Science of Stupid (2014) s08e09 Episode Script

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DALLAS (off-screen): This
is the Science of Stupid.
DALLAS (off-screen): Yes,
this is the show that splices scientific reason with
the DNA of stupidity.
Witness as random
people from here, there,
and everywhere try to bend the
rules of science and suffer the consequences.
We'll explain what
went wrong and why, with the help of sciences
least compromising principles.
Stuff like centrifugal force,
angular velocity,
and that unseen
terror, the vortex.
Please don't try any of
this at home, or even there.
Watch out, it's the
Science of Stupid.
DALLAS (off-screen): In this
episode we'll be looking out for hydrodynamic drag,
look out, balancing our
combined centers of mass over two wheels,
with any luck, and learning
about the strength of trees, but first this.
DALLAS: Whether
rough riding over rolling hills or careering through
wooded glades, a set of two
knobbly tires is your key to access all areas adrenalin.
MAN: Dropping, 3, 2, 1.
DALLAS (off-screen): Although
a knife-edged mountain ridge
is an area I'd prefer
not to access.
When you think you can
take a tumble just peddling in the park,
this does seem like
pushing your luck, and if you don't believe me
just ask him.
MAN: Elland, yo, Elland.
DALLAS: So we're looking at
biking along mountain ridges, whether on motor bikes or
mountain bikes it's a pursuit
that should definitely be left to the pros who will no doubt
appreciate the importance of
such science as normal force.
DALLAS (off-screen):
Friction is proportional to the normal force.
When two surfaces are pushed
together normal force being a contact force acting
perpendicular to a surface.
Riding up a slope, or even
along it, less of the force of his weight is acting
perpendicular to the slope,
so there's less normal force,
less friction and more
chance he'll lose his grip.
Surface structure
is also critical.
If the surface is granular and
crumbly it can be easily sheared away by sideways
forces, and that's no
good for grip either.
DALLAS: Any riders
heading off road should also consider their impact on the
environment and steer
clear of any sensitive areas off the trail.
But as we've seen,
to stay safe riders want lots of friction,
which they can get by avoiding
steep slopes and crumbly rock,
which basically rules out
this entire activity.
DALLAS (off-screen): Err,
that looks a bit steep. How does it feel?
BIKER: Ooo-hoo-hoo-hoo-hoo-hoo.
DALLAS (off-screen): Yeah,
I thought you'd say that.
BIKER: So narrow.
BIKER: Don't look down.
DALLAS (off-screen): I'm
trying not to, but I can't help thinking that surface
looks a bit crumbly.
Yeah, definitely crumbly.
(laughter).
DALLAS (off-screen):
Keeping lined up with the ridge he was okay,
but as his wheel moved
sideways the force applied to the ground overcame the sheer
strength of the
crust, causing it to slip.
MAN: Oh.
(laughs).
MAN: Yeah.
BIKER: Which way
are you going to go?
DALLAS (off-screen):
Well hopefully not down.
Oh.
BIKER: Oh.
BIKER: Oh. Ow.
DALLAS (off-screen): Yeah,
it's crumbly down there too.
So how about we ride somewhere
with a more grippy surface?
A lot more grippy than that.
A crumbly dirt ridge half
covered in snow, not the obvious choice given the
science, but at least we're on
fairly level ground, and now we're on the slope,
and now we're losing friction.
MAN: Come on now, come on now.
DALLAS (off-screen): Okay.
Going uphill less of the force
from your weight is acting perpendicular to the surface,
so less normal force and
therefore less friction.
Apply a little
too much throttle and
your bike becomes
a taboggan.
But once our riders get used
to dealing with reduced normal force and easily shearable
surfaces it's just a matter of
freewheeling it to the bottom to catch up with friends.
MAN: Oh, oh.
MAN: Yes, he's got it.
MAN: Oooh.
DALLAS (off-screen): Oh,
they'll be so glad to see you.
DALLAS: Some things
just don't go together.
Oil and water, petrol and
matches, tequila and fireworks.
