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Destination Tomorrow - Episode 2

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Subido el 28 de mayo de 2007 por EducaMadrid

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NASA Destination Tomorrow Video containing five segments as described below. NASA Destination Tomorrow Segment exploring the issue of ice formation on aircrafts. The segment explains how the icing research tunnel is helping engineers combat icing on aircraft. NASA Destination Tomorrow Segment exploring morphing technology and how it can change the future of aircraft. NASA Destination Tomorrow Segment describing sensor technology and explains what they are and how they work. NASA Destination Tomorrow Segment exploring the soundbarrier and how the theory of area rule enabled efficient, supersonic flight to be possible. NASA Destination Tomorrow Segment describing the new tools that NASA scientists have designed, including the ultrasonic probe, to make dentist visits more pleasant.

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My Outro For My 20th Birthday 00:00:00

Coming up on Destination Tomorrow, painless dentistry becomes a reality with a new dental 00:00:30

probe designed by NASA to detect periodontal disease. 00:00:41

We'll also see how future technologies might allow planes to fly like a bird. 00:00:45

And we'll meet the man who enabled efficient supersonic flight to become a reality. 00:00:50

All this and more, next on Destination Tomorrow. 00:00:54

Hello everyone, I'm Steele McGonigal. 00:01:01

And I'm Kara O'Brien, and welcome to Destination Tomorrow. 00:01:02

This program will uncover how past, present, and future research is creating today's knowledge 00:01:06

to answer the questions and solve the challenges of tomorrow. 00:01:11

We begin with an issue that affects all aircraft that fly in our atmosphere. 00:01:14

The formation of ice on airplanes is not only an issue on the runway during cold weather, 00:01:19

but can form on airplanes in flight. 00:01:23

This problem can be a dangerous situation for any piloted aircraft. 00:01:25

Fortunately, NASA has been conducting research on icing with a unique wind tunnel facility 00:01:29

that creates icing conditions on aircraft. 00:01:34

Jennifer Pulley takes Destination Tomorrow behind the scenes to see how this icing research 00:01:37

tunnel is helping engineers combat icing conditions on aircraft. 00:01:42

Thanks for the ice. 00:01:53

You know, there's nothing like a beverage chilled with ice during a long flight. 00:01:54

Inside an airplane, ice is something passengers desire. 00:02:01

However, outside an airplane, ice can be dangerous, especially if it forms on the wings or engines. 00:02:05

I had the opportunity to speak with Judy Foss-Vanzanti at the NASA Glenn Research Center in Cleveland, 00:02:11

Ohio. 00:02:17

She's researching the effects of icing on aircraft at a unique facility called the Icing 00:02:18

Research Tunnel. 00:02:22

Researchers at this facility study the formation of ice on the exterior of aircraft. 00:02:24

So while flying, the only ice you'll need to worry about is the ice inside your cup. 00:02:28

Well, I'm standing right here in the Icing Research Tunnel. 00:02:33

Right here, we create on Earth what it's like for an airplane to fly through an icing cloud 00:02:37

up there. 00:02:41

To do that, we've got to make it windy, cold, and wet. 00:02:42

Now, right now, I'm standing in front of the fan. 00:02:45

We have the fan to create the wind, and in the test section, which is a much smaller 00:02:48

cross-sectional area, we can get winds up to 400 miles per hour. 00:02:51

So that's about as fast as a plane might fly through in an icing environment. 00:02:55

We create the cold with our heat exchanger, 1,700 ton. 00:03:00

It can cool 500 homes. 00:03:03

That's how big it is. 00:03:05

We can get from zero Celsius down to about minus 20, which is where the icing might occur 00:03:07

in nature. 00:03:12

And we have spray bars. 00:03:13

The spray bars is what makes the icing tunnel. 00:03:16

We create the rain. 00:03:19

We create a mist that the airplane would fly through. 00:03:20

Now, the thing about the spray bars is the researchers need to control both how much 00:03:23

water is in the cloud, the liquid water content, we call it, and how big the drop size is. 00:03:28

And we have spray bars specially designed to create those conditions. 00:03:34

So in our test section, we create what it's like for an airplane to fly through an icing 00:03:37

cloud. 00:03:41

So why did NASA build an icing research tunnel? 00:03:42

As it turns out, during World War II, the Allies lost more aircraft to icing than enemy 00:03:46

fires. 00:03:53

They were trying to fly supplies over the Himalayas. 00:03:54

So the Air Corps turned to NACA, that's NASA's predecessor, and asked them to build an icing 00:03:56

research tunnel so we could understand what was going on and how to fix the problem. 00:04:01

