Science of Stupid (2014) s08e11 Episode Script
Scooters, Roofs and Snowmobiles
1
DALLAS (off-screen): This
is the Science of Stupid.
DALLAS (off-screen): Yes,
this is the show that tips a beaker full of stupidity
over a filter of science.
Relax as amateur researchers
and wannabe pros
test the laws of the universe
so you don't have to.
We'll reveal what went wrong
and why with the help of
scientific principles such as
lift, or lack thereof.
Flexural strength
and our
old favorite angular momentum.
So, watch and learn but
never copy because this is
the Science of Stupid.
DALLAS (off-screen):
In this episode we'll be studying how science can
improve your log press.
The material strength
of rooves
and we'll be getting
to grips with reaction force,
but first, this.
DALLAS: Back in the 1930s
Joseph-Armand Bombardier invented the snowmobile in the
hope of opening up the frozen
wastelands of the world but he could scarcely have imagined
that that would
merely be the start.
DALLAS (off-screen): As
extreme winter sports fans saw other opportunities for
racing, jumping
and, of course, crashing.
DALLAS: As the name suggests,
snowmobiles are great at traversing snow but when
there's a gap in the snow,
like a riverbed or ditch, it seems some people are also
using them for
traversing thin air.
That is not a good idea,
even if it is scientifically possible.
DALLAS (off-screen): A
snowmobile's trajectory will be determined by its speed on
take-off and the
angle of the launch area.
Once airborne its trajectory
is fixed, however by hitting the throttle,
or brake, they can
alter their pitch mid-air.
This is because of
conservation of angular momentum,
which dictates there must
be a rotation in the opposite direction to the track's
angular acceleration to keep
the total angular momentum the same but under or overcook it
and you're eating snow.
DALLAS: Okay, it is possible
to jump a gap on a snowmobile but with all that science to
go wrong it's also
unequivocally dangerous and therefore utterly inadvisable.
We can only hope our intrepid
researchers have at least done their homework.
DALLAS (off-screen): The
biggest gap ever jumped was a staggering 412 feet.
This guy is setting
his sights a little lower
but not low enough.
Starting so close to the
drop he doesn't have enough time to build up speed and
with no ramp his trajectory
intersects with the steep slope of the bank.
Thankfully he was wearing
a helmet and then he wasn't.
Maybe it's safer to keep
the gap over dry land.
Hmm, maybe not.
This time there's enough
velocity and there's a ramp but don't forget that due to
the conservation of
angular momentum, hitting the throttle mid-air
pitches the
snowmobile backwards.
I think he might have
overcooked it a little.
Will it be third time lucky?
Success, until he
hits his friend.
His trajectory is just
sufficient to clear the gap and by hitting the throttle
he's carried up the bank
and straight into his friend.
I mean, former friend.
But if you still can't
get the science right there is another option,
simply hide.
Sh, I think you
got away with it.
DALLAS: We've learnt
all manner of science from people getting it wrong but
occasionally some of
us do get it right, so right in fact that they
set new world records.
DALLAS (off-screen):
Like China's Hou Kai.
He's attempting the most
handsprings in a confined space in one minute and,
no, this footage
hasn't been sped up.
I couldn't even do a
single handspring but who can?
Hou Kai can.
That's 50 and a
new world record.
DALLAS: Now then, attempting
any gymnastic move without proper training is not a good
idea but don't
take my word for it.
DALLAS (off-screen):
Take hers.
(laughter).
DALLAS: As all professional
gymnasts know, the handspring is all about angular velocity
and the vestibular system.
DALLAS (off-screen): A
handspring requires a decent base of support and a strong
push off to
generate angular velocity.
It requires an intermediate
hand support and then a fully extended body flip with enough
angular velocity to
complete the rotation.
The vestibular system is also
important, liquid in our inner ear sloshes around which the
brain uses to monitor balance.
Continuously spinning means
the fluid builds up momentum and can lead to dizziness.
DALLAS: So, breaking this
record requires not only the mastery of physics to achieve
the correct amount of
rotation but also a brain accustomed to dealing with
the vestibular system's
dizziness inducing signals.
Something you'd probably want
to master in private before committing to an audience.
DALLAS (off-screen):
Our first wannabe record breaker does like to make
a big entrance though.
(laughter).
DALLAS (off-screen): And
possible a speedy exit.
She loses her base of support
as her left foot slips, meaning she's not able to
generate enough
angular velocity.
