- Today's episode is
sponsored by Puzzle Quest.
(web shooting and grunting)
Spider-Man has a problem.
He's supposed to be
able to do anything that
a spider can and, yet, he
covers it all up with a suit.
If a radioactive spider bit
you and gave you spider powers,
why would you make a suit that
covered up all of your spider hairs?
You know, the thing
that lets you 'spider'?
I think there is a way around the suit's
stickiness problem and it's with science.
Duh.
(light techno music)
Uncle Carben.
Here is the scene I'm talking about
from the first Spider-Man film.
In it Peter Parker grows tiny
barbed hairs on his hands,
and presumably, his feet, and it's implied
that it's those hairs that allow him
to scale surfaces like a spider can.
But, if that's the case, wouldn't putting
a full bodysuit over all of your skin
negate the effect that that hair produces?
Yes, yes it would.
But before we figure that out,
how do spiders climb stuff?
Here is a tiny, poorly drawn spider.
Now, enhance.
(light clicking)
Those little hairs on its feet
that you can see with your own eyes
what are on Tobey Maguire's hands
are called setae and they
are just micrometers thick.
They are very, very small, but that's
not why spiders stick to stuff.
Now, enhance again.
(light clicking)
At the end of every one of those setae
are hundreds of spatulae.
They are just nanometers
thick and the real reason
why spiders can stick to stuff.
And maybe how the Powerpuff
Girls' hands work.
Oh, gross!
Let's take a closer
look at those spatulae.
These spatulae are so small, in fact,
they are on the scale of individual atoms.
And because they are so small,
if you brought them close
to another set of atoms,
like the atoms that make
up a wall, for example,
there can be a weak electrical attraction.
Because the electrons
that orbit the nucleii
of atoms aren't really like particles,
they're more like clouds of charge,
if you bring two atoms
close enough together
there is a chance those
charges, as they whiz around,
will end up attracting each other,
even though the atoms
themselves may be neutral.
This is a weak force,
but it's still something
and it's called the Van der Waals Force.
Van der Waals forces are where most people
trying to explain
Spider-Man's stickiness stop.
(web shooting)
If you add up all the tiny interactions
at the atomic level over the millions
of spatulae that spider's have,
that explains how they stick to walls.
Even the Marvel Handbook,
the official one,
says something like this.
Spider-Man enhances the
flux of interatomic forces
on the surfaces that he touches,
increasing the coefficient of friction
between that surface and himself.
The first part is, essentially,
Van der Waals forces
and the second part is wrong,
but we'll let that go for now.
But we can go further.
Do Van der Waals forces explain
how a human-sized thing
could stick to a wall
and does it solve the suit problem?
If Spider-Man tried to climb
walls with actual spider hair,
(squishing) it wouldn't work.
You may have heard of this study
that came out a couple of years ago.
It looked at a number of
different species to determine
whether or not humans could
ever climb like spiders.
It looked at 225 different species
with Van der Waals
forces-enabled foot pads
and concluded that across a
wide range of surface areas
they were directly
proportional to the mass
of that animal, from geckos to mites.
The authors of this study
then extrapolated it
to the body mass of humans
and, as you can see,
the surface area would have to go way up.
The authors concluded that you would need
to devote a full 40% of your
entire body's surface area
to sticky Van der Waals pads in order
to cling to a wall like Spider-Man.
This is far more than we
ever see Spider-Man use.
It'd be like if your whole chest was just
one big spider foot and
you had to put your chest
against a wall and kind of, like,
shimmy around if you wanted to climb.
And then you'd kind of look like a,
like Slug Man, and no one wants
to be Slug Man, or Snail
Girl, or Snail Boy.
But all this doesn't necessarily mean
that Peter Parker can't climb stuff.
Another way to interpret
this study is that nature
is focusing on surface area
and not actual stickiness
of the Van der Waals pads
across a range of body sizes.
So, what if Peter Parker,
instead of having a lot of surface area,
had abnormally sticky Van der Waals pads?
