"Life Beyond Earth" was developed by the Museum of Science, Boston for A Science Odyssey.

Are we alone? Or will our continual explorations of space finally reveal those "little green men?" "Life Beyond Earth." It looks at the technological and scientific advances over the past century that have made looking for life "out there" a seemingly common dinner-table topic. In the course of the demonstration, participants will learn about radio waves, rocketry, computer enhancement, and scanning electron microscopy.

"Life Beyond Earth" is approximately 40 minutes in length and was originally developed for use in science centers. Check with your local museum to find out if it is offering the demonstration to the public.

You may also print the script for the demonstration from this Web site and use in your classroom, club, church, library or home. Feel free to modify or delete any parts of it that will make it better fit your needs. Many of the activities use very simple materials, such as popcorn or cereal, to model scientific phenomena. Some useful references and suggested modifications are included for your convenience. References in the script to slides and video refer to materials distributed to science museums. These materials are not available, but substitutions may be made to suit your organization.

When performing "Life Beyond Earth," please include the following language on any related signage (e.g., programs, invitations, fliers, etc.):

"Life Beyond Earth" was developed as part of the national A Science Odyssey™ Project. Major funding for A Science Odyssey is provided by the National Science Foundation. Corporate sponsorship is provided by IBM. IBM is a registered trademark of IBM Corporation. Additional funding comes from public television viewers, the Corporation for Public Broadcasting, The Arthur Vining Davis Foundations, Carnegie Corporation of New York, and Becton Dickinson and Company. A Science Odyssey is a production of WGBH Boston.

Demonstration Outline

This outline is for the full length (approximately 40 minute) public demonstration, "Life Beyond Earth," the script for which immediately follows in this section. Please feel free to use this outline as a base of your program. Sections can be added, deleted, or modified to suit each institution's needs. Demonstration materials are listed, as are additional modifications. These modifications are described in greater detail in the sections following the script.

Introduction
Focus: Create context for demonstration
Establish relationship to A Science Odyssey

Materials:
Slide: Life Beyond Earth?

Extraterrestrial fascination
Focus: Pre-1900s
Questioning "life beyond Earth" throughout the century
Percival Lowell

Activity:
Pantomime Lowell looking through a telescope

Materials:
Slides: Mars, Lowell's "canals"

Modification:
Discuss other pre-1900s scientists, e.g., Schiaparelli

Radio
Focus: 1900s
Nikola Tesla
Radio waves and serendipity

Activity:
Use radio waves to light a fluorescent bulb

Materials:
Tesla coil, fluorescent light bulb, and volunteer

Modification:
May replace Tesla coil with anything that uses radio waves; microwave, "boom box," RADAR, etc.

Atoms and subatomic particles
Focus: 1910s
Hans Wilhem Geiger
Subatomic particles and radioactivity

Activity:
Build model Geiger counter
Demonstrate real Geiger counter

Materials:
Van de Graaff generator, fluorescent light bulb, metal ball on a plastic dowel, Geiger counter, and a smoke detector

Modification:
Smoke detector may be replaced with any other radioactive material; lantern mantle, original Fiesta Ware, etc.

Radiometric dating
Focus:
Radiometric dating

Activity:
"Popcorn dating" analogy

Materials:
Popcorn popper and bowls of popcorn that have popped for varying times

Electron lens
Focus: 1920s
Hans Busch
How lenses can bend light and beams of electrons

Activity:
Glass lens demonstration
Electron lens demonstration

Materials:
Large glass lens and "Ham Cam" (See Schematic Drawing section)

Modification:
May also be done with any black & white television. (This is not recommended for a color monitor!)
Computer animation of an electron beam scanning. (See Suggested Modification section)

Scanning electron microscopy (SEM)
Focus: 1930s
"Seeing" new worlds with a scanning electron microscope

Materials:
Slides: ant head, dog tapeworm, fecal coliform bacteria

Search for Extraterrestrial Intelligence (SETI)
Focus: 1960s
Radio waves and long distance communication versus spaceships/ alien UFOs

Materials:
Slide: SETI dish

Space probes
Focus: 1970s and 1980s
Viking mission

Activity:
Mars atmosphere test analogy

Materials:
Graduated cylinders with stratified cereal (See Schematic Drawing section)
Slide: Viking model

Modification:
Discuss any type of interplanetary mission; Mariner, Pioneer, Galileo, etc.

