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Quieting The Skies - Contenido educativo

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Subido el 28 de mayo de 2007 por EducaMadrid

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NASA Connect Video containing four segments as described below. NASA Connect segment exploring the research and study efforts applied towards acoustics and noise, especially that related to aircraft. The segment also explains the study of psychological effects of noise on people. NASA Connect segment featuring a panel of two experts from NASA that answer students' questions by phone and email. The questions pertain to aircraft and noise reduction. NASA Connect segment exploring all the basics of sound including how it works and how it travels. The video also explains how the ear works. NASA Connect segment involving students in an activity called the Speed of Sound. The students investigate how sound waves travel at different speeds under various conditions.

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TAP FOR SOUND 00:00:00
TAP FOR SOUND 00:00:30
TAP FOR SOUND 00:00:38
TAP FOR SOUND 00:00:40
What is that noise? 00:00:41
TAP FOR SOUND 00:00:42
Watch out! 00:00:49
TAP FOR SOUND 00:00:50
TAP FOR SOUND 00:00:54
TAP FOR SOUND 00:01:01
TAP FOR SOUND 00:01:03
TAP FOR SOUND 00:01:17
TAP FOR SOUND 00:01:21
TAP FOR SOUND 00:01:26
Hi, Van! Hey! 00:01:32
Hey! 00:01:34
Hey, hey, I gotta ask you a question. 00:01:35
What was all that about out there? 00:01:37
Well, Mr. Murphy seems to think that, uh, 00:01:39
practicing for the NASCONet cast party was disturbing his nap. 00:01:41
I don't even see how he could hear us from all those other noises outside. 00:01:45
Well, I know what you mean. I mean, he was talking to me. 00:01:48
I couldn't even hear him because of the plane that was passing by. 00:01:50
We can't hardly even hear ourselves because the plane's around here. 00:01:52
Let me introduce you to the band. 00:01:55
Oh, great. 00:01:56
We have Ben Googler on the bass guitar. 00:01:57
Nick Bartolotta on the drums. 00:02:03
And Tyler Cain on the keyboard. 00:02:07
So, you ready to hear our song? 00:02:11
Uh, no, I don't think so, guys. 00:02:12
You know, given your little visit you just had from Murphy, 00:02:14
don't you think you might need to think about reducing the noise level 00:02:17
instead of practicing right now? 00:02:21
Well, we could just close the garage door. 00:02:22
Well, yeah, Van, I'm sure that would help. 00:02:24
But you know, somehow I think if you had a little bit more knowledge 00:02:26
about the science behind sound and sound properties 00:02:29
that you and your band might be able to reduce your noise level 00:02:32
just a little bit further. 00:02:34
Matter of fact, I know. 00:02:36
I've got some friends at NASCON Langley who are studying noise abatement. 00:02:38
That is, how do you eliminate or reduce noise? 00:02:41
Maybe they could give us some insights as to how to stop disturbing poor Mr. Murphy. 00:02:44
Hey, guys, the Children's Museum of Virginia in Portsmouth 00:02:49
has some information about sound. 00:02:52
It's not too far from here. 00:02:54
Hey, that's a great idea. 00:02:56
You know, I think that would be a great place to start. 00:02:57
So, Van, why don't you and the band kind of pack up, 00:03:00
head on over to the museum and see what you can learn about sound. 00:03:02
Meanwhile, I'll head on over to NASA, 00:03:06
contact some acoustical researchers at NASA Langley in Hampton, Virginia, 00:03:08
and see what I can learn about noise control. 00:03:12
And, gang, you're invited along also. 00:03:15
You're part of the sound team. 00:03:17
So as we go along, we want you to take some sound notes 00:03:18
as we interview each of our program guests. 00:03:21
And as we go through the show, 00:03:23
you'll be challenged to analyze data from an experiment about sound 00:03:25
that students at Ruffner Middle School in Norfolk, Virginia, performed for NASA. 00:03:28
And with the help of our program partner, the FAA, 00:03:32
students from Lexington, Massachusetts, 00:03:35
will also join us with some tech talk about the Quiet in the Skies website. 00:03:37
And speaking of the website, when you see this sign, 00:03:42
that's your clue to check out the cool NASA Connect website 00:03:45
