Musical Instruments: Science of Sound

• Explore: Before building their own instruments with cardboard and Makedo, have students stretch a rubber band across a cardboard tube and pluck it. Ask them to notice how the pitch is different when the rubber band is plucked at the top versus when it is plucked along the long side of the tube. There is no interference with the vibration at the top of the tube, but it is also stretched tighter. So what happens to the pitch when stretched over a hole versus over something solid?

• Build: Tell students they will experiment with pitch and sound by building a stringed instrument on a shoe box with Makedo tools, Scrus and rubber bands. Challenge students to create their instrument with one low note, one note with a middle pitch, and one high note.  As students stretch rubber bands from Scru to Scru, ask them to match the pitch of the rubber band on both sides of the Scru. 

• Model: Model how to make the low note by connecting one Scru near the base of the box and one near the top. Ask students how they will add tension to make a note that plays a middle pitch. Model how to twist the band to shorten it and use another Scru to keep the tension tight. Optional: Students can cut a hole in the shoebox to see how it enhances the sound.

• Discover and Explain: Once all students have three notes, have them test the variables (length/tension), record observations, and explain what’s happening as they pluck. The goal is for students to be able to complete the sentence: “When I change (length/tension), the pitch gets (higher/lower) because the vibration gets (faster/slower).

  • String length: On their lowest note, press a finger at different points on the rubber band to shorten the vibration length. Does it get higher or lower? Why?

  • String tension: Tighten the rubber band anchored to the Scru by doubling it around the Scru. What happens to the sound?

  • String thickness: If you have rubber bands of different widths, try placing them on the stringed instrument to test the difference in thick versus thin rubber bands. 

• Share: Ask students to share with an elbow partner one design choice for their instrument and what they noticed about the rubber band vibration throughout their experiment.

Time allocated: 5 minutes

Have the students journal their responses to the following prompts:

• If you had two rubber bands that were the exact same length, but one was pulled much tighter, which one would have the higher frequency?

• How was plucking the rubber band similar to humming with your hand on your throat at the start of class?

• What is one thing you thought would happen to the sound that turned out to be different once you started building your instrument?

• Fill in the blank: "My favorite part of being a sound engineer today was _________."

• Explore cardboard sound: Give students a few minutes to experiment with cardboard by tapping boxes, using tubes as mallets, etc., to start listening for how cardboard can sound as a percussion instrument.

Suggested Script:

“The percussion family is the oldest and loudest instrumental family. If you can bang it, shake it, or scrape it, it’s percussion. You use your hands or mallets to send a shockwave through the instrument, producing a beat. Before building something with Makedo, let's build your engineer’s ear by experimenting with cardboard scraps. Tap, pat, use cardboard as mallets to listen for sounds and ask yourself, “What sounds does cardboard make? Does thicker cardboard sound different from thinner cardboard?"

• Makedo a percussion instrument: Challenge students to make a percussion instrument that can be played at both fast and slow tempos. Give students or pairs cardboard, Makedo tools, and Scrus, then challenge them to make their own percussion instrument. They can make a drum, a shaker (a box with Scrus inside), a scraper (cardboard with Scrus on top as a rigid surface that kids would play by scraping across the ridges), or anything their imagination can come up with.

Once all instruments are created, bring the class together to perform as a “cardboard orchestra”. Act as a conductor and lead music at various tempos to see whether the groups can keep the beat together. If needed, use a metronome to count the steady beat and have students play along with their improvised instruments.

• Instrument families: Discuss how each session has focused on a different instrument family and review how a sound is made for the string/rubber band instruments compared to a percussion instrument. See key concepts for a suggested description of each of the instrument families. If you have them available, show students different instrument types and see if they can identify the instrument family it belongs to.

• Dynamics and mood: Dynamics can change the feeling of a song. Before creating their own compositions, composers need to think about the dynamics they want to use. Dynamics describe how soft or loud a piece of music should be performed. Ranging from soft like pianissimo, mezzo (medium), or loud like fortissimo. These dynamics can change throughout their musical piece. 

• Composition challenge: Divide students into small groups of 3 or 4 and have mixed instrument families in each group. Give each group a composition challenge card to help them plan their composition. Give groups a few minutes to plan and 10 minutes to rehearse.

• Composition requirements see printable: 

  • Use all instrument families throughout the piece.

  • Include one dynamic change (soft to loud or loud to soft)

  • Length should be 16 beats

• Ask each group to perform their composition for the class, and have students actively listen to the performances so they can answer these three questions:

  • The tempo change from this song made me feel….

  • The timbre of the instrument that stood out most was….

  • The dynamics in this composition made me feel…