TeachRock

Materials Needed for this Lesson:

• 2 medium sized bowls
• Plastic wrap
• A metal coil, such as a Slinky®
• 1 cup of sugar, salt, or sand
• A tuning fork (the larger the better)
• A large baking pan
• A large wooden spoon
• Water
• A small piece of string or yarn

Preparation:

1. Create the following stations where students will conduct activities related to sound waves:
   • Station 1: Drum/Vibrating Membrane Activity
     
     • Tightly cover the plastic wrap over the top of the bowl. Place a spoon and cup of salt, sugar, or sand next to the bowl.
     • Provide copies of Handout – Drum/Vibrating Membrane Activity at the station.
   • Station 2: Coil Spring Wave Simulation
     • Tie a short piece of string or yarn approximately in the middle of the metal coil.
     • Provide copies of Handout – Coil Spring Wave Simulation Activity at the station.
   • Station 3: Tuning Fork and Water Activity
     • Fill a medium bowl with water, and place the tuning fork next to the bowl.
     • Provide copies of Handout – Water and Tuning Fork Activity at the station.

Motivational Activity:

1. Play Clip 1, Introducing the Mickey Hart Band, which showcases musicians working with percussionist Mickey Hart. Direct students to pay attention specifically to the instruments in the video, and the ways they are performed.
2. After watching the video, and together as a class, create a list of the instruments featured in the clip. Then, go through the list and ask students to try their best to describe how each instrument is played. Finally, ask students:
   • Based on the observations we made on the board, how are these instruments being “activated” (played) to produce sound? Were they all activated in the same way, or a different way?
   • Using physics or motion, how could you describe how each instrument is activated to make sound?
3. Display Image 1, Definition of “Sound” and ask a student to read the definition aloud for the class.
4. Return to the list the class created and ask students:
   • How did each of these instruments create vibration? (Play Clip 1 again if needed.)

Procedure:

1. Inform students that they will be exploring the science of sound: how it operates, and how it is explained and represented scientifically and mathematically.
2. Explain to students that to understand the science of sound, they will first have to understand the physical principles of sound by conducting a variety of activities and making observations. Direct students to go to the stations around the classroom (students can either volunteer to go to a particular station or be assigned to one). Explain to students that at each station they will be conducting activities and answering the questions as described in each station handout:
   • Station 1: Drum/Vibrating Membrane Activity
     • Handout – Drum/Vibrating Membrane Activity
     • Optional: Video Demonstration
   • Station 2: Coil Spring Wave Simulation Activity
     • Handout – Coil Spring Wave Simulation
     • Optional: Video Demonstration
   • Station 3: Tuning Fork and Water Activity
     • Handout – Tuning Fork and Water Activity
     • Optional: Video Demonstration
3. Have students share with the class what they observed as a group by providing the answers they gave for the handout questions. Ask students:
   • What might these activities say about the nature of sound waves, or waves in general?
   • In each activity, you could visually experience the effects of sound waves. After having seen waves in operation, what might be some ways to measure waves? What variables exist that change the effects of sound waves? (If helpful, provide a list of student answers on the board). (Note: If this lesson is broken into two class sessions, this is an ideal place to end the first session.)
4. Explain to students that the class will summarize what they learned while doing the activities using a graphic organizer. Pass out Handout – Longitudinal Vs. Transverse Wave Graphic Organizer to each student. Encourage students to take notes in the organizer as they learn about the science of sound in class.
5. Explain that sound waves operate as longitudinal waves, which have characteristics students observed in the three activities.
6. Direct students to examine Figure 1 in the graphic organizer handout. Ask students:
   • When striking the bowl rhythmically, what did you notice about the sugar/salt/sand? Did the sugar/salt/sand continuously move in one direction, or did it move back and forth?
   • At what point were the sugar/salt/sand grains close together, and at what point were they separate?
7. Explain to students that the sugar/salt/sand acts in a similar way as air molecules react when producing sound waves. Like the sugar/salt/sand moving up and down, air molecules are not pushed out at a constant rate, but “pumped” according to how rapidly the material is vibrating.
8. Direct students to examine Figure 2 in the graphic organizer handout. Ask students:
   • Is the illustration in Figure 2 similar to what you observed when doing the coil activities?
9. Explain to students that, much like the sugar/salt/sand in the membrane activity and air molecules in a sound wave, the coils expanded and contracted. The point at which the coils are farthest apart is called rarefaction. When the coils are closest together, it is called compression. Direct students to label the moments of compression and rarefaction in Figures 1 and 2.
10. Explain to students that the coil activity revealed another characteristic of longitudinal waves: that the molecules move in parallel with the energy source. The piece of string in the middle of the coil moved in parallel with the energy source, in the activity the energy source was the student’s moving hand.
11. Direct students to examine Figure 3 in the graphic organizer handout. Explain that in this activity students actually used the longitudinal waves produced from the tuning fork to create transverse waves, which move perpendicular to the energy source. The classic example of transverse waves are water waves, which move up and down. When the tuning fork was placed in the water, ripples appeared.
12. Direct students to examine Figure 3 in the graphic organizer handout. Explain that while longitudinal waves operate differently than transverse waves, they are mathematically represented as transverse waves. Modeling longitudinal waves like this makes it easy to mathematically represent the measurable variables of any wave.

Summary Activity:

1. Using their graphic organizer for support, direct students to turn to their partner and briefly explain the science of sound and how sound operates.
2. Watch Clip 2 – The Big Bang. Then ask students:
   • Why does Mickey Hart state that “rhythm and vibration are the building blocks of the universe”? What evidence does he provide to support the statement?
   • Why might The Big Bang be considered a vibration? Do you agree with this description? Why or why not?
3. Play Clip 3 – Vibrational Expressionism. Ask students:
   • How does Mickey Hart create his paintings? What is his process in painting?
   • Scientifically speaking, why would different sounds, when amplified into a canvas with paint on it, result in different patterns?
   • What is Hart attempting to achieve in his painting process?
   • Do Hart’s ideas of sound and vibration relate to how ancient people conceptualized sound and vibration? How so?
4. See the lesson The Mathematics Behind Sound to learn about the variables of sound, how they are measured, and the mathematical relationships between them.

Extension Activities:

1. Before computers were able to visually represent soundwaves, German scientist Ernst Chladni used metals plates and sand to visualize the characteristics of sound waves. Watch Clip 4 – Reproducing the Chladni Plate to see how Mickey Hart has reproduced the experiment using a drum. Then, using your notes from the Handout – Longitudinal Vs. Transverse Wave Graphic Organizer, write a brief paragraph considering how Chladni plates might represent the physical characteristics of sound.
2. Can sound be felt or experienced without being heard? Work through this Distance Learning Pack to discover the ways deaf and hard of hearing people experience music.

Handout – Ancient Theories of Sound Handout – Coil Spring Wave Simulation Activity Handout – Drum/Vibrating Membrane Activity Handout – Longitudinal Vs. Transverse Wave Graphic Organizer Handout – Tuning Fork and Water Activity