How do the vibrations of the sound compare for louder versus softer sounds?
- Do Now– Please get out your ISN. Add to the Table of Contents: “Motion Detector p.68” (Left Side). Head p.68 properly with “Motion Detector-2/25/20.”
- Collecting Our Thoughts About the Motion Detector– Write your answers to each question in a complete sentence on ISN p.68. How could this stick represent a guitar string or tuning fork? How do you think it will move? Why not just use the instruments we’ve already looked at? What differences in motion might we see when we are trying louder sounds versus softer sounds?
- Investigation- Predicting & Testing Softer & Harder Pushes– On the “Motion Graphs” handout, predict what the graph would look like when the stick is at rest. Use a pencil to sketch onto both graphs what you think it will look like when the stick is not moving. Then demonstrate the graph when the stick is at rest. Draw an arrow pointing to that line on each graph and label it “stick not moving.” Predict what the graph would look like for softer vs harder pushes on both your Condition 1: Light Push and Condition 2: Harder Push graphs using a dashed line. Label these lines “prediction” on both graphs. Then observe Test Condition 1 as we push the stick lightly. After the test, draw a solid line and label it “actual.” Repeat for Test Condition 2: Harder Push.
- Simulation- Speaker’s Motion– This simulation will graph the motion of the speaker while it’s making sounds. Observe soft and loud volumes. Sketch the speaker graphs below the graphs for the Light & Hard pushes on the “Motion Graphs” handout. Title the graph sketches for which sound is which and label the axes.
- Notebook Work– Tape the “Motion Graphs” handout as a flip page to ISN p.68.