## 20121113

Physics 205A, fall semester 2012
Cuesta College, San Luis Obispo, CA

Students have a weekly online reading assignment (hosted by SurveyMonkey.com), where they answer questions based on reading their textbook, material covered in previous lectures, opinion questions, and/or asking (anonymous) questions or making (anonymous) comments. Full credit is given for completing the online reading assignment before next week's lecture, regardless if whether their answers are correct/incorrect. Selected results/questions/comments are addressed by the instructor at the start of the following lecture.

The following questions were asked on reading textbook chapters and previewing presentations on waves.

Selected/edited responses are given below.

Describe something you found interesting from the assigned textbook reading or presentation preview, and explain why this was personally interesting for you.
"Watching the whip in slow motion uncoil, bend, and snap. The fact that dinosaurs might have been able to whip their tails is amazing and a little scary."

"Sound waves are longitudinal, and each small volume of air vibrates back and forth along the direction of the wave. This is interesting because we talk all the time."

"A guitar string being plucked is almost purely transverse."

"I thought that waves were just waves and that was it. I did not realize that there were different movements to waves, and how sound has a specific type of wave versus any other wave."

"The infamous Tacoma Narrows Bridge is very interesting and scary!"

"The textbook states a difference between 'musical sound and noise' by whether their waves repeat the same pattern or not. Are they familiar with noise music?? : )"

"Just by making a building stronger doesn't mean that it will stand up to earthquakes any better. the building needs to be built with something that will absorb the shock or resonance of the earthquake."

"How water waves are both transverse and longitudinal. This caught my attention because love to bodysurf and never knew why it was so much easier to swim through the bottom of the way than the top of it. With the longitudinal properties of the wave near the bottom it is easier to throw all my body weight directly against the motion of the wave. When I try to go through the top I get picked up and then dropped by the transverse component."

"The videos of the musicians were personally interesting to me. Being a musician, I have always wondered how the mechanics of the instruments work. Seeing the guitar strings, and the different speeds of vibration was really interesting and made me view music in a whole new light. The video on the metal band was also personally interesting to me, because for some time I played in a metal band and to see things slowed down, such as hammer-ons and pull offs were interesting. I also learned that an octave is an direct multiple of one another. I also learned that fifths are 3:2 ratio, and how simple a musical fraction can change the mood of a song and how some one sees it. The presentation really made me see music in a new way."
Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"Most things."

"The differences between longitudinal and transverse waves."

"Formulas. I mean I get it, but I don't. Same problems, different topic."

"The speed at which a wave propagates is not the same as the speed at which a particle in the medium moves."
Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"What will the lab final be like?" (There is no lab final, but there is a final lab.)

"I've taken a natural disasters course, so much of this is familiar to me since we studied the heck out of seismic waves. : )" (Then, uh, you rock.)

"Dinosaurs are awesome! Are you a vegetarian?" (If I could eat a dinosaur, I totally would.)