(laughter).
DALLAS (off-screen):
Which I assume is what her friend was pointing out.
Now, he looks more the part.
WOMAN: Come on, Joey!
DALLAS (off-screen):
Yeah, come on Joey. Go for the record.
WOMAN: Yeah, come on.
DALLAS (off-screen): Or just
do that. It's up to you, Joey.
Joey completes the
handspring okay but he didn't have enough
angular velocity to
complete the flip.
WOMAN: Yeah, come on.
WOMAN: I told him not to do it.
DALLAS (off-screen):
Well, he didn't listen, did he?
It's the rodeo
and time for the traditional handspring act.
(screams).
DALLAS (off-screen):
Maybe best done before the horses had been out.
She's lost her balance,
most likely due to information from her vestibular system.
Let's hope she's lost
her sense of smell as well, and taste.
So, are we ready to
beat Hou Kai's record?
MAN: Oh.
DALLAS (off-screen): No.
DALLAS (off-screen): Well,
this kid's got all the moves.
The floss, err, that
one but can he guess the scientific principle
he's about to demonstrate?
DALLAS (off-screen): Did you
guess the science this kid's dance demo would lead to?
Yeah, that's right.
It's impact force.
When he lands he applies the
force of his weight plus his downwards momentum,
which produces a large impact
force exceeding the material strength of the barrel.
There are easier ways
to tap a barrel, kid.
DALLAS: The aquatic ape
theory proposes that our ancestors lived in water
at least part of the time.
It is contentious and many
dismiss it but one thing I think we can all agree on is
that some modern day humans
are more aquatic that others.
WOMAN: Where is it?
WOMAN: Arggghhh!
WOMAN: Oh my God.
DALLAS
(off-screen): But what is it?
(screams).
WOMAN: I see it.
WOMAN: I see it,
it's right next to me.
DALLAS (off-screen): Is
it a Great White Shark?
An alligator?
Nope.
In fact it's a humble manatee.
(screams).
WOMAN: Look at that!
WOMAN: Look at it!
WOMAN: It's huge!
DALLAS (off-screen): Yes,
huge but completely harmless.
Herbivorous and rather
sensitive, so please if you do meet a manatee keep your
distance and avoid
being shouty, splashy or annoying in anyway.
WOMAN: It's like 40ft long.
DALLAS: Some animals are
simply more adapted to cutting it through the water
than us homo sapiens.
DALLAS (off-screen): Fish have
smooth streamline bodies which reduce hydrodynamic drag
through the water.
They swish their tails from
left to right to propel themselves forward.
Whales and dolphins have
horizontal tail fins as they evolved from four-legged
animals with limbs underneath
their bodies, so their backbones naturally
bend up and down.
While most creatures have
their thrust at the back, sea lions use their front flippers
to push themselves forward
with their back flippers used for steering.
DALLAS: Yes, marine creatures
move in all manner of ways and their ability to glide through
the water is often a
matter of life and death.
DALLAS (off-screen): This sea
lion is after a fishy snack but will the fish's rear tail
propulsion be enough to
out-swim the sea lion's front flipper power.
MAN: He's missed it.
DALLAS (off-screen): Yes,
it will but he's still hungry.
(screams).
(laughter).
DALLAS (off-screen): By
rotating their hind flippers underneath their bodies sea
lions can also walk on land,
which is unfortunate for this fisherman.
(laughter).
DALLAS (off-screen): Here's
a family hoping to get a closer look at the silver
carp's marine movement.
MAN: Oh, shit.
MAN: He got you in the face.
DALLAS (off-screen):
Close enough for you, madam?
The streamlined body of the
silver carp reduces hydrodynamic drag,
helping it to build
up enough propulsive force to hit granny.
MAN: In the face!
DALLAS (off-screen): But
if it's propulsive force you're after imagine having
to breach 40 tons of bodyweight
through the surface.
That's a lot of work for
a mouthful of plankton.
DALLAS: Roofing is the
trade of constructing and repairing rooves,
it's the fourth most dangerous
profession in the US and a job that takes balance,
a head for heights
and years to master.
MAN: We have a roof.
MAN: Where did it go?
MAN: We have a roof
that we built
on the ground
that's got to go
up here.
MAN: Let's see if we
can get it up there.
MAN: Wish us luck.
DALLAS (off-screen):
Um, good luck.
And we're all set.
MAN: I'm losing it!