for further information and activities related to today's topic. 00:03:48
And as we go along in this program, 00:03:52
I'd like you to be thinking about some questions 00:03:54
that you can phone or e-mail into our researchers during today's program. 00:03:56
Now then, Nick, how about a little drum roll, please? 00:03:59
Ready, gang? Let's shake, rattle, and roll! 00:04:03
All right, I'm here at the Children's Museum of Virginia, 00:04:10
located in Portsmouth, Virginia. 00:04:13
And this is Leslie Bowie, the museum's curator. 00:04:15
Hi, Leslie. 00:04:17
Hi, Van. I understand you want to learn about sounds. 00:04:18
Yeah, I want to learn about how sound works and especially how sound travels. 00:04:21
Well, let's have a look at some of our exhibits 00:04:25
and get the answers to those questions. 00:04:28
Okay. 00:04:30
The Children's Museum of Virginia is a place 00:04:32
where kids can experience science firsthand. 00:04:34
Here they can feel it, touch it, explore it, learn it. 00:04:37
Let's first consider how sound is produced. 00:04:40
When sounds travel, we actually are hearing 00:04:43
how the vibrations affect the air molecules. 00:04:45
A way I can demonstrate this is with a slinky. 00:04:48
Van, hold the other end, please. 00:04:51
What we perceive as sound is due to the alternate squeezing 00:04:54
and stretching of molecules through the air. 00:05:00
This we refer to as sound waves. 00:05:02
Sound waves travel through the air at 344 meters per second. 00:05:05
They travel slower than light. 00:05:10
You can see this for yourself the next time you see a thunderstorm. 00:05:12
You can work out how far away the storm is from you 00:05:15
by timing the interval between the lightning and the clap of thunder. 00:05:18
A storm is about one mile away for every five seconds you count, 00:05:22
or one kilometer for every three seconds. 00:05:26
Now that you know what sound is and how fast it travels, 00:05:29
let's do some testing. 00:05:32
What do you notice? 00:05:36
The longer the tube, the lower the pitch. 00:05:37
Well, sure. 00:05:40
The air molecules in the long tube vibrate more slowly, 00:05:41
producing a lower sound. 00:05:44
Higher sounds vibrate more quickly. 00:05:46
The difference in the number of vibrations per second we refer to as pitch. 00:05:49
Want to try? 00:05:53
Okay. 00:05:54
Cool. 00:06:04
We can also use a recorder to demonstrate pitch. 00:06:05
You use your fingers to lengthen and shorten the tube 00:06:08
and create higher and lower notes. 00:06:11
♪ 00:06:14
Well, that's great, but how do you make it louder? 00:06:18
Well, with a recorder, just simply by blowing more air into the tube. 00:06:21
But there's another way to make sounds louder, 00:06:25
and that's to focus sound. 00:06:27
Let's come have a look. 00:06:29
Okay. 00:06:30
Here, the parabolic dish collects sound from a huge area 00:06:33
and funnels it right to this point. 00:06:37
If you're standing in just the right place, you can even hear a whisper. 00:06:39
So, Van, why was Mr. Murphy only bothered by your sound? 00:06:45
Wait. 00:06:49
Somebody just asked me about Mr. Murphy. 00:06:50
Who asked that question? 00:06:52
Well, Van, I'd like to introduce you to Dr. Lynette Roth. 00:06:54
Dr. Roth is an audiologist. 00:06:57
She specializes in hearing problems. 00:06:59
Oh, you mean like Mr. Murphy? 00:07:01
Well, the question I have is, how come he singled out my band 00:07:03
when there were so many other noises in the neighborhood? 00:07:07
It might be, Van. 00:07:09
Like many older people, you couldn't hear the higher frequency of noise 00:07:10
that came from the other sound sources. 00:07:13
The higher pitches? Why? 00:07:15
Let me explain how the ear works first. 00:07:17
Sound waves travel through the air and enter the ear canal, 00:07:20
causing the eardrum to vibrate. 00:07:24
The vibrations from the eardrum cause the three bones in the middle ear to move. 00:07:26
The last bone is called the stirrup. 00:07:30
The stirrup's attached to a thin membrane. 00:07:32
On the other side of this membrane is fluid 00:07:34
housed inside a curled snail-shaped tube called the cochlea. 00:07:36
The vibrations from the stirrup causes this membrane to flex, 00:07:40
which in turn sets the fluid into motion. 00:07:43
The moving fluid tickles thousands of delicate, 00:07:46
