Sound 'Speriments

Inspired by the fact that Abby is starting to talk up a storm, I decided to dedicate Friday morning to learning a little bit about sound, and more specifically, sound waves.

Towards the end of breakfast, while everyone’s sitting down, I ask my now three year old and my 1.5 year old what they think causes all of the sounds we hear.  I get lots of answers – “Abby screaming.” “When you bang on something.”  “The TV.” “Up abub da world so high.  Like a ningun in da sky” (Abby’s very into singing ‘twinkle twinkle’ right now). Then I explain what is really happening, in a toddler understandable way.  When anything makes a sound, it pushes the air in a wave, just like when you push the water to make waves in the bathtub.  (We love making “waves” in the bathtub.  And by “we”, I mean the kids.  For the record, the mommy does not like it when the waves crash over the side of the tub and create a mess to clean up.  Even when it happens to a fit of cute giggles.  But I digress.)  The sound waves go in our ears to our brains and our brains tell us what the sound was.

“Mommy, are we going to do ‘speriments today?” asks my very intuitive Briana.  She knows that when Mommy starts explaining something in detail, it probably means I’m going to show her how it works. “Of course we are.” I tell her as she screams "yeah", “All about sound and how we can push the air to make sound waves.  Now, what did Mommy say makes sound?” “When you push the air waves into your ear.” Pretty good start.  She’s listening.  On to the experiments… 

First let’s just use our voices.  Everybody blow the air around.  Poor Abby looks like she’s hyperventilating, but she’s happy to be joining.  Then I say, “Let’s blow the air softly and say aaahh.“ Everyone giggles and says aaah for a few seconds.  Then I say, “Let’s blow the air hard now and say aaah.  We made the sound wave bigger so our voices sounded louder.”  The kids get questioned to see if they get it, and they do, so we move on. 

I grab an empty paper towel roll and tell the kids to hold on.  I scream “Boogedy Boogedy Boo”.  Why do I scream that…just to make the kids laugh.  So when the silliness is over I try to refocus my crew from grabbing the roll and screaming “Boogedy Boogedy Boo”, or “Boozy Boo” as Abby manages.  Ok, give Mommy the roll again and everybody hold on.  This time I scream “aaaahhhhh” into the roll.  “Did you guys feel that?”  I do it again.  “The paper roll is vibrating because Mommy’s yell pushed the air in it all around.”  Then I grab a toilet paper roll, which is shorter.  “What do you think is going to happen when I yell into this one?” I ask.  “The air waves will make it move.  That’s my hypothesis.” answers Bree. Then we test it with a big “aaahhh!”

Hmmm.  It was different from the first time wasn’t it?  Briana is critical at first and says that I yelled differently.  So I scream again and while I scream I put the big roll and then the little roll in front of my mouth.  Then I explain, “When I push the sound waves down a long tunnel, the sound is lower.  When I push the sound waves down a short tunnel, the sound is higher.”  Awe inspiring.  Big smiles on the kids faces and I have their full attention.  This is going better than expected!

I give the kids their own rolls and we play with it for a bit.  Let’s see who can push the most air.  Then we take turns yelling loudly then quietly and long yells and short yells.  Surprisingly, the kids don’t get bored for quite some time.  I think we shout for a good 15 minutes, which is forever in the toddler world.  Then I ask what makes a sound we hear.  “Pushing all the air all around in the thing.  Then that makes an airwave.”  Pretty great for what I’d planned as the beginning of our little sound experiments.  I decide not to correct her with "sound waves" just yet.

Then I grab my clarinet, put it together and blow a few notes.  I play a few bars of Mendelssohn’s Overture to Midsummer Nights Dream.  I think it there were ever a real Pied Piper of Hamelin that this is definitely what he played.  You can’t fight the urge to skip along when you hear it.  Ok, maybe YOU can J I explain that the concept is the same as our paper rolls. The buttons make the clarinet’s tube longer or shorter by letting the air out at different areas and that’s why the sounds (ie. notes) are higher when the tube is shorter and lower when the tube is longer.  I show them the reed and tell them that when you blow into the clarinet, the reed starts vibrating and that starts the air waves.  Abby likes pushing the buttons while I try to play, but wants nothing to do with putting that thing in her mouth.  Surprising since everything else in the house seems to go straight in.  Bree tries to play too, and is surprisingly competent on the clarinet, getting out real notes, not just squeaks and honks.  She says she can feel the air moving on her fingers….and she can feel her spit too.  Time to pack up the clarinet!

We play the guitar too.  The kids are used to the guitar since it stays visible on it's stand in the library and the kids both love to strum away on it.  I try to chime in and ask them if they noticed the vibrations of the strings before.  “Ok Mommy.  I know about the guitar” is all I get.  But I see her watching the strings vibrate, which she has never done before.  I explain the frets on the guitar are the same as the tube and the clarinet.  As we make the strings shorter, the notes get higher.  Bree has to try to tune the guitar to change the length on the strings.  Now we can no longer play anything that sounds right, although that doesn’t stop her from singing her ABCs while strumming away.  Abby plucks a string or two and backs up.  She’s more interested in dancing and trying to sing while her sister plays.  Bree plays a couple rounds of 'Twinkle Twinkle' for her.  The picture below is actually of Bree as a baby playing for the first time, but it’s so cute, so I posted it anyway J

My coup d’ grace, the glasses, requires some restraint so that everyone (and my glasses) stay safe, so I decide put Abby back in the high chair and have Bree sit down.  You’ve all probably seen this demonstration a million times, but the beauty of little kids is that it’s new and fascinating to them.  I get 4 glasses and fill them to different levels with water.  I tap each lightly with a spoon.  We listen and watch the ripples in the water and talk about how the glass with the most water made the lowest note.   I talk briefly about sound travelling faster through water (though I skip the lesson on conductivity, clogged ears, and other complexities as to why we don’t actually hear better underwater and why the sound doesn’t travel out of the water to someone standing out of the water), but since I see that their attention spans are waning, I mostly just let them have fun SOFTLY tapping the glasses.  

Then I empty the 4 glasses.  I refill the first one with water, the second with the strawberry milk the kids were drinking, the third with maple syrup, and the fourth with vinegar, all to about the same level.  (Thank you dishwasher!).   We talk about how the sound changes (and skip the lesson on viscosity).  I wanted the kids to sort the cups by highest notes to lowest notes, but Bree wants to sort them by color so we do that instead.

Now it’s time for coffee for a very tired mom of two very excited kids.  We clean up, pack up, and head out on a Starbucks run.  Hopefully the idea of sound waves will pulsate through their little minds while they ride.