MAN: Everybody OK?
MAN: Yes, good.
DALLAS (off-screen):
Never been better.
DALLAS: A prime example
of why you don't need luck in the roofing business.
You need knowledge of
the scientific principles.
DALLAS (off-screen): Flat
rooves are less expensive and quicker to build but are less
durable than pitched rooves
and there is more risk of water pooling,
which can weaken
them overtime.
Pitched rooves are built uses
trusses, their triangular shape gives them high strength
and rigidity by
distributing the load throughout the structure.
The slope allows water to
drain off more easily, however it also reduces friction as
less of the force of
your weight is acting perpendicular to the slope,
increasing the
likelihood of a fall.
DALLAS: Given that rooves are
usually high up and generally made from materials not
designed for walking on
it's easy to see the dangers.
Best left to the
professionals.
MAN: Today I'm
setting trusses up.
DALLAS
(off-screen): Lesson one.
A strong roof needs strong
trusses, in this case made from dense wood.
MAN: Just gently
lift it up there.
DALLAS (off-screen):
Lesson two.
Erect your trusses with care.
MAN: Yeah, just like that.
MAN: And that's
all there is to it.
MAN: You know.
DALLAS (off-screen):
And lesson three, don't speak too soon.
BOY: Just got home from school.
DALLAS (off-screen): This
wannabe future roofer wants to get some practice in.
BOY: So now I'm going
to go jump off my roof.
BOY: Normal.
DALLAS (off-screen): It
sounds like a terrible idea.
BOY: It's much
higher than it looks.
DALLAS
(off-screen): And much weaker.
Don't try this at home,
or anyone else's home.
Unfortunately for him flat
rooves are generally less durable than pitched rooves.
This one looks rotten so its
material strength is unable to support his weight.
BOY: I had a feeling
that was going to happen.
DALLAS (off-screen):
Ah, so you were just demonstrating structural
integrity for us, were you?
Oh, thank you.
Pitch rooves are
typically more durable.
MAN: Ah.
(laughter).
DALLAS
(off-screen): And slippier.
Pitched rooves might
allow rain to run off but not always snow.
An icy covering combined with
the angle makes for very little friction and now we
re-join our roofer
friend at the final stage of construction.
MAN: We have a window
that we wanted to put up
on the second
floor as we're doing this.
MAN: Just want
to see how it goes.
DALLAS (off-screen): This
guy has got all the kit.
He just hasn't got a window.
DALLAS: There's no better
place to start with scooter tricks than the bunny hop.
50. See?
It's easy but then I do
know an awful lot of science.
Thanks.
DALLAS (off-screen):
Let's see how much our first researcher knows.
Great bunny hoop but you
need to work on your ledge grind 360,
yeah and buy me a new camera.
DALLAS: The bunny hop looks
simple enough but there's an awful lot of complex science
packed in, so let's get
the basics right, shall we?
DALLAS (off-screen):
The rider rolls to build up linear momentum,
then crouches and pushes
down hard with his feet.
This produces an equal and
opposite reaction force, launching him upwards.
At the same time he pulls up
with his arms to lift the scooter.
On landing he must flex his
knees to reduce the impact force and keep his center of
mass over his base of support
to ride away successfully.
DALLAS: It's a lot of science
to get wrong, so best to practice somewhere with plenty
of space like, I
don't know, a skate park?
DALLAS (off-screen):
Okay then.
GIRL: I'm a bunny, duh.
DALLAS (off-screen):
She vaguely knows the name of the trick.
DALLAS (off-screen):
Just not how to do it.
Failing to pull up on the
handlebars enough means the front wheel hits the object to
be jumped, resulting in
her hitting the floor.
DALLAS (off-screen): Maybe
it's best to keep the scooter party tricks outside.
Like Dad showing his
daughter he's still got it.
All that just to teach his
daughter a science lesson.
What Dad was clearly showing
her was that if you pull
up the handlebars but don't
generate a reaction force with
your feet you'll put the handle
bars under too much stress.
Lesson learnt.
Let's try with
someone less middle-aged.
A bunny hop with a slick rail
grind and he's not even finished yet.
MAN: Oh.
DALLAS (off-screen):
Yeah, he is now.
The rider generates a reaction
force and pulls up on the handlebars at the same time,
placing him on the rail.
He controls the grind by
making sure his center of mass remains over his base of
support but when he
then tries a tail whip
he misses the
scooter and is now possibly missing some teeth.
