Resonance
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Resonance is central to the study of music. Resonance is the name for the condition that occurs when a vibration is prolonged and amplified due to air in a space or on a material like a sound board moving synchronously with a vibration. In a musical scenario it makes for beautiful, rich tones, while in other areas it's undesirable.
If a building resonates with seismic waves, it's a bad thing! That's because one consequence of resonance is that the wave causing the seismic vibration will impart more energy to a structure that resonates at the seismic frequency than it would to a structure that doesn't. This is generally true of resonance.
If the dashboard of your car resonates with road surface vibrations, it's also bad since it will annoy the driver and passengers with a buzzing sound. So in many instances attempts are made to both dampen vibrations and if possible to design structures that don't have resonances in frequency ranges that the object is expected to encounter in the environment. An example of this is the resonance of a skyscraper with seismic waves. Structural engineers go to great lengths to design buildings that won't resonate at seismic frequencies, or which will dampen those vibrations. Changing the stiffness and/or density of the structure will change the frequencies at which a skyscraper vibrates, and damping has been done in different ways. One way is to hang a pendulum of large mass down the centerline of the skyscraper. Another method is to install large water tanks to slosh around and dampen vibrations. Sometimes they just introduce structural components that act like shock absorbers in cars, which are really just objects that can change length against a force of friction - either sliding friction or fluid friction.
But let's return to resonance. A good way to think of resonance is that it is a frequency-dependent ability to absorb energy from waves. In the context of our sound cancelling ceiling tiles from the interference chapter we generally thought of waves going in, and cancelling on their way out. Another way of thinking of it is that the energy of the incoming sound was absorbed by the air cavity, or caused the air cavity to resonate. In order for that cavity to really cancel the sound, something about the walls of the cavity would have to resonate with the tone that's trapped, and dampen the vibration. This is often done with fabrics of various densities and insulating materials not unlike fiberglass used in homes for thermal insulation. The vast network of interwoven fibers ends up vibrating and produces heat from the sound energy, thus damping it.
A general design feature of musical instruments is that they are meant to resonate at very specific frequencies. I wish to take you on a tour of music, harmony, instrument design and resonance in a way that I hope you will find both enjoyable and educational.