Mega Monsters -- Science Study Break


Uploaded by utaustintexas on 28.10.2010

Transcript:
>> Good evening and welcome to Science Study Break.
This is the last one for the fall semester, and I want you
to have a great deal of pre-Halloween fun
with the biomechanics of movie monsters.
I'm Roxanne Bogucka, and I'm at the Life Science Library,
and I'm one of the hosts of Science Study Break.
One of the things I have to tell you first
of all is the legalese.
This is being video recorded, so by entering this room,
we are going to record you and distribute images
and sounds throughout the universe without restriction.
So be aware of that.
The other thing you should be aware of is that since,
we are talking about the biomechanics of monster movies,
we are talking about a certain genre that tends
to lean toward the violent and the gory,
and there will be scenes from movies
that deserve their R ratings for various things
such as harsh language, horrific images, fights,
children in danger, dismemberments and real estate
and inhabitants stomped.
So it may not be appropriate for those with tender sensibilities.
I want to tell you a little bit -- I was talking to Anne,
our presenter this evening, about the research
that she was doing, and she was telling me
that she uses the database PubMed quite often
which made me happy, because it's one
of my favorite data bases.
And I just want to point out that
if you are using this database,
you should sign in with an account.
And if you don't have one, aha, then you can simply register
for an account, fill in your information here
and click Register, and then when you log into PubMed,
your account information will show up here,
so that the next thing you'll want to do is to set it up in
such a way that you can not only do the search
but see the full text results.
So what you'll want to do is come
to the outside tool information and scroll
down until you find the University of Texas Libraries,
click the button, save it, and then it's going to show
up here as your outside tool.
And then you might also want to do something about the way
that your result sets display in PubMed by changing it,
so that in stead of just the citation,
you get the whole abstract, and you get them
in reverse chronological order.
Once you've saved that, go ahead and do your search,
and you'll notice as your type in your terms,
there is an autosuggest for search terms.
And then you get some information like this,
and if you like an article, you can just click on the Find It
at UT button to go out to the full text of the article
in HTML, or if you prefer, you can look at it in the PDF.
So, that's the happy way to use PubMed and to get
to the full text of articles.
Now I'm going to tell you a little bit
about Science Study Break.
It's a UT Libraries program
where we evaluate the presentations of science,
technology, medicine, engineering and what have you
in popular movies and TV shows.
And you can see that we have quite a --
quite a pleasant history here in the past with several shows
and several people who have come like Dr. Ruth Buskirk to talk
about the Spider-Man movies.
You can also see some of the ones that you may have missed
in the past on the UT YouTube channel, so if you go to YouTube
and search Science Study Break,
you can see these past Science Study Break programs,
in the comfort and privacy of your own home.
We're not the only cool science program around on campus.
I really want to draw your attention
to our good friends, Science in the Pub.
They meet every other Friday at 5:00 in the Cactus Cafe
for a little beer, a little science talk.
So if you're not old enough to drink beer, that's okay,
you can still come to Science in the Pub
and have a softer beverage,
and next Friday they will have Jeff Jenson
on computing life and death.
So be sure to show up for Science in the Pub.
So tonight's Science Study Break is about the biomechanics
of movie monsters, and our presenter is Dr. Anne Silverman
from Mechanical Engineering.
Dr. Silverman got her Bachelor's Degree at Arizona State
and her Master's and Ph.D. here
at the University of Texas at Austin.
She was a recipient
of a National Science Foundation Graduate Research Fellowship
and was recognized by the Society for Women Engineers
as the 2010 Outstanding Graduate Collegiate Member.
She served as an editorial referee for the journals,
Gait and Posture, Journal of Biomechanics and Journal
of Rehabilitation Medicine, and she is now a researcher
in Dr. Richard Neptune's Neuromuscular Biomechanics Lab
with research that focuses on the analysis of human movement
with an emphasis on identifying muscle compensation strategies
and pathological populations, and she's going
to tell you what that means.
She works to understand the biomechanical consequences
of using specific muscle compensations
and to use this understanding to provide a quantitative basis
for developing effective rehabilitation
training programs.