MAN: Oh.
DALLAS: The pillars of
Hercules, the key toss, the fridge carry.
They're all impressive enough
but when it comes to peculiar weightlifting challenges
I like a log press.
DALLAS (off-screen): This
particular log is 33 feet long and weighs over 1,400 pounds.
It's basically a tree.
DALLAS: But as impressive
as that was it wasn't technically a log press.
For one of those you'd need
to grab a special piece of equipment called a log bar
and get to grips with some
heavy lifting science.
DALLAS (off-screen): Log bars
have a much larger radius than a traditional barbell,
so the lifted is forced
to hold the log further away from the body.
This moves their combined
center of mass further forward meaning the lifter needs to
lean back to keep his
center of mass above their base of support.
Once pressed the log will
transfer momentum to whatever it lands on.
DALLAS: It's all about
keeping that center of mass above the base of support
by leaning back.
We've sent a few of our more
muscular researchers out to put the science into practice.
DALLAS (off-screen):
Great start.
Shame about the finish.
He didn't even manage to get
it above his head before leaning the combined center of
mass too far outside
of his base of support.
Trying to compensate he
introduces horizontal momentum,
which he's unable to stop.
This guy looks like a pro and
he's got it above his head.
MAN: Oh.
DALLAS (off-screen): For
all the good it did him.
After an initial good start he
lets the log move too far backwards taking the combined
center of mass outside
his base of support.
Luckily his friend is
there to check that he's okay using his own special
form of sign language.
MAN: Are you OK?
DALLAS
(off-screen): Yes, I'm fine.
But let's not forget that with
the log press the lift is only half the battle.
You still need to put it
down when you're finished.
Gently does it.
DALLAS (off-screen):
Due to its large radius the lip on the wrack wasn't big
enough to stop it rolling off.
He was okay but do bear in
mind the log press may be good for your arms but not always
great for your tum tum.
DALLAS: No matter how
foolish they might seem, it's important to recognize
how much we learn through
the deeds of others.
Sir Isaac Newton once said,
'If I had seen further it is by standing on the shoulders
of giants.' Of course, the
problem withstanding on giant shoulders is that it does
rather hurt when you fall off.
(music plays through credits)
♪
Captioned by Cotter
Captioning Services.
DALLAS (off-screen): This
is the Science of Stupid.
DALLAS (off-screen): Yes,
this is the show that tips a beaker full of stupidity
over a filter of science.
Relax as amateur researchers
and wannabe pros
test the laws of the universe
so you don't have to.
We'll reveal what went wrong
and why with the help of
scientific principles such as
lift, or lack thereof.
Flexural strength
and our
old favorite angular momentum.
So, watch and learn but
never copy because this is
the Science of Stupid.
DALLAS (off-screen):
In this episode we'll be studying how science can
improve your log press.
The material strength
of rooves
and we'll be getting
to grips with reaction force,
but first, this.
DALLAS: Back in the 1930s
Joseph-Armand Bombardier invented the snowmobile in the
hope of opening up the frozen
wastelands of the world but he could scarcely have imagined
that that would
merely be the start.
DALLAS (off-screen): As
extreme winter sports fans saw other opportunities for
racing, jumping
and, of course, crashing.
DALLAS: As the name suggests,
snowmobiles are great at traversing snow but when
there's a gap in the snow,
like a riverbed or ditch, it seems some people are also
using them for
traversing thin air.
That is not a good idea,
even if it is scientifically possible.
DALLAS (off-screen): A
snowmobile's trajectory will be determined by its speed on
take-off and the
angle of the launch area.
Once airborne its trajectory
is fixed, however by hitting the throttle,
or brake, they can
alter their pitch mid-air.
This is because of
conservation of angular momentum,
which dictates there must
be a rotation in the opposite direction to the track's
angular acceleration to keep
the total angular momentum the same but under or overcook it
and you're eating snow.
DALLAS: Okay, it is possible
to jump a gap on a snowmobile but with all that science to
go wrong it's also
unequivocally dangerous and therefore utterly inadvisable.
We can only hope our intrepid
researchers have at least done their homework.
DALLAS (off-screen): The
biggest gap ever jumped was a staggering 412 feet.
This guy is setting
his sights a little lower
but not low enough.
Starting so close to the
drop he doesn't have enough time to build up speed and
with no ramp his trajectory
intersects with the steep slope of the bank.
