Invasion of the Pupae Snatchers
Just Add Water
Killer whales, the ocean's greatest predators, they just won't
stop talking. Listen in while Scientific American Frontiers.
Also a new cure for brain tumors--it takes, just twenty minutes.
Glaciers of the Swiss Alps. What's going on inside? The battle
of the water balloons between teenage scientists. And a life-and-death
battle on the forest floor. All coming up on Scientific American
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WOODIE FLOWERS Hi. I'm Woodie Flowers, host of Scientific American
Frontiers. We have just been running through some scuba-diving
signals down there. This one means "watch out for the shark."
This one doesn't mean "it's too late the shark just got me."
It actually says, "I'm running low on air." You know, wherever
we go we take along the need to communicate. Under water,
a language is very primitive. Divers are restricted to just
a few dozen signals. Most are concerned with survival. Of
course, there are plenty of creatures that are much more at
home in the water than we humans. And some of them seem to
communicate all the time. Is it just survival that's their
concern? Could it be something else?
It's early August in the Puget Sound. Every summer the orcas
or killer whales, return to these sheltered waters off Washington
state. For many years the whales have been photographed and
observed by Ken Balcolm and John Ford. There are 85 orcas
that enter the sound. And for Ken Balcolm, they provide a
subject of endless interest.
KEN BALCOLM I personally am fascinated
by their social behavior and their very apparent intelligence.
I wonder what's going On in that huge brain of theirs.
Orcas are so well organized they can take on anything -large
whales, sharks, whole schools of salmon.
KEN BALCOLM We've
got a foraging pattern. Probably have some fish under about
60 or 90 feet down that are ahead of them. And they are just
keeping track of them. They probably have already eaten. They
are just not going to let them get away. They will follow
them for the rest of the day and then when they are hungry
they will eat some more.
The biologists have learned to recognize every whale in Puget
Sound. Dorsal fins are one marker: females have short ones,
and males, they are twice the size. Some fins have odd shapes.
This wavy one belongs to a male from J Group, or J-pod, as
KEN BALCOLM We just saw J-l, the one with the
wavy margin to his fluke, his fin. J-3 bent over about halfway
up. J-5, J-17.
They have discovered a whole catalog of distinctive marks.
This big male is J-6. He's got pieces missing from the back
of his dorsal fin. This female acquired a clear nick out of
her fin, as did this one. They're minor wounds picked up during
rough play when the whales were young. And they have all been
recorded. Ken Balcolm can recognize most of these white markings
too. They are called "saddle patches." So now he can keep
track of all the whales in the three pods that use Puget Sound.
KEN BALCOLM Who do we have here? Just Ks maybe?
We got K-1. Two notches. Good indication of K.
No, you can't mistake him. in here? What else have we got
JOHN WARD K-17. There he is.
The identification system has become the key to understanding
whale behavior. And Ken's discovered that orca pods stick
KEN BALCOLM Now here is the new one. K-21.
JOHN WARD Oh yeah.
KEN BALCOLM And it's traveling with K-187
JOHN WARD Yeah, it's right next to its mother right there.
KEN BALCOLM We see a new calf. And it's right next to its
mother. We know it's its mother because it's always right
next to its mother. And we see it nursing from its mother.
So we can tie that one in. And then we watch that calf grow
up. Two or three years later, it has a brother or a sister.
And then that one is the one that's next to her. But the other
one still stays alongside, but not as closely.
Today they are getting ready for a recording session. It may
seem like a quiet day on the surface, but under water, things
KEN BALCOLM Yes, they are chatting all right.
The S-2 called and a couple of S-ls. So, you can confirm the
JOHN WARD Yes, definitely Js. No doubt about it.
The challenge now is to try and relate whale behavior to whale
KEN BALCOLM Each pod has about a dozen really stereotyped
calls that they use over and over again. And these different
calls can sound quite different from one another, within the
repertory of calls. Some might be sort of a squawk and others
might be quite a elaborate squeal with an upsweep on the end.
The scientists spend long hours studying computer voice prints
of the calls.
JOHN WARD J seems to have that really distinctive
down sweep on the end, so each call seems to go up and then
ends on a down sweep. So you can see that one--S-3.
This call is only used by J-pod.
KEN BALCOLM Next is L. We'll
just listen to some Ls and their...
This one only L-pod uses. If each pod stuck to its own call,
they might just be recognition signals. But it seems pods
KEN BALCOLM There's the J version of call S-2.