So what do you test in the icing research tunnel, or the IRT? 00:04:05

What we test in the IRT is what makes sense to test. 00:04:09

Now, if you think about it, if you're in an airplane flying through an icing cloud, what 00:04:12

surfaces are most critical to keep ice free? 00:04:16

Well, it's the wings, which provide the lift, get you off the ground, and it's the engine 00:04:18

inlet, which provides the forward thrust. 00:04:23

So we typically can test just those components, just the wing or the engine inlet. 00:04:25

So what happens when ice forms on an airplane's wing? 00:04:30

Well, ice can disrupt the airflow over a wing and will eventually cause the airflow to separate. 00:04:34

This separation of airflow creates more drag and less lift. 00:04:41

If ice continues to form, the wing will no longer produce the appropriate amount of lift 00:04:46

needed to keep the airplane in flight. 00:04:51

In some cases, ice creates airflow separation over movable parts, like an aileron. 00:04:54

This could create handling or control problems, and the plane could suddenly roll. 00:05:01

As the wing is flying through the air, the ice only accumulates around the leading edge. 00:05:07

So that's why ice protection systems only wrap around the first part, the front part 00:05:11

of the wing. 00:05:15

The biggest factor in how the ice grows is temperature. 00:05:17

So if it's really cold, the water droplet comes in, hits the front part of the wing, 00:05:22

and freezes on impact, and you get this nice, pointy, rhyme shape. 00:05:26

The more dangerous ice comes during warmer conditions, those closer to freezing, where 00:05:30

the water comes in, hits the leading edge, and actually runs back a little bit. 00:05:35

If that happens, the next droplet might come in, see that droplet that is frozen, and start 00:05:39

to grow. 00:05:43

So you might get these ram's horns that grow upstream. 00:05:44

Now that significantly disrupts your airflow, and that is not, that's way off design, and 00:05:47

that's very bad. 00:05:52

Judy, tell me a little bit more about the icing protection system. 00:05:53

Do all planes have it? 00:05:56

There's what we call an anti-ice system, where you don't allow the ice to grow at all. 00:05:58

Ice, if you've got a very hot leading edge, you see that in jets, and there's a de-icing 00:06:02

system which has pneumatic boots, that the boots will wrap around that leading edge, 00:06:07

they'll inflate and pop the ice off, so you let the ice grow, and then you've got to get 00:06:12

it off. 00:06:15

The pneumatic boots are typically what you see with turboprop aircraft. 00:06:16

Does icing affect planes in, say, a warm climate? 00:06:21

Icing occurs everywhere. 00:06:25

You've got to be aware of it. 00:06:27

I've got a pilot friend who told me the worst icing he encountered was flying from Florida 00:06:29

to the Caribbean in July at 16,000 feet, the worst icing he ever saw. 00:06:34

But icing really can occur anywhere and anytime. 00:06:39

One of the things we do here at NASA is to have better designs, so maybe a system that 00:06:42

would automatically turn on the ice protection system if a sensor goes off. 00:06:47

The short-term solution is to train the pilots and educate them about how to detect icing, 00:06:51

how to be aware of it, train them how to get out of the icing environment if and when 00:06:57

they need to. 00:07:02

Ideally, icing is a non-issue in the future, and we're working to get there. 00:07:03

In 1987, the Icing Research Tunnel was designated an International Historical Mechanical Engineering 00:07:08

Landmark for its leading role in making aviation safer for everyone. 00:07:13

Coming up, we'll see how a new dental probe designed by NASA will make going to the dentist 00:07:17

a little easier. 00:07:22

But first, did you know that during World War II, the Allies lost nearly 1,000 planes 00:07:23

over the Himalayan Mountains due to icing? 00:07:28

Flight conditions here were so treacherous that pilots called this dangerous route the 00:07:31

Hump, or the Aluminum Trail. 00:07:34

When you hear the word dentist, what word immediately comes to your mind? 00:07:40

Pain? 00:07:44

Unfortunately, pain and dentistry have always been synonymous with each other. 00:07:45