microscopic hair-like cells called cilia. 00:07:48
The cilia convert the vibrations into electric nerve impulses, 00:07:51
which the brain interprets as sound. 00:07:54
High frequencies are heard by the cilia at the beginning of the cochlea. 00:07:56
Lower frequencies are heard at the end. 00:07:59
If sound intensity is too great, 00:08:02
or if it happens for a prolonged period of time, 00:08:04
the cells will die at the beginning of the cochlea. 00:08:07
Sound energy, or intensity, is measured in decibels. 00:08:10
Generally speaking, the human ear can comfortably hear between 10 to 80 decibels. 00:08:13
A quiet library typically registers between 40 to 60 decibels, 00:08:18
while a loud rock concert registers above 110 decibels. 00:08:22
Van, it's likely Mr. Murphy has lost some of his ability to hear at high frequencies. 00:08:26
So this explains why Mr. Murphy singled out our band. 00:08:30
Yes, Van, but I'm more concerned about the ear safety of young people, 00:08:35
and in particular the noodles. 00:08:38
Be careful how loud you practice your music, 00:08:39
not for Mr. Murphy's comfort, but for your safety as well. 00:08:41
You bet. 00:08:44
Dr. Roth, Mrs. Bowie, 00:08:45
thanks for letting me come over to the Children's Museum of Virginia 00:08:47
to learn about sound and how the ear works. 00:08:50
Okay, I now have a better understanding of the science of sound and how people hear, 00:08:52
but how do I control the amount of sound coming from my garage? 00:08:58
Well, to find the answer to that, we're going to go back to Shelly at NASA Langley 00:09:01
to see what she's learning about noise abatement. 00:09:04
Perhaps she can pick up a tip or two I can use. 00:09:06
Meanwhile, I'll share this information with my band, and I'll catch you later. 00:09:08
Oh, great, you're just in time. 00:09:15
Everybody, let me introduce you to Brenda Sullivan and Rich Silcox. 00:09:17
We're here at NASA Langley in a building where they do acoustical research. 00:09:21
Let's go here first to Rich. 00:09:25
You are a senior research engineer, right? 00:09:27
Correct. 00:09:29
All right, and Brenda, I'm going to get this name wrong. 00:09:30
Brenda, you are a psychacoustician. 00:09:33
Now, can you correct my wording and then tell me a little bit about what that is? 00:09:35
Well, I'm a psychoacoustician. 00:09:40
Psychoacoustician is somebody who designs, conducts, and analyzes tests 00:09:42
to study the psychological effects of noise on people. 00:09:48
Oh, psychological effects, now that's kind of interesting. 00:09:51
And, Rich, how about you? 00:09:54
Can you describe for us just what exactly is a senior research engineer? 00:09:55
Well, Shelly, there's a lot of noise research that goes on here relating to aircraft noise, 00:09:59
and I work with researchers both here and at NASA Glenn in Ohio, 00:10:03
and NASA Ames in California to come up with ways to reduce the noise that aircraft make. 00:10:07
The word acoustics means the scientific study of sound 00:10:12
and how the qualities of space affect sound to transmit well or poorly. 00:10:15
Why don't we begin with the research that Brenda's doing? 00:10:20
Brenda, why don't you introduce Shelly to your fellow sound researcher? 00:10:23
Certainly. Shelly, meet Fred the Head. 00:10:27
This is Fred. 00:10:29
This is Fred. 00:10:30
Fred and his friend Norm here are essentially my research. 00:10:31
Testing for noise starts with deciding what aspect of noise to study. 00:10:35
For instance, the sound in a community near an airport or the noises inside an actual airplane. 00:10:39
See, that's where Norm comes in. 00:10:45
I take him up in the air inside the airplane so he can record the noises in there in flight. 00:10:47
See, he's got a microphone in each ear. 00:10:52
They're kind of hard to see on Norm. They're easier to see on Fred. 00:10:54
Let me show you. 00:10:57
Okay. 00:10:58
Ouch! 00:10:59
It's all right. He's used to that sort of treatment. 00:11:00
See, he's got a mic in there. It's hard to see. Let me take his skull off. 00:11:02
Oh, wow. 00:11:06
See, he has a microphone in each ear. 00:11:08
Anyway, these little microphones record the sound that's heard by each ear, 00:11:10
just as you would hear it yourself. 00:11:14
I take these binaural recordings I make with Norm and bring them back to the lab. 00:11:16
