05x12 - Dive Bombs, Push Ups and Frisbee Golf

[bunniefuu]

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

Yes, this is the show that squeezes the
science out of the stupid.

As our band of
reckless researchers.

[man off-screen] [bleep].

[Dallas off-screen] Test the boundaries
of scientific knowledge,

so you don't have to.

We'll reveal what went
wrong, and why,

demonstrating key
principles along the way.

Such as ricochet,

relative motion,

and gravitational acceleration.

So, buckle up
and hold on tight

because this is the
Science of Stupid.

In this show, we'll
be looking at torque,

optical illusions.

[man off-screen] Digby!

[Dallas off-screen] And
the coefficient of friction.

But first this.

There are very few things that you can
do with a human body

that come close to the grace,

beauty or physical
poetry of a good dive.

The body caught for a split second,
looking almost weightless,

before entering the water
with barely a ripple.

I could watch it all day.

See what I mean.

These people are like
Icarus, daring to dream,

but flying slightly too close to
the limits of classical physics.

Yes, all those dives had
two things in common.

One, they were rubbish, and
two, they made a lot of splash.

If you want to look like a pro, you'll
need to go for a splash-less dive,

and to do that you need to understand a
little bit about hydrodynamic drag.

So, trunks on and listen up.

She needs to hit the water as close to
vertical as possible

by making a streamlined body shape.

The smaller her frontal surface area,

the less hydrodynamic drag she will
experience.

Keeping her palms flat, creates
a cavity that swallows her body,

moving the water sideways rather
than upwards for minimum splash.

So, it's all about having a near
vertical entry angle,

a small frontal surface area,

and a relatively low impact force.

There's a lot to remember here, so let's
take it one step at a time.

A good bounce maximizes his takeoff
height, facilitating the perfect dive.

But this was not that.

On his final bounce, he leans
too far backwards,

compromising the desired vertical
trajectory

and sending him crashing
horizontally into the water,

creating a large surface
area, and a big splash.

Throwing a flip into the mix
makes entering the water

with a streamlined body
position a bit harder.

Luckily, these two
are professionals.

Well, at least you were in sync.

A lack of form in their entry led to
lots of drag, large impact force.

And nul points.

To be good, you really
need to start young.

Yeah, that was OK, you just need
to work on your entry a bit.

Let's see how your friend
does from higher up.

[man off-screen] Oh!

[Dallas off-screen]
Eh, not so great.

A higher fall means hitting the
water with a greater velocity,

and the surprise of
a slipping foot doesn't help,

ruining his
streamlined body shape,

so he hits the water with
a large surface area.

Ahh, now these guys' bodysuits can
actually cut down the hydrodynamic drag

they experience as
they enter the water.

That's smart.

But that isn't, and sort of
ruins the effort they must have

put into getting those suits
on in the first place.

I always say that there are just three
things I can't live without,

my fat-free orange mocha Frappuccino, my
weekly full body wax,

and of course, my moped.

But not everyone has my taste.

There is a scientific consensus
that all moped wheelies

look cool... as long as
that doesn't happen.

There are risks though.

That's dented his bike
and his street cred.

If you have to show
off, don't do that.

Anytime you attempt anything like a
wheelie on a moving vehicle,

you are putting your life in the danger,

so best to pay close attention to some
science.

To pop a wheelie, our man accelerates

in order to create a torque around the
back wheel.

This then generates a reaction torque
that lifts the front up off the ground.

Accelerate too hard, however, and you'll
be back on the ground pretty quickly.

Seating position
is also important.

The further forwards he's sat,

the more reaction torque he needs to do
the wheelie,

which requires more
power and more grip.

Just make sure you look
where you're going.

For the perfect moped wheelie,

you need to keep your body towards the
back and control

your torque as you
accelerate hard.

But not that hard.

[man off-screen] Oh no!

[Dallas off-screen] This guy has no
trouble

getting the front of his moped
off the ground,

but he opens the throttle and
another burst of acceleration

creates more torque
around the back wheel.

[man off-screen] Oh no!

[Dallas off-screen] And
spoils his paint job.

[man off-screen] Not
looking good now.

[Dallas off-screen]
Ahh, a cruise.

Everybody in their finery,
showing off and looking good.

Except that guy.

He's standing out for
all the wrong reasons.

