Submitted by Stephen Wight, Greenback, Tennessee
Idea posted June 17, 2008
Below is Stephen's response to a fellow List Member's question regarding how to explain the science of sound to third graders:
In Tennessee, one of the Learning Goals under Standard 8 in second grade is "Illustrate the science of sound through the use of musical instruments." The Level 1 performance indicator is "Identify the source of vibrations in classroom instruments." Level 3 performance indicator for it is "Anticipate, correctly, the sounds that will be produced by instruments of different sizes."
I think I would use xylobottles pitch lessons as a culminating activity. Then, to get the answer to your question I would go to the source. Sometimes if you want a grade-level explanation, the best way is to ask the kids. (Example: after I explained my Participation rule to the K's, I asked them what the poster meant and they said, "Everybody does the same thing." I couldn't have said it better.)
Here's what I would do:
I would start by reviewing a little bit about the string family, being sure to ask someone to remind me why the bass had a lower voice (longer strings). Then I'd adjust the wording a bit by saying, "So it's because there's more string to vibrate." That wording is important because then you can substitute anything in for "string." "Because there's more water to vibrate with the glass." "Because there's more air to vibrate."
Then I'd get out my xylobottles and we'd pass them out to groups. Using mallets, I'd have them put them in order from lowest note to highest note. Then I'd ask them to take some time to play the instrument and figure out where the vibration was coming from. Many would probably say, "the glass." I'd say "True, but is it just the glass?" hoping they'd see the vibration in the water. So once we gotten them in order, I'd ask the students to explain the difference in pitch - not accepting just "The ones with more water are lower." "Well I can see that, but WHY do they have a lower pitch?" Next, we'd play a song.
After the song I'd bring out MY set and have the students help me arrange them in order from lowest to highest based on the water level.
Then I'd play them by blowing them and ask if the result was the same as they thought it would be. I'd then ask if they thought the vibration was coming from the same place. No? "Then where do you think it's coming from?" (No answers, I'm guessing.) "Let's see if we can figure it out then. Which bottle do you think has the most of whatever's vibrating? Which has the least of whatever's vibrating? Ok, well, then, what does this bottle have the most of? (looking for "air," although "empty space" would be close enough for a little help-along like "Is it really empty space, though, or is there something in that space?") So where do you think the sound is coming from? (The air is vibrating.) And why does this one have the lowest pitch? (Because it has the most air.)
Then I'd ask them to formulate two sentences describing how xylobottles worked. One would address playing using mallets, and the other would address playing using an airstream.