I can edit them on the computer and play them back to the people who come in to act as subjects in my tests. 00:11:20
For instance, I can take some of the tones made by the propellers of a plane and reduce them. 00:11:25
And people can tell me if they prefer the reduced versions and how much they prefer them, 00:11:30
so that we can predict their reactions to future noises. 00:11:35
Oh, how interesting. 00:11:37
Shelly, if you'd like, I can arrange to show you NASA's 757 research aircraft, 00:11:39
and I can show you the physics involved in producing the sound and how one goes about controlling the sound. 00:11:44
Oh, man, that would be so cool. 00:11:49
I know I'd be interested. 00:11:50
I'm sure the viewers would be interested in seeing a real live NASA Jumbo Jet research plane. 00:11:52
Music 00:11:56
Shelly, this is the NASA 757 in which we conduct various types of research. 00:12:04
NASA has a ten-year goal to reduce noise impact from aircraft 00:12:09
so that communities hear one-half the noise that they heard in 1997. 00:12:12
The amount of noise reduction is similar to the difference between heavy traffic noise and light traffic noise. 00:12:17
The noise impact reduction effort is led by NASA Langley Research Center 00:12:22
and is conducted in close partnership with NASA Glenn Research Center in Ohio 00:12:26
and NASA Ames Research Center in California, 00:12:31
along with help from academia, industry, and the FAA. 00:12:34
Wow, this aircraft is huge. 00:12:38
Where do you even begin to start to find the many sources of noise that must come from this aircraft? 00:12:40
In some modern aircraft like this 757, a lot of noise is generated from the air turbulence 00:12:45
created by the wing flaps, slats, and landing gear slicing through the air. 00:12:50
To control this type of noise, we use computers to create detailed models of the airflow over these surfaces 00:12:56
and look for ways to smooth out the flow and reduce the turbulence. 00:13:02
Shelly, of course, most of the noise is produced by the jet engine. 00:13:06
Modern jet engines have these large fans that move large volumes of air through the engines. 00:13:10
However, the fan itself produces what we call fan tones. 00:13:15
This type of noise is reduced by treating the inlet and exhaust duct with special acoustic liners, 00:13:18
sort of like towels for office ceilings. 00:13:23
And Shelly, the biggest noise problem we have is that of jet exhaust noise. 00:13:27
And working with us in jet exhaust noise is Martha Brown. 00:13:31
Hi, Martha. 00:13:33
Hi, Rich. 00:13:34
Hi, Martha. 00:13:35
Hi, Shelly. 00:13:36
Martha, Shelly has a particular problem in noise abatement. 00:13:37
I was wondering if you could explain to Martha what it is. 00:13:40
Yeah, thanks, Rich. 00:13:42
My problem is that I'm trying to get some pointers on how to reduce noise for my friend Van and his band, The Noodles. 00:13:43
They rehearse in a garage, and it seems that their rehearsals are disturbing the neighbor as he's trying to take a nap. 00:13:50
So we're trying to figure out how can we reduce the noise or the sound coming out of the garage. 00:13:56
Do you think you can help? 00:14:00
I'll be glad to help. 00:14:01
But first, let me tell you a little bit about myself and what I do at NASA Langley. 00:14:02
I work as an engineer in the Jet Noise Laboratory. 00:14:06
I study ways to change the air coming out of a jet with the hope of reducing noise created by this air. 00:14:09
High-speed air is needed to move an airplane forward. 00:14:15
I work with a team of engineers to invent ways to change the speed of the air exiting the jet by jet mixing. 00:14:19
So just how do you increase jet mixing? 00:14:26
Well, Shelly, we use non-round shapes like this rectangle nozzle, this elliptical nozzle, and also this corrugated nozzle. 00:14:29
Oh, now, this reminds me of a flower with petals. 00:14:40
I see what you mean. 00:14:43
But in fact, they're called lobes. 00:14:45
Lobes. 00:14:47
Yes. 00:14:48
And also we may change the round nozzle and how it looks by adding tabs at the ends that you see here. 00:14:49
Oh, now, these tabs look like shark teeth. 00:14:55
What other ways do you have to reduce noise? 00:14:58
Well, Shelly, we use materials to line the inside of the nozzle. 00:15:00
You see, this is called a liner, and what it's used to do is to absorb the sound before it exits the nozzle. 00:15:07