Computer enhancement
Focus: 1990s
Hubble Space Telescope
Galileo and Europa
Digital computer enhancement

Materials:
Slides: Hubble Space Telescope, Europa ice rifts

Modification:
Computer animation of digital enhancement with Abraham Lincoln's face. (See Suggested Modification section)

"Rock Story"
Focus:
Meteorite ALH84001

Activity:
Pantomime finding a meteorite

Materials:
"The Rock Story" video production

Testing an unknown rock sample
Focus:
Radiometric dating of an unknown rock
Determine the origin of an unknown rock

Activity:
"Popcorn dating" analogy and Mars atmosphere test analogy from previous demonstrations, and an "unknown" rock sample

Materials:
Bowls of popcorn, tubes of cereal, and a small beaker filled with a mixture of cereal and popcorn

Separation techniques
Focus:
Light spectrometry
Mass spectrometry

Activity:
Demonstrate light spectrograph
Make a "cereal spectrometer"

Materials:
Rainbow projector, Van de Graaff generator, volunteer, insulating platform, and a mixture of cereal. (See Schematic Drawing section for projector and insulating platform)

Modification:
"Cereal spectrometer" demonstration may be done without a Van de Graaff or volunteer. (See Suggested Modification section)
May also discuss paper chromatography as a separation technique. (See Suggested Modification section)

Mars meteorite ALH84001
Focus:
Mars meteorite
"Evidence" of life on Mars, to date

Materials:
Slides: ALH84001, carbonate globules, possible Martian fossils

Liquid fuel rocket
Focus: 1920s
Robert Goddard
Similarity between balloon and rocket

Activity:
Rocket car demonstration

Materials:
Balloon and rocket car (See Schematic Drawing section)

Modification:
Rocket car may be replaced with a potato chip can rocket, a water rocket, or any other type of rocket. (See Suggested Modification section for potato chip can rocket)

Closing
Focus:
Discuss other Science Odyssey resources available


Sample Stage set-up

For the following full-length demonstration, the stage is set-up as follows.

Stage right
1. There is a cart on which are a small Tesla coil and a small Van de Graaff generator.

2. Beneath the cart are: Geiger counter, various 4-foot fluorescent bulbs, a hollow metal ball on a plastic dowel, and an insulated platform (see schematic drawing).

Stage left
1. There is a second cart on which are three clear glass bowls, a hot-air popcorn popper, a smoke detector, a large glass lens, and two tall, clear glass cylinders filled with breakfast cereal.

* Two glass bowls are filled with pre-popped corn; one that has popped less than five minutes (mostly unpopped kernels), one popped more than five minutes (mostly popped corn).

* The glass tubes (graduated cylinders) are filled with rice crispies and wheat chex. One tube is half chex & half crispies. The other has twice the volume of crispies than chex (see schematic drawing).

Downstage
1. Across the whole width of the stage, there are several wooden "time posts" with decades marked on them (see schematic drawing).

Upstage center
1. There is a large screen (20' X 20') that is used for video and slide projection and for various lighting effects.

Off stage left
1. There is a camera on a tripod used in the scanning electron microscope ("Ham Cam") demonstration, a go-cart from which the engine has been removed and to which a carbon dioxide fire extinguisher has been fastened, and a small stool (see schematic drawing for "Ham Cam" and go-cart).

Off-stage right
1. There is a lab coat, a small radio, and a parka.

NOTE: You may want to use a male and female presenter for this full-length demonstration. The female would be Presenter One, the male would be Presenter Two in the following script. This may be modified to be presented by same gender presenters or a single presenter.


Life Beyond Earth -- Complete Script

Introduction & Extraterrestrial fascination

Slide of LIFE BEYOND EARTH on back screen.

Several minutes before the program begins, the popcorn popper is started and a kitchen timer is set for five minutes. When the timer goes off, the program is ready to begin. Presenter One enters stage left, turns off popcorn popper and empties contents into empty glass bowl.

Slide of LIFE BEYOND EARTH fades. Presenter Two is downstage in silhouette with a telescope pantomiming Percival Lowell.

Presenter One:

At the turn of the century, a scientist in Massachusetts by the name of Percival Lowell began to study Mars.

Mars slide

Lowell was using nineteenth-century technology, so he could not see the planet as clearly as we can today.

Lowell's "canals" slide

He thought he saw straight lines on the surface of the mysterious planet. He thought that those straight lines were artificial canals built by intelligent life. It was the start of a century of fascination with extraterrestrial life. My name is _____.

