Physics
Acoustic Impedance Matching
Quick fact
In medical ultrasound, a gel is applied to your skin—not just for lubrication, but to match the acoustic impedance of the transducer to your body, boosting the amount of sound that enters by up to 99%.
Why this is interesting
Why does a singer's voice sound muffled when they sing into a thick glass pane, yet a guitar string can make a whole room resonate? The secret lies in whether sound energy is allowed to 'step' seamlessly into a new material.