Hmm, like a muffler. 00:15:14
Yes. 00:15:15
Okay, let's go back to Van now. 00:15:16
What one point might you make back to Van that could help him with his problem? 00:15:17
Hmm, I recommend that he buy ceiling tiles to line the ceiling of his garage. 00:15:23
Oh, okay. 00:15:28
And, Shelly, he can install carpet on the floor and draperies on the windows to help reduce the sound. 00:15:29
Oh, Rich and Martha, that's great sound advice, and I will share that back with Van. 00:15:34
Thank you so much. 00:15:39
You're very welcome. 00:15:40
All right, and to the rest of you, gang, I'm going to send you to find Van and see what he's up to. 00:15:41
Meanwhile, I'm going to head back to the NASA Connect studio and get ready for our special guest. 00:15:46
And if you haven't thought of some questions, think about some, because in a moment, you'll be able to call in with your questions. 00:15:50
I'll see you back at the studio. 00:15:55
Well, while I get things arranged with my band, the Noodles, I'm going to send you to Ruffner Middle School in Norfolk, Virginia, 00:15:59
where you'll see students from the classroom of science teacher Ms. Susan Begay and math teacher Mr. Stephen Davis. 00:16:05
They're conducting an experiment examining the speed of sound. 00:16:11
Follow along, and after that, you can make your own analysis and predictions based upon their results. 00:16:15
So I'll catch you all later. 00:16:20
Hi, we're students from Ruffner Middle School in Norfolk, Virginia. 00:16:24
NASA Connect asked us to investigate how sound waves travel at different speeds under various conditions. 00:16:30
In this project, we'll be measuring the speed of sound and calculating the percentage of error with our science teacher Ms. Begay and our math and science teacher Mr. Davis. 00:16:38
To prepare the experiment, pour one or two tablespoons of powdered sugar onto the middle of four sheets of tissue paper. 00:16:49
Pull up the corners and tie it with string. 00:16:56
Make four bags for the experiment and two additional bags in case of accidental breakage. 00:16:59
Now we're ready to go. 00:17:05
First, we record the wind direction, weather conditions, and outdoor temperature in Celsius. 00:17:07
Next, we mark the spot where the sound engineer will hit the pots. 00:17:13
From this point, we measure our 50-meter intervals. 00:17:17
The linear speed engineer teams are located at each of these intervals. 00:17:21
The sound assistants hold up the bulletin board paper to create a dark background behind the sound engineer, 00:17:26
to see the puff of smoke. 00:17:34
The sound engineer tapes one of the bags of powder to the middle bottom of the pan. 00:17:36
When the sound person hits the two pans together, bursting the bag of powder, 00:17:41
the linear speed engineers start their stopwatches at the first sign of smoke and to stop them as soon as they hear a sound. 00:17:46
Warning, be ready to use a quick reaction time. 00:17:54
Ready, set, go. 00:17:58
The experiment is performed at least three times to get a range of data. 00:18:02
Now we return to the classroom to analyze data. 00:18:07
Mr. Davis gives us the formula for determining the speed of sound. 00:18:11
Speed equals distance divided by time. 00:18:15
Using the data collected, we calculate the speed of the sound at each location. 00:18:18
We compare results between the locations. 00:18:23
Mr. Davis asks, what do these numbers represent? 00:18:26
Next, each group calculates the accepted value for the speed of sound at the recorded outside temperature. 00:18:30
After we've posted our results, Mr. Davis asks us to calculate the percentage of error in the experiment 00:18:37
using the following formula of amount of error divided by the accepted value times 100. 00:18:43
We had a good time applying math to solve a problem. 00:18:50
All right, welcome to the NASA Connect studio. 00:18:55
Now joining me in the studio are Rich Silcox, a senior research scientist, 00:18:58
and we're also now joined by Dennis Huff from NASA Glenn Research Center in Cleveland, Ohio. 00:19:02
But before we talk to our researchers, let's give you a chance to do some analyzing 00:19:07
using the data from the experiment you just saw. 00:19:11
After this segment, our two researchers will be answering your e-mail questions 00:19:14
