Transcript for NASA Connect - Quieting The Skies

[RJ:] What is that that noise?

[RJ:] Watch out.

[RJ:] Hi Van hey, hey.

Hey I got to ask you question.

What was all that about out there?

[Van Hughes:] Well, Mr. Murphy
seems to think there are

[inaudible] for the NASA Connect
class party was disturbing his nap

[ Laughter ]

I don't even see how
he could hear as much

as there are noises outside.

[RJ:] I know it's nearly when he
was talking to me I couldn't hear

because of the plane
that was passing by.

[Van Hughes:] We can
hardly even hear ourselves

because of the planes around here.

Let me introduce you the band.

[RJ:] Oh great.

[Van Hughes:] We have our
Van Huber on the bass guitar,

Nick Brian Lara on the drums and

[inaudible] on the keyboard, so
you are ready to hear us all.

[RJ:] No, I don't think so guys.

You are giving a little
visit you just have

from Murphy don't you think
you might need to think

about reducing the noise level
instead of practicing right now.

[Van Hughes:] No we can
just close the garage door.

[RJ:] Oh yeah Van I am
sure that would help,

but you know somehow I think if
you have little more knowledge

about the science, behind sound
and some properties, that you

and your band might be all reduce
your noise level just a little

bit further.

As a fact, I know.

I have got some friends
at NASA Langley

who are studying noise abatement
that is how do you eliminate

or reduce noise maybe they could
give us some insights as to how

to stop disturbing poor Mr. Murphy.

[Van Hughes:] Hey guys, the
children's museum of Virginia

and Portsmouth have
some information

about sounds it's not
too far from here.

[RJ:] Hey, that's great idea.

You know I think that be
a great place to start.

So Van, why don't you and
the band kind of pack up,

head on over to the museum, and
see what you can learn about sound.

Meanwhile I will head on over

to NASA contact some
acoustical researchers

at NASA Langley in
Hampton Virginia.

And see what I can learn
about noise control.

And gang, you are invited
to Lang NASA you are part

of the sound team.

So as we do along we want
you to take some sound notes

as we interview each
of our program guests.

[RJ:] And as we go through the
show, you will be challenged

to analyze data from an experiment
about sound that students at

[inaudible] Middle School

in Norfolk Virginia
performed for NASA.

[RJ:] And with the help of
our Program Partner the FAA,

students from Lexington
Massachusetts will also join us

with some of the tech talk about
the fly in the skies website.

[RJ:] And speaking of the website,

when you see this sign
that's include to check

out the cool NASA Connect
website for further information

and activities related
to today's topic.

[RJ:] And as we go along in
this program I like you to be,

think about some questions
that you can phone or email

into our researches
during today's program.

Now then Nick, how about a
little drums more please.

Ready gang, let's
shake revel and roll.

[Van Hughes:] All right, I am
here at the Children's Museum

of Virginia located in
Portsmouth Virginia.

And this is Leslie

[inaudible], the Museum's Curator.

Hi Leslie!

[Leslie:] Hi Van.

I understand you want
to learn about sounds.

[Van Hughes:] Yeah, I want to
learn about how sound works

and especially how sound travels.

[Leslie]: Well, let's have a
look at some of our exhibits

and get the answers
to those questions.

[Van Hughes:] Okay.

[Leslie:] The Children's
Museum of Virginia is a place

where kids can experience science
first hand here they can feel it,

touch it, explore it, learn it.

Let's first consider
how sound is produced.

When sounds travel we actually are
hearing how the vibrations affect

the air molecules.

A way I can demonstrate,
this is with the slinky,

Van hold the other end please.

What we perceive as sound is
due to the alternate squeezing

and stretching of
molecules through the air.

This we refer to as sound waves.

Sound waves travel through
the air at three hundred

and forty-four meters per second.

They travel slower than light.

You can see this for yourself the
next time you see a thunder storm.

You can work out how far
away the storm is from you

by timing the interval between the
lightning and the clap of thunder.

A storm is about one mile away
for every five seconds you count,

or one kilometer for
every three seconds.

Now that you know what sound
is and how fast it travels,

let's do some testing.

What do you notice?

[Van Hughes:] The longer
the tube, lower the pitch.

[Leslie:] Oh, sure!

The air molecules in a long tube
vibrate more slowly producing

a lower sound.

Higher sounds vibrate more quickly.

The difference in the number

of vibrations per second,
we refer to is pitch.

Want to try?


[Van Hughes:] Cool.

[Leslie:] We can also
use a recorder

to demonstrate pitch you
use your fingers to lengthen

and shorten the tube and
create higher and lower notes.