Throughout history, dentists and engineers have attempted to make dentistry more comfortable 00:07:49

by making tools and equipment more patient-friendly. 00:07:54

Now NASA and its research partners have made pain-free dentistry a reality. 00:07:57

Jennifer Cortese examines how a new dental instrument, which was originally designed 00:08:01

at NASA, will finally make a trip to the dentist a painless experience. 00:08:05

Have you ever had this experience at your dentist? 00:08:12

It seems most people do not like to visit their dentist regularly. 00:08:21

Why? 00:08:25

Pain. 00:08:26

To some people, the sight of dental instruments often invokes feelings of anguish and fear. 00:08:27

In fact, most dental instruments are not pleasing to the eye, or to your mouth. 00:08:33

Until now. 00:08:38

NASA and its partners have developed an instrument that will help keep periodontal disease, which 00:08:39

is the leading cause of tooth loss in adults, in check. 00:08:43

This technology was originally designed to help detect cracks in airplanes, but is now 00:08:47

currently being used to design and manufacture a revolutionary dental instrument called the 00:08:51

Ultrasonographic Periodontal Probe. 00:08:56

The technology that's in the probe is ultrasonics. 00:08:59

These are the sound waves that we use to probe inside materials, such as the aircraft wings. 00:09:03

Ultrasonics is very high-frequency sound. 00:09:10

We at NASA use high-frequency sound to actually look inside materials. 00:09:14

We like to be able to assess the health of a material, just like a physician would assess 00:09:19

the health of a person. 00:09:25

When you look with ultrasound inside a material, you can find defects. 00:09:27

Defects such as internal damage. 00:09:33

Defects such as corrosion that would lead to a loss of strength of a material that might 00:09:36

cause a mission failure. 00:09:42

Now, how did you discover the specific problems that the probe solves? 00:09:44

The specific problem was actually discovered while we were trying to assess the integrity 00:09:48

of aircraft. 00:09:54

Ultrasonics could characterize the desponds and micro-cracking that occurred near rivets 00:09:56

on aircraft. 00:10:01

That same ultrasonics could be used to find desponds between the teeth and the gums. 00:10:03

In other words, periodontal disease. 00:10:09

Periodontal disease is an infection of the tissues that help anchor your teeth. 00:10:12

If left untreated, it can lead to tooth and bone loss. 00:10:16

Currently, the most widely performed method to measure periodontal disease is not the 00:10:18

most comfortable. 00:10:23

It involves the insertion of a small, blunt probe between your tooth and gum to measure 00:10:24

the depth of the periodontal pocket. 00:10:29

This process is highly invasive, uncomfortable, and inconsistent. 00:10:31

This new instrument, developed by NASA Langley and its partners, uses ultrasonic sound waves 00:10:36

that interact with your teeth and map the periodontal pocket. 00:10:40

NASA works very closely with medical people during the technology transfer that allows 00:10:45

us to take what we have learned in studying materials and apply it to materials that are 00:10:52

human tissue. 00:10:57

We've had many people contribute to its success. 00:10:59

One of those individuals is John Companion. 00:11:02

John worked at NASA Langley Research Center for 27 years and now works in the Applied 00:11:05

Science Department at the College of William and Mary. 00:11:09

We met up with John at the Dental Hygiene Research Center at Old Dominion University. 00:11:12

The new probe simply touches the surface of the gum and slides along. 00:11:17

The only coupling between the gum and the probe is just water. 00:11:23

So it's totally non-invasive, doesn't hurt at all, should provide more information because 00:11:26

of the way the information is gathered, and it should be faster. 00:11:33

The problem that you have with the current technology is one, obviously, that's highly 00:11:38

invasive and this hurts. 00:11:42

Ultrasound doesn't. 00:11:45

No sensation, no penetration. 00:11:46

They simply run it just along the edge of the gum and you get a nice little image on 00:11:49

the screen of a computer that shows you a map. 00:11:54

All the information retrieved by the probe can be archived on a computer. 00:11:57

A physician can then compare real-time data and past data to diagnose the condition of 00:12:01

the patient. 00:12:06

And the nice thing that dentists like about this is they can show the map to the patient 00:12:07

so we can actually see what's going on in the gum. 00:12:13

And of course, if you can evaluate the disease, you can also evaluate the treatment. 00:12:17