Thankfully he was wearing
a helmet and then he wasn't.
Maybe it's safer to keep
the gap over dry land.
Hmm, maybe not.
This time there's enough
velocity and there's a ramp but don't forget that due to
the conservation of
angular momentum, hitting the throttle mid-air
pitches the
snowmobile backwards.
I think he might have
overcooked it a little.
Will it be third time lucky?
Success, until he
hits his friend.
His trajectory is just
sufficient to clear the gap and by hitting the throttle
he's carried up the bank
and straight into his friend.
I mean, former friend.
But if you still can't
get the science right there is another option,
simply hide.
Sh, I think you
got away with it.
DALLAS: We've learnt
all manner of science from people getting it wrong but
occasionally some of
us do get it right, so right in fact that they
set new world records.
DALLAS (off-screen):
Like China's Hou Kai.
He's attempting the most
handsprings in a confined space in one minute and,
no, this footage
hasn't been sped up.
I couldn't even do a
single handspring but who can?
Hou Kai can.
That's 50 and a
new world record.
DALLAS: Now then, attempting
any gymnastic move without proper training is not a good
idea but don't
take my word for it.
DALLAS (off-screen):
Take hers.
(laughter).
DALLAS: As all professional
gymnasts know, the handspring is all about angular velocity
and the vestibular system.
DALLAS (off-screen): A
handspring requires a decent base of support and a strong
push off to
generate angular velocity.
It requires an intermediate
hand support and then a fully extended body flip with enough
angular velocity to
complete the rotation.
The vestibular system is also
important, liquid in our inner ear sloshes around which the
brain uses to monitor balance.
Continuously spinning means
the fluid builds up momentum and can lead to dizziness.
DALLAS: So, breaking this
record requires not only the mastery of physics to achieve
the correct amount of
rotation but also a brain accustomed to dealing with
the vestibular system's
dizziness inducing signals.
Something you'd probably want
to master in private before committing to an audience.
DALLAS (off-screen):
Our first wannabe record breaker does like to make
a big entrance though.
(laughter).
DALLAS (off-screen): And
possible a speedy exit.
She loses her base of support
as her left foot slips, meaning she's not able to
generate enough
angular velocity.
(laughter).
DALLAS (off-screen):
Which I assume is what her friend was pointing out.
Now, he looks more the part.
WOMAN: Come on, Joey!
DALLAS (off-screen):
Yeah, come on Joey. Go for the record.
WOMAN: Yeah, come on.
DALLAS (off-screen): Or just
do that. It's up to you, Joey.
Joey completes the
handspring okay but he didn't have enough
angular velocity to
complete the flip.
WOMAN: Yeah, come on.
WOMAN: I told him not to do it.
DALLAS (off-screen):
Well, he didn't listen, did he?
It's the rodeo
and time for the traditional handspring act.
(screams).
DALLAS (off-screen):
Maybe best done before the horses had been out.
She's lost her balance,
most likely due to information from her vestibular system.
Let's hope she's lost
her sense of smell as well, and taste.
So, are we ready to
beat Hou Kai's record?
MAN: Oh.
DALLAS (off-screen): No.
DALLAS (off-screen): Well,
this kid's got all the moves.
The floss, err, that
one but can he guess the scientific principle
he's about to demonstrate?
DALLAS (off-screen): Did you
guess the science this kid's dance demo would lead to?
Yeah, that's right.
It's impact force.
When he lands he applies the
force of his weight plus his downwards momentum,
which produces a large impact
force exceeding the material strength of the barrel.
There are easier ways
to tap a barrel, kid.
DALLAS: The aquatic ape
theory proposes that our ancestors lived in water
at least part of the time.
It is contentious and many
dismiss it but one thing I think we can all agree on is
that some modern day humans
are more aquatic that others.
WOMAN: Where is it?
WOMAN: Arggghhh!
WOMAN: Oh my God.
DALLAS
(off-screen): But what is it?
(screams).
WOMAN: I see it.
WOMAN: I see it,
it's right next to me.
DALLAS (off-screen): Is
it a Great White Shark?
An alligator?
Nope.
In fact it's a humble manatee.
(screams).
WOMAN: Look at that!
WOMAN: Look at it!
WOMAN: It's huge!
DALLAS (off-screen): Yes,
huge but completely harmless.
Herbivorous and rather
sensitive, so please if you do meet a manatee keep your
distance and avoid
being shouty, splashy or annoying in anyway.
