Raining Cats and Dogs

We better have good flowers this spring to compensate for all this rain...

Honors Physics conducted a series of lab investigations on sound. The first experiment allowed students to determine the speed of sound at room temperature and compare that to the speed of sound in heated air. Based on kinetic theory, we would expect that the speed of sound in the heated air would be greater due to the greater velocity of the air particles, and this was found to be the case. The next set of experiments dealt with properties of sound produced by different sources. A softly and firmly struck tuning fork demonstrated the fundamental tone and the fundamental tone and overtones, respectively. The human voice is not like a tuning fork. A variety of tones are produced with each vocalization and this makes the more complex waveform that you saw on the computer. The final experiment let students determine how tones are used by a telephone to send number information. On a touch pad, there are column and row frequencies. Each number is designated by two tones – the one corresponding to its row and the one corresponding to its column. Tomorrow, we’ll go over the labs in more detail and then begin our discussion of musical instruments and harmonics.

Physical Science B discussed their lab and took time to make a few corrections to some calculations. Attention was then turned to reflection and plane mirrors. the law of reflection holds regardless of surface type, but different surfaces vary in their reflective abilities. We contrasted diffuse and specular reflection and used the plane mirror as an exemplar for how to analyze reflection on smooth surfaces. Tomorrow, curved mirrors and color!

Physical Science E took time to review the basic principles of reflection and plane mirrors and then extended this to curved mirrors. Based on mirror type and distance of object to mirror, we have the possibility of forming both real and virtual images. We then turned attention to color and discussed the role of reflection in color production. Tomorrow, we will watch a video that summarizes basic properties of light and does a nice job of explaining additive and subtractive color systems.

Physics F and G discussed the factors that affect how loud sounds seem to people. We disentangled the relationships between intensity, relative intensity, loudness and the decibel scale. We also took time to discuss the effects of sound on humans and the topic of noise pollution. Tomorrow, G Block will conduct their lab investigations for sound and F block will move into the area of harmonics.

Homework

Honors Physics A: Complete lab write up
Physical Science B: None
Physical Science E: None
Physics F: Conceptual Challenge p. 502 and the 13.3 Section Review
Physics G: Read lab protocol sheet and complete the 13.3 Section Review and Conceptual Challenge (p. 502) for Friday