ETA’s Slack and Goudey Demo Solar Oven at Local School

May 5, 2015
As part of Marin Elementary’s math and science festival, Jonathan Slack and Howdy Goudey helped students bake cookies with a solar oven that uses the focusing power of parabolas. The have researched how solar concentrating ovens can be used to bake bread inexpensively. They also demoed a sonic candy maker. Students watched and listened as cereals, cinnamon, cocoa powder, raisins, M&M’s and mini marshmallows got mixed in a sound speaker. “During this mixing, we cycle through a range of frequencies, and find the resonant frequency of each component,” explains Jonathan Slack. “When we hit the resonant frequency of cinnamon (a very narrow frequency range), it all jumps up into the air as a “cinnamon cloud,” and just as suddenly drops back down to the drum head surface once the frequency changes just a bit beyond the resonance point.”