and taking questions from the viewing audience. 00:19:18
Okay now, look carefully at the data and using the information in the following diagram, 00:19:21
work with your fellow students to answer the questions as read aloud by Rich Silcox. 00:19:25
As the distance increased from 50 meters, what happened to the mean time? 00:19:32
Music 00:19:55
Use the formula percent of experimental error equals calculated value minus accepted value 00:20:14
divided by the accepted value times 100 to calculate the percentage of error at 50 meters and 300 meters. 00:20:22
Why do you think they are different? 00:20:31
Music 00:20:33
The speed of sound is directly proportional to air temperature. 00:20:54
Is the speed of sound faster in the summer or winter? Why? 00:20:57
Music 00:21:02
All right, we're back. 00:21:32
And with me are Rich Silcox and Dennis Huff to answer your questions. 00:21:34
But let's start things off by asking Dennis, what is it, Dennis, that you actually do there at NASA Glenn? 00:21:37
I'd be glad to answer that. 00:21:42
Hello, my name is Dennis Huff. 00:21:43
I'm the Chief of the Acoustics Branch at NASA's Glenn Research Center. 00:21:45
It's located in Cleveland, Ohio. 00:21:48
Our contribution to quieting the skies looks at ways to making the engines quieter. 00:21:50
Our goal is to develop engine noise reduction technology 00:21:54
without compromising the engine performance or the aircraft's safety. 00:21:57
Some members of our team develop mathematical models to be able to predict the sound from the engine, 00:22:01
while others test different parts of the engine inside wind tunnels and anechoic chambers. 00:22:06
Our best noise reduction concepts will eventually be tested on engines 00:22:11
to make sure that we can really make the airplanes quieter. 00:22:14
You've got a lot of good stuff going there that I could ask a lot of questions about. 00:22:17
And I just might do that, Dennis. 00:22:21
But I've got some e-mail questions that have come in for both you guys. 00:22:23
So let me start with an e-mail question. 00:22:26
The first question is, does the shape of a plane affect the sound? 00:22:28
And this is from Jonathan in Virginia Beach. 00:22:33
Yeah, Shelley, the shape of the airplane does change the sound dramatically. 00:22:36
For instance, when the airplane is coming in for a landing or taking off, 00:22:41
the flaps in the landing gear are deployed. 00:22:44
In that case, the flow is very dirty and it makes a lot more noise 00:22:48
than when those components are stowed away. 00:22:51
Yes, and in fact, it's interesting on the engine itself. 00:22:55
You'll notice that some of the older aircraft have smaller diameter engines. 00:22:58
And the smaller diameter actually passes a lot more flow at a higher velocity, 00:23:02
and this causes the jet noise to be very loud. 00:23:06
We have a general rule of thumb that we say that the exit of the velocity 00:23:09
raised to the eighth power is proportional to the jet noise. 00:23:13
So the newer aircraft that have larger diameter engines actually end up being quieter. 00:23:16
All right, and let's go back to this. 00:23:21
I kind of answered this already, but I'm thinking about me who flies an awful lot 00:23:23
on these small little, they call them puddle jumpers or commuter planes 00:23:26
compared to your bigger 757s. 00:23:30
How is there a difference on those size of engines 00:23:34
and the noise that they are generating? 00:23:38
Sure, those engines are some of the newer engines. 00:23:41
We call those higher bypass ratio engines. 00:23:43
And so you've got a lot of flow going through that. 00:23:45
It's a lot of thrust in that engine, but it's going at a lower velocity, 00:23:47
so it's a much quieter engine than the older ones. 00:23:50
Oh, okay. 00:23:52
In a lot of cases, the propeller airplanes are quieter too. 00:23:54
They're quieter than the large jets are. 00:23:57
All right, I've got a question. 00:23:59
You keep talking about research to reduce noise around communities. 00:24:01
What is the community that you all are referring to here? 00:24:05
Well, generally we're talking about that area around the airport 00:24:09
that's affected by the operations of the airplanes taking off and landing. 00:24:12
Once the airplane climbs to altitude, 00:24:16