[Van Hughes:] Well, that's great.

But how do you make it louder.

[Leslie:] Well, with
the recorder just simply

by blowing more air into the tube.

But there is another way
to make sounds louder

and that's to focus sound.

Let's go have a look.

[Van Hughes:] Okay.

[Leslie:] Here the parabolic dish
collects sound from a huge area

and funnels it right to this point.

If you are standing in just the
right place you can even hear

a whisper.

So, Van our Mr. Murphy is
only bothered by your sound.

[Van Hughes:] Great, somebody
just asked me about Mr. Murphy,

who asked that question.

[Leslie:] Oh Van I would like to
introduce you to Dr. Linnet Roth,

Doctor Roth is an Audiologist, she
specializes in hearing problems.

[Van Hughes:] Oh!

You mean like Mr. Murphy.

Well, the question I have is
how come he singled out my band

when there are so many other
noises in the neighborhood.

[Leslie:] And might he Van like
many older people couldn't hear the

higher frequency of noise that
came from other sound sources?

[Van Hughes:] The
higher pitches, why?

[Leslie:] Let me explain
how the ear works first.

Sounds waves travel through the air

and enter the ear canal
causing the ear drum to vibrate.

The vibrations from the ear
drum cause with three bones

in the middle ear to move.

The last bone is called
the stirrup.

The stirrup is attached
to a thin membrane.

On the other side of this membrane
is fluid housed inside a curled

snail shaped tool
called the cochlea?

The vibrations from the stirrup
causes this membrane to flex

which in turn sets
the fluid into motion.

The moving fluid stipples thousands

of delicate microscopic
hair-like cells called cilia.

The cilia convert the vibration
in collective nerve impulses

which the brain interprets
as sound.

Higher frequencies
are heard by the cilia

at the beginning of the cochlea.

Lower frequencies
are heard at the end.

The sound intensities degrade or if
it happens for up to a long period

of time the cells will bay at
the beginning of the cochlea.

Sound energy or intensity
is measured in decibels.

Generally speaking the human
ear can comfortably hear

between ten to eighty decibels.

A quiet library typically
registered between forty

to sixty decibels, while a
lot of rock concert registered

above a hundred and ten decibels.

[RJ:] Van its likely Mr. Murphy
has lost some of his ability

to hear high frequencies.

[Van Hughes:] So this explains why
Mr. Murphy singled out our band.

[RJ:] Yes, Van but I am more
concerned about the ear safety

of young people and in
particular The Noodles.

Be careful for how loud
you practice your music,

not for Mr. Murphy's comfort
but for your safety as well.

[Van Hughes:] You bet.

Dr. Roth, Mrs.

[inaudible] things will let me
come over to the children's Museum

of Virginia to learn about
sound and how the ear works.

Okay. I now have a better
understanding of the science

of sound and how people hear but
how do I will control the amount

of sound coming from my
garage or to find the answer

to that we are going to go to
back Shirley at NASA Langley

to see what she is learning
about noise abatement.

Perhaps she can pick up
a tip or two I can use.

Meanwhile I will share this
information with my band

and I will catch you later.

[Shirley:] Oh!

Great, you are just in time.

Everybody let me introduce you
to Brenda Sullivan and Richard


We are here at NASA
Langley in a building

where they could do
acoustical research.

Let's go here first to Rich.

You are a Senior Research
Engineer, right?

[Richard:] Correct.

[Shirley:] Hi, and Brenda get
this name wrong Brenda you are a

Psycho Acoustician.

Now can you correct my wording

and then tell me little
bit about what that is?

[Brenda:] I'm the
Psycho Acoustician.

Psycho acoustician is
somebody who designs, conducts

and analyzes tests to study
the psychological affects

of noise on people.

[Shirley:] Oh!

Psychological affects so
that's kind of interesting.

And Rich how about
you, can you describe

for us just what exactly is
a Senior Research Engineer?

[Richard:] Well Shirley, there is
lot of noise research that goes

on here relating to
Air Craft noise.

And I work with researches both
here and at NASA Glen in Ohio

and NASA Engine California
to come up with ways

to reduce the noise
that Air Craft make.

The word acoustics means the
scientific study of sound

and how the qualities
of space affect sound

to transmit were recorded.

Why don't we begin with the
research that Brenda's told?

Brenda why don't you
introduce Shirley

to your fellow sound researchers?

[Brenda:] Certainly
Shirley, meet Fred the Head.

[Shirley:] This is Fred.

[Brenda:] This is Fred, Fred
and his friend Norm here,

are essentially my research.

