Yesterday's exploration and excitement was the foundation for students to come full circle in understanding exactly how sound waves travel, use what they learn today to expand on the fun we had. To support the Disciplinary Core Ideas of this standard about energy transfer, I wanted students to enjoy Ms. Frizzle and the Magic Schoolbus as she takes her students through a Haunted House filled with sound energy! I wanted them to understand the concepts of how when energy vibrates the air, it produces sound. They will learn how it bounces, reflects and is amplified.
I asked them to take notes in their science journal so we could discuss some of their new ideas afterward. After we finished up, I asked my students to consider their instruments that they created yesterday. How does what you learned apply to what you have learned from Ms. Frizzle?
Students raised hands and offered up answers that showed they understood. They told me that the strings on their instruments vibrate. "They push the air around and make noise," one student said. I asked them to go back to their seats and get their instruments from yesterday so we could discuss more about what was going on.
Students placed their instruments on their desks. I asked them to play them again. They enjoyed strumming the rubber bands, plucking them and hammering them with pencils. I allowed them to revisit their experiences to help them remember what they had learned. They remembered things like how some strings vibrate faster. The room was filled with goofy zingy sounds. We hashed out some misconceptions as students shared their thinking. I asked students why some strings sounded higher? Even though we had discussed it yesterday with the dulcimer, they did not grasp the concept of length of the string and tried to say that it was because of how hard the string was plucked.This was a good place to integrate some math! Measurements of the strings would prove to the students that the shorter strings were a higher sound. I asked one student if he measured the strings? The student shared his measurements of the higher sounding strings. I wrote 7 cm on the board. Then I asked him to measure the lower pitched strings. They measured about 10 cm. Because we had measured the strings, they understood right away that the longer the string, the lower the pitch.
To clarify the difference between pitch and dynamics, I modeled dynamics for those that weren't grasping it, showing them that the force produced a louder sound. I wrote on the board: The harder the force, the louder the sound. Long strings create low sounds and short strings create high sounds. They copied these notes into their notebooks. I emphasized the difference between "low" and "soft" sounds. They seemed to confuse the two thinking they were one and the same.
Energy Transfer: I asked: How do we know that energy is transferred into our instruments? As we discussed it, students showed understanding because they could explain that the energy comes from our hands, moves the strings which vibrate and create sound.
I asked: Why did different shaped boxes made of different materials make different sounds?
We played a little bit with the instrument made from cardboard, one from and icecream bucket and then the book box. We concluded that the material it was made of made different sounds. I asked if they thought my dulcimer would sound different if if were made of plastic? They agreed it would.We also discussed the placement of holes in the body of the instrument and why guitar holes are in the center in the front, vs in the back.
When I asked why, one student shared it was because it would echo differently. They were starting to gain a deeper understanding of how sound is absorbed or bounces, making it echo or reflect from the surface.
I told them that I wanted them to write about their understanding to prove their knowledge. I explained that they needed to carefully consider everything they had learned about vibrations, pitch, and dynamics.
I passed out the Sound Waves Show Me What You Know Assessment. I read each item that needed to be proved in their understanding. I explained that I wanted them to use those topics to plan their writing using the Simple Mind app on their iPad. They began planning their work immediately. I roved and helped students to plan their writing. I explained that I wanted them to start their assessment here, but they could take it home and finish it tonight for homework. When they turned them in, I would use the Sound Waves Assessment Rubric to assess their understanding.