Presenter Two enters stage right:

And my name is _______. Join us as we take a journey, a science odyssey, through the twentieth century. This demonstration was developed as part of the national Science Odyssey Project. Other parts of this project include a PBS television series and <mention other activities in your museum or community>. During this demonstration we'll see how some of this century's scientific discoveries and technological inventions, often developed for completely different reasons, have been used to search for life beyond Earth.

Presenter One:

Also during this program, we are going to present to you what scientists know about life beyond Earth at this point in time, and we will show you the most promising evidence we have so far of finding life on another planet.

Presenter Two:

These "time posts" across the front of the stage make a time line. As we talk about different inventions and discoveries, you can use the time line to place them in the century. Can you find your birth date on the time line? How about your mother's? Your grandfather's? Our science odyssey starts at the turn of the century.

Radio

Presenter One narrates Tesla coil demo as Presenter Two, wearing an old-fashioned lab coat, carries it out as Tesla.

Presenter One:

St. Louis 1901. You may think that what we are about to tell you has nothing to do with life on other planets, but just wait. At a lecture for the National Electric Light Association a young Serbian-born scientist demonstrated a device similar to this.

Presenter One gestures stage right towards Tesla Coil.

His name was Nikola Tesla.

Presenter Two:

My newest invention I call the "transmitter group." In order to demonstrate it, I need a volunteer.

Presenter Two brings volunteer to the Tesla coil and hands her a fluorescent light bulb.

Presenter One:

Our volunteer has been given a fluorescent light bulb; just like the kind we have in our homes.

Pause. Presenter Two conducts the demonstration as Tesla, pantomiming a lecture. Presenter One continues as a storyteller.

Imagine being in the lecture hall back then, in 1901. Tesla calls for the lights to be dimmed. The audience is silent as he walks slowly over to the switch of his machine. Perhaps some of the people in the front row get a bit nervous; what if something goes wrong with the equipment? Tesla throws the main switch, the device hisses with corona and as if by magic, the light bulbs glow brightly. We can only imagine the awe that must have filled that St. Louis auditorium years ago. Electric light itself was a new invention, but here was Tesla lighting bulbs without any wires! Thank you to our volunteer.

Volunteer exits. Presenter Two puts away fluorescent bulb and gets a small radio.

Presenter One:

The energy that left what we now call a Tesla coil, traveled to the light bulb in the form of radio waves. You see, sometimes scientists try to do one thing and end up doing something very different. Tesla wanted to light bulbs without wires, but he ended up inventing radio.

Presenter Two fiddles with radio.

Presenter One continues:

It didn't take long for people to realize that radio could be used to communicate across long distances. Tesla even dreamed that one day it would be possible to communicate with Mars.

Pause.

Atoms & subatomic particles
Presenter One continues:

Now, at about the same time in history, scientists were also learning about atoms. While most scientists at the time believed that there could be nothing smaller than an atom, a few scientists thought atoms themselves were made of even smaller things, called subatomic particles.

Presenter Two:

Does it seem a bit strange to you that scientists would disagree? Sometimes science is confusing to people because while one group of researchers says they have found the answer, the next group says they are wrong. Scientists disagree all the time. They are always skeptical of new ideas until there is enough proof, enough evidence, to convince them. How could the scientists prove subatomic particles existed? What they really needed was a way to "see" or at least detect the particles. Imagine the problem! These atoms scientists were trying to see were so small that you can fit many trillion-trillions of them in a postage stamp! Subatomic particles are even smaller than that.

Presenter One:

In 1913, Hans Wilhelm Geiger invented a way to detect subatomic particles. Today we call the detector a Geiger counter. We have a real Geiger counter to show you later, but first we will demonstrate how it works, with a model.

Presenter Two:

To make our model we need three things. First something that makes high voltage electricity like this Van de Graaff generator. Next, there is some kind of a detector that tells us when the Geiger counter detects a subatomic particle. This light bulb will be our detector.

Presenter One hands Presenter Two a fluorescent light bulb and Presenter Two holds it up.

Presenter Two:

To make our model of a Geiger counter complete, we need a gap -- a space between two things, in this case between the bulb and the top of the generator.

Indicates gap and holds fluorescent light bulb by one end. The other end is about ten inches from the dome of the generator.

