avoid slipping.

DALLAS: And it's that

backwards force where most of the problems come from.

To investigate this phenomena

we've sent a crack team of scientists out into the field

and by 'field' I mean 'lake'.

DALLAS (off-screen):

Calm conditions, check.

WOMAN: Nice, stand up.

WOMAN 2: I'm not too confident.

DALLAS (off-screen):

Properly prepared net, check.

WOMAN: That's alright,

I believe in you.

DALLAS (off-screen): So do

I believe you've demonstrated

exactly how not to do it.

Conservation of momentum means

that as she swings the net she gains backwards momentum,

causing her feet to apply a

backwards force to the kayak.

Due to the low resistance to

movement on water the kayak moves backwards,

causing her to lose balance

and hence the early bath.

This young fisherman

has poise, balance

and slippery feet.

Those wet feet apply a

backwards force to the kayak

that overcomes the friction,

sticking him to it.

Oh, for a sensible

pair of deck shoes.

Look, so long as you remember

conservation of momentum

and friction

you should be fine.

Oh, that's more than fine.

He generates the perfect

amount of momentum for a decent net spread and his boat

is big enough to withstand

the backwards force his feet apply to it.

Nice grippy footwear too.

(screams).

DALLAS (off-screen):

Unfortunately he missed the fish completely but it could

be worse, you could be

fishing with this chap.

At least he caught

something but I'm not sure you can eat that.

DALLAS: Now then,

cheerleaders bring a little bit of razzmatazz

and a whole lot of pompoms

to any sporting event

but luckily for us they

also bring the science.

DALLAS (off-screen): And

one of their most famous

and hardest experiments is

the one-man stunt where one

of the cheerleaders raises the

other cheerleader into the air

and then acts like a platform

for the raised cheerleader to

perform acrobatic stunts.

To perfect the move it

takes hours of practice

and maybe a few

more hours than that.

Hey, don't forget about the guy

who caught you with his face.

DALLAS: The beauty of this

move is the coordination between the flier,

the person being thrown in the

air, and the base, the person that needs to do all the

catching when it all goes

wrong but here's how it works when it goes right.

DALLAS (off-screen): On

launching the flier jumps and the base pushes upwards,

transferring some of his

momentum onto the flier allowing her to jump higher.

The flier tucks in her

arms and legs closer to her center of mass,

reducing her moment

of inertia so she can complete her rotation.

In order to remain stable the

flier's center of mass must

stay within her base

of support, her feet.

DALLAS: Moment of

inertia, it's a curious thing.

It's basically how a mass,

i.e our body will rotate faster the more tucked

in it is and slower

the more spread out it is.

It's one way of controlling

how you fly through the air

and more importantly

how you fall.

Other than that pretty simple.

Push, spin, land.

DALLAS (off-screen):

Push, spin, nearly land.

WOMAN: Oh my God.

Oh, oh God.

DALLAS (off-screen): She

hasn't tucked in enough so her

moment of inertia is too high,

so she under rotates.

The catcher leans backwards to

compensate but misses one of

her feet, causing her

to lose her balance.

WOMAN: Oh my God.

Oh, oh God.

DALLAS (off-screen): And

almost the rest of her day.

Yeah, it's not a great start.

Will it get any better?

Err, no.

Not only was it an awful

launch but the flier failed

to keep her center of mass

within her base of support.

Gravity can't help but

to act on her posterior,

giving her a crash

course on impact force.

Okay, this looks promising.

Good balance, she's keeping

her center of mass inside her base of support,

just the

dismount to go and

needs work.

She didn't land evenly between

the two catchers, thankfully for

her this guy absorbed some

of her momentum with his nose.

So, your best bet is to

start practicing young.

DALLAS (off-screen):

And then give up before you really hurt yourself.

GIRL: Oh, we got

that on video.

DALLAS: And that's your lot.

Please do not attempt

any of the dangerous stuff you've just seen.

As author Arthur

C. Clarke once said,

"I'm sure the universe is

full of intelligent life,

it's just been too

intelligent to come here",

and judging by

this lot he's probably right.

(music plays through credits)

♪

MAN: He's got me.