08x01 - Cornering in a Go Kart, Using an Outboard Motor, Jumping Out of a Plane Withou...

[bunniefuu]

DALLAS (off-screen): This

is the Science of Stupid.

Yes, this is the show that

extracts scientific wisdom

from pure stupidity.

MAN: Oh.

DALLAS (off-screen): Take

notes as people with too much

time and too little sense

test the boundaries of science

in pursuit of fun.

MAN: Oh.

DALLAS (off-screen): We'll

reveal what went wrong and why

with the help of

such key principles as

the coefficients of friction,

animal defense mechanisms,

and our old

friend, lift force.

MAN: Ah.

DALLAS (off-screen):

Taunt science and you're tempting fate.

So watch out, it's

the Science of Stupid.

In this episode

we'll be taking control

of terminal velocity.

He was okay.

Looking closely

at tire traction,

and diving headfirst

into propeller science,

but first this.

It's hard to imagine anything

more terrifying than clinging

desperately to

a sheer rockface.

40 feet up,

scrambling around for

the slightest hint of friction.

MAN: Ah. Ah, ah!

DALLAS (off-screen):

Pretty scary.

MAN: Thank you.

DALLAS: But not scary

enough for some climbers

who like their rock faces to

be, mmm, somewhat slippier.

The ice climber, a rare breed

that scales gravity taunting

ice incrusted cliff faces

and even frozen waterfalls.

Yeah, just not for me.

What makes ice

climbing possible,

aside from an inhuman head

for heights and an enormous

insurance premium, is the

high strength of ice's unique

internal structure, but it

does have its weak points.

Ice consists of water

molecules arrange hexagonally

to form crystalline

structures.

This tightly organized

arrangement can make an icicle

strong enough to support the

weight of an ice climber.

However, as ice grows it can

create networks of weak roots

between the crystals.

These are more perilous

near the top of an icicle,

which bears more of its weight

and so is under more stress.

Strike a weak point

here and that fracture can spread in an instant.

Okay, before we

grab our crampons,

let's experiment with

that unique structure.

Here we have a man

demonstrating how an ice shelf

composed of zillions of tiny

hexagons is strong enough to

stand on.

(screams)

DALLAS (off-screen):

But not stamp on.

Note how

excessive force applied by

stamping results in sudden

fracture along weaker routes

between ice crystals.

Okay, let's ice climb.

MAN: Here we go!

DALLAS (off-screen):

Close one. Still, the ice did hold strong there.

Let's see how it

does further up.

MAN: Woah.

DALLAS (off-screen):

Err, not great.

Although the icicle did

kind of stay in one piece,

it's just that it

wasn't very well stuck to the grass at the top.

MAN: You alright, Wallis?

MAN: I'm fine.

DALLAS (off-screen): Okay,

Wallis, but you do have to pick your icicles carefully.

And that is not an

icicle I would pick.

Ice weighs nearly

60 pounds per cubic foot,

so that icicle is already

supporting over a tonne of its

own weight, or

at least it was.

Remember, the higher you are

the more stressed the icicle

and the more

likely you are

to suffer a

different kind of stress.

And now we briefly avert our

gazes from people doing stuff

wrong and focus on someone

doing something right.

Record breaking right.

Consider the

skydiver in freefall,

initially accelerating

to earth at a terrifying

32.2 feet per

second per second.

Imagine the relief when that

parachute finally pops open,

but what if they're not

wearing a parachute.

Like

Yasuhiro Kubo here going for a Guinness World Record title.

He'll be

freefalling from around

10,000 feet and attempting to

catch up with his parachute

attached to this canister.

The record is determined by

how long he waits

before jumping,

at 50 seconds

later off he goes.

♪

DALLAS (off-screen):

Well that was a relief, and a World Record.

Freefalling without a

parachute is one of the most

dangerous stunts imaginable.

Do not even

consider considering to consider to do it, ever.

Especially when even regular

skydivers have their off days.

Err, little help please mate.

Go on, you can do it, go on.

Great, thank you.

Alright, so how does a

skydiver fall fast enough to

catch up with a parachute thrown

our nearly a minute beforehand?

Well to find out we need to

swot up on terminal velocity

and air resistance.

As an object falls it collides

with trillions of tiny air

molecules, resulting

in air resistance.

As the object accelerates the

air resistance acting on it

increases until it matches the

force of the object's weight.

It's now at terminal velocity,

the maximum speed it can fall.

A larger surface area

increases air resistance and

so decreases

terminal velocity.

A smaller surface area

decreases air resistance

and so increases

terminal velocity.

A sky diver in spread-eagled

position hit terminal velocity

around 120 miles an hour

after about 12 seconds,

but for Yasuhiro

to catch up with his chute that is just too slow.

