Why spend time to understand the the underlying physics of your ultrasonic transducer? Four simple reasons:

(1) To help you discern when you are making incorrect measurements

(2) To help you discern when something is grossly wrong with your device

(3) So you don't try random things to fix problems based off of faulty intuition

(4) So you will be able to take incoherent data from several sources and make logical engineering decisions from them