1. Warm-Up Activity: Students finish adding final information to their musical instrument models with Brian pressing students to show how the sound is traveling from the instrument to the listeners.
2. Tuning Fork & Ping-Pong Ball Demonstration: Brian asks students to imagine what will happen when he holds the ringing tuning fork up to a Ping-Pong ball suspended from a string. Students imagine that the ball might pop/shatter from the sound or that the ball might amplify the sound of the tuning fork. Brian touches the ringing tuning fork to the ball and it makes the ball bounce off of the fork. Students are impressed with the amount of vibration from the fork.
3. Exploring Three More Tuning Fork Activities: In addition to the Ping-Pong ball, students observe the tuning forks vibrating and ringing, tuning forks buzzing against a sheet of paper, and tuning forks buzzing in a small cup of water. Students draw diagrams of what is happening and add information to a graphic organizer observation sheet making notes about what they cannot see, but can infer, such as the rapid vibration of the tuning forks and paper. Brian walks from table to table using three rounds of back-pocket questions to engage students in conversation:
• Round 1 – Questions clarifying the instructions for the activity itself.
• Round 2 – Questions prompting students to talk about what they are observing and noticing about the different tuning fork activities.
• Round 3 – Questions pressing students to theorize about possible explanations for the tuning fork behavior.

Drawing a Model of Tuning Fork Sounds: On the back of the observation sheets, students draw how a large and a small tuning fork make sounds and how those sounds travel away from the tuning fork.

Discussion Questions: 1) Brian chose to spend 2 days eliciting students’ ideas about sound in 2 different ways. What are students’ initial understandings about sound from tuning forks? Add to the RSST tool that you completed after viewing the lesson about musical instruments. 2) Brian felt that the tuning fork observations and drawings elicited slightly different student ideas than the musical instrument experiences. What did you notice about the students’ thinking on Day 1 vs. Day 2?