You're lucky to be getting this presentation from her tonight,
because in January, Dr. Silverman is going
to join the Mechanical Engineering Faculty
at the Colorado School of Mines in Golden, Colorado.
So, please welcome Dr. Anne Silverman.
[ Clapping ]
>> Dr. Anne Silverman: Thank you all for coming and thanks
to Roxanne and her team for putting this all together.
This is a lot of fun for me.
I've been going to the Science Study Breaks for awhile,
and I think they're a lot of fun, so it was a good stretch
for me to think out of my graduate student box
and start thinking about movie monsters.
As Roxanne said, I just finished my Ph.D. in the summertime
in August, and I did my Master's and Ph.D. in Dr. Neptune's lab
in Mechanical Engineering,
and I really enjoyed my time here at UT.
So, I study biomechanics, and what that is is the application
of mechanical engineering principles
to biological systems.
And when I was in high school and an undergrad, I really,
really like biology, and I really, really liked physics,
and so biomechanics is kind of perfect for me
because it's putting those two subject areas together
to understand the human body and how we move.
There are a lot of different branches of biomechanics.
For example, cellular biomechanics is looking
at the structure of the cell.
Joint biomechanics has to do with orthopedic implants
and looking at tiny deformations in the cartilage,
injuries at the joint.
Cardiovascular biomechanics is looking at fluid flow
through your arteries and veins, designing stents
and learning how your heart works.
And what I do is musculoskeletal biomechanics
which is how the whole body moves as a mechanical system,
how our muscles and bones and joints work together
to achieve a movement, and my specific project here
at UT has had to do with people with amputations
between their knee and their ankle, and they're missing part
of their leg, they're missing the muscles down there, and so,
how do the compensate because of this change
to their musculoskeletal system?
How is their energy cost affected?
How do the loads on their joints change,
and how can we improve their overall mobility?
So that's kind of a little background of my project.
So you can answer a lot of questions with biomechanics,
and we try to get at these in our lab
in mechanical engineering.
For example, just looking at muscle function,
if you fire a muscle in your body,
it can accelerate every single body segment,
so what does each individual muscle do?
We also look at designing equipment and devices.
This picture in the middle here with the ankle was designed
by someone in our lab, and it's a addition
to a traditional prosthetic foot
that you can manufacture very easily and very cheaply
in Third World countries
and improve the performance of a prosthetic foot.
You can also look at rehabilitation
which is what I'm really interested in,
so if someone has a specific impairment,
how can we train them to overcome that impairment.
We can also study and optimize athletic performance.
There is a study that came out of our lab that looked
at optimizing the shape of a chain ring and cycling
to maximize power output.
We found that a ellipsoid shape by a student
in our lab was better for elite athlete to maximize their power.
There are a lot of different questions we can ask.
Some examples up here, looking at surgical planning
and why people fall, why we move the way we move.
But that's a background on biomechanics in general
in our lab, but you are all here to learn about movie monsters,
so we'll get to those.
[ Music ]
[ Movie clip ]
>> Dr. Anne Silverman: Okay.
So that first clip showed his footprint.
And the second clip showed sort of the size of King Kong.
And one of the main concepts that seems to apply
to all these different movie monsters is looking
at being the right size.
There's a historical essay from 1928 from John Haldane
that talked about how as you increase
in mass you increase your volume and therefore your mass
with the cube of that increase.
So, you look at this diagram here
and see we have a unit length and then an area by unit lengths
as the dimensions and then volume of that unit length.
And if we double the length, we actually quadruple the area,
and we multiply the volume times eight.
So, there is this huge difference for a same scale
of an object in the mass,
even if the length isn't all that different.
So looking at his foot size, I guess it to be
about four feet based on that clip.
And looking at the scale of a gorilla,
a regular-sized gorilla, that means that King Kong is probably
about 24 feet which um --
is what the actor suggested that he might be.
So that seems somewhat reasonable.
We look at his weight.