So when they start treating it, you can go back and you can check on it and see is this 00:12:22

particular treatment doing any good, do we need to modify it, do we need to do something 00:12:26

different here. 00:12:30

And because this will all be computerized, you only need one person to do it. 00:12:31

Right now you have to have one person to take the measurement, one person to write down 00:12:35

the measurement. 00:12:38

There's time savings, there's money savings. 00:12:39

Patients like it. 00:12:43

I liked it. 00:12:44

I've actually used myself as a guinea pig. 00:12:45

I've had all three types of probing done by several different dentists now and let 00:12:47

me tell you, the ultrasound is the only way to go. 00:12:52

The use of ultrasound in dental diagnostics provides an alternative approach to conventional 00:12:55

probing. 00:12:59

Patient discomfort and the need for drugs like Novocain are virtually eliminated. 00:13:01

This technology could eventually touch every person who visits the dentist regularly. 00:13:05

Today many planes break the sound barrier with relative ease, but it wasn't too many 00:13:14

years ago that the sound barrier was just that, a seemingly impenetrable invisible wall. 00:13:19

In fact, many aerodynamicists thought that the sound barrier may never be broken by man 00:13:25

until one man named Richard Whitcomb developed a theory called area rule that enabled efficient 00:13:30

supersonic flight to become a reality. 00:13:36

Before October of 1947, attempts to break the sound barrier usually ended in disaster. 00:13:40

That was until Chuck Yeager and the X-1 flew through the sound barrier on October 14, 1947. 00:13:46

The sound barrier had finally been broken. 00:13:52

But there it was what I call a brute force approach in the sense that your rocket just 00:13:55

rammed that airplane through the speed of sound, but the drag was so high that they 00:14:00

used up all the fuel in just about five minutes. 00:14:05

So it was not practical supersonic flight, but it did accomplish breaking of the barrier. 00:14:08

There needed to be a more efficient way to break the speed of sound. 00:14:14

Dick Whitcomb set out to find a way. 00:14:18

Whitcomb found that when a plane reached near supersonic speeds, the drag around the wings 00:14:20

would increase by as much as a factor of five. 00:14:25

He saw that much like a bullet, the fuselage was extremely aerodynamic without the wings, 00:14:28

but when the wings were added, an aerodynamic bump was causing incredible amounts of drag 00:14:34

that was slowing the plane down. 00:14:39

It became obvious to him that he had to find a way to take the bump out of the equation. 00:14:42

Whitcomb's tests showed that when he added the entire area of wings and fuselage together, 00:14:47

the drag, or aerodynamic bump, was exactly the same as the drag of a fuselage with wings. 00:14:52

He worked tirelessly to find a solution, when one day, as he was thinking about the problem, 00:14:59

the solution hit him like a bolt of lightning. 00:15:04

He must indent, or pinch in, the waste of the fuselage. 00:15:07

This new shape of the fuselage would closely resemble the shape of a Coke bottle. 00:15:12

Whitcomb was astonished to find that by changing the shape of the fuselage, he took the bump 00:15:17

out of the equation and allowed the plane to become as aerodynamically smooth as a fuselage 00:15:22

without wings. 00:15:27

This very simple fix came to be known as the area rule. 00:15:29

I had the idea, then we built some models to try and demonstrate it. 00:15:33

We built airplanes with Coke bottle shaped fuselages, and lo and behold, the drag of 00:15:38

the wing just disappeared. 00:15:46

Now there was when I was really thrilled. 00:15:47

That was far, that was a year or two before anything flew, but there the wind tunnel showed 00:15:51

that it worked perfectly. 00:15:56

It was not some oddball theory, it was a practical means of reducing drag. 00:15:59

When the area rule concept was flight tested on the newly converted F-102 fighter, the 00:16:05

plane soared through the sound barrier with ease. 00:16:10

Whitcomb's discovery revolutionized the way that supersonic fighters, bombers, and transports 00:16:14

were built from the 1950s through today. 00:16:19

In fact, the area rule concept is still used on many modern planes, including the B-1 bomber 00:16:21

and the Boeing 747. 00:16:27

Dick Whitcomb's intuition and daring led to a revolution in air technology that has forever 00:16:30

changed the history of flight. 00:16:35

For his effort in developing the area rule concept, Dr. Whitcomb won the prestigious 00:16:40

