Physics is one of those classes high school students often dread. It’s intimidating for those not gifted in math or science and when taught as a series of facts and figures its relevance can be hard to grasp. Often, students that struggle with a particular subject benefit from finding a connection between the material and their own lives.
Kristy Bibbey, a physics teacher at Poudre High School in Fort Collins, CO., is helping students make that connection through a unique class experiment that ties together math, physics, music and technology. The experiment makes use of a SMART interactive whiteboard, Vernier microphone and Vernier Logger Pro software to create a visual representation of musical notes that can be captured and analyzed on the interactive whiteboard. Bibbey is careful to point out she can’t take all the credit for this idea. She modified the lesson from one her husband created as a junior high school science teacher.
“It turns out that my physics class always has a number of talented musicians who are willing to perform for the class,” Bibbey explains.
These talented musicians are students who participate in band. They play a variety of instruments like the violin, cello, saxophone, guitar or the upright bass, to name a few. These students play their instruments as Bibbey catches data to be analyzed as a class. The collection time is very short—around 5 milliseconds. Students start simple, first using a tuning fork to create sound that is collected via the Vernier microphone probe. The collected wavelength is then projected onto the interactive whiteboard. Bibbey then highlights a wavelength on the board and the Vernier Logger Pro software shows the Delta T, which represents the time period in milliseconds. Students use their calculators to find the inverse of the time period, which turns out to be the frequency of the tuning fork.
“We repeat with a few more tuning forks to be sure we can recognize a wavelength and understand the inverse relationship between period and frequency,” Bibbey says.
Next is the fun part. Students who can play an instrument are invited to do so as their classmates listen. Each student has the opportunity to play the same single note on whatever instrument they’ve brought in.
“We get the same wavelength and the same time period, but a much different waveform,” Bibbey explains. “So we talk about overtones and what makes a string instrument sound different than a wind instrument even if they’re really playing the same pitch.”
This experiment is a fun way to explore harmonic sound and it relates physics concepts to music, something most teenagers can relate to.
“Kids who are in band and orchestra are really good at laying the foundation for music theory and then I can tie some of the math and physics into it,” Bibbey says.
This musical experiment also includes a look at frequency. Bibbey will have her students measure the frequency of a string instrument. Then, she takes them into a back room that is dark and uses a strobe light to match the fundamental frequency or a multiple of it. A student plucks the strings of their instrument and the class can see nodes and antinodes of the standing wave in the string.
“The upright bass yields particularly amazing visual results due to the low frequencies it can play,” Bibbey says. This portion of the experiment serves as a refresher on standing waves and natural frequencies.
Students also play harmonic notes on their instruments as well as dissonant notes. They find the latter has an erratic waveform. The captured data is then discussed and analyzed.
“We find out that the same things that look bad sound bad to our ears,” Bibbey says. “[Students] don’t realize that when they’re playing or composing music. There’s a whole lot of science and math that’s gone into that.”
For a student not mathematically inclined, this experiment offers another way in, allowing Bibbey to capture their attention in a less scary, more creative way—and it’s technology that allows this to happen in such a visually engaging way.
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