is it cruise altitude maybe at 35,000 feet? 00:24:18
You don't really hear it much anymore. 00:24:22
Okay, all right, good. 00:24:24
Well, I've got someone telling me we've got a caller out there, 00:24:26
so let's go ahead and take that caller. 00:24:28
Caller, could I have your first name, please, and your question? 00:24:30
My name is Timothy, and my question is 00:24:34
how fast is the sound travels through water? 00:24:40
Oh, okay, the sound traveling through water. 00:24:49
And is there a difference between the speed that sound travels in air and water? 00:24:53
Yes, the speed travels through water much more quickly than it does in air. 00:24:57
I can't recall the exact number. 00:25:02
I think it's three or four times faster in water than it is in air. 00:25:04
Okay, all right, so we know that it is going to travel faster through water than in air. 00:25:08
Good question there, Timothy. 00:25:13
I'm going to take a final question I have here by e-mail. 00:25:15
Very quickly, well, no, final advice. 00:25:18
What advice would you, Dennis, give to viewers about thinking about careers? 00:25:21
I'd be glad to answer that. 00:25:25
My father gave me the advice to keep your options open. 00:25:26
You can get into a lot of different activities 00:25:28
and make sure you involve yourself in extracurricular activities 00:25:30
but also stay with your math and science and your English. 00:25:33
Different courses are very important. 00:25:36
All right, there you've heard it from us. 00:25:38
And I see we're quickly running out of time. 00:25:40
Thank you, Dennis and Rich. 00:25:42
And now students from Jonas Clark Middle School in Lexington, Massachusetts, 00:25:44
share some technology notes that are sure to sharpen your investigation on sound 00:25:48
following this program. 00:25:52
One part of the website is called the NASA Sound Machine. 00:25:57
With it, you'll learn about the shapes and characteristics of sound waves, 00:26:01
how an airplane produces different kinds of noise, 00:26:05
and what some words would sound like if you had severe or partial hearing loss. 00:26:07
Another part of the NASA Connect website features NASA researchers 00:26:11
talking about their jobs. 00:26:15
It's called Career Corner. 00:26:17
There's also a fun quiz that will test your knowledge of sound and hearing. 00:26:19
Hey, a big thanks now to our Jonas Clark Middle School for that technology tease. 00:26:23
And thank you to all our program guests and partners. 00:26:28
If you wish a videotaped copy of this NASA Connect show and lesson plans, 00:26:32
then contact CORE, the NASA Central Operation of Resources for Educators. 00:26:36
Well, gang, that's it for this season of NASA Connect. 00:26:41
But join us again next season for more NASA Connect programs, 00:26:45
math, science, and researchers. 00:26:48
And, of course, for more of Van and me, 00:26:50
I'll be joining you from our nation's capital, Washington, D.C., 00:26:53
as a special correspondent to NASA Connect. 00:26:56
Let's do a final sound check on Van as he professionally records his song. 00:26:59
Okay. I think we have something pretty good for you, Shelley. 00:27:04
Ready, guys? Hit it. 00:27:07
♪♪♪ 00:27:10
♪♪ Follow your heart, pursue your dream. 00:27:16
But when you set out on some new scheme, 00:27:24
look all around, know what's out there. 00:27:32
Connect your feelings and goals with care to reach your star. 00:27:36
Connect with who you are. 00:27:42
♪♪♪ 00:27:46
♪ Know where you're going, know where you've been. 00:27:52
Look to the future to help you win. 00:28:00
Know what's inside, know what's out there. 00:28:08
Connect your feelings and goals with care to reach your star. 00:28:12
Connect with who you are. 00:28:18
♪♪♪ 00:28:22
Connect with who you are. 00:28:26
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Idioma/s:
en
Materias:
Matemáticas
Niveles educativos:
▼ Mostrar / ocultar niveles
      • Nivel Intermedio
Autor/es:
NASA LaRC Office of Education
Subido por:
EducaMadrid
Licencia:
Reconocimiento - No comercial - Sin obra derivada
Visualizaciones:
459
Fecha:
28 de mayo de 2007 - 16:53
Visibilidad:
Público
Enlace Relacionado:
NASAs center for distance learning
Duración:
28′ 31″
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:
480x360 píxeles
Tamaño:
170.79 MBytes

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