WOMAN: It's like 40ft long.
DALLAS: Some animals are
simply more adapted to cutting it through the water
than us homo sapiens.
DALLAS (off-screen): Fish have
smooth streamline bodies which reduce hydrodynamic drag
through the water.
They swish their tails from
left to right to propel themselves forward.
Whales and dolphins have
horizontal tail fins as they evolved from four-legged
animals with limbs underneath
their bodies, so their backbones naturally
bend up and down.
While most creatures have
their thrust at the back, sea lions use their front flippers
to push themselves forward
with their back flippers used for steering.
DALLAS: Yes, marine creatures
move in all manner of ways and their ability to glide through
the water is often a
matter of life and death.
DALLAS (off-screen): This sea
lion is after a fishy snack but will the fish's rear tail
propulsion be enough to
out-swim the sea lion's front flipper power.
MAN: He's missed it.
DALLAS (off-screen): Yes,
it will but he's still hungry.
(screams).
(laughter).
DALLAS (off-screen): By
rotating their hind flippers underneath their bodies sea
lions can also walk on land,
which is unfortunate for this fisherman.
(laughter).
DALLAS (off-screen): Here's
a family hoping to get a closer look at the silver
carp's marine movement.
MAN: Oh, shit.
MAN: He got you in the face.
DALLAS (off-screen):
Close enough for you, madam?
The streamlined body of the
silver carp reduces hydrodynamic drag,
helping it to build
up enough propulsive force to hit granny.
MAN: In the face!
DALLAS (off-screen): But
if it's propulsive force you're after imagine having
to breach 40 tons of bodyweight
through the surface.
That's a lot of work for
a mouthful of plankton.
DALLAS: Roofing is the
trade of constructing and repairing rooves,
it's the fourth most dangerous
profession in the US and a job that takes balance,
a head for heights
and years to master.
MAN: We have a roof.
MAN: Where did it go?
MAN: We have a roof
that we built
on the ground
that's got to go
up here.
MAN: Let's see if we
can get it up there.
MAN: Wish us luck.
DALLAS (off-screen):
Um, good luck.
And we're all set.
MAN: I'm losing it!
MAN: Everybody OK?
MAN: Yes, good.
DALLAS (off-screen):
Never been better.
DALLAS: A prime example
of why you don't need luck in the roofing business.
You need knowledge of
the scientific principles.
DALLAS (off-screen): Flat
rooves are less expensive and quicker to build but are less
durable than pitched rooves
and there is more risk of water pooling,
which can weaken
them overtime.
Pitched rooves are built uses
trusses, their triangular shape gives them high strength
and rigidity by
distributing the load throughout the structure.
The slope allows water to
drain off more easily, however it also reduces friction as
less of the force of
your weight is acting perpendicular to the slope,
increasing the
likelihood of a fall.
DALLAS: Given that rooves are
usually high up and generally made from materials not
designed for walking on
it's easy to see the dangers.
Best left to the
professionals.
MAN: Today I'm
setting trusses up.
DALLAS
(off-screen): Lesson one.
A strong roof needs strong
trusses, in this case made from dense wood.
MAN: Just gently
lift it up there.
DALLAS (off-screen):
Lesson two.
Erect your trusses with care.
MAN: Yeah, just like that.
MAN: And that's
all there is to it.
MAN: You know.
DALLAS (off-screen):
And lesson three, don't speak too soon.
BOY: Just got home from school.
DALLAS (off-screen): This
wannabe future roofer wants to get some practice in.
BOY: So now I'm going
to go jump off my roof.
BOY: Normal.
DALLAS (off-screen): It
sounds like a terrible idea.
BOY: It's much
higher than it looks.
DALLAS
(off-screen): And much weaker.
Don't try this at home,
or anyone else's home.
Unfortunately for him flat
rooves are generally less durable than pitched rooves.
This one looks rotten so its
material strength is unable to support his weight.
BOY: I had a feeling
that was going to happen.
DALLAS (off-screen):
Ah, so you were just demonstrating structural
integrity for us, were you?
Oh, thank you.
Pitch rooves are
typically more durable.
MAN: Ah.
(laughter).
DALLAS
(off-screen): And slippier.
Pitched rooves might
allow rain to run off but not always snow.
An icy covering combined with
the angle makes for very little friction and now we
re-join our roofer
friend at the final stage of construction.
MAN: We have a window
that we wanted to put up
on the second
floor as we're doing this.