[RJ:] Testing the noise start

with deciding what
aspect of noise to study.

For instance, the sound in
a community near an Airport

or the noise is inside
an actual airplane.

So that's where Norm comes in.

I take him up in the air
and inside the airplane

so he can record the noises
as in there in flight.

See he has got a microphone in
each ear that I try hard to see

on Norm they are easier to
see on Fred let me show you.

Yeah! He is alright.

He is used to that
sort of treatment.

See he has a mike in there its hard
to see, let me take his skull off.

[Shirley:] Wow!

[Brenda:] See he has a microphone

in each ear anyway this little
microphones record the sound that's

heard by each ear just as
you would hear yourself,

I think this binaural recordings I
make with Norm and bring them back

to the lab I can edit them on
the computer and play them back

to the people who come in
direct to subject in my test.

For instance, I can take some of
the turnings made by the propels

of the plane and reduce them.

And people can tell me if they
prefer to reduce directions

and how much they prefer them.

So we can predict their
reactions to future noises.

[Shirley:] Oh!

How interesting!

[RJ:] Shirley if you
would like I can raise

to show you NASA's
757 Research Air Craft

and I can show you the physics
involved in producing the sound

and how one goes about
controlling the sound.

[Shirley:] Oh!

Man there would be so cool.

I know I am a viewer, I am sure
the viewers would be interested

in seeing a real life NASA
Jumbo Jet Research Plane.

[RJ:] So this is the NASA 757,

in which we conduct
various types of research.

NASA has a ten year goal to
reduce noise impact from aircrafts

so the communities see
a one half of the noise

that they heard in 1997.

The amount of noise reduction
is similar to the difference

between heavy traffic noise
and light traffic noise.

The noise impact reduction
after it's led

by NASA Langley Research
Center and is conducted

in close partnership with NASA
Glen Research Center in Ohio

and NASA Engine Research Center
in California along with help

from Academia industry and the FAA.

[RJ:] Wow, this aircraft is
huge, where do you begin to start

to find the main resources of
noise that come from the aircraft.

[RJ:] In some modern aircraft like
the 757 a lot of noise is generated

from the air turbulence
created by the wind flaps,

slaps and landing gear
slicing through the air.

To control this type of
noise we use computers

to create detailed models of the
air flow over these surfaces.

Look for ways to smooth out the
flow and reduce the turbulence.

Shirley, of course most

of the noise is produced
by the jet engine.

Modern jet engines have these
large fans that move large volumes

of air through the engines.

However the fan itself produces
what we will call fan terms.

[RJ:] This type of noise is
reduced by creating the inlet

and exhaust duct, with
special acoustic liners sort

of like towels for office ceilings.

[Richard:] And Shirley the
biggest noise problem we have is

that of jet exhaust
noise and working with us

in jet exhaust noise
is Martha Browne.

Hi! Martha.

[Martha:] Hi!


[Shirley:] Hi!


[Martha:] Hi!


[Richard:] Martha, Shirley
has a particular problem

in noise abatement.

Wonder if you could explain
to Martha, what it is?

[Shirley:] Yeah!

Thanks Rich.

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.

They were rehearsing in the garage.

It seems that their rehearsals
are disturbing the neighbor

as he's trying to take a nap.

So we are trying to figure
out how to reduce the noise

or the sound coming out of garage.

Do you think you can help?

[Martha:] I will be glad to help,
but first let me tell a little

about myself and what I do at
NASA Langley I work as an engineer

in the Jet Nose Laboratory.

I study ways to change the air
coming out of the jet with the hope

of reducing noise
created by this air.

High speed air is needed to
move an airplane forward.

I work with the team of engineers
to invent ways to change the speed

of the air exceeding
the jet by jet mixing.

[Shirley:] So just how do
you increase Jet mixing?

[Martha:] Watch Shirley?

We use non round shapes
like this rectangle nozzle,

this elliptical nozzle and
also this quadric nozzle.

[Shirley:] Oh, now this reminds
me of a flower with petals.

[Martha:] I see what you mean
but in fact if they call lobes

and also we may change the
round nozzle and how it looks

by adding tabs at the
ends that you see here.

[Shirley:] Oh no, these
tabs looks like short teeth,

so what other ways do
you have to reduce noise.

[Martha:] Well Shirley,
we use materials

to line the inside of the nozzle.

You see this is called a liner
and what it is used to do is

to absorb the sound
before it exits nozzle.

[Shirley:] Like a mop.

[Martha:] Yes!

[Shirley:] Okay, let's
go back to the end now.

What one point, might you make
Dr. Van help him with his problem?

