Chapter 2 Sound Waves: Section 2.2 (2.2.3) & 2.3 (before Experimenting) - Anqi

· 2.2.3 Sound Propagation

This section explains several phenomena in sound propagation. 2.2.3.1 The Effects of Time Delay starts with a nice scenario at a baseball stadium and demonstrates this effect from a broad view, and then goes into a micro effect caused by a time difference of one millisecond. With Figure 2.26, the scenario is well described. Although Figure 2.27 and 2.28 show the phase relationship between sine waves of different frequency one millisecond apart, these two figures did not show the add and interference of sound waves very well. Plus we have been talking about the adding and cancelling of frequencies since earlier this chapter, a graph demonstrating the adding of sine waves might help the readers understanding this phenomenon better up to this point. 2.2.3.2 The Effects of Temperature is very interesting. It presents the effects which I encountered a lot but never noticed. Not many scientific terms are used in this part, making it easy to get. Most part of 2.2.3.3 Resonance in 3-D Space makes a lot of sense, but the very last paragraph, along with the example of a square plate and the figure, took me a little while to realize what was going on. I guess it is because that the picture was taken from an overlooking view, making it hard to get what it shows, and no before and after comparison was made that the appearance of pattern of sand seems fairly sudden (considering the fact that some readers might be holding the paper-based version, I still think the book should be able to explain itself without the supplementary materials, but it is just personal opinion).

· Learning Supplements:

With Eric’s explanation, the MAX Demos make so much more sense to me now. I was having difficulty interpreting all the values and the displays yesterday, but everything is clear now. I guess this would be a part where, in a course, the students may need the instructors to demonstrate and explain well.

· 2.3 Science, Mathematics, and Algorithms

- 2.3.1 Experimenting with Sound Waves in Max and Pure Data

Ahah~ Here comes the demo of adding sine waves! This demo would help the readers to visualize the process of interference of sine waves, which I guess has kept the readers waiting for a while. I would be nice to mention the existence of this demo in earlier sections talking about sine waves and effects of sound propagation if no other explanatory materials would be added.

- 2.3.2 Experimenting with Sound Waves in MATLAB and Octave

As a computer science major, I am very excited to try this part out. I just skimmed through this section and found it is very instructive overall. I will write a separate blog as feedback to this part.