If a subatomic particle gets into the gap, it "bridges the gap" and electricity jumps into the bulb making it light up. This ball will be our subatomic particle. Watch what happens to our light bulb.

Presenter One holds up "ball." "Ball" is a hollow metal ball placed on a plastic dowel. Presenter One turns on Van de Graaff generator and moves ball into gap. Light bulb flashes on for a moment. They repeat the process several times. Van de Graaff is turned off. Presenter Two gives fluorescent bulb back to Presenter One, she puts the bulb away and picks up Geiger counter.

Presenter One:

Here we have a real Geiger counter. It has an source of electricity, a gap, and a detector. Unlike our model, the detector is not a light -- it's a sound. The clicks you hear are from subatomic particles passing through the gap.

Presenter One walks around stage and "tests" different materials (Van de Graaff, Tesla coil, time posts, etc.).

Presenter Two:

Subatomic particles are often given off by radioactivity. We are always surrounded by a small amount of safe, natural radioactivity. It is happening all the time all around you -- in the air you breathe, in the chairs you are sitting in, and even inside your body. When something is radioactive, some of the atoms that make it up can change into a different kind of atom, giving off a subatomic particle. It is sort of like popcorn.

Presenter Two takes kernels from bowl and holds them up.

Unpopped kernels change into popped kernels and give off something -- that smell we all love.

Presenter Two picks up smoke detector. Presenter One tests smoke detector.

Presenter Two continues:

Inside this smoke detector, the element that detects the smoke is slightly more radioactive -- still completely safe -- and it gives off subatomic particles. You can hear there are a lot more clicks which tell us that there are more subatomic particles going through the gap.

Radiometric dating
Presenter One:

Radioactivity can also tell us how old something is. At the beginning of the program, we popped this popcorn for five minutes.

Holds up glass popcorn bowls as she questions the audience.

About half the kernels popped. Here is a second bowl. Only a few of the kernels popped. I used the same popper and the same amount of popcorn. How many of you think this bowl was popped for more than five minutes? Less than five minutes? Here is a third bowl where almost all of the kernels have popped. How many of you think it was popped for more than five minutes? Less than five minutes?

Presenter Two:

You see, it doesn't take a nuclear physicist to figure this stuff out. Knowing the percentage of popped popcorn, you can get a pretty good idea how long the corn was popping. You can do exactly the same thing with radioactive materials to find out how old something is. It will become important later on when we talk about the ways in which we are trying to find life on other planets.

Electron lens
Presenter One:

Now, let's move on to the 1920s, to talk about yet another invention that has advanced our search for life on other planets. In 1926, Hans Busch invented something called an electron lens to bend beams of electrons -- one of those subatomic particles we just discussed -- just as a glass lens can bend beams of light.

Presenter Two picks up large glass lens, holds in front his face and distorts his face by moving the lens back and forth.

Presenter One continues:

You can see the large lens that _______ has bends the light and makes him look a little more strange than usual.

The electron lens was a very important development because many of us use it every day -- an electron lens produces the picture in your television. To show you how an electron lens can move a beam of electrons, we need another volunteer, a volunteer who loves to make faces, a volunteer who is a real ham.

Presenter Two brings video camera and stool from off-stage. Stool is placed center stage. Presenter One gets volunteer and places on stool. Presenter Two focuses volunteer's face.

Presenter Two:

This is the museum's "Ham Cam." You can see the face of our volunteer on the screen. Remember that a television screen uses a beam of electrons and an electron lens to produce the picture. By bending the beam with this second electron lens, we can change the picture. Look what happens to our volunteer's face!

Face on large screen is distorted by electron lens (powerful magnet).

Thanks to our volunteer!

Volunteer exits. Presenter One puts away the stool.

Scanning electron microscopy (SEM)
Presenter Two continues:

Bending light with a glass lens can be used to make a light microscope, which can magnify things to up to 1000 times. In the same way, scientists in the 1930s bent an electron beam with an electron lens to make an electron microscope, which can magnify things up to hundreds of thousands of times. These microscopes revealed a whole world of strange creatures. Let me show you some of them.

Slides of several scanning electron microscope images.

Presenter One:

These creatures may look like the beings from other planets we've been searching for, but they're not. They all live much closer to home.

Presenter Two:

Does anyone recognize this? That's right, it's the head of an ant. How about this? This is a head of a dog tapeworm. And this one? This is a kind of bacteria that actually lives in us.

Pause.