So you can imagine my
concern when I heard about a combination of
kayaking and surfing.
DALLAS (off-screen): Then I
saw this and thought, 'Perhaps I'm worrying about nothing,'
and then I saw this and
realized I was right the first time.
DALLAS: Alright, if we're
gonna go treating a kayak like a surfboard we'd better swat
up on center of buoyancy
and hydrodynamic drag.
DALLAS (off-screen): To remain
stable our kayaker keeps his center of mass directly over
the kayaks center of buoyancy,
which is in the middle of its submerged volume.
Traveling out to sea
it helps to keep the kayak perpendicular to the wave,
because turning sideways
can mean more hydrodynamic drag and a salty roll.
When catching a wave
he must ensure the nose doesn't dig into the water,
otherwise the resulting
increase in hydrodynamic drag
could produce a turning effect.
DALLAS: Waves can travel
hundreds of miles, relentlessly building speed
and power before smashing
into your kayak, but we should be okay
providing we remember the rules.
DALLAS (off-screen):
Hold on a minute, should we be perpendicular to the
wave or parallel to it?
Ah yes, it was perpendicular.
By hitting the wave almost
parallel he presents a large surface area,
which leads to
enough hydrodynamic drag to flip the kayak.
We're out and
ready to catch a wave.
MAN: I'm videoing this just
in case things don't go well.
DALLAS (off-screen):
That's a little negative.
MAN: Confident, confident, oh.
DALLAS (off-screen):
But well founded.
Good start, but here
the nose digs in, slows down, and our friends
MAN: Oh, oh, oh.
DALLAS (off-screen):
Enjoy the benefits of the turning effect.
DALLAS (off-screen): Now
these guys have got it.
Nice and perpendicular,
minimal drag.
WOMAN: Ooh.
DALLAS (off-screen): Like a
knife through salty butter.
Maybe it's safer to avoid all
that nasty drag and head out of the surf to calm open sea.
MAN: There it is!
DALLAS (off-screen): Oh look,
a delightful little fish.
DALLAS (off-screen): Can
you work out what scientific principle this dormitory
sledder is going
to demonstrate?
DALLAS (off-screen):
Now, did you guess the science our hallway
roller is about to enjoy?
(laughs).
DALLAS (off-screen): Yes,
that's right, it's impulse momentum theorem.
Impulse is the change in a
objects momentum when acted upon by a force over time.
Less time, more force.
Instead of gently rolling to a
stop, the hard door ensured he lost momentum quickly,
so he experienced more force.
Please, even if your friend is
this insufferable, don't shut the door on him.
DALLAS: And now we turn
briefly from people getting it horrendously wrong,
to someone getting
extraordinarily right.
The next time you're
gridlocked on the motorway watching bikers effortlessly
squeeze between lanes,
consider there may be another option.
DALLAS (off-screen): As
stunt driver, Alistair Moffatt, could prove as he attempts a
Guinness World Record title
for the tightest gap driven through on two wheels.
Those posts are just 78
inches apart, and that is a world record.
DALLAS: On second thoughts,
I recommend you don't try this dangerous stunt on your local
highway, or anywhere else,
because whilst motorbikes operate perfectly
well on two wheels, cars
DALLAS (off-screen): Are
definitely safer on four.
DALLAS: But if you want to
know the science that makes it possible,
buckle up for your physics,
courtesy of our record breaking friend, Alistair.
DALLAS (off-screen):
Alistair builds velocity as he approaches
a specially designed ramp.
This generates just enough
angular momentum to tilt his car to about 50 degrees,
so that its center of mass is
directly over its new much narrower base of support.
As he drives he makes
continuous adjustments with the front wheel,
dynamically moving the base of
support so it remains under the center of mass.
DALLAS: Now then, ramps may be
your professional stunt method of gaining angular momentum,
but some of our wannabe record
breakers have been experimenting by using the
centrifugal force you
get from turning a corner.
Wonder how that's
working out for them?
DALLAS (off-screen): Not great.
