Based on a great suggestion by @wslaton, today’s lab practicum for the Oscillating Particle Model unit was to have students modify the volume (e.g., add water to) their Helmholtz Resonators (e.g., water bottles) to produce the specified frequency. The results were fantastic. Students based their calculations on this article.
I also shared a video of how Dyson uses a Helmholtz cavity to reduce the noise of their vacuum.
2 thoughts on “Day 130: Helmholtz Resonators”
Hi, Can you describe a little more what the students were given and what they calculated? Did they already know the 1/sqrt dependence on volume or take measurements to determine this?
They read the linked article which presented the equation to calculate the frequency of the resonator. They then made careful measurements of their bottle. Once I presented them with the target frequency, they did additional calculations to determine the required volume and how much water they would have to add to their bottle to achieve that volume.
Students struggled as much with keeping track of units and measuring accurately with Vernier calipers as they did with the application of the equation.