So where are we in our search for life beyond Earth? The discoveries and inventions we've been talking about are all starting to come together.

Presenters walk past 1960, 1970, 1980, and 1990 time posts.

Search for Extraterrestrial Intellegence (SETI)

Slide of radio telescope.

Presenter One:

In 1960, SETI, which stands for the Search for Extraterrestrial Intelligence, began using sophisticated types of Tesla's radio receiver to try to detect signals from other civilizations.

Presenter Two:

It appears that Nikola Tesla back at the turn of the century was not far off. You see, it is so much easier and faster to send radio signals from one planet to another, than to send spaceships around. A radio wave is about one million times faster than a supersonic airplane. Radio waves also use less energy. Almost certainly, another civilization would contact us first by radio. Today, SETI is using radio receivers that can listen to a billion radio channels at once. Now that is channel surfing!

Space probes

Slide of Viking model.

Presenter Two continues:

The 1970s and 1980s were the golden years for interplanetary space probes. Viking was sent to Mars and looked for life, but didn't find any. Does that mean there is no life on Mars or are we looking in the wrong way? Are we wasting our time?

Presenter One:

We are not wasting time because one thing Viking did do was test the atmosphere of Mars. We have here two glass tubes filled with cereal.

Presenter Two holds up glass tubes as they are mentioned.

Presenter One continues:

Imagine that the different cereals represent different gases in the atmosphere -- crispies and chex. Both tubes have both cereals in them, but this one is 1/2 crispies and 1/2 chex. This other tube has twice as many crispies than chex. By examining the proportions of cereals in each tube we can determine which tube a small sample came from. Viking measured the proportion of gases on Mars, we know the proportion of gases on Earth, and we can compare the two to determine what planet we are discussing.

Computer enhancement

Slide of Hubble Space Telescope.

Presenter Two:

In the 1990s, computer enhanced pictures from the Hubble Space Telescope showed scientists that there are far more galaxies and solar systems and probably more planets than anyone ever expected. With so many planets out there, how many of you think it is likely there is life beyond Earth, somewhere?

Presenter polls audience.

Slide of Europa ice rifts. Presenter One exits and puts on large parka.

Presenter Two continues:

This picture, taken in 1996 by the Galileo space probe, and enhanced by a digital computer, seems to show giant cracks in a mile-thick sheet of ice on a moon of Jupiter called Europa. Some scientists believe that under all that ice, there may be liquid water. So far, what we have found is that water is an essential ingredient to all life as we know it. Still, with all the things we've talked about up to now, no one had found any evidence for life beyond Earth until last year when scientists took a second look at a rock found in 1984 by Roberta Score.

Presenter One in silhouette pantomimes finding a rock.

Presenter Two continues:

She was taking part in a search for meteorites in Antarctica and found one, but at the time, she had no idea how important her discovery was. She recalls that there was "something weird" about the rock. Let me show you a short video of how scientists think the rock got to Earth.

"Rock Story"(video not available)

"Rock Story" video. Images show the rock being formed on Mars 4.5 billion years ago, being catapulted into space by a comet colliding with Mars, and eventually coming to Earth. The video uses Mars by Holst as background music and sound effects.

After video ends, Presenter One:

Now, you've got to ask yourself, How could scientists possibly know that much? How do we know that this rock came from Mars? How do we know it is 4.5 billion years old, older than any of the rocks here on Earth? And how does it lead us to understand anything about life on Mars?

Testing an unknown rock sample
Presenter Two:

It all has to do with the atoms that make up that rock. Remember those bowls of popcorn and those tubes of cereal we spoke about earlier? Let's imagine you were walking along one day and found a strange rock. You wonder how old it is and where it came from, so you look closely and notice that it is made up entirely of popcorn and cereal.

Presenter Two holds up a small beaker containing popcorn and cereal and dumps it into hand.

Presenter One:

After separating the cereal and the popcorn, you find that your sample contains three popped and two unpopped kernels of popcorn. If you compare this sample to the bowls we popped earlier, how many of you think the popcorn in the rock popped for less than five minutes?

Takes poll of audience and points to bowls as mentioned.

For five minutes? For more than five minutes? We could be wrong, because our sample is very small, but it seems as though the popcorn in our sample, our rock, popped for about five minutes. We have just "dated" our rock.

Presenter Two:

You also find out that the sample contains four pieces of crispies and two chex. Do you think our rock came from this tube?

Takes poll of audience and points to tubes as they are mentioned.