He goes up to 23,000 pounds, and, in general gorillas eat
about an eighth of their weight in food a day, and so that means
that King Kong has to eat 3,000 pounds of food
which is a lot of food.
When I was researching a little bit about this,
this mass estimate that I have is probably a little bit low.
I think he looks to be about 25 feet tall when he's
in a crouched position, and so some people are saying, "Oh,
he's even -- as opposed to four times taller, he's actually more
like more like seven times taller,
in which case he would be almost 60 tons,
so King Kong is very big, [Chuckle] and he would have
to eat a lot of food, and it's hard to imagine eating
that much food per day.
So, he probably couldn't exist.
For a creature that big, and there's a researcher,
John Hutchinson at the Royal Veterinary College
that looks a lot at the biomechanics of animals,
of large animals, and as you get bigger,
like I said a few slides ago, your volume and your mass varies
with the cube of our increase in height,
and you need a lot more muscle mass to accelerate
that big body mass around.
And so if King Kong is 11 to 60 tons, he might be able to stand
up and shuffle around, but the forces
on the musculoskeletal system if he were bounding around
and jumping as he is all throughout the movie would
likely crush his bones.
So, he maybe could exist but wouldn't move in the same way.
And the other point I kind of wanted to make here is
that in general we look at this,
animals don't move very quickly once they get bigger.
If you think about an elephant,
it's a pretty slow-moving animal,
and the elephants rely a lot on their skeletal system.
They lock their joints and just rest on their bones as opposed
to a cat or a frog which is in a very crouched position
that can move very quickly.
Let's go on to our next clip.
[ Movie clip ]
>> Dr. Anne Silverman: Okay.
So T-Rex -- that's who he was fighting, several T-Rexes --
was approximately 12 feet tall,
and during the battle scene it looked as if T-Rex
and King Kong were similar sizes,
so that's probably an exaggeration from the movie.
T-Rex should be a little bit smaller relative to King Kong,
as our estimate was around 25 feet tall for King Kong.
What's interesting about T-Rex is John Hutchinson,
the researcher I mentioned earlier that looks
at biomechanics of large animals,
has done a really interesting study published in Nature
about the biomechanics of T-Rex based on the fossil record
and based on where the center of mass location of this --
of this dinosaur is, you can see he kind
of almost looks like a chicken.
His center of mass is really high,
and he has got those short little legs.
His top running speed is about ten to fifteen miles per hour,
which, on -- on the order of a very elite athlete sprinting.
So, in Jurassic Park, there's that scene
where T-Rex is chasing a jeep, and the jeep is supposedly going
at 40 miles an hour, and T-Rex would definitely not be able
to keep up with that jeep, so,
it's an interesting application of biomechanics.
The other thing -- I think I even heard a couple
of people laughing about it --
is the brachiation in that scene, so that swinging
from the tree limbs down the gorge.
I think it's pretty clear that those vines would snap
under the weight of three T-Rex es and King Kong, [Laugh]
but they seem to be just fine sitting
in there like a little swing.
So, tendons and ligaments rupture at 60
and 20 megapascals respectively.
That measure, megapascals, is a measure of stress,
which is sigma down there in the lower right
which is force-over area.
So if you have a really big area and a small force,
you're not going to fail.
But as you get that area smaller and smaller
with that same size force, your tendons
and ligaments will break.
And so with King Kong swinging from those branches
with one arm, and he's got that really big heavy mass;
I did the calculation, and it seems
like with my pretty low estimate of 11 tons or right around that,
maybe he could do it, maybe he couldn't do it range,
but for those higher estimates of 60 tons,
he would probably have a rotator cuff injury [Background Laugh]
which would happen before the bones broke and probably vastly
after when the actual branches would break.
So, any comments, thoughts
about King Kong before we move on to Godzilla?
>> I guess, the thing that always strikes me,
watching this is - is - you know, the character -
the Ann Darrow character should be like [Inaudible ]
>> Dr. Anne Silverman: Squished.
[Laughter]
>> Yeah.
>> Dr. Anne Silverman: Uh huh.
Yeah, those -- I mean, he was being very careful.