So which of our wannabe record

breakers has remembered how we

speed up our

terminal velocity?

Not these ones.

That is the complete opposite.

Their raft has a

large surface area,

thereby increasing

air resistance and slowing them down.

Okay, anyone else.

Yeah, that's

it, going upside down and reducing his surface area

decreases air resistance and

increases terminal velocity.

Trouble is, oh, woah,

it's very hard to control.

Oh, is that guy inverted too?

Yes, he was.

Once he's caught up with his

chute Yasuhiro needed to steer

himself into

position to grab it.

How did he do that?

Well skydivers can also use

air resistance to maneuver.

For example, by adjusting his

body shape this chap deflects

more air backwards,

which pushes him forwards.

Bullseye.

Somehow all of our

high flyers were fine,

but I think we should leave

the record to Yasuhiro.

Now can you guess what

scientific principle this free

runner is about

to demonstrate?

DALLAS (off-screen):

Did you work out the science he's about to show us?

Yes, it's angular momentum.

As he lands he pushes

back with his feet,

tipping the trash can.

This rotates him around

his center of mass,

giving him angular momentum

he probably didn't want.

Who ways

recycling can't be fun?

In 1956 race car mechanic,

Art Ingels, and partner,

Lou Borelli, took an old

lawnmower engine and fashioned

the very first go-cart.

They got about

two horsepower out of it,

but go-carts aren't all

about straight-line speed.

Races can be won and

lost on the bends.

Sometimes with a little help,

but when you've crossed the

line seconds ahead of the

rest it's a moment to treasure.

Selfie?

The secret to winning those

corners lies in not losing too

much speed or traction, and

the secret to that lies in

straight lining a bend.

Our driver decelerates as

he approaches the corner,

sweeping in from wide and

cutting across the apex of the

bend, before accelerating

out wide again.

This is called

straight lining a bend.

It maximizes the radius

of the curve he follows,

allowing him to

maintain a higher speed,

with less risk

of an understeer,

where the front

wheels lose traction,

or an oversteer where the

rear wheels lose traction.

Okay, visors down

and let's see who can

straight-line a bend.

Well he can.

Beautifully sweeping

in from wide,

tickling the apex and

accelerating out wide again,

maximum the radius and

protecting the lead.

Another one?

Yeah, not quite as good.

Approach the turn too tight

and straight lining that bend

is going to be hard.

So how about we take

it a little wider?

Err, yeah, not that wide.

An oversteer causes his rear

tires to lose traction.

A little corrective steering

later and now it's a massive

understeer.

Two for one.

Okay, we've got this.

Find the line,

maintain traction,

and he's stolen the lead.

Now defending a corner means

forcing your attacker to take

the worst possible route.

Yep, that was a bad one.

As our driver cuts in his

attacker is squeezed out and

oversteers significantly.

So it's like I said,

go-carts aren't all about

straight line speed.

The path to victory lies in

mastering the tightest of turns.

Admittedly that is

a little too tight.

For thousands of years the key

to engineering strength

has been down to a simple

shape, this one.

From the 4,000-year-old

pyramids of Giza,

to dad's bike.

Well, the frame anyway.

The triangle has been

recognized by engineers as the

strongest of all polygons.

Squares, rectangles,

pentagons, nonagons, decagons,

no shape is in better shape

than the mighty triangle.

Apply force to a square and

you can change its angles,

collapsing it even if

its sides don't fail.

This is true of all polygons,

except the triangle.

No matter how much

force is applied,

a triangle will not collapse

as long as its sides don't fail.

Systems of triangles,

like trusses,

are particularly effective at

transferring loads to their

supports, and squares and

rectangles can be reinforced

simply by adding cross

braces which, yep,

turn them into triangles.

We owe the mighty

triangle so much.

Because of it, huge cranes can

hoist thousand tonne weights,

factories, stadiums and

stations can bear vast roofs

without supporting columns.

And the legs of this child's

swing set can easily hold the

weight of these, err, adults.

Unlike the rotten

beam at the top.

So how do you strengthen

an entire structure?

Well trusses like these roof

supports are a system of

connected triangles

that transfer the weight of the roof to the walls.

MAN: This is

either going to work

or it's not.

DALLAS (off-screen): Now I'm

hopeful because there is yet

another triangle, making

your ladder very sturdy.

See, the ladder's

completely fine.

MAN: Boy, that hurt.

DALLAS (off-screen): Now

rectangular structures,

like a wardrobe, can be

reinforced by inserting a

cross brace to form triangles.

This wardrobe. Yeah,

that's just a rectangle.