Or this tube? Since there were twice as many crispies than chex, I think you are right, it came from this tube. Scientists have done the same thing with the atoms that make up the meteorite. By separating the atoms in the meteorite, they are pretty sure it is 4.5 billion years old and came from Mars. But how do you separate things as small as atoms?

Separation techniques

Presenter Two joins Presenter One.

Presenter Two:

White light can be separated with a prism like this.

Rainbow projector turned on.

Presenter Two continues:

This is called a light spectrometer. Atoms can be separated with something called a mass spectrometer, another twentieth-century invention. I'll show you how a mass spectrometer works by making a "cereal spectrometer," but I will need another volunteer to help.

Presenter Two selects volunteer. A volunteer with long, loose, fine hair will work best. They all move to stage right cart and the Van de Graaff generator. Presenter Two puts insulated platform next to cart.

Presenter One (to volunteer):

I would like you to stand on this platform. It is an insulator that will make sure you don't feel any shock. Now take your right hand and place it gently on top of this generator. With your left hand, take a handful of crispies and chex and close your hand. We will turn the Van de Graaff generator on and when I tell you, I want you to open your hand and see what happens.

Presenter Two turns on Van de Graaff generator. Volunteer's hair may stand on end and audience will respond. When audience stops, Presenter One signals volunteer to open hand. Most of the rice crispies will fly out of hand, but most of the wheat chex will stay in hand. Presenter Two turns off generator.

Presenter Two:

As you saw, most of the lighter crispies flew out of our volunteer's hand, but most of the heavier chex didn't. We just separated the cereal. A mass spectrometer can do the same thing for atoms with different masses. Let's have a big hand for our brave "cereal spectrometer."

Volunteer exits.

Presenter One:

So now we know a couple of ways scientists have studied the rock found in Antarctica. They used radioactive dating and analyzed an atmosphere sample trapped in the rock. This tells us that the meteorite is 4.5 billion years old and came from Mars. This is what the meteorite actually looks like.

Mars meteorite ALH84001

Slide of ALH84001 meteorite.

Presenter One continues:

If you were to cut it open and look inside with an electron microscope, you would see this.

Slide of carbonate globules in meteorite.

Presenter Two:

This picture does not look very exciting, but all of the colors you see represent different chemicals found in the rock. These brown areas are made from the same chemical you put on your lawn to make it green, lime. It could have been made by something alive on Mars. This black and white band around the lime is made from two other chemicals that are sometimes made by living things on Earth. Again, it could have been made by something alive on Mars. Still another chemical is spread throughout the meteorite. More toward the center than toward the outside, is a chemical with a very complicated name that is abbreviated PAH. PAHs can be made by living things decaying. That black junk on a barbecue grill is loaded with PAHs. I'm not trying to say that someone's been having a barbecue on Mars, but again, it could mean there is or was life on Mars. Some say that all of this information is convincing evidence that there was life on Mars, but then again, some scientists disagree. If you take another close look at the meteorite with an electron microscope, you will see something quite interesting.

Slide of possible fossils in meteorite.

Presenter Two continues:

Don't they look a lot like the bacteria we saw earlier in the program? They are about 1000 times smaller, but some scientists think they could be fossils of Martians. This may be what we've be looking for all century. Life beyond Earth.

But is it? Scientists disagree, just as they disagreed at the turn of the century about atoms and the canals on Mars. The only way we will know for sure is to go to Mars and get more evidence.

Liquid fuel rocket

Presenter One gets rocket car as Presenter Two blows up a balloon.

The only way we have of getting to Mars right now is to use yet another twentieth century invention, the liquid fuel rocket. It was invented by Robert Goddard in Massachusetts in 1926. It's not going to blast me off into outer space, but it will get me from one place to another.

Presenter Two:

This rocket works sort of like a balloon. When you blow up a balloon, and let go of the opening, the air escapes from one end and the balloon itself is pushed in the other direction.

Presenter Two lets go of balloon and continues.

When the valve on the compressed gas is opened, gas will rush out the back, and that will push the car forward.

Presenter One sits in car.

Presenter One:

Maybe one day, an astronaut like me, or you, or you, will board a space ship and blast off for Mars. The evidence that she finds could prove once and for all if there is life on Mars.

Presenter Two:

Let's all give her a great big count down...five, four, three, two, one . . .