Take this call. J-pod uses it like this. And L-pod uses this
modified version. John Ford's discovery of these dialects,
as he calls them, has added a new layer of complication and
mystery to the study of orcas calls. And it's led to an unusual
laboratory: Sea World in San Diego. The Orcas learn their
tricks and they also keep right on calling. Biologist Ann
ANN BOWLES There are several questions that we have
not been able to answer in the wild. The first is, how did
the calves develop their calls? We can't isolate a calf from
other whales in the unit to be able to determine even what
a calf call sounds like. So here in captivity we have the
unique opportunity to watch the individual separated from
its mother and other whales, see how it behaves to find out
how long it takes to develop adult calls. And all this kind
of very basic information.
There are three whales in this pool: two adults and one two
This is Corky and she's from the Puget Sound area, in the
Pacific Ocean. This is Kassatka, and she is from off the coast
of Iceland. And then that is Orkid, and she was born right
here, at Sea World.
Two years ago, as the Sea World cameras rolled, everybody
waited in suspense for the moment of Orkid's birth. What nobody
knew was that an extraordinary experiment was about to begin.
Like her wild cousins, Orkid kept close to her mother. She
heard her mother's calls and she picked them up.
Well at one year of age she was making still kind of baby
babble, but those calls that were discrete were very much
like those of her mother's. And she would give these in sequences
of calls with her mother, as though she were imitating her
And then soon after Orkid's first birthday, her mother died.
She started swimming with companions unrelated to her, whales
that used different calls. So suddenly there was an experiment
going on in the Sea World pool. The question was, would Orkid
learn new calls? There were certainly plenty to choose from.
Now, one year after Orkid was orphaned, it's time for Ann
Bowles to find the answer.
ANN BOWLES O.K., the hydrophone
is about two meters down and a meter and a half away from
the acrylic panel number one. And we are waiting for the calf
to come by. Orkid is swimming around, close to the hydrophone.
Now there's a call. Orkid. And I can hear her response in
air from Kassatk behind. Super.
Ann Bowles recognizes all the calls in the pool, including
those from a whale called Kassatka.
ANN BOWLES I'm finding
exactly what I thought I was hearing out there which is that
they are calling back and forth to each other. This is a very
typical Kassatka call right here, very classic. This sequence
here is Orkid first, Kassatka second, Orkid buzz with upsweep,
Kassatka, buzz with upsweep--imitating each other. And Orkid
is using Kassatka's call.
It means that killer whales aren't locked into using standard
calls that they inherit. But they wouldn't need this learning
ability or their dialects just to recognize each other, or even
to round up salmon. John Ford believes the whales are much farther
along than that.
JOHN WARD In humans, the ability to, to learn sounds is the
key to the development of languages. And it may be the key
to the development of potential languages in the whales. I
don't believe that they have the sort of language that we
do. But they must be on some point along that road towards
a true language. And I think the dialect system of killer
whales is a very good indication that they are progressing
towards that stage.
WOODIE FLOWERS Our next story is a medical one. We often
do medical stories on Scientific American Frontiers because
there is no other field where the direct benefits of science
are so obvious. But medical stories are sometimes difficult
to cover on television because they can be painful to watch.
I want to warn you that there is something in the first minute
of this story that looks painful--although it really isn't.
So please stay with the story. Close your eyes for a moment
if you have to, and you'll find out how one branch of medicine
is making some major advances in helping one particular patient.
NARRATION Ken Walkerhas a brain tumor. But the chances are
that by the end of tomorrow a new kind of radiation therapy
will have killed the tumor--in a single treatment.
KEN WALKER Initially
when the doctor said, would you like to try it, I said "Absolutely!',
The traditional radiation would probably be every day for
six or seven weeks, which is kind of from a life, going on
with your life, difficult to work in. This has the possibility
of being a one-and-done, so it sounds great to me. I'm all
Eight A.M. the next day, at Boston's Brigham and Women's Hospital.
It's a startling scene as doctors prepare to attach a metal
ring to Ken's head. It's essential for the ring to stay in
position throughout the day, so they'll use blunt plastic
pins to tightly clamp the supports to his skull.
Mr. Walker, right? This is the worst part of the day.
KEN WALKER It may look like medieval torture, but Ken feels no
pain. In fact, the little lumps on his forehead are filled
with a liquid pain killer.
