Sound and Vibration Lesson 3
This lesson began with our customary review: What are vibrations? What happens to sound when vibrations stop? What kind of instrument uses a vibrating membrane to make sound? What kind of drum makes a low sound, large or small? This may seem rote, but each time I plan a lesson I think carefully about the wording of these questions. At first, I gave them the definition of vibration and simply asked them to recall the term. Now, after a few weeks with this concept, I am giving them the simple term vibration and asking them to define it according to what they have learned in this unit. Using the turn-and-talk method, along with pulling popsicle sticks, seems to have been working well, so I continued with that strategy.
I explained the concept simply: “Last time we talked about membranophones. In a membranophone, the vibrating material is the drumhead. In an idiophone, the vibrating material is the instrument itself. Here’s another slow-motion video: Watch what happens to this cymbal when it is struck by a drumstick! You can see that what is vibrating is the instrument itself. Even though we can’t see it with most idiophones, (because it happens so fast!) it’s always the instrument itself that vibrates.”
Using another short clip from YouTube helped explain the basics of idiophones. As with each category of instrument, it is defined by its vibrating material, which is why studying instrument families worked so well for this unit on Sound and Vibration. Idiophones are a fairly complex instrument family, so I used another PowerPoint with examples and nonexamples to help them understand.
To show their vote for “idiophone” or “not an idiophone,” I asked the students to show a thumbs up or thumbs down rather than calling out. By holding their thumbs under their chins (a suggestion from Mrs. Nelson), I was better able to assess each child without them influencing each other’s votes quite as much. This was a great formative assessment strategy I plan to use again in future lessons!
I saw some great evidence of deeper learning begin to emerge in this lesson. As I showed an example of a handmade xylophone, pictured above, one of the students asked, “I though you said the instrument itself vibrates? That whole thing isn’t vibrating, only the bars.” I was impressed to see such a high level of discernment! “It’s true, the entire frame isn’t vibrating, but that part is just a support structure. The bars are the real instrument, and they are the source of the vibrations.”
The last picture of an idiophone that I showed was this:
At which, of course, the students got very excited! (The answer, of course, was yes)
The instruments pictured above are called Boomwhackers: inexpensive durable plastic tubes cut to a precise length to produce a certain pitch. They are popular in general music classrooms across the United States, and Mrs. Nelson happened to have a couple of sets for her classroom. The children love to use them- but before they did, we set up some procedures.
Procedures are essential to good classroom management, especially when working with instruments. If students are not given clear expectations and consequences, handing out instruments is just asking for noice, chaos, and loss of control. My procedures were these:
- Only play your Boomwhacker when you are told.
- Play your Boomwhacker by holding it in one hand and smacking it into the palm of the opposite hand. Do NOT hit you Boomwhacker against the floor, your desk, your neighbor, or anything else but your free hand.
- Whenever you are not playing your Boomwhacker, you must hold it in TWO hands.
Pretty simple, but it works! When you’re holding a Boomwhacker with both hands, you can’t bang it into anything. It also helps to give the students a bit of time at the beginning and end to just make a bunch of noise with their instrument. It’s a lot of fun and it lets them get that urge out so they can focus better the rest of the time. These procedures need to be repeated several times, of course, throughout the activity, and it was very nice to have Mrs. Nelson in the classroom to assist with modeling and enforcing these procedures. But they worked, and on the whole, everything went smoothly.
I created some simple iconic notation for the Boomwhackers, color-coding squares to match the color of the tubes and arranging them into simple songs, and displayed them in a PowerPoint. This activity requires focus and teamwork, as the students have to play only when their assigned note comes up in the song. With a little practice, these first graders did a great job! They correctly identified both songs, which demonstrated to me as well as them their own ability to play together as an ensemble. Pretty impressive!
Larger is Lower
The last part of this lesson involved making a few observations (going back to Lesson 1) about the Boomwhackers as idiophones. “Which Boomwhacker makes the LOWEST sound? Which makes the HIGHEST sound? Which one is larger?”
Just like with drums, the students discovered, the larger the instrument, the lower the sound.
The lesson ended with a quick review and recollecting the Boomwhackers from the students. I was very happy with the evidences of deeper learning that I saw during this lesson, and the opportunity each student had to experience actually USING an instrument’s vibrations to make sound.