Presenter One interrupts:

Wait! What if we find that there isn't life on Mars? Well, it won't be the end of the world. Remember, there are lots of other places out there. We'll probably be looking for a long time to come.

Zero!

Rocket car blasts off.

Closing
If you would like to learn more about twentieth-century science and technology, check out the Science Odyssey Web site at <www.pbs.org/aso>.

Presenters say their good-byes.

End of demonstration


Suggested Modifications

The script for the full-length demonstration may be expanded, condensed, and modified to make it suitable for almost any setting and audience. Because all organizations will not have all of the equipment needed for the full-length demonstration, here are some suggested modifications that make use of cheaper and more easily obtainable materials and equipment.

Electron lens
Materials:
Glass lens
Computer animation of electron beam scanning

Current script :

Presenter picks up large glass lens, holds in front of his face and distorts his face by moving the lens back and forth.

Modified script:

Presenter shows animation of electron beam scanning.

Busch's electron lens led to the invention of television. In a TV picture tube, a beam of electrons is shot down the tube and hits the front screen. On the screen, there is a powder that glows when it is hit by the electrons. If the beam is shot down the center of the tube, a dot will be made in the center of the screen. Now watch how an electron lens can move the beam. If the dot moves very quickly from one side to the other, we begin to see a white line. If the line moves quickly from the top to the bottom, we begin to see a picture. That's how a TV works.

Current script (continue): Bending light with a glass lens can be used to make a light microscope . . .

NOTE: The "Ham Cam" was designed for use with a large audience (see schematic drawing). Any black & white TV monitor and a powerful magnet will achieve the same effect for a smaller audience.
Not recommended for use on a color monitor.

Computer enhancement
Materials:
Computer animation of digital enhancement of Lincoln's face
Current script: Not in this version of the script.
The following may be placed between scanning electron microscopy and search for extraterrestrial intelligence, or added to the computer enhancement section.

Modified script:

Presenter walks to 1940 time post.

In the 1940s one of the very first digital computers was built by Jay Forrester and then used to help control radar. It was called Whirlwind. In a decision that was destined to affect the computer industry for decades, IBM was chosen by the US government to make the next generation of digital computers for a nationwide defense system.

Presenter moves to 1950 time post and presents digital enhancement demonstration with Lincoln's face.

By the 1950s, many scientists worked as part of a team. Science was big and getting bigger. In 1958, the team of Gordon Pettengill, Robert Price, and Paul Green Jr. got the idea of using digital computers to improve pictures of the planet Venus. Our eyes are very good at seeing things, but computers can help us to see even better. Let me show you what I mean. Take a look at this picture made of lots of gray squares. When you recognize what it is, shout it out.

Video image of Lincoln displayed on screen.

That's right, it is a picture of Abraham Lincoln. At first, all the gray squares looked pretty much the same, but there was a slight difference between them. A digital computer looked at the picture and measured the tiny differences between the squares, differences that our eyes could not see. After measuring the differences, the computer made the differences bigger, big enough for us to see. Your brain acts sort of like the computer. The picture is still not perfect, but your brain filled in enough missing information for you to recognize Lincoln. Remember Percival Lowell? He thought he saw canals on Mars because his brain was filling in missing information, too. Unfortunately for him, it was the wrong information. Scientists now use computers to improve or enhance pictures of stars and galaxies and planets.

Current script (continue) : So where are we in our search for life beyond Earth? The discoveries and inventions we've been talking about are all starting to come together . . .

Separation techniques: "Cereal spectrometer"
Materials:
Rainbow projector
Rice crispies
Wheat chex
Inflated balloon
Volunteer

Current script: I'll show you how a mass spectrometer works by making a "cereal spectrometer," but I will need another volunteer to help.

Modified script:

Presenter selects volunteer.

I'm going to give you a handful of crispies and chex. Now, I'm going to take this balloon and rub it on your hair. If I hold the balloon a little bit above your hair, look what happens!

Volunteer's hair stands on end, audience will laugh.

Now, watch what happens when I hold the balloon above your hand.

Rice crispies will be attracted to balloon, wheat chex will not.

Current script(continue): As you saw, most of the lighter crispies flew out of our volunteer's hand but the heavier chex didn't. We just separated the . . .

NOTE: The rainbow projector was designed for use with a large audience (see schematic drawing). A flashlight and a prism will achieve the same effect for a smaller audience.