EBEN ALEXANDER developed this treatment, along
with radiation therapist
JAY LOEFFLER on the right. They wii1 use the ring and this
metal cage which fits onto it to find the exact position of
the tumor. Eight-fifteen A.M. Ken is going to have an x-ray
called a CAT-scan.
DOCTOR Ken, now don't hold your head. Relax. Relax your neck.
NARRATION It's routine for most large hospitals, but here
the team will add a special feature. As Ken's wife, Gloria,
looks on nervously, the metal cage has been fastened securely
to the ring. Now it will show up on the x-ray, and provide
fixed reference points for precisely locating the tumor. It's
like putting a grid of lines on a map to allow a map reference
to be read off. The x-ray procedure begins. In twenty minutes
the machine will take a series of pictures through the head.
The pictures are arranged in slices an eighth of an inch thick,
piled one above the other, like the floors of a building.
The tumor shows up as a dark shadow just behind the left eye.
It's clear to the doctors, and to Ken's wife.
DOCTOR We'll probably target a little bit off center.
With these pictures the team will work out the exact shape,
size, and location of the tumor, and then plan the therapy.
The planning is going to take several hours so now for Ken
comes the most difficult part--just sit and wait, with the
rings still in place. It's the vital reference point needed
for the treatment later today. The team moves over to the
computer system at the nearby Dana Farber Cancer Institute.
EBEN ALEXANDER begins work.
EBEN ALEXANDER Right now what
we're doing is just marking in the contours as we see them
here, of the tumor itself. What this enables us to do is to
come up with a three-dimensional reconstruction in space.
Eventually the computer will have a complete picture, not
only of the tumor but also of the eyes and other critical
structures nearby that the treatment must avoid. Here the
optic chiasma--the delicate structure where nerves from the
eyes join together--is being mapped. And here they are marking
out one of the optic nerves, another critical structure. After
three hours spent marking out every x-ray picture, it's clear
that the tumor is dangerously close to two crucial structures.
They have got to be left unharmed by the treatment.
So here is our real challenge. It's right here. Because here
we have the tumor itself and then immediately within four
to five millimeters away is something that we don't want to
give any radiation dose to. The tumor we will get maximum
dose to. And the optic nerve and chiasma, very low dose.
It's two in the afternoon. The planning session is now being
led by physicist Hanne Kooe. It's his job to work out how
to safely direct the radiation at the tumor, using this three-dimensional
computer map. It shows the tumor in blue, and close by, the
crucial structures, all precisely located above the circular
metal ring which Ken is still wearing. If Ken were going to
have conventional radiation treatment, his entire head would
be given a small but damaging dose every day for a couple
of months. It only works because the healthy parts recover
more quickly than the tumor, which gradually dies. In contrast,
the new treatment will use concentrated beams of radiation
directed just at the tumor, possible only because they can
fix its position so accurately. A single treatment will kill
the tumor. In the planning session they are now trying out
different pathways for directing the radiation beams at the
tumor. The computer keeps track of places where a beam would
pass through a critical structure. And it becomes clear that
getting enough radiation in to kill the tumor will inevitably
means some exposure of the optic nerve.
HANNE KOOE At this point we have to decide, given those set
of beams and placement of those targets, what is the actual
dose we will be delivering to the tumor, and what is the actual
dose that we will be delivering to a critical structure.
Here the computer shows in red the high-radiation dose area.
The tumor is covered but so is a small part of the optic nerve.
There will be some damage--but not enough, it's judged, to
harm Ken's vision. It's now late afternoon. And the constant
pressure of the ring has given Ken an excruciating headache.
It's turning into a very long day.
GLORIA WALKER Well it's
real harm to look at him like that. The lights on. I'm not
real good with needles or anything like that, so I always
have to look away with IVs or anything. So this is not a real
pleasant visual appearance.
KEN WALKER This morning I, the
anxiety had to do with putting this contraption on. And I'm
not at all anxious about getting the radiation treatment.
I'm just anxious about getting this thing off.
NARRATION Finally, at six o'clock, it's time for the treatment.
The ring is locked into position. Now the tumor inside Ken's
head has become a precisely located target, that the beam
from the radiation machine will be able to reach with pin-point
accuracy. There's a quick run through of the moves which the
team spent the day planning. Then it's back to the control
room for the real thing. There'll be just twenty minutes of
WOMAN 2.91 going to the ...
Ken will avoid entirely the unpleasant side effects which
would go with conventional, long-term radiation treatment.
