Activity 1.3 - Make sound visible

Learning Aims:
  • Learning how to record sound with a sound sensor
  • Interpreting the recorded sound waveform graphs
  • Understanding that the sound signal is changing periodically
  • Introducing concepts of frequency, pitch and loudness
  • Exploring how the sound waveform is changing by changing loudness and pitch
Materials:
A sound sensor, interface and software that displays sound waveforms (e.g. CMA Coach 6)
Suggestions for use:

Start the activity by asking students: ‘What do you think a sound would look like if we could see it?’ Have student volunteers come up to the board to illustrate.

Divide the class into groups, hand out Classroom Material: Make sound visible (Part I)and let students do their own investigations with a sound sensor and tuning forks. If needed, help students to set up the experiment and perform measurements with the computer.

Hand out Classroom Material: Make sound visible (Part II), discuss the recorded sound waveform and let students calculate the frequency of the recorded sound signal. Then let them perform Investigation 1 and 2 and summarize their findings by defining the properties of sound: loudness (defined by sound amplitude), pitch (defined by sound frequency).
Possible questions:
  • How sounds can be made visible?
  • What is the frequency of vibrations?
  • Determine the frequency of the tuning forks used in your experiments? How did you figure this out?
  • Can you notice any relationship between the tuning forks appearance and the sound they produce?
  • What determines pitch?
  • What determines loudness?