Separation techniques: Paper chromatography
Materials:
Two different black markers (water soluble)
Chromatography paper or paper towel
Water
(See Schematic Drawing section)

Current script: But, how do you separate things as small as atoms?

Modified script: Let me show you how paper chromatography can be used to separate atoms or chemical compounds.

The technique of chromatography was first described by a Russian scientist by the name of Tswett in 1910. He used this technique to demonstrate that there are two different types of chlorophyll in plants. Chlorophyll is the stuff that makes plants green and is used to convert sunlight into energy.

Here is how chromatography works. I have two different black markers. On one piece of paper, I will draw a line with one of the markers and on the other piece of paper I will draw a line with the second marker. Both lines look the same color. However, there are many ways to make black ink. I want to detect if the dyes that make up the black ink are the same for both samples.

I will set up a chromatograph using paper towel and some ink from this first pen.

Presenter runs the chromatography demo.

When I place the end of the paper in the water, the water will travel up the paper past the ink. Each different pigment that makes up the black ink travels through the paper at a different rate, separating the dyes. Once the dyes are separated, you can use your eyes to detect the differences.

Show the two different chromatographs of the two different inks.

We won't have time today to finish our test of the two inks, so here are chromatographs that I ran earlier. As you can see, even though both inks look black, they are made of different dyes. Using a technique similar to this, scientists have been able to separate the atoms in the meteorite to tell how old it is and where it came from.

Current script (continue):

Slide of ALH84001.

This is what the meteorite looks like . . .

Liquid fuel rocket
IMPORTANT! Read safety instructions before attempting.
Materials:
Potato chip can
Hydrogen gas
Small stand
Candle or match attached to a meter stick
(See Schematic Drawing section)

Current script: The only way to get to Mars right now is to use the last twentieth-century invention we are going to talk about, the liquid fuel rocket.

Modified script:

Presenter brings out can with small holes in the top and bottom, small tank of hydrogen gas and a base to hold the can upside-down without covering the bottom hole.

This potato chip can is going to be a real, honest-to-goodness rocket. I'm going to tape over the hole in the metal bottom of the can, turn it over, then fill it with hydrogen gas and put on the plastic cover. Now I'll put it on this base. As soon as I peel off the tape from the metal end and hold a match near the hole, the hydrogen gas, which is lighter than air, will escape through the top hole and burn. Oxygen from the air will go in the bottom hole. When the oxygen and hydrogen reach a critical mixture of two parts hydrogen to one part oxygen, H₂O, watch out! By adjusting the flow of oxygen and a fuel, a rocket can be controlled.

This part requires exact timing to make the can "blast off" at the correct moment.

Maybe one day, an astronaut like me, or you, or you, will board a space ship and blast off for Mars. The evidence that she finds could prove once and for all if there is life on Mars.

Presenter peels off tape and lights can. Lights dim except for slide of possible Martian fossil on screen. Presenter starts count-down with audience.

Current script (continue): Five, four, three two, one . . .

Safety Precautions for potato chip can rocket
1. Wear safety glasses.
2. Be sure that can is completely filled with hydrogen gas before lighting.
(Can is filled when resonance pitch in the can is steady)
3. Light can with a long fireplace match or a candle attached to a meter stick.
4. Ensure plenty of vertical room for the rocket to go.
5. Back off!
6. Practice with timing.

Helpful references

Ebbing, D., "General Chemistry." Third Edition. Houghton Mifflin, Boston. 1990.

Goldsmith, D., "The Hunt for Life on Mars," Dutton, New York. 1997.

International Tesla Society Home Page <http://www.tesla.org>
Information about Nikola Tesla with several links.

Mars Pathfinder home page <http://mpfwww.arc.nasa.gov>
All you ever wanted to know about the Pathfinder mission.

Miller, J.,"Chromatography: Concepts and Contrasts." Wiley & Sons, New York. 1998.

NASA home page <http://www.nasa.gov>

National Space Science Data Center home page <http://nssdc.gsfc.nasa.gov>
Information on Viking mission.

Rovin, J., "Mars!" Corwin Books, Los Angeles. 1978.

SETI Institute home page <http://www.seti-inst.edu>

Sky & Telescope magazine
Great reference for various articles on astronomy and life on other planets.

Space Telescope Science Institute home page <http://oposite.stsci.edu>
Information about the Hubble Space Telescope.

Tesla: The Electric Magician <http://www.parascope.com/en/0996/tesla1.htm>
Great Web site for information on Nikola Tesla.