From “science on a budget” YouTuber Nick Moore, watch this drop of mercury being vibrated from ~120Hz down to ~10hz. We’ve seen resonance demonstrated before in Chladni Pattern videos: sound frequencies become visualized as patterns via the vibrations. Higher frequencies = more complex shapes and patterns. Adam Frank explains in more detail at NPR:
In the video above, sound waves passing around and through a drop of mercury set it oscillating. But the physics of the system — determined by things like the speed of sound in mercury and the strength of its surface tension — allow some sound waves to excite special vibrations in the drop. In other words, the mercury drop has resonances with the sound at specific frequencies.
These are called the resonant modes of the drop. When the frequency of the sound waves matches the frequency of the drop’s resonant modes, highly organized patterns of pulsation are triggered. You know you’ve hit strong resonances when something like a multiple-armed, star-shaped pattern emerges.
It’s a remarkable reminder of the hidden architectures embedded in the world around us.