MAN: Just want
to see how it goes.
DALLAS (off-screen): This
guy has got all the kit.
He just hasn't got a window.
DALLAS: There's no better
place to start with scooter tricks than the bunny hop.
50. See?
It's easy but then I do
know an awful lot of science.
Thanks.
DALLAS (off-screen):
Let's see how much our first researcher knows.
Great bunny hoop but you
need to work on your ledge grind 360,
yeah and buy me a new camera.
DALLAS: The bunny hop looks
simple enough but there's an awful lot of complex science
packed in, so let's get
the basics right, shall we?
DALLAS (off-screen):
The rider rolls to build up linear momentum,
then crouches and pushes
down hard with his feet.
This produces an equal and
opposite reaction force, launching him upwards.
At the same time he pulls up
with his arms to lift the scooter.
On landing he must flex his
knees to reduce the impact force and keep his center of
mass over his base of support
to ride away successfully.
DALLAS: It's a lot of science
to get wrong, so best to practice somewhere with plenty
of space like, I
don't know, a skate park?
DALLAS (off-screen):
Okay then.
GIRL: I'm a bunny, duh.
DALLAS (off-screen):
She vaguely knows the name of the trick.
DALLAS (off-screen):
Just not how to do it.
Failing to pull up on the
handlebars enough means the front wheel hits the object to
be jumped, resulting in
her hitting the floor.
DALLAS (off-screen): Maybe
it's best to keep the scooter party tricks outside.
Like Dad showing his
daughter he's still got it.
All that just to teach his
daughter a science lesson.
What Dad was clearly showing
her was that if you pull
up the handlebars but don't
generate a reaction force with
your feet you'll put the handle
bars under too much stress.
Lesson learnt.
Let's try with
someone less middle-aged.
A bunny hop with a slick rail
grind and he's not even finished yet.
MAN: Oh.
DALLAS (off-screen):
Yeah, he is now.
The rider generates a reaction
force and pulls up on the handlebars at the same time,
placing him on the rail.
He controls the grind by
making sure his center of mass remains over his base of
support but when he
then tries a tail whip
he misses the
scooter and is now possibly missing some teeth.
MAN: Oh.
DALLAS: The pillars of
Hercules, the key toss, the fridge carry.
They're all impressive enough
but when it comes to peculiar weightlifting challenges
I like a log press.
DALLAS (off-screen): This
particular log is 33 feet long and weighs over 1,400 pounds.
It's basically a tree.
DALLAS: But as impressive
as that was it wasn't technically a log press.
For one of those you'd need
to grab a special piece of equipment called a log bar
and get to grips with some
heavy lifting science.
DALLAS (off-screen): Log bars
have a much larger radius than a traditional barbell,
so the lifted is forced
to hold the log further away from the body.
This moves their combined
center of mass further forward meaning the lifter needs to
lean back to keep his
center of mass above their base of support.
Once pressed the log will
transfer momentum to whatever it lands on.
DALLAS: It's all about
keeping that center of mass above the base of support
by leaning back.
We've sent a few of our more
muscular researchers out to put the science into practice.
DALLAS (off-screen):
Great start.
Shame about the finish.
He didn't even manage to get
it above his head before leaning the combined center of
mass too far outside
of his base of support.
Trying to compensate he
introduces horizontal momentum,
which he's unable to stop.
This guy looks like a pro and
he's got it above his head.
MAN: Oh.
DALLAS (off-screen): For
all the good it did him.
After an initial good start he
lets the log move too far backwards taking the combined
center of mass outside
his base of support.
Luckily his friend is
there to check that he's okay using his own special
form of sign language.
MAN: Are you OK?
DALLAS
(off-screen): Yes, I'm fine.
But let's not forget that with
the log press the lift is only half the battle.
You still need to put it
down when you're finished.
Gently does it.
DALLAS (off-screen):
Due to its large radius the lip on the wrack wasn't big
enough to stop it rolling off.
He was okay but do bear in
mind the log press may be good for your arms but not always
great for your tum tum.
DALLAS: No matter how
foolish they might seem, it's important to recognize
how much we learn through
the deeds of others.
Sir Isaac Newton once said,
'If I had seen further it is by standing on the shoulders
of giants.' Of course, the
problem withstanding on giant shoulders is that it does
rather hurt when you fall off.
(music plays through credits)
♪
Captioned by Cotter
Captioning Services.