EBEN ALEXANDER When he leaves that room, the tumor has been
altered in such a way that it is now essentially dead. So
this has a very dramatic effect on the tumor, and just with
this one twenty-minute trip into that room, we are going to
kill the tumor.
The treatment itself is virtually automatic: except for the
tumor, nothing is going to change now. But somehow it doesn't
seem that way.
GLORIA WALKER It's probably just that nerves
are a part of the whole thing. Just waiting and knowing that
it's really going on. That this is the whole reason why we
came here. So, I'll be glad when it's all over.
It quickly is. Now the moment Ken's been longing for.
EBEN ALEXANDER Take it easy for a moment. O.K.
Relief, though, is not immediate. He's got the worst headache
he's ever known.
KEN WALKER One of the problems with the frame
when it's on all day is that you get used to it being on.
And when you release the tension of it, it's, that's the worst
time for the headache. And this kind of pressure headache
will go away very quickly.
And the next day Ken had no problem keeping an appointment
with our cameras.
KEN WALKER Just after I got the ring off
I was feeling pretty poor, but within, I guess the doctors
said within an hour or so, most of it would go away. By the
time we got down and got the taxi, got back to the hotel,
I felt good enough to go downstairs and eat dinner.
GLORIA WALKER It's a good feeling to know it's all over and done
with and it was successful and he's feeling better and all
one piece. And it's great.
There are just a few places in the world where this kind of
high accuracy treatment is possible. But for
JAY LOEFFLER, that won't last long.
JAY LOEFFLER We're tired of having long-term complications
to radiation. You have to be more specific--get in the radiation
to where tumors are, and avoid normal structures on the way
in and out. I think this is just the beginning of a lot of
changes in radiation therapy.
OF THE PUPAE SNATCHERS
It's a sunny Tuesday afternoon in the Chiricahua Mountains
of Arizona. And there's a strange group of people who are
looking for something.
TOPOFF We’ve got a colony-with the queen and brood! And, but
she got away. But she certainly was onto the rock.
NARRATION Yes, believe it or not, this is a hunting trip
for ants. Howard Topoff and his students at the Southwest
Research Center know exactly where to find them--which is
about everywhere. But they are after just one particular kind.
DR. HOWARD TOPOFF The vast majority of ants can take care
of themselves. But a small group have lost all those abilities.
They become parasites. They can't get any food for themselves,
they can't clean their nests, they can't feed their young,
they can't feed their queen. The only adaptation they seem
to have left is the unique ability to get other ants to do
all these jobs for them.
And these are the crafty parasite ants. They are called Polyergus,
red in color, about a quarter inch long--and ruthless. The
Polyergus parasites are good at just one thing: making war.
Howard, they're raiding.
TOPOFF There they go. Up here.
NARRATION Practically every afternoon, not just Tuesdays,
the parasite ants send out their armies. As the marauding
hordes stream over any obstacle, other ants in the forest
are cowering in their nests. Who is going to get hit today?
The parasites have found their target. The first innocent
victim is slaughtered. And it's always these peaceful Formica
ants that are attacked. Now the raid is in full swing. Quick
as a flash the parasite ants climb down into the nests and
haul out the living white pupae of unborn Formica ants. The
red parasite rush their booty back across the obstacles into
their own nests. And inside is the most amazing sight. It's
full--not of red ants, but of their victims, peacefully looking
after red-ant pupae, as well as their own. Today's raid has
brought more victim pupae, ants that will be born into slavery.
In his lab Howard studies this strange relationship. The victims
are well armed. They give off poisonous formic acid. So do
the red Polyergus parasites. But look at what happens when
the two types meet. In this test they will be kept apart with
a wire mesh, but they can still use their chemicals on each
other. The result is always the same: even though they both
have the same weapons, it's clear that the Formica victims
are not doing well out of the exchange.
DR. HOWARD TOPOFF After just a few minutes, all the Formica
workers are dead and all the Polyergus workers are still running
around. This suggests to us that the Formica workers are indeed
sensitive to this noxious chemical formic acid. The couldn't
care less. They seem to be virtually immune to it.
The parasites are unbeatable. And they're superbly organized
TOPOFF This scout has just begun scouting. It's kept a relatively
straight line from the nest, moving in a southwest direction.
It hasn't even started to lock for nests yet.