Just enough angular momentum
to get on two wheels, but he fell out the side,
which meant the center
of mass suddenly moved the other way and outside of
the base of support.
So how about we stick to a
proper stunt car, or stunt mobility scooter?
DALLAS (off-screen):
The central driving position and low mass
of the mobility scooter
means our man can easily control the combined
center of mass
simply by leaning.
Great style, although you may
have missed a red light there.
(horn).
DALLAS (off-screen):
Yeah, maybe best to take this off the road.
Build a good old fashioned
ramp and get behind the wheel of a proper vehicle.
This looks good.
DALLAS (off-screen): Oh no.
Okay, the positives.
The ramp allows the car to
generate enough angular momentum to get onto two
wheels, and he managed
to keep the center of mass over the base of support.
And the negatives,
it lasted less than two seconds, then he fell over,
somehow rolled back up,
then the car caught fire, then he had another go,
and did exactly
the same thing.
DALLAS (off-screen): Alright,
all of our wannabe stunt drivers were okay,
but I think the
record's safe for now.
Oh, not again. Okay.
DALLAS: Long before
homo sapiens, way before the mega mammals,
before the dinosaurs even, the
land was ruled by trees,
around 350 million
years in the making,
trees biology gives us
life supporting oxygen,
and their great strength
makes us feel like idiots.
That evolutionary journey has
spawned over 60,000 tree species and an extraordinary
variety, each perfectly
designed to survive and thrive in its particular environment,
starting from the roots up.
DALLAS (off-screen): A trees
roots absorb water and nutrients from the soil.
Some trees can spread their
roots to three times wider than their height,
anchoring them
firmly into the earth.
The trunk contains vascular
tissues to transport fluid and nutrients,
and ground tissues
with thick cell walls that provide strength
and also a degree
of flexibility.
But if it's subjected to
enough compressive stress, as wood fibers on one side are
squeezed, and tensile
stress, as fibers on the other side are stretched,
its flexural strength will
be overcome and it'll break.
DALLAS: Steadfast, sturdy but
flexible and willing to yield at the right time,
in many ways trees
just seem more advanced than we homo sapiens.
MAN: This is going
to be hilarious, this.
DALLAS
(off-screen): See what I mean?
And there's the proof.
MAN: One more go!
DALLAS (off-screen):
Well I don't know.
I mean, that tree might have
an extensive root system so could be very hard to
MAN: Ooh.
DALLAS (off-screen):
No, that's done it.
Once the soil was dislodged
from the roots there was less heavy earth to anchor it,
but thanks to the trees mass
of dense woody tissues it had a lot of weight too.
MAN: Ooh.
DALLAS (off-screen): As that
forklift truck discovered.
MAN: Oh no.
DALLAS (off-screen): I know.
If only you had a machine
that could lift
something heavy, hmm.
Some trees can last thousands
of years, but thanks to its precarious angle and some high
winds, this one is enduring a
lot of compressive stress here and tensile stress here.
Luckily the tree surgeons have
arrived to lower it safely to,
oh for goodness sake.
WOMAN: Yes!
WOMAN: Timber!
DALLAS (off-screen):
Yeah, that's a bad idea.
But whilst less sturdy than
the last tree, this taller thinner tree is more flexible,
so it can bend
without breaking.
MAN: Coming down.
DALLAS (off-screen):
Until it's flexural strength is overcome.
He was okay.
This man has developed
an incredible scientific technique for finding
out if a tree is rotten.
Yep, it is rotten.
He was okay too.
DALLAS (off-screen): When
trees rot, as that one has, the tissues that made them
strong and flexible breakdown,
making it easier to exceed their flexural strength.
But knowing what we
now know about a trees anchoring system,
strength and weight,
it seems wiser to remove them bit by bit.
I said seems.
DALLAS: These days our lives
are made so much easier by gadgets like smartphones,
satnav and the Bluetooth
umbrella, but scientific solutions to everyday problems
aren't a modern phenomenon.
Take the wheelbarrow.
