The concepts of Distribution and Dispersion are, again, the core of this section. Students are asked to find a way to measure and define the frequency distribution of the pure tone they have 'measured' with the apps on their mobiles.

In Section H1a students will find:

1. a basic introduction to the decibel scale. This part may be skipped. However a basic knowledge about the difference in dB between two intensities may be important to understand the relative importance of two intensities. For example to evaluate the significance of the background on which the peak stands. Another useful application could be a discussion about the harmonic components of the 1 KHz "pure tone" at 2 KHz and 4 KHz. Again, we stress that all these aspects may be safely overlooked.
2. the form "Frequency Distribution of a pure tone", designed to stimulate reflections about the concept of distribution of a sound in the frequency domain. Students are given a rough definition of Dispersion and are asked to find a way to evaluate the dispersion of the "pure tone" distribution.
3. A final discussion involving the entire class may be useful to collect different ideas, highlight weak and strong aspects of the student's reasonings and to define a common knowledge.