Every day parasite scouts move out in different directions
to look for victims. Now this one is about a hundred feet
TOPOFF She starts circling around, making loopity loops, running
in a kind of a tortuous path. Now she's actually looking for
Formica nests. And as she moves she sticks her head, sort
of pokes her head underneath rocks and leaf litter, and underneath
There's a quick fight when a nest is located. The inevitable
outcome. And then back runs the scout to call out the troops
for a raid. But not so fast. bigger than you. If you're an
ant, there's always something There'll be no raid today. It
occurred to Howard that it was not just spiders that could
stop the raiding. He's mixing up some honey water. And he'll
place it where some Formica victims will find it.
DR.HOWARD TOPOFF I'm putting the honey water down on the ground
where there's a trunk trail of Formica workers. They are going
back and forth, looking for food. And it will take but a minute
for them to find the honey water and they'll probably start
to recruit nest mates within a couple of seconds.
Remember: these are victim ants. They work for the parasites,
and feeding their masters is one of their tasks. Very quickly
they clean out the dish of honey water and then they will
head back to the parasite ants' nests, their adopted home.
Inside the nest they regurgitate the honey water and feed
their masters. Table manners aren't a big thing in the ant
world. There was one striking result of Howard's feeding program.
TOPOFF We find that if we keep feeding the Formica workers
over a period of several days, slowly but surely the number
of raids starts to decrease in frequency. And it remains low
throughout the entire summer. So what we have learned from
this experiment is that the Polyergus raids are at least in
part motivated by hunger.
So when the parasites steal pupae, they get new workers--and
food. But for parasite ants, perhaps the biggest challenge
is starting a new nest.
TOPOFF In most of this species of ants, the queen, after mating,
digs a little hole, lays a few eggs, and when those eggs hatch
into larvae, she feeds them. But a Polyergus queen is kind
of in a unique situation because she is, after all, a parasite.
She can't take care of her own eggs. She can't even take care
This is a Polyergus parasite queen. She is being released near
a Formica colony, so far undisturbed by any parasites. The Polyergus
queen is peacefully laying eggs surrounded by her attendants.
Almost immediately, Formica guards rush to attack the parasite
queen--but it's no use. Then the parasite queen pulls an astonishing
trick. She plays dead, and allows herself to be dragged into
the nest, as if she were a piece of food. By now the threatened
o~ queen has retired to the corner, but her attendants don't
seem to realize the mortal danger. Suddenly the Polyergus parasite
queen reveals her true identity. There's panic in the nest.
She rushes to attack her target--the hapless Formica victim
TOPOFF The fight between the Polyergus queen and the Formica
queen is very, very prolonged, very, very brutal, and very,
very intense. We think that the Polyergus queen, by continuously
biting the Formica queen, is perhaps getting some of the chemicals
that identify the Formica queen as a queen. She covers herself
with them. That may be why the workers of the Polyergus queen
eventually treat the Polyergus queen as their own.
The battle royal took over fifteen minutes--but the Formica
queen was doomed from the start. She's dragged away by her
own offspring, who have become a peaceful new nest of victims,
ruled over by the parasite queen.
They are tropical carpenter ants, like the kind that will
chew up your house if you are not careful. Now listen. Know
what they're doing? They are actually banging their tails
on the floor. And like the killer whales in our first story,
they are communicating. That's what Norm Carling at this lab
here at Harvard has figured out. He thinks they are saying,
"Trouble. The nest has been disturbed." He thinks that because
right after the alarm is sounded, every single ant starts
putting the nest back together. Ants don't just use sound
for communication. It's more common as the ants and other
insects use chemical messages. Like the parasite queen in
our story. She fooled her new victims with a chemical lie
that announced that they should now serve her. Actually, that's
a good example of the kind of odor trickery that's beginning
to serve a very useful purpose. It can provide new ways to
control pests without using large doses of environmentally-sensitive
FLOWERS School's out at Saguaro High School in Phoenix, Arizona,
and it's practice time for the Science Team. They're in heavy
training for the National Science Olympiad, just three weeks
away. Today it's a rigorous test on the behavior of water
balloons. It's the key to a challenge issued by Scientific
We don't have to exert this untenable force ....
And the forces involved will become quite important as they
begin their mission. The challenge is to build a machine to
move water out of this space. The water must start in a balloon,
but somehow be released into a funnel ten feet away. Time
limit--one minute. Weight limit--22 pounds for machine and
water. No electric power allowed. Saguaro is just one of dozens
of schools across the country developing different solutions
to the challenge. Andy and Julie have built this test vehicle.