Collier Trophy, which is awarded annually for great achievement in aeronautics and astronautics 00:16:44

in America. 00:16:48

Coming up, we'll see how NASA researchers are working on a morphing technology that 00:16:50

will allow future aircraft to fly like birds. 00:16:54

But first, did you know that Jacqueline Cochran was the first woman to break the sound barrier? 00:16:56

Cochran broke the barrier May 18, 1953 in an F-86 Sabre jet. 00:17:01

At the time of her death in 1980, she held more speed, altitude, and distance records 00:17:06

than any other pilot, man or woman, in history. 00:17:12

Imagine how most people felt the first time they heard that one day man would be able 00:17:20

to fly, or that we hope to actually land a man on the moon. 00:17:26

Those ideas seemed pretty crazy at the time, but today we know just about anyone can fly 00:17:30

in an airplane, and we have astronauts actually living in space. 00:17:34

Now, what if I told you that one day we would be able to fly in an aircraft that could bend, 00:17:39

twist, and maneuver just like a bird? 00:17:44

Sound crazy? 00:17:47

Well, I spoke with Anna McGowan at the NASA Langley Research Center, who's working to 00:17:48

incorporate something called morphing technology into aircraft. 00:17:52

And these morphing technologies could turn those crazy ideas into reality. 00:17:56

Morphing is looking at really advanced materials and other technologies that will make airplanes 00:18:02

even better than they are today. 00:18:07

We got the word morphing actually from the word metamorphosis. 00:18:08

The word morph means to change, and we're using a lot of advanced materials and technologies 00:18:13

to make airplanes change from one configuration to the other. 00:18:18

Our task at NASA Langley is to look 20 years into the future. 00:18:23

Some of our challenges are making the airplanes even safer, making them more efficient, meaning 00:18:26

you could fly farther on the same tank of fuel, or carry more passengers, for example. 00:18:31

And we're working on making airplanes as versatile as a bird is. 00:18:37

So we're taking some lessons from nature. 00:18:41

To get aircraft to perform with bird-like agility, first you have to understand how 00:18:44

birds fly. 00:18:49

Efficient wing design, feathers, and hollow, lightweight bones allow birds to fly better 00:18:50

than any man-made machine. 00:18:55

By drawing on the inspiration of birds, Langley researchers are hoping to develop technologies 00:18:57

that will enable aircraft to perform with bird-like agility. 00:19:02

For example, synthetic jets will cover parts of the wing and replicate the effects of feathers. 00:19:06

These technologies can alter the airflow over the wings for superior maneuverability. 00:19:12

Microspheres will replicate the bird's hollow bones and allow lightweight wings to be manufactured 00:19:17

for increased performance and efficiency. 00:19:24

Sounds like science fiction, but in fact, these technologies are real. 00:19:26

We make airplanes as efficient as birds by trying to replicate or mimic some of the characteristics 00:19:31

birds have. 00:19:36

As an example, birds use feathers to control the airflow over the wings. 00:19:37

We are doing that by using what are called synthetic jets. 00:19:42

Synthetic jets suck in their own air and then pump it out very quickly, creating a fluctuating 00:19:45

plume of air. 00:19:51

This little plume of air basically simulates what a feather would do. 00:19:52

On a bird, the feathers are used to adjust the airflow over the wing of the birds so 00:19:56

that the bird flies optimally no matter what the air conditions are outside. 00:20:02

Now, on an airplane, we do the same thing. 00:20:06

We put these jets inside the wing of the airplane and say, for example, we had a gust 00:20:08

of wind coming into the airplane. 00:20:12

We would turn on very specific jets at the right time and at the right frequency. 00:20:14

And by doing so, then we can adjust the airflow over the wings of the airplane, thereby making 00:20:19

the airplane very stable and comfortable and maneuverable at all flight conditions. 00:20:23

We also want to be able to mimic the porous inside section of a bird bone because that 00:20:28

porous inside section is lightweight, but it adds extra strength. 00:20:33

We do that by using what are called tiny microspheres. 00:20:38

You would take these microspheres and actually inject them into a composite material. 00:20:42

