Physics
Acoustic Coupling
Quick fact
Acoustic coupling is why a glass can 'sing' when you run a wet finger around its rim—the vibration of the glass couples strongly to the air, producing a clear tone.
Why this is interesting
Have you noticed how a vibrating smartphone on a wooden table sounds much louder than when held in hand? That’s not just vibration—it’s acoustic coupling at work. But how does sound 'jump' from one object to another?