They are using weights to simulate the water.
Kind of like a little windup car where you pull it back and
let it go.
They have concocted a unique drive train.
When I pick my mass up here, it wants to go down because gravity
is acting on it. It wants to fall. And that falling of it
will spin the axle, as it's wrapped around there, and cause
the car to go.
Time for a test.
The results are encouraging.
This is great because you only want to kind of leave it, take
more work and now you are taking more potential energy, so
we can even put more mass on it than we have now.
We're going to go for maximum capacity. And we'll get to a
certain point where we can say, o.k., this is too much. This
is too little. This is just right. Kind of like the Goldilocks
story, you know, maybe we'll end up with a happy ending.
But getting it just right isn't easy. There's so much to worry
This string didn't make it.
But mistakes are all part of it. Coach Tom Vining.
VINING You get to hear ideas in minds that are fresh. Most
of them are not trained engineers by any means so they are
working on the trial-and-error system. Build it, see how it
works, and then go back. Kind of like the Wright Brothers.
Across the country in Greensboro, North Carolina, the Page High
School team is perfecting a very different machine. They have
decided to keep the balloon at the start, mounted in a water
tower. This way they can put the weight into the water, not
VINING It's hard to build a vehicle that's going to carry
a large amount of water. And this, you know, we can get a
lot of water there without a lot of weight.
The key is this plastic hose which will be unrolled by the
water itself. And to get it flowing, a pin triggered by a
mouse trap which will also release this bridge that directs
the hose toward the funnel. The trigger works great. But that's
It worked, yeah!
More work for the team.
I'll do it over again.. Well, every time you fail, then you
have got to keep it going
BOY Do it all over. See if you can improve it in some way,
#2 What I think happened was that as the bridge was coming
down, and the bridge was still coming down, the water got
to the coil. It was just the coil didn't have any, it couldn't
go this way. It popped off the side.
Can they get things going in the right direction?
Don't touch it if we can avoid it.
#2 Oh, oh, it's going to work.
The scheme has got a lot of promise. BOY If the stand weighed
nothing, we could get about 3.1 gallons. So if we can get
two and half, somewhere between two and a half and three gallons
in, we'll be doing good.
There's more work ahead to improve reliability, but it's already
worth the effort, according to Blythe.
It just starts out ... and it works. And then it's just getting
more and more refined and then it gets working more and more
often now. And it's exciting.
That excitement reaches a peak as 2000 students descend of Pennsylvania's
Clarion University. Fifty teams will compete. Everyone is raring
to go. In their motel, Saguaro High unveils their finished vehicle.
There is now a strong nylon thread and a huge water balloon.
Julie and Andy have loaded it with two gallons.
Basically the balloon will drop and it will pull it. The car
coach, and as soon as it falls in the ditch...Oh my!
NARRATION Two gallons--that's a lot of water.
GIRL They are going to hate us here, they are going to hate
It's competition morning. Time to weigh in. A few last-minute
adjustments. And some aerobic stretching before filling up.
The first contender is a car from Colorado which uses an elevated
ramp to pick up speed. The car works--but there's a problem.
BOY We got up to the top but it was splashing over. There's
a clog in the drain ....
Many teams opt for long arms, but the thin tubing on this
one yields only half a liter, about a pint. For better flow,
this team uses wide tubing.
I don't think so. That's just right.
They hit the three-liter mark, nearly a gallon.
It's coming. I'm happy!
Arms and tube machines, however, are complicated.
#2 Which will cause this to close. And that will go straight
And prone to breakdown. Some just don't get there. Some trip
on their own tubing. And for others, it's just a simple twist
of fate. Arms are unreliable. Cars are better. Here's Saguaro
High. They take the lead, delivering a gallon and a half.
That is great! It worked!
But waiting in the wings is South Carolina's Irmo High, a
powerhouse team. They've entered two different machines. The
first uses a hose truck.
What we are going to do is we are going to release the ramp.
The car is going to go down the ramp and into the funnel.
And once it gets there, the balloon is popped. The water goes
through the hose, into the funnel.
Its light weight allows a large water load. They're ahead
of Saguaro with over six liters--nearly two gallons. Irmo's
second machine uses the same tower design, but a more complex
delivery system--a catapult powered by rubber bands will send
a hose flying over the course. There's a balloon-popping mousetrap.
And the end of the hose is weighted to help it fly the distance.