DALLAS (off-screen): For
nearly 2,000 years this simple yet ingenious tool has made
light work of heavy lifting.
DALLAS (off-screen): For those
who appreciate how they work.
And for those who don't,
we open our physics textbooks to chapter three,
class two levers.
DALLAS (off-screen): When a
wheelbarrow is lifted the base of support becomes very small,
and so it requires a lot of
control to maintain stability.
With long handles and a wheel
at one end, a wheelbarrow is
what scientists refer to
as a class two lever.
It's also known as a force
multiplier, as it allows a small force to be converted
into a large force,
meaning heavy loads can be lifted more easily.
DALLAS: It is believed that
the Chinese invented the wheelbarrow around the
second century, revolutionizing
efficiency for their construction workers.
DALLAS (off-screen): And it's
just as popular today in Grimsby, England.
MAN: Come on flower,
you can do it.
DALLAS (off-screen):
Ah, not quite as efficient as the ancient Chinese.
MAN: Brilliant!
DALLAS (off-screen):
Wheelbarrows function well as force multipliers
when you're at
the same level.
MAN: Come on flower,
you can do it.
DALLAS (off-screen):
Otherwise they work better as humiliation multipliers.
MAN: Brilliant!
DALLAS (off-screen):
At least it's only soil.
This chaps
pushing horse manure.
DALLAS (off-screen):
And now he's wearing it.
Slipping on the ramp, he
actually turns his class two lever into what scientists
refer to as a class one lever,
or what we call a teetertotter.
DALLAS (off-screen): But keep
your barrow at ground level and you'll be fine.
Unless you're riding in it.
Driver lifts too high,
wheel guard hits ground.
Force multiplied.
DALLAS: Standard two-armed
cartwheels, near-armed cartwheels,
far-armed cartwheels,
one-armed cartwheels, no-armed cartwheels,
quarter-turn-out cartwheels.
To the gymnast cartwheels are
the gift that keeps giving.
So wouldn't it be nice to
have a friend to join in?
DALLAS (off-screen): Well as
luck would have it there's a two-person cartwheel,
but if that seems a little
tricky for the non-gymnast, here's another slightly less
official method for
two pals to get in on that rotational fun.
It's still a bit
tricky though.
DALLAS: So that's two ways
that two can spin, two ways of impressing your friends,
two ways of doing yourself an
injury, two ways of swatting up on your angular velocity.
DALLAS (off-screen): In this
example one gymnast generates only enough angular velocity
so they land with their
combined center of mass over their base of support.
Whereupon the other pushes
back to generate enough
angular velocity
to counterrotate.
In the second version, our
gymnasts generate enough angular velocity to keep the
rotation going, whilst
gripping tightly to keep their combined center of mass
central to the rotation.
DALLAS: Alright, so let's
start with our first example, the waist hold.
Remember how that works?
MAN: Like that? Or like that?
MAN: How do you do it?
DALLAS (off-screen):
Go on lads, it doesn't matter which way round,
just focus on
getting enough angular velocity for the rotation.
MAN: 1, 2, 3.
DALLAS (off-screen):
That, as you may have deduced, was not enough.
This chap didn't push off
enough, so their combined center of mass was nowhere
near being over their base
of support when they landed.
Ah well, it's a good
excuse for a friendly cuddle.
Loads of angular velocity
DALLAS (off-screen): Except
for the last bit, and that lack of rotation meant
she couldn't get her legs
underneath, and so he basically threw her on her
back, then landed on top.
Not quite a perfect
ten, but progression.
So we graduate to the official
proper two person cartwheel.
Oh yes.
DALLAS (off-screen):
Stunning angular velocity, combined center of mass,
nice and centrally positioned,
and for a final flourish,
half a roly-poly and
jazz hands, classic.
DALLAS: Cosmologists have
often pondered whether our universe is just one of an
infinite number of universes
where infinite versions of ourselves live out the
infinite possibilities
of our existence.
Who knows, but we can't
all be making the same mistakes can we?
(music plays through credits)
♪
Captioned by Cotter
Captioning Services.