At first, he seems to be controlling his
torque well,

with perfect weight
distribution

and acceleration, but he
then shifts too far back and

regrets wearing those shorts.

The fastest ever wheelie was
just over 190 miles an hour.

It had nothing to do
with him, obviously.

The relatively small back wheel provides
less gyroscopic stability

and, of course, in general it's hard to
steer when your front wheel

is off the ground, making him fall off,

and the bike take off.

Can you guess what
key scientific principle

this pioneering paraglider
is about to demonstrate?

[Dallas off-screen] So, have you guessed
what science we're about to see?

If you said aerodynamic
lift, give yourself

a gentle pat on the head.

A paraglider's canopy works
by generating a lift force,

which counteracts the glider's weight to
allow him to descend very gradually.

However, this glider did not have enough
lift to keep him higher than that tree,

resulting in a face
full of needles.

When I'm on holiday,

I like nothing more than standing on top
of a majestic waterfall

looking out at mother
nature's triumphs.

However, if it's a hot day,

there's always a temptation to dip your
toe in the water to cool off.

That would be a bad idea.

As she has just discovered.

One of the problems with overheating...
is impaired judgement.

This guy isn't even hot,
he's just very clumsy.

Water and slipping
go hand in hand.

Throw a hard rock
surface into the mix

and you have the recipe for a
potentially deadly situation.

So, remember, waterfalls are better to
look at than to slide down.

Some waterfalls and cascades
are sloped surfaces on which

an object, or a person,
can slide down.

This is thanks in part to the
water acting as a lubricant

between him and the
rock reducing friction.

However, as his feet easily slide,

his center of mass risks going outside
his base

of support, allowing gravity and the
water's drag to pull him down.

Of course, the world's highest waterfall
is Angel Falls in Venezuela,

at an impressive height of
nearly 1,000 meters,

but that's a bit high for my liking.

Personally, I prefer something
a little less intimidating.

But even something relatively shallow
could be dangerous and painful.

See what I mean?

This guy has found a shallow inclined
plane

with some water to reduce his
friction,

which worked a bit more effectively than
he was expecting,

proving a little dribble can be as
dangerous as a mighty waterfall.

This chap is having
the time of his life.

Or was that his life
flashing before his eyes?

He didn't factor in the algae on the
rock,

this super slippy slime further
reduces the

friction between the
man and the rock,

causing him lots
of embarrassment,

and a fair amount of pain.

These guys seem
to have it sussed.

Lots of water means lots of drag,

helping to carry them down and over the
rocks.

But waterfalls are dangerous.

That's right, you might be drowning,

but just make sure you save your selfie
stick.

There's a funny whiff in here.

Harmsworth, was that you?

Open the window.

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

That part of the show where we put some
science under a microscope

and try and make
sense of it all.

So who can tell me what scientific
process

links the following foolish
feats?

These silly scientists.

[boy] Oh my gosh!

[Dallas off-screen]
This imprudent igniter,

and this brash bottle opener.

That's not gonna improve
the flavor one little bit.

The answer, of course,
is molecular diffusion,

the process by which
molecules mix and spread.

So when a gassy expulsion works
its way across the room,

you can blame it on molecular diffusion.

And Fick's Law of Diffusion describes
how liquids and gases spread out.

Substances with high viscosity,
like this treacle,

don't easily mix with the water.

But substances with a lower
viscosity, like this ink,

are able to diffuse
more quickly.

Heating the water gives the
molecules more energy,

so they move around more quickly,

allowing the ink to
diffuse even faster.

Have you got it?

Let's see.

Question one, if something
has low viscosity,

will it spread quickly or slowly?

[man off-screen] Don't
be a wuss, let's go.

[Dallas off-screen] Ahh, the
ghost pepper challenge.

Saliva has low viscosity.

[woman off-screen] Don't puke.

[Dallas off-screen] So allows the
capsaicin molecules

from the chili to diffuse quickly.

[boy] No.

[Dallas off-screen] When the ghost chili
comes into contact

with the sensory receptors

in his mouth, it causes
him a lot of pain.

[boy] Hurts!

[Dallas off-screen] And that's why you
should never do this at home.

Question two, if the molecules
are first kept under pressure,

such as in a carbonated liquid,

how fast will they
diffuse given the chance?

