In Anticipation

Depending on whom you listen to, we are going to be missed by tomorrow's snow, get hit starting at noon, get hit starting in the evening, get 4", get 8"...who knows. But I hooked the barometer probe up to one of the laptops and set it to collect the atmospheric pressure once a minute for the next 48 hours. It will be interesting to correlate the pressure values with the weather over that time. Right now it is clear and bright...

Honors Physics discussed yesterday’s lab investigation for simple harmonic motion of a mass-spring system. Looking over the data, seems like people found the relationships that we would predict – frequency of oscillation was independent of amplitude, but did vary with mass. If we had tried the experiment using the same masses, but with a different spring, we would predict a different frequency. Oscillation of a mass-spring system depends on mass and the spring constant of the spring. For a pendulum system, period/frequency varies based on pendulum length and the value for acceleration due to gravity. Folks did a nice job with the math portion of the lab and the extensions. We added a bit of flesh to this topic in class today with a discussion of the measurements associated with simple harmonic motion and then began an exploration of the wave formations produced by oscillating systems.

Physical Science B concentrated on musical instruments and the function of the ear in today’s class. The association of standing waves with musical instruments and harmonic production was discussed, as was the relationship between musical instruments and resonance. We then expanded our exploration of the phenomenon of resonance to discuss its effects on construction and engineering (generally, not good) and how it functioned in our hearing process. Students got the chance to take a proverbial walk through the ear, identify the main parts and describe their function in terms of receiving, transferring and processing sound waves. Tomorrow, we’ll look at specific applications of sound waves and do a bit of review for this sound material.

Physical Science E examined the uses of ultrasonic and infrasonic waves. Both are used for communication by different species and we have put ultrasound to work in medicine and maritime applications. Students got the chance to do a bit of review on sound topics and we’ll go over those review sheets in class tomorrow. After the review, you'll have an open-book quiz on sound - just sound. Thursday - a lab on the speed and properties of sound. Friday - starting in on light.

Physics G conducted a lab that examined the factors affecting the period of a pendulum system. Of the possibilities (length, mass, amplitude), it was found that only length had an appreciable effect. Thinking back to the equation for the period of a pendulum, its not so surprising. Neither mass nor amplitude makes an appearance in the equation, but length sure does. A lengthening of the pendulum should increase the period and decreasing the length should shorten the pendulum – a pattern of results that groups demonstrated. We’ll discuss the lab tomorrow and review basic properties of simple harmonic motion before we continue on with our introduction to wave formations. You'll have time in class tomorrow to finish up making the graphs and completing the lab extension component.

Physics F reviewed types of waves and properties of waves such as wavelength, amplitude, period, frequency and speed. Attention was then turned to behaviors or interactions of waves. Waves can interact with each other, since they can exist in the same place at the same time, and with matter. Constructive and destructive interference were contrasted and a discussion of reflection was added to ultimately facilitate the understanding of standing wave formation. We will get a lot more practice with these topics in the next unit on sound, so the cursory overview today is only the beginning…

Homework

Honors Physics A: Chapter Review items #10-13, 17, 19-22
Physical Science B: None
Physical Science E: Complete sound review worksheet
Physics F: Read lab protocol sheet and complete Chapter Review items #37-45 for Thursday
Physics G: None