Maybe not, but it does seem like if you're battling
with three T-Rexes and grabbing your love interest,
you might not be as careful.
[ Movie clip ]
>> Dr. Anne Silverman: Okay,
so he mentioned there is a electric fence surrounding the
city, that is 300,000 volts.
Now, an electric chair, for a human, to kill a human,
uses about 2,000 volts, and we know that voltage is equal
to current times resistance.
And so, the amount of current it requires
to kill a human is very small.
It is on the order of milliamps.
And so, our resistance, our biological stuff,
our resistance is very high.
And so resistance is a function -- the second equation there --
of rho's resistivity, which is a property of the material.
So metals have a very low resistivity.
Insulation would have a high resistivity.
And then, we have that multiplied by length, over area.
So really, long wires have a higher resistance
than short ones.
And really fat wires have a smaller resistance
than skinny ones.
So if we assume that Godzilla is made
out of the same biological stuff as a human,
so it has the same resistivity, we find out that the resistance
of Godzilla is one-sixtieth of that
of a human because he's so wide.
That might even actually be kind of high.
I'm assuming he's the same dimensions of a human,
and he seems to be a little bit wider than he is tall,
compared to the scale of a human if you had a human that size.
So, actually, because Godzilla is so wide,
his resistance is much lower than that of a human,
so he would definitely be killed
with 2,000 volts, much less 300,000.
[Background Audience Laugh] So, in the movie he doesn't seem
to have any problem just going straight on into the city,
but that would most definitely bring him down.
[ Movie clip ]
>> Dr. Anne Silverman: So, one thing I forgot to mention
from the first clip is that you see Godzilla is moving very
slow, which is actually a little more realistic.
I mentioned that a little big with King Kong.
I think Godzilla is about 300 feet tall,
and so he would absolutely crush under the weight
of his own body, but when you're jumping and bounding around,
those forces on your skeletal system are many times more,
so it's good that's he's walking slow,
and so in a way the 1950s-60s version
of Godzilla is more realistic than our 2005 King Kong movie.
But he - he's moving very slow, and he's on this bridge,
and I don't know very much about bridges.
I'm sure that there might be a couple of civil engineers
in the audience, but looking at the Golden Gate Bridge
which is a suspension bridge, not a stone arch bridge
like was shown in the video, has a maximum capacity
of two tons per linear foot.
And a ton is 2,000 pounds, and Godzilla is 18,000 tons.
So, for Godzilla to not crush a bridge
that has this capacity rating, it would have
to be 9,000 feet long for a static load of him just standing
on it as opposed to stomping on it, like he did, and the bridge
in the movie was definitely not that long.
So, you saw it vibrate, but I think it would absolutely crush
as soon as he stomped his foot on it.
[ Movie clip ]
>> Dr. Anne Silverman: Okay.
So this clip shows Godzilla walking along the sea floor,
which is probably realistic --
unrealistic, because none of us would walk along the sea floor.
There's a reason we don't walk when we're underwater.
There's a reason we swim, and that's largely due to the force
of drag of the fluid that we're moving through.
So the drag force from the water is proportional to the area,
so it behooves you to make that area that's perpendicular
to your direction of travel as small as possible,
which is why we swim with only our head facing forward
as opposed to our entire body.
That's not very efficient.
So Godzilla would move a lot faster
if he also employed this technique.
It's likely that they don't make him do this,
because this is a very old movie,
and they don't really have the technology to show him swimming.
Go ahead.
>> I was actually going to comment in the interest
of like credit where credit is due.
In the newer Godzilla movies,
what they usually do is they actually have him --
well they sort of have him floating on the surface
when he's on the surface [Inaudible] a guy walking a
pool, like you know they try a [Inaudible].
>> Dr. Anne Silverman: Uh huh.
>> Then they've actually sort of done more scenes
where they shoot him underwater, and he's swimming more
like a whale or an alligator.
>> Dr. Anne Silverman: Great.
So my guess is that his movie is just a little too old for them.
You know, it's a guy in a suit,
so what else can you do but walk.
But, as these movies progress,
then maybe they make them a little more realistic.