And once we inject them in, we would use heat to fuse them together. 00:20:47

So therefore, we could achieve a lightweight structure that is also very strong, which 00:20:51

is the same thing that birds use when they fly. 00:20:56

Anna, besides birds, are there any other designs inspired by nature? 00:20:58

Well, we're also looking to the water for some inspiration from nature. 00:21:02

Fish and shark and whales swim very efficiently in the water. 00:21:06

And the flow of water over the skin of a shark is very similar to the flow of air over the 00:21:11

wings of an airplane. 00:21:16

If you look at shark skin under a microscope, you'll actually see a bunch of little teeny 00:21:17

grooves. 00:21:21

So our hope at NASA Langley is that perhaps our material scientists can create the same 00:21:22

groove-like material and we can apply that to the skin of airplanes and make them much 00:21:27

better flyers. 00:21:31

We're also looking at flapping wing airplanes, believe it or not. 00:21:33

This design was inspired by the wings of a hummingbird. 00:21:37

If you use an airplane that does not have flapping wings, you have to have two things, 00:21:39

an engine and wings. 00:21:44

Flapping wing airplanes do not need an engine. 00:21:46

The wings will provide you forward motion or thrust, as well as lift, which goes up. 00:21:48

So Anna, tell me how you design a flapping wing without using an engine. 00:21:53

We actually use what are called smart or active materials instead of using an engine. 00:21:57

And why is it referred to as smart material? 00:22:03

Well smart materials actually move on command. 00:22:05

These are materials that when you apply a stimulus, like electricity or heat or in some 00:22:08

case magnetism, they actually move. 00:22:13

Another very common one that we've just developed is called a macrofiber composite. 00:22:15

The macrofiber composite works by when you apply electricity to it, it will move in the 00:22:21

direction you'd like it to move. 00:22:25

So what we would do is when we adhere this, or if you were embedded inside an airplane 00:22:27

wing or the tails of a fighter airplane, it would actually absorb the vibration. 00:22:32

As a consumer, you can put these in your washing machine to absorb vibration. 00:22:37

You can put it in your cars. 00:22:40

You can even use it to absorb sound. 00:22:41

So we think that these materials like this one are really going to revolutionize how 00:22:44

we build things in the future. 00:22:48

We're also looking at a material called a shape memory alloy. 00:22:50

We would use this material to bend and twist airplane wings. 00:22:53

Now you might wonder why we'd want to do that kind of thing. 00:22:56

Well birds also bend and twist their wings in flight. 00:22:59

Now being able to bend and twist airplane wings is really difficult because airplane 00:23:03

wings tend to be very stiff. 00:23:07

If you bend this material, this shape memory alloy, it will actually go back to its original 00:23:09

shape. 00:23:14

So if you bend this, I'll show you what it looks like. 00:23:15

Now I'm going to apply this lighter to it, and you can watch it go back to its original 00:23:19

shape. 00:23:23

Now this simple little material can pull around 700 pounds. 00:23:24

So by placing a couple of these in an airplane wing, we can make the airplane bend or twist. 00:23:29

We hope that by flying more like a bird does, we can save a lot of money on fuel, as well 00:23:35

as reduce the complexity of the mechanisms within the airplane wing. 00:23:40

So we're using a lot of these biologically inspired materials and technologies to make 00:23:43

aircraft and spacecraft a lot safer to fly. 00:23:48

Ground and wind tunnel testing are currently underway in the morphing program to bring 00:23:53

these fascinating technologies to fruition. 00:23:57

Sensor technologies have been around for quite some time. 00:24:00

In fact, sensors are virtually everywhere. 00:24:03

But what are they? 00:24:06

And how do they work? 00:24:07

For some answers, we turn to Johnny Alonzo. 00:24:08

Sensors. 00:24:17

Sensors. 00:24:18

Sensors. 00:24:19

Sensors. 00:24:20

Sensors. 00:24:21

Sensors. 00:24:22

They're just about everywhere. 00:24:23

Most people probably couldn't live without them. 00:24:24

Have you ever slammed a snooze bar on your alarm, opened your garage with a remote control, 00:24:25

set your car alarm, or changed the channels on your television with a remote? 00:24:27

Sure you have. 00:24:31

They're all controlled by sensors. 00:24:32

With today's technology, most sensors are extremely small or invisible to the naked 00:24:34

eye. 00:24:38

Heat, light, sound, pressure, or a particular motion can trigger a sensor to perform a specific 00:24:39

action. 00:24:46

There are sensors in our cars, our homes, offices, even in our own bodies. 00:24:47

But what exactly is a sensor? 00:24:52

And how does it work? 00:24:54

For some answers, I spoke with Dr. Gary Gibbs at NASA Langley Research Center. 00:24:56