That's fine, it would get around
that problem and we can't
really speak to that,
we'd have to invent some new biology.
But, we still have the suit problem.
Because Van der Waals
forces work on the scale
of nanometers, any suit,
even if it's very thin,
would interfere with that interaction.
And so, Spider-Man's suit needs to be made
out of material that is just as sticky
as his abnormally sticky hands and feet.
Do we know of any
material that can do that?
If Spider-Man augmented his suit,
just like he did with his web shooters,
with science that we already have,
he would be able to get
around the suit problem
and climb just like a spider does.
Looking to the stickiness of gecko feet,
university researchers at Dayton, Akron,
the Air Force and the Georgia
Institute of Technology
have created a material
out of carbon nanotubes.
A material so thin and so fine
it has a Van der Waals interaction
10 times that of a gecko's foot.
And remember, the gecko is
basically the best at this.
Time to do the math.
If Peter Parker is 76 kilograms
and is under Earth's gravity
and the new material made
out of carbon nanotubes
can support a hundred newtons of weight
for every square centimeter,
then Spider-Man's suit would only need
to devote seven and a
half square centimeters,
in total, to stickiness.
But is this enough?
When Spider-Man is climbing
it looks like he's only
using his fingertips and,
presumably, his toe tips.
So is there enough surface area across
all of your fingers and
toes to hold you up?
Well, given that each one of my fingertips
is around three square centimeters,
and I have 20 of those, I get nine.
Which means that there is
nine times more surface area
than you need to stick
to a wall like Spider-Man
if you're using this
carbon nanotube material.
That means you could definitely climb
like Spider-Man if your suit was using
this material on just
fingertips and toe tips.
In fact, you could climb a wall
just like Spider-Man and hold your
whole body weight on a
wall using just three...
(squirting) Oh, oh!
Three fingers.
And also, Spider-Man's skin would need
to be this sticky to work.
Eww, ugh, ehhhh, ehhhh!
So how does Spider-Man climb
walls if he's wearing a suit?
Well, Peter Parker is a science whiz,
he would know that the
nanoscale interactions
that allow him to climb
a wall with his bare skin
would be negated if a suit came
in between a wall and his skin.
So, what I think he is
doing is augmenting his suit
with science just like how
he did with the web shooters.
He has created a material
that goes on the outside
of the suit that gives it
the adequate stickiness
to give him super spider powers.
Spider-Man can do anything a spider can.
And so his suit has to, too.
It just needs a little help.
Because science.
(webs shooting)
(light techno music)
Thank you so much for watching.
Make sure to follow me
on Twitter @Sci_Phile
where you can suggest
ideas for future episodes.
And on Facebook and Instagram where I'm
now posting mini-episodes, Amy.
And if you want more silliness
check out one of my shows
with my colleague, Dan Casey,
it's very, it's very weird.
It's called Muskwatch, that's
all you need to know about it.
And if you want something a
little bit more, ooh, premium,
check out my new show on ProjectAlpha.com
called the S.P.A.A.C.E Program.
It's like Cosmos had a
weird, long-haired baby
with Mystery Science Theater 3000.
Thanks.
Special thanks to Marvel Puzzle Quest
for sponsoring today's episode.
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No, I'm not talking about teens,
I'm talking about Spider-Man Homecoming.
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Thanks, Puzzle Quest.
It's not just about how
Spider-Man sticks to stuff,
it's also, if you're
climbing, you think about it,
it's also how you unstick from stuff.
Using that material that
we just went through he'd
be able to do three points of
contact and climb just fine.
He could hold onto the wall
with just three fingers.
But how do you stick and then unstick?
Well, the cool thing is the orientation
of this material matters.
If it's at one angle it's sticky
and it will stay on a wall.
If it is at another angle,
it will just detach,
that's how gecko feet work.
I mean, just using, (squirts) oh!
Gotta stop.
Gotta stop doing that.
(techno jingle)