Watch how it works in slow motion. First, a bridge is released
which rolls out on a castor, guiding the hose. A string attached
to the bridge triggers the catapult. Finally, a second, longer
string on the right triggers the balloon popper. Two and a
half gallons! So now it's Irmo High first and second. For
many machines a basic problem keeps popping up. But for others,
things happen before they should.
I hate this!
And some designs are having trouble going the distance. The
designer of this car has built in more than enough power to
get up the ramp and into the funnel. It's a leak back at home
base that's his downfall.
BOY Well that's where the rubber gasket fell out.
Page High School is up next. But they are still having problems
aiming the hose.
The bridge, oh it's loose. And it can land all different ways,
and we should have fixed it but we don't have time now.
They line it up.
Yes. That's it.
The bridge works. And makes them a top contender with over
seven liters. Two gallons.
BOY We had to get the bridge ... right, to be able to decide
that it worked.
Practice. We're all practice. Patience did it.
Time for the top four teams to run off in the finals round.
It's between Saguaro's water-carrying vehicle, Irmo High School's
hose truck and Irmo's catapult, and Page High School's rolling
hose. It's a closely-matched field. Irmo's catapult draws
the first run. Reliable and effective. Two gallons--seven
liters make it. Page High could beat that. There's two and
a half gallons in their water tower. But it's the old problem--aiming
the hose. Irmo's hose truck is next. And they top their own
team's other machine, the catapult, with two and a quarter
gallons--eight and half liters--to take the lead. So it's
up to Saguaro's vehicle. They've loaded it with three gallons--right
up to the weight limit. They've never tested so much. But
it's the only way they can now win. But friction from the
increased load stops the machine only inches from victory.
The champion is Irmo High School's unstoppable hose truck.
It's been a hard-fought competition but that hasn't interfered
with the fun of it all.
This has been a blast.
It worked. At least it worked once. Got us into the finals!
You've got to make things work--and not just on paper, but
in the real world. That's what the contestants found out.
It makes everything real. It's something that I'm doing, I'm
not just hearing about it. I'm, I'm doing it myself. I'm experimenting
and if I am wrong, I change it. And it's like real life. And
so, it's really, probably the most exciting thing I've ever
done in high school.
FLOWERS For the contestants in that last story, water was
the source of a lot of laughter. But also the source of energy
to power most of their machines. Usually though, water power
works more like this. O.K., here goes. As the water trades
height for speed, it spins the homemade turbine wheel, which
runs the little generator in the middle-voila! We get electricity.
Aside from the bits and pieces of hardware, there are just
two things that you need to do this--some water and some height.
And we just used about fifteen pounds of water falling about
nine feet to make a few watts of electricity for a few seconds.
Clearly, if you want a lot of electricity, it would be nice
to have a lot of water and a lot of height. Well, there's
at least one country in the world that has both.
Switzerland. It's summer time and the tourists are enjoying
themselves. Most people spend their time down in the valleys,
where the towns and cities are. Or perhaps there will be a little
hiking on the lower slopes. At 10,000 feet up, it's a different
world. Even in summer this is rugged and inhospitable country.
But it's the ideal time of year to see the one unmistakable
feature of these mountains--glaciers. You are looking at a stupendous
block of ice. it in this one section. There may be about 15
million tons of There are dozens of them in the Swiss Alps,
filling up the high mountain valleys, looking as solid and timeless
as the mountains themselves. But, as these British scientists
are discovering, glaciers are constantly changing. Martin Sharp
leads the group.
SHARP What I see is effectively a large river of ice which
derives its nourishment from the snowfall which accumulates
directly on its surface during the winter. And from snow which
is transported from the slopes around it in spring and early
summer by avalanches. Now as that snow accumulates on the
surface of the glacier, it compacts under its own weight.
It's compressed and it's gradually transformed into glacier
This is the scientists' second summer on the upper Arolla Glacier,
not far from the famous ski resort of Zurmat. Here the glacier
is disguised with a thin gray crust of rocks and pebbles, but
underneath it's ice all the way down. Just how deep the scientists
are now measuring. They'll use a depth sounder that bounces
sound waves off the bed rock underneath the glacier to gauge
the ice thickness. The Arolla is about four miles long, and
here at the two-mile mark, the ice is at its deepest--over 700
feet. The Arolla would be a much simpler thing for the research
team to study if it weren't for one awkward fact: when summer
comes, the ice begins to melt. That's why, although the glacier
is moving slowly, it never gets anywhere. In fact, it's gradually
disappearing. The surface of the glacier becomes covered with
an ever-changing network of little rivulets and rushing streams.