The other thing this clip showed is that Godzilla was sinking,
and both -- that's related to buoyant force which is --
the buoyant force is equal to the weight
of the displaced fluid of the --
of the ocean that he's sinking into.
So humans and alligators both have density that is very close
to water, and it can fluctuate based
on how much air is in our lungs.
So, as I'm sure all of you know,
when you go swimming you can float pretty easily
or you can also make yourself sink by expiring all that air,
and I would assume that -- he a --
Godzilla has a similar density to water as well.
So, if he's more dense than water, which would be
if he expired his air, he would sink, just fine,
and if he was holding his breath,
he would probably float like we do.
So, I'd say that's pretty realistic.
Any other Godzilla comments?
He's a pretty fun monster.
[ Movie clip ]
>> Dr. Anne Silverman: Okay.
So this is from the movie, The Host.
I'm not sure even how to pronounce it.
It seems like that they have a lot of names for this monster:
Gweemul, Gwoemul, the dolphin monster.
[Laughter] So, looking at the way this monster moves,
it seems like they are really trying to combine land
and sea animals, and they sort
of didn't do a good job of either.
[Laughter].
What struck me is the monster's tail is really more
like a lizard than a fish, which is kind of strange for swimming,
similar to the reason that Godzilla doesn't walk
across the sea floor, but when you're a fish,
you want a big broad tail so you have a greater area to push
against the fluid and propel yourself forward.
So, he has this long tail, but it doesn't seem
like it would be advantageous in swimming
and doesn't seem to do a whole lot.
This monster also has those muscular limbs,
but they are pretty small, and if it's a water monster,
he probably doesn't need those limbs.
Fish have their muscles in their body to move against the force
of the water as opposed to supporting their body.
Because of the buoyant force, they don't need
to resist gravity, so we can have these huge whales
and not worry about supporting that huge mass.
So it's pretty unlikely
that a water monster would have those muscular limbs,
and for him to move that quickly --
you could see he was outrunning all of the people --
he would probably have to have much more muscular limbs to move
that big body mass around.
[ Movie clip ]
>> Dr. Anne Silverman: I'm going
to play the Cloverfield clips, as well.
[ Movie clip ]
>> Dr. Anne Silverman: So, the alien queen --
she looks kind of like a large bug,
but you can tell there's definitely vertebrae there.
The same concept that keeps coming up, she's very big.
She has a lot of mass.
She looks kind of like a skeleton to me.
I don't know where her muscles are,
and she would really need big muscles in order
to move around like she does.
She is also often in a crouched position, leaning forward,
which I'm sure you can all relate, but you could stand
up straight for hours and hours,
but as soon as you bend your knees and squat,
all your muscles activate, and that can be very tiring.
So, she might have some super-strong skeleton made
out of alien material, and so I think her overall size
and skeletal system is reasonable, but I don't know
where the muscles are.
The other thing I wanted to point out is just,
she's often leaning forward and she has this really long tail
which is a good thing, because she needs
to maintain her balance and not fall over,
especially when she's doing these rapid movements.
So when we're talking about stability,
Alexander Hoff has a paper that identifies dynamic stability,
so what this basically means is that your center of mass needs
to be within your base of support
when you are standing still.
So, if you're standing on one leg, that's what this model is
in the lower right, an inverted pendulum model.
That mass can move back and forth but only as far
as your base of support is.
And then when you're crouching and jumping around,
your velocity also comes into play.
So you can't deviate too much,
and so the queen's long tail causes her center of mass
to actually be more concentrated by her legs,
so that's a very good thing for her, not for Sigourney Weaver.
[Background Audience Laugh] Similar idea with Clovie.
This monster seems to be really top-heavy to me,
and I think in the extras for this film the designers
of the creature say that this monster should be able to walk
on two legs, but I don't really see that happening.
And as you saw from the clips,
moving around the monster really does sort of ambulate
on four different legs, and when you have those four legs,
you have a much wider base of support, and so, therefore,
the center of mass can deviate through a greater distance,
and so that helps Clovie maintain balance.
