[ music ]
Would you believe it if I told you that sound waves move through the air like
ripples do in water? Well it's true!
Sound waves are actually vibrations of air molecules,
the more vibration the bigger the sound.
We know that because
scientists have developed ways to see sound.
At NASA being able to see sound
helps us to understand how sound works.
Have you ever heard a really loud airplane fly overhead?
Airplane noise can be really annoying
making airplanes quieter is one of NASA's biggest challenges.
Meet the X-59 NASA's newest X-plane.
The X-59 will break the sound barrier without
creating a loud sonic boom.
Now it's your turn! Let's create a way for you to see sound!
But before we go I just wanted to give a special shout out to all the
students in Galveston Texas! NASA really wants to thank your community for
helping us with our latest test. With your help we're one step closer to a
future of supersonic flight for everyone. And now on to the demo.
To start take a large balloon and cut off its neck
This is to make the opening larger and allow the balloon to be stretched more
easily over the PVC pipe.
Now stretch the balloon over one end of the pipe making
something that looks like a drum, and use duct tape to secure it.
Make sure the balloon is stretched as tight as possible.
If you tap the surface it should vibrate.
Next, glue a small square mirror to the center of the balloon.
Hold it firmly for a few seconds to allow the glue to dry before letting it go.
Once the glue has dried turn the drum on its side with the balloon end facing a wall.
Using duct tape, firmly secure the device to the table so it can't move.
In order for the laser to stand out the wall should be light colored,
if it isn't, tape a sheet of white paper on the wall.
Remove the laser pointer from its case and
if necessary install the batteries.
Safety note: be sure to avoid shining the laser place the tripod on
directly into anyone's eyes.
Place the tripod the table to one side of the drum.
Insert the laser pointer into the cradle on the top
making sure that the cradle is keeping the laser pointer's button firmly
in the on position.
Lastly, align the laser dot so that the
beam of light is aimed at the mirror on the balloon and reflected onto the wall.
At this point the reflection on the wall should resemble a dot with very little movement.
Now, speak into the open end of the pipe and watch the effect it has on the dot.
Change the volume of your voice and see how that affects the dot.
Try a big laugh, a whisper or whistle.
Snap your fingers, clap your hands...
Make as many different sounds as you can.
Try other audio sources like a speaker
or even a musical instrument.
Lastly see what happens when you use a tuning fork to create a sound.
To do this strike the fork firmly on the activator
to start it vibrating,
then place it gently against the skin of the balloon.
Notice the shape this sound makes compared to the other examples.
Now that you've tested some basic sounds,
it's time for some fun!
Try different kinds of music playing on the speaker.
Can you predict what a particular song may look like?
You've now made sound energy visible. Great work!
you
For more infomation >> LSE Student Video Diary: Magdalena's reading week - Duration: 1:31. 
Không có nhận xét nào:
Đăng nhận xét