[Martha:] I recommend
that he buys ceiling tiles

to line the ceiling of his garage.

[Shirley:] Okay.

[Richard:] And Shirley, he can
install carpet on the floor

and draperies on the windows
to help reduce the sound.

[Shirley:] Oh!

Rich and Martha that's
great sound advice

and I will share that
back with Van.

Thank you, so much.

[Richard:] You are very welcome.

[Shirley:] I and to the rest of
you gang I'm going to send you

to find Van and see what he
is up to meanwhile I am going

to head back to the NASA
Connect studio and get ready

for our special guest.

And if you haven't thought some
questions, think about some

because in a moment you will be
calling in with your questions.

I will see you back at the studio.

[Van Hughes:] Well while
I get things arranged

with my band The Noodles.

I am going to send you to

[inaudible] Middle School
in the Norfolk Virginia.

We will see students
from the classroom

of the science teacher, Miss Suzan

[inaudible] and Math
teacher Mr. Steven Davis.

They are conducting an experiment
examining the speed of sound,

follow a long and after that,
you can make your own analysis

and predictions based
upon their results.

So I will catch you all later.

[Students:] Hi, we
are students from

[inaudible] Middle School
in Norfolk Virginia.

NASA connect asked us to
investigate how sound waves travel

at different speeds
under various conditions.

In this project we will be
measuring the speed of sound

and calculating the percentage of
air with our science teacher Miss

[inaudible] and our Math and
Science Teacher Mr. David.

To prepare the experiment pour one
or two tablespoon of powdered sugar

onto the middle of four
sheets of tissue paper.

Pull up the corners
and tie it with string.

Make four bags for the experiment
and two additional bags in case

of accidental breakup.

Now we are ready to go.

First we record the wind
direction, weather conditions,

and outdoor temperature associates.

Next we mark the spot where the
sound engineer will hit the bags.

From this point we measure
out fifty meter intervals.

The linear speed engineer teams are
located at each of these intervals.

The sound assistants hold up
the bullets and board paper

to create a dark background
behind the sound engineer

which will help the speed
engineers to see the puff of smoke.

The sound engineer takes
one of the bags of powder

to the middle bottom of the pan.

When the sound person hits the two
pans together, bursting the bag

of powder the linear speed
engineers start their stop watches

at the first sign of smoke
and to stop them as soon

as they hear the sound.

Warning, be ready to use
a quick reaction time.

Ready, set go.

The experiment is performed
at least three times

to get a range of data.

Now we return to the
classroom to analyze data.

[RJ:] Mr. David, gives
us the formula

for determining the speed of sound?

Speed equals to distance
divided by time.

Using the data collected,
we calculate the speed

of the sound at each location.

We compare results
between the locations.

Mr. David asks what do
these numbers represent?

Next, each will calculate the
accepted value for the speed

of sound at the recorded
outside temperature.

After we have posted our
results, Mr. David asks us

to calculate the percentage
of error

in the experiment using the
following formula of amount

of air divided by the accepted
value times one hundred.

We have a good time applying
Math to solve the problem.

[Shirley:] Alright, welcome
to the NASA Connect studio,

now joining in the studio Richard

[inaudible] a Senior
Research Scientist

and we are also now joined by Denis

[inaudible] from NASA Glen
Research Center in Cleveland Ohio,

but before we talk
to our researchers,

let's give you a chance to do
some analyzing using the data

from your experiment you just saw.

After this segment, our two
researchers will be answering your

e-mail questions and
taking questions

from the viewing audience.

Okay, now look carefully at the
data and use the information

in the following diagram.

Work with your fellow students
to answer the questions

as well allowed by Richard


[Richard:] As the distance
increase from fifty meters,

what happened in the meantime?

Use the formula, percent

of experimental error equals
calculated value minus accepted

value divided by the accepted
value times one hundred

to calculate the percentage
of air at fifty meters

and three hundred meters.

Why do you think they
are different?

The speed of sound is directly
proportional to air temperature.

Is the speed of sound
faster in summer or winter?


[Shirley:] Alright, we are
back and with me are Rich

[inaudible] and Denis

[inaudible] to answer your
questions but lets start things off

by asking Denis what is it Denis

that you actually do
there at NASA Glen?

[Denis:] I'll like to answer
that; however my name Denis

[inaudible] I'm the Chief
of the acoustics branch

of NASA's Glen Research Center.

It's located in Cleveland, Ohio.

Our contribution acquiring
the sky looks so waste

in making the engines quieter.

Our goal is to develop engine
noise reduction technology

without compromising
the engine performance

or the Air Craft safety.