And, the last thing I want to talk about --
well, any monster comments, ideas?
Okay. Yeah?
>>[ Inaudible audience question ]
>> Dr. Anne Silverman: Uh huh.
[ Inaudible audience question ]
>> Dr. Anne Silverman: Uh huh.
[ Inaudible audience question ]
>> But, if you were to bring such science to Earth and how
to show you, would such science --
would the gravity of Earth affect the biomechantics?
>> Dr. Anne Silverman: Definitely,
and I think you can kind of think of that, similar to just
on earth between air and water.
So gravity isn't so much a problem in water, so we're able
to have these whales that are the size of ships,
and they move a lot differently than they would on land.
For the alien movie, obviously Sigourney Weaver
and the little girl are walking around just fine,
I would assume that's similar to earth.
But, yes, I mean - this -- most of my comments are all based
on the weight of the creature,
and if you have a smaller gravitational force,
that's not going to be as big of an issue.
Yeah?
[ Inaudible audience comment ]
>> Dr. Anne Silverman: Uh huh.
[ Inaudible audience question ]
>> Dr. Anne Silverman: Yeah.
>> [ Inaudible audience comment ]
>> Dr. Anne Silverman: Really?
Okay.
[ Inaudible audience comment ]
>> Dr. Anne Silverman: Yeah.
[ Inaudible audience comment ]
>> Dr. Anne Silverman: Uh huh.
[ Inaudible audience comment ]
>> Dr. Anne Silverman: Oh, definitely.
[ Inaudible audience comment ]
>> Dr. Anne Silverman: Uh huh.
[ Inaudible audience comment ]
>> Dr. Anne Silverman: Yeah.
Well, that's a great point.
I don't know about that iguana,
so there's definitely options there.
I would imagine it's relatively small, though, and not nearly
as big as the movie monster, right?
>> Right. Yeah, exactly.
>> Dr. Anne Silverman: Right.
Right. So I think the take-home message
from all these monster is just how big they are.
And that's why we don't have big monsters here on earth.
[Laughter] Any other comments?
Oh, yeah?
[ Inaudible audience comment ]
>> Dr. Anne Silverman: Uh huh.
[ Inaudible audience comment ]
>> Dr. Anne Silverman: Right.
[ Inaudible audience comment ]
>> Dr. Anne Silverman: Uh huh.
[ Inaudible audience comment ]
>> Dr. Anne Silverman: Uh huh.
Great point.
So several times it's height, big massive,
ig massive monster going to splatter.
Uh huh?
>> In the Alien flick, you cut it off right before -
this doesn't involve the actual alien, per se -
But Sigourney Weaver is like holding on to a ladder rung...
>> Dr. Anne Silverman: Uh huh.
>> ...with her arm.
And the alien [inaudible].
>> Dr. Anne Silverman: I would imagine she has a shoulder
dislocation [laughter] after that one.
[Audience laughter]
>> Okay. Weaver's tough.
[Audience laughter ]
>> Dr. Anne Silverman: She is pretty tough.
I would want her around if I were meeting the alien, so.
Uh huh.
[ Inaudible audience comment ]
>> Dr. Anne Silverman: Uh huh.
[ Inaudible audience comment ]
>> Dr. Anne Silverman: I believe it's...
[ Inaudible audience comment ]
>> Dr. Anne Silverman: Right.
[ Inaudible audience comment ]
>> Dr. Anne Silverman: Well, you would think maybe it wouldn't,
but given the fact that Sigourney Weaver
and her child are walking around just fine.
I mean, it looks like earth,[Background Talking]
and so even though it's a ship, they probably have some sort
of gravitational field generator, some explanation
for why they're not floating through.
[ Silence ]
>> Okay. So the last thing I want to talk about is related
to movie monsters but is also related to the work,
the research we do here at ET, which is motion capture.
So, to make the movie monsters move realistically in a movie,
the movie companies use the same sort of equipment and technology
that we use in the lab in order
to assess how impaired populations might be moving
differently from non-impaired populations.
>> Dr. Anne Silverman: Ooh.
[ Movie clip ]
>> Dr. Anne Silverman: Okay.
So, you saw from those clips and also these pictures right here
that there are these reflective markers on the actors,
and they can look at how the body moves in order to recreate
and enhance that digitally.
So, in the lab, when we're doing research,
we use the same markers and similar cameras,
and we put the markers on the skin, or,
you can see this man is swinging a golf club.
There are some markers on the golf club,
and the camera has near infrared light, and it shoots the light
at the marker, and the markers --
they're covered with the same sort of reflective tape
that would be on your athletic shoes, so that's kind
of like tiny ping pong balls
with that reflective tape on them.
And the position of the marker is measured in 3D space,
and then within the computer program, we can say,
okay this particular marker is attached
to the thigh segment or the foot segment.
And we can get joint angles from this data
or the movement of the golf club.
And so, one of the things in the pirates clip you saw,
the actors had on suits and the markers were on top
of the clothing, which is probably good enough
for the movies, but that's actually really a big no-no
when you're talking about clinical research just
because your clothes can move so much relative to your body,
and we want to capture the motion of the bones themselves
through this technique.
People -- these pictures I show you here,
these markers are just taped onto the skin
with double-sided tape, really strong double-sided tape.
But there are certain cities out there
where people have actually agreed to put pins
in their bones so that with a marker attached to the ends,
which is very few and far between.
But just like your clothes can move relative to your body,
your skin can move a lot relative to your bones,
so that's a way to sort of get away the noise from --
get away from the noise of the measurement.
So you can see here, these graphs I have
at the bottom are your hip, knee and ankle angle during walking,
very stereotypical patterns.
You can see one of my amputees in the in the middle there.
And so, here's a video.
One of the trials, on the left, this is just the regular video
of a subject we have walking across the lab, and then,
on the right is the video of the trial
that really highlights the marker positions.
The butterfly pattern you see is the trajectory
of the force on the ground.
So you'll see those plates in the frame
where the subjects are stepping,
and those plates can let us know what force they're putting
on the ground on each foot.
Are they asymmetric, and we can measure those forces.
And that also helps us to know the forces of the joints,
the movements about the joints.
So we use similar technology but a little different approach.
And I think, more and more, the movies are focusing
on the facial expressions.
That was really a big deal for Avatar and for Pirates
as well with Davy Jones.
And I personally have never put markers on the face,
because I'm interested in what the legs are doing,
but you can get some really detailed motion
of all the different aspects of your expressions.
And that's all I had.
So...
[ Applause ]
[ Inaudible audience comment ]
>> Dr. Anne Silverman: Uh huh.
[ Inaudible audience comment ]
>> Dr. Anne Silverman: [inaudible].
[ Inaudible audience comment ]
>> Dr. Anne Silverman: All of the above [laughter].
This type of technology, we use to measure how they're walking
and whether we're testing different types
of prosthetic feet or the same prosthetic foot
but different walking speeds or inclines, declines
and just how they respond to rehab, pre and post.
There's a lot of different questions you can look at.
Any other questions?
[ Background Noise ]
[ Applause ]
>> Don't leave quite yet.
I have a couple of housekeeping things here.
A couple of housekeeping notes for...
Okay, everything that we saw today, all the movies
that we saw, you can find these on DVD here at the UT Libraries.
They're all - well, they will be available when I turn them in.
But you can look at all of these movies from the UT Libraries.
I want to thank Nancy Elder and all the people at Life Science
such as Michael, Travis and a bunch of people at PCL, and,
of the folks at Know
who provided our video recorder tonight , and,
of course, especially Anne.
You all got feedback forms, so please do fill them out
and let us know what you'd like to see shows on next.
Don't leave here.
I want you people amped up on caffeine and sugar,
so hit that snack table on your way out.
And there are recycling bins over in front
of the main building for your cans.
So if you would please recycle we would appreciate it.
And that's our last Science Study Break for the fall.
In the spring, on February 9th we will have Sheril Kirshenbaum,
author of The Science of Kissing
for a very special Valentine's Day Science Study Break.