A sensor is a device that detects physical phenomena such as light, heat, air flow, pressure, 00:25:00

temperature, even sound. 00:25:06

And generally speaking, how do sensors work? 00:25:08

They work through a mechanism called transduction, where we're converting one form of energy 00:25:10

into another. 00:25:14

Maybe a form of energy that's less useful into, say, electrical energy. 00:25:15

And an example would be like a solar cell, where it takes energy from the sun and converts 00:25:20

it into electrical energy that we can use. 00:25:24

All sensors utilize transduction to convert energy such as light or heat into typically 00:25:26

electrical energy. 00:25:31

Another example might be a telephone button, which when pressed, converts mechanical energy 00:25:32

from your finger into an electrical signal in the form of a tone. 00:25:36

So Gary, what are some typical examples of sensors that we use every day? 00:25:41

Sensors are around us everywhere. 00:25:45

In fact, when we go to the grocery store, there's barcode scanners to detect the barcodes 00:25:46

on products we buy. 00:25:50

In fact, in our car, there's sensors to detect a crash, to open airbags. 00:25:51

And in fact, the telephones that we use every day have sensors called microphones that sense 00:25:56

the sound of our voice. 00:26:01

So it would be safe to say that there are millions of sensors out there, right? 00:26:02

Absolutely. 00:26:06

Really? 00:26:07

Do they all work the same? 00:26:08

No, they actually work quite differently. 00:26:09

We've got quite a few examples of microphones today, and they were designed for different 00:26:11

reasons. 00:26:14

In fact, the first item we see here is an ancient telephone from the 50s. 00:26:15

I love it. 00:26:18

And you can see here a typical microphone from a CB radio or intercom type system. 00:26:19

Sure. 00:26:25

In fact, this is a microphone like you might see on your home computer, and we have a cell 00:26:26

phone here that even has a very tiny microphone that senses the sound of your voice. 00:26:30

And they all sense the same kind of phenomenon, but each one is designed specifically for 00:26:34

a particular purpose. 00:26:38

They're all configured quite differently. 00:26:40

So a microphone is a sensor? 00:26:42

Yes. 00:26:44

Okay. 00:26:45

So how does a microphone sense sound? 00:26:46

Well, we have a laboratory-grade microphone here connected to an oscilloscope, which is 00:26:47

a device that shows the electrical signal produced by the microphone. 00:26:51

And you can see when I whistle, it displays a sine wave. 00:26:56

A microphone is constructed with two plates, one thick and one thin, and the sound from 00:27:01

our voice, for example, strikes the thin plate, causing it to vibrate. 00:27:05

That vibration produces an electrical signal similar to what we saw in the oscilloscope. 00:27:10

Okay, so earlier I mentioned biological similarities between sensors and human senses. 00:27:13

Right. 00:27:19

Okay. 00:27:20

How is a microphone similar to the human ear? 00:27:21

That's pretty interesting, because sound travels through the ear until it strikes the eardrum, 00:27:22

causing it to vibrate, similar to the plates in the microphone we talked about earlier. 00:27:27

This vibration is transferred through tiny bones to the cochlea, which contains small 00:27:32

hair follicles that vibrate, producing an electrical impulse, similar to the microphone. 00:27:37

So the hair follicles are like sensors? 00:27:42

Yes. 00:27:44

Well, Gary, thanks for your time and for showing us how sensors work. 00:27:45

Sure. 00:27:47

Thanks for coming out to the National Atlantic Research Center. 00:27:48

No problem, man. 00:27:49

No problem. 00:27:50

I guess that's a wrap. 00:27:51

Hey, is this thing still on? 00:27:52

Sure. 00:27:53

Yeah. 00:27:54

Thanks for joining us on this edition of Destination Tomorrow. 00:27:55

I'm Steele McGonigal. 00:27:58

And I'm Kara O'Brien. 00:27:59

And for all of us here at NASA, we'll see you next time. 00:28:00

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618

Fecha:

28 de mayo de 2007 - 17:04

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Enlace Relacionado:

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Duración:

28′ 32″

Relación de aspecto:

4:3 Hasta 2009 fue el estándar utilizado en la televisión PAL; muchas pantallas de ordenador y televisores usan este estándar, erróneamente llamado cuadrado, cuando en la realidad es rectangular o wide.

Resolución: