when a tree falls, the tree and the ground vibrate, setting up sound waves in the air that strike the ears.sound waves vary in amplitude and frequency.the amplitude of a sound wave is its intensity.a bolt of lighting produces sound waves of great amplitude.loudness is a sensation related to ampiltude but not identical to it. for example,a rapidly talking person sounds louder than slow music of the same physical amplitude If you complain that television advertisements are louder that the program, one reasons is that the people in the advertisements talk faster