Some members of our team
develop mathematical models deal

to predict the sound from the
engine while others test different

parts of the engine inside wind
tunnels and anti-clog chambers.

Our best noise reduction
concepts will eventually be tested

on engines to make sure we can
really make the Airplanes quieter.

[Shirley:] Yet a lot of good stuff

[inaudible] I could ask a lot of
questions about and I just might do

that Denis but I have
got some e-mail questions

that have come in
for both you guys.

So let me start with
an e-mail question.

The first question is, does the
shape of a plane affect the sound

and this is from Jonathan
in Virginia Beach.

[Richard:] Yeah, Shirley the shape

of the Airplane does change
the sound dramatically.

First as when Airplane coming in
for landing or taking-off the flaps

in the landing gear are deployed
in that case the flow is very dirty

and makes a lot more noise

than when those components
are stored away.

[Dennis:] Yes, and in
fact it's interesting

on the engine itself
you've noticed that some

of the older Aircraft have
smaller diameter engines

and the smaller diameter
actually passes a lot more flow

at a higher velocity and
this causes the jet noise

to be very loud.

We have a general rule formed
that we say that the velocity

of the exit of the velocity
raised is powered, is proportional

to the jet noise so
the newer Aircraft

that have larger diameter engines
actually end of being quiet.

[Shirley:] Alright
and let's go back to

[inaudible], how we answer this
alright but I am through about me

who flies not along these small
little of the compactor jumpers

or commuter planes compared
to your bigger 757's

and how's there a difference on
those size of engines and the noise

that they are generating?

[RJ:] Sure, those engines are some

of the newer engines we call
those higher by pass ratio engines

and so you got a lot of fog on
through that so lot of thrust

in that engine but it's
going at a lower velocity

so its a much quieter
engine than the older ones.

[Shirley:] Oh!


[RJ:] In a lot of cases propeller
Airplanes are quieter too they are

quieter than the large jets on.

[Shirley:] I got a question
you keep talking about research

to reduce noise around
communities, what is the community

that you all are referring to here.

[RJ:] Generally we are
talking about that area

around the airport that's
affected by the operations

of the Airplanes taking off

and landing once the Airplane
climbs how about to as a cruise

out about to may be at 35,000
feet you don't really hear much

any more.

[Shirley:] Okay, alright, good.

Well I have got someone tell me,
we have got a caller out there

so let's go and take that caller.

Caller can I have your first
name please and your question.

[Boy:] My name is Timothy

and my question is how fast
does sound travel through water?

[Shirley:] Oh, okay, the
sound traveling through water

and is there a difference
between the speed

that sound travels
in air and water?

[RJ:] Yes, the speed travels
through water much more quickly

than that does in the air.

I can't recall the exact
number I think it's three

or four times faster in
water than it is in air.

[Shirley:] Okay, alright so we know
that it is going to travel faster

through water than in air
good question there Timothy

and we will take a final question.

I have here by e-mail very quickly.

Well know final advice what advice
would you Dennis give to viewers

about thinking about careers.


[inaudible] answered that my
part of game in the advise

to keep your options open
you can get into a lot

of different activities and
make sure you involved there

so often extracurricular
activities but also stay

with your math and science

and your English all the different
courses are very important.

[Shirley:] Alright
there you got it from us

and I see we are quickly
running out of time.

Thank you Dennis and
Rich and now students

from Jonas Clarke Middle School

in Lexington Massachusetts share
some technology notes that are sure

to shop in your investigation
on sound following this program.

[RJ:] One part of the website is
called the NASA sound machine.

We think you all learned about
the shapes and characteristics

of sound waves, how an Airplane
produces different kinds of noise

and what certain words would
sound like if you had severe

or partial hearing loss.

Another part of the NASA Connect
website features NASA researches

talking about their jobs.

It's called Career Corner.

There is also a fun quiz
that will test your knowledge

of sound and hearing.

[Shirley:] Hey, a big thanks now
to our Jonas Clarke Middle School

for that technology
T's and thank you

to all our program
guests and partners.

If you wish a video tape copy
of this NASA Connect show

and lesson plans then contact
CORE the NASA Central Operation

of Resources for Educators.

Well, gang that's it for
this season of NASA Connect

but join us again next season from
more in NASA Connect programs math,

science and researchers and of
course for more event and me.

I will be joining you from our
nation's capital Washington D.C.

as a special correspondent
to NASA Connect.

Now let's do a final
sound check on Van

as he professionally
records his song.

[Van Hughes:] Okay I think
we have something pretty good

for you Shirley, ready guys.

Hit it.


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