So the force of the

impacts have no trouble

altering its angles.

Still it's much

easier to pack up now.

Good work lads.

But remember, even a triangle

is only as strong as its sides.

So as a tornado

tears through Russia,

even a gantry that can support

hundreds of tonnes in weight

has its limits.

DALLAS: The inventor of

the first outboard motor,

French electrical

engineer, Gustave Trouve,

was also responsible for

the first electric vehicle,

the portable

electric safety lamp,

the endoscope and the

light-up ballet dress.

In short, the

man was a genius.

But thanks to the simplicity

of Gustave's outboard motor

you don't have to

be a genius to use one.

The outboard motor,

distinguishable from the

inboard in that it sits

outside the body of the

vessel, can be rigged to very

small lightweight boats,

giving them a high

power to weight ratio.

So with all that

power in your hands,

wouldn't it be

good to understand a little of the science?

As propeller blades rotate

they accelerate a column of

water backwards, producing a

reaction force that thrusts

the boat forwards.

The propeller can be moved

left or right to steer.

It could also be angled

up, called tripping up,

which raises the bow, reducing

hydrodynamic drag when at

speed for greater

efficiency, or angled down,

called trimming down, which

lowers the bow into the water,

giving the hull

more stability.

Just watch out for your depth.

Exactly how and when you

alter the direction of thrust

through trimming is

a science in itself.

Trimming up raises

the bow, reducing drag for efficient planing.

MAN: Or not.

DALLAS (off-screen):

Yeah, or not.

MAN (off-screen): Ooh.

DALLAS (off-screen): When in

a boat with a high power to

weight ratio it's best not to

slam the throttle on and off.

MAN (off-screen): Ooh.

DALLAS (off-screen):

Okay, onto steering.

And where better to learn

than dinghy derby practice,

where boats can race upriver

and over 50 miles an hour.

And now for a textbook 180.

Ah, I've not read

that textbook.

One dramatic change

of thrust direction,

one massive increase

of drag at the side,

leading to two damp sailors.

Reverse propeller direction

to thrust backwards, nice.

Trim up, keeping that

prop clear of the bottom,

loving your work, sir, and to

finish, a little showboating.

Classic.

Drop your prop in extremely

shallow water and your boat

may stop, but you might not.

But once you've perfected

thrust and trim control

you can move onto

more advanced skills.

Like diving.

The humble baseball,

more complex than it looks,

comprising of an outer

layer of leather,

several layers of yarn,

two types of rubber and a

cushioned cork center.

Its mass gives it

lots of momentum.

Okay, lots of

momentum not always ideal,

so a safer option

might be this.

Plastic, hollow, lightweight,

its kinder on your furniture.

And harmless fun for kids.

WOMAN: Nice shot.

DALLAS (off-screen):

But not for mums.

Alright, so plastic ba*ls,

not 100% pain free,

but with whole tournaments

across America dedicated to

this variant of baseball a few

extra hours backyard batting

for junior could

yield a future star,

provided they first complete

their homework on velocity,

momentum, angles and vortices.

Some plastic ba*ls are

perforated and spinning them

can allow air to

rush into the holes,

creating vortices inside

that can curve the ball,

making it harder to hit.

Being hollow, the ball

also has a lower mass than a

regular baseball, so he needs

to strike with a lot more

velocity for it to gain

sufficient momentum and fly far.

And striking

underneath the ball,

so it launches at

around 25 degrees also helps maximize distance.

Therefore the ba*ls' lower mass

means they're safer for kids

and beginners, and thanks

to those internal vortices

curving the ball

is child's play.

You just have to

know how to pitch it.

This is not how to pitch it.

MAN: I'm not going to

try to hit you though

I'm going to go to your

MAN: Oh.

DALLAS (off-screen): Face?

With that excessive amount

of velocity and therefore

momentum they really didn't need

to bother with a curve ball.

Because he didn't

see that coming.

That's it, nice fast

swing, plenty of momentum,

but for distance you'd also

want to aim a little higher.

MAN: Oh.

DALLAS (off-screen): Yeah,

a bit higher than that.

You're looking for

that 25 degree angle.

MAN: Ah.

DALLAS (off-screen): It was

closer to minus 25 degrees.

Yeah, that's more like it.

A high velocity swing and an

angle closer to 25 degrees

means even his hollow plastic

ball is heading for the stands.

Now let's see if we can

launch it into next door.

Oh, yeah, not, not quite.

The achievements of science in

this century alone are really

quite staggering.

We've detected water over

30 million miles away on Mars,

we've grown

functioning human organs,

and discovered that 68% of

our universe is composed of a

mysterious dark energy,

but we're still not quite sure

why people do this.

♪