That it'd be very fast.

Gas naturally diffuses from
carbonated drinks into the air.

By shocking the bottle with the impact,

he agitates the molecules and
releases the

pressure, accelerating
this process,

starting married
life with a bang.

Question three, how long do odorous
molecules take

to diffuse through the air?

These guys are about to find out with
some fermented Baltic sea herring.

[man] What the [bleep]
is that [bleep]?

[Dallas off-screen]
Apparently not that long.

Once released, the odorous molecules of
stinky fish

diffuse rapidly through the air,

reaching their noses
pretty quickly.

So that's the end of our
lesson on molecular diffusion.

[man off-screen]
Smell Mum's feet.

[boy] Oh!

[Dallas off-screen]
Class dismissed.

[Dallas] Now, neuroscientists believe
that everything we see and hear

is a figment of
our imaginations.

What we see may seem accurate,
but it's not necessarily true

to the physical world around us.

Like this cat who really
doesn't like his greens.

Or this squirrel who's spotted
some food, but not that window.

And this athletic alley
cat was not expecting that.

Yup, in the animal kingdom nothing is
ever as it seems,

and optical illusions
make survival that little bit harder.

So, if you want to thrive
with the best of them,

better pay attention to some science.

Both animal and human brains
make shortcuts

when interpreting
the visual world around them.

For many animals, the quickest way to
gain information is through sight.

But even that lets
you down sometimes.

The brain makes assumptions
about what it sees,

because survival
requires fast reactions.

When experiencing a visual illusion,

they may see something that's not
actually there,

or fail to see something that is, like
this hungry lion in the foreground.

Appearances can be deceiving,

with our lazy brains making
shortcuts whenever possible.

The human brain can detect
some visual stimuli

that last as little as 13 milliseconds,

but something tells me that these
animals are not quite as fast.

[man off-screen] Digby!

Digby!

[Dallas off-screen] Poor
Digby was deceived.

[man off-screen] Yeah,
that'll teach him.

[Dallas off-screen] Both the color and
the texture of the algae are misleading,

creating an optical illusion
of the grass continuing.

That's right, Digby, you
just shake it all off.

As the saying goes, seeing
is believing, right?

This kitten uses sight as its
primary sense,

so can't tell that the other cat
is a fake.

Its brain has made an assumption
in order to react quickly,

and I think he might have
the edge on his opponent.

Of course, you can't process something
visually if you can't see it.

[man off-screen] What are you
going into the box for, kitty?

You OK, Kitty?

[Dallas] I love everything about
Russia, except their dolls.

They're just so
full of themselves.

But my favorite Russian
export is the kettle bell,

great for a workout and
there are even competitions.

Like this one.



And that's less impressive.

This lady came to use the treadmill, but
it was in use so instead

she's just k*lling time.

Of course, there are other
ways to life kettle bells,

but they aren't recommended.

Kettle bells can be used to perform
ballistic exercises

that combine cardiovascular

and strength
training with rhythm.

So, if you fancy yourself as a muscly
dancer, this could be your sport,

as long as you
understand the science.

Kettle bells contain
a lot of mass.

He, therefore, needs the
muscular strength

to generate a large enough force
to lift it,

and the right technique to make the most
of his skeletal strength.

More mass means more inertia,

so he needs adequate grip when changing
its speed or direction.

So it all comes down to
these three things:

muscular strength, technique and grip.

This guy is going
to demonstrate...

how not to do it.

He manages to generate a large enough
force to lift the kettle bell,

but can't use his skeletal
strength to keep it up there.

And he makes an
exhibition of himself.

Now there's kettle bells and then
there's extreme kettle bells.

And that was extremely bad.

This kettle bell has a lot of
mass, and therefore inertia,

making it very hard to change
its direction once in motion.

[woman off-screen]
Shall I carry on?

[man off-screen] No,
just relax now.

[Dallas off-screen] Good.
I think that's for the best.

As we've seen, kettle
bells can be complicated,

so adding this ball into the
equation is probably unwise.

Yeah, I thought
that might happen.

Adding an unstable base of support

means that when he moves his center of
mass backwards

to balance the kettle
bell, he takes a tumble.

That's it for now, but I
will leave you with this.

Last night I was reading a book on
antigravity,

it was so good I couldn't
put it down.

[music plays through credits]