Physical Science, Module 14, Waves and Sound

--Videos we watched for Module 14.
--Play  Quizlet.  Just scroll down and click on Physical, then scroll to find the Module you want.

Sound waves!  
Exp. 14.1, The Medium Through Which Sound Waves Travel

The kids learned about transverse waves and longitudinal waves.  See this video.
They also learned that sound waves need a medium through which to travel.  They need something which they cause to oscillate (move up and down).  That would be air.
They made a "drum" with the 2-liter bottle, saran wrap, and a rubber band.  They listened to the sound wave, felt the oscillating air on their cheek,  then used the sound waves' oscillation to blow out a candle.  Think of how your eardrum vibrates when it feels vibrations and your brain interprets it as sound.

They had a GREAT time banging on pots and pans.  You'd think they were still three years old, lol.  =D
We even had to trash a small frying pan.  It was cheap, and Cousin A was very enthusiastic!  (Well, I was the one who, when it wasn't very loud, told her she should hit it a little harder, lol.)

They put saran wrap on bowls, and banged on pans held near the bowls.  The sound waves hit the saran wrap and made it vibrate, and the rice bounce.  They discovered if they kept doing it louder and louder, the rice would vibrate right off the bowl.
We did need to sweep.

Exp. 14.2, The Speed of Sound - we were running short on time, and left this one until last.
We ended up not getting to do it.  =\
Sound does not travel as fast as light, so at a distance, one would be able to see two rocks being hit together just before being able to hear them.

Exp. 14.3, Wavelength and Sound

When the kids blew across the tops of the glass bottles, they moved air around inside the bottle.  If they blew at a constant rate, air began traveling up and down, forming a wave.  Different amounts of water allowed the sound waves to travel at shorter or longer distances.  If the wave was allowed to travel all the way to the bottom of the large jug, it made a much lower sound.  Long wavelengths produce a lower pitch.
So then, shorter wavelengths make a higher pitch.
This is the same as when someone plays a wind instrument.  When musicians cover various holes with their fingers, they are changing the wavelength of the sound waves produced.


Exp. 14.4, The Doppler Effect
We didn't have time for this one either, but they had watched a video.
Scroll down to #7, The Doppler Effect.

Exp. 14.5, The Amplitude of a Sound Wave
With the stringed instruments, they plucked a string, then plucked it harder.  The sound did not change pitch, but it did change volume.  This shows that the amplitude changed, not the wavelength.
In order to change pitch, they needed to turn the key thingy (no, I don't know what it's called).  This would lengthen or shorten the string, which would change the pitch.

Overview:


With every item of expensive jewelry, famous paintings, a cleverly-written book, a very expensive car, we usually want to know who is the designer?  The creator of something we really like or admire.
Suppose someone told you, oh, that just happened by chance; someone just found it, and it was already like that.  Or that we had a bunch of stuff in storage in a warehouse for years and years.  When we opened it one day, we discovered all these things were put together, and no one really knows how it happened.
We would not accept that answer.  Most will be determined to find out who did this great work!
I just can't imagine that anyone who has studied science would believe it all came about by chance.  Creation is so much more complex than jewelry, cars, or artists.
No, there is a designer, and He is God!
I think this with every chapter I read of science.  =)