And there's another complication. Right down at the lower end
of the glacier, where it's completely covered with rock falls,
the melt water ends up in a series of rivers. But the water
doesn't flow off the top of the glacier. Somehow it emerges
from underneath. How does it get there? That's one question
that fascinates the scientists. And it's also something the
Swiss people are very interested in too. This is the reason.
It's called the Grand Dixence Dam, and it's the highest altitude
dam in the world. The lake is 7000 feet above sea level, and
it's made up entirely from glacier melt water. Project engineer
BEZINGE The glacier is like a bank account for Swiss hydroelectricity.
Switzerland is the water capital of Europe. And the glaciers
are solid water banks which melt and yield interest in the
summer. That interest is the water which is collected in the
So much water so high up couldn't be better for generating electricity.
It's fed down from pipelines to a series of power stations which
provide a fifth of Switzerland's entire power needs. There's
only one problem. The Swiss need most of their power during
the winter when the glaciers are frozen solid. So during the
summer melt, they have to concentrate on collecting as much
water as possible. And that's where the research team might
be able to help. On a typical day team members are spread out
down the glacier. This is Keith Richards.
RICHARDS I'm measuring the discharge of the river so that
we can see how it relates to the rate of melting on the glacier.
And the water is freezing. Well, almost.
Sharp. But cold feet are the least of their problems. Martin
SHARP The water doesn't run off from the glacier as soon as
it's actually produced by melting. It has to find its way
through the glacier by some sort of drainage system. And that
draining system has to develop through the year as water is
put into it. So what we are trying to do here is to understand
what drainage systems within glaciers look like, and how they
change through time.
And that's turned out to be a very tricky question because
of this: The glacier is covered with holes. A team member
is preparing to investigate one of the hundreds of drainage
holes that come and go during the season.
How long has this site been opened?
#2 Been opened for just over a week.
At a pre-arranged time, he pours in a batch of red dye. It's
biodegradable so it won't contaminate the stream. Meanwhile,
in the valley below the glacier, other team members are setting
up to sample the water flowing down. The hose is connected
to an instrument that very accurately measures the color of
the water. They will be able to detect any red dye that passes,
even though by now it will be too dilute to be seen by the
eye. In this case it was two hours before any dye arrived.
And it took twenty minutes for that single release to run
past. The water had somehow been caught up in the glacier's
internal structure, and then slowly released. What's going
on inside the glacier? Inside it must look like this--a series
of large cavities, probably formed where the ice contacts
the uneven bedrock. Connected by small cracks in the ice,
the cavities trap the water, slowing down its flow. It sounds
simple enough, but this drainage hole, lower down the glacier
than the first, is going to produce a completely different
result. The dye disappears into the glacier. And at the same
point down the valley, the measuring team is in position.
But this time the dyecomes past almost immediately.
It arrives within ten minutes of release, and it runs past in
just two minutes. Levels drop back to zero and then they pick
up again for another couple of minutes. The water had drained
out rapidly. There must be free-flowing channels--at least two
different ones to account for the double pulse of dye that appeared.
After running hundreds of tests, the team is pretty sure they
know what's happening.
SHARP All we find at the beginning of a melt season in the
spring is that we have a short system of channels at the bottom
of the glacier and then a cavity system above that. Now as
the season progresses, the cavity system is gradually converted
into a channel system. So we find that the channel system
grows progressively upwards here and eliminates the cavity
And that's a finding that's not just of interest to the research
team as they hike through the mountains. To collect the summer
melt water, Swiss power engineers have built a series of catchments
where the glacier runoff drops down through grids like this.
The water enters an elaborate network of pipelines and tunnels,
150 miles of them, carved into the mountains. Water from 38
different glaciers finds its way through the network into the
storage lake behind the dam. Running the system efficiently
is a constant headache because the water flows change all the
time. So as the team learns more about how glaciers work, the
engineers' job should get easier.
FLOWERS The research team now has a pretty good idea of what
goes on inside the Arolla. And it's a good thing they figured
it out in time. At the rate it's melting, it will be completely
gone in about a century. Well, that is, of course if it never
snows again in Switzerland. Which is not very likely. In fact,
the Arolla will still be around when the next Ice Age arrives.
Stay tuned--it's due in about 15,000 years. That's all for
today. See you next time for Scientific American Frontiers.