College-Prep Physics: I had a clear 250-W bulb plugged into an variac and slowly increased the voltage from 0 to 120 V. We saw the color of the glowing filament change from red to orange to yellow to white. The temperature and the brightness of the filament increased as well. Now that we have a way of measuring the color of light (by its wavelength), we can look for a mathematical relationship between the temperature of the glowing filament and the peak wavelength of the light emitted. We used a blackbody applet to collect data: http://bit.ly/blackbodysim.
AP Physics C: Students wrapped up their investigation of Val’s grouse, concluding with the creation of a bifurcation diagram. Here’s a bifurcation program I made in GlowScript.
Conceptual Physics: Students continued work on their bike light presentations. Some groups used http://circuitlab.com to make professional-looking circuit diagrams for their presentations.
College-Prep Physics: Used the long slinky to generate discussion about how we might make the waves travel faster down the slinky. That lead into a dissucssion about frequency, wavelength, wave source, and wave medium. Then students used constant speed buggies, adding machine tape, markers, rulers, and a metronome app on their phones to experimentally determine the relationship between frequency and wavelength. (Sorry, I’m reposting the video from last year.) Also showed this I Love Lucy clip:
Conceptual Physics: Students finished building and testing their modified bike light circuits and began making their final annotated circuit diagrams.
AP Physics C: All but one student was taking the AP Macroeconomics exam today. We’ll finish reading Arcadia tomorrow.