'If a Tree Falls In the Forest, and There Is No One
There To Hear It, Does Sound Actually Occur?'
By definition, sound is an acoustic wave pattern
which is caused when a sound source disturbs the
normal random pattern of the molecules in air,
or in any other molecular medium, such as a liquid
It is safe to assume that if a forest of trees exists,
there must be air surrounding the trees,
and if there is air, there are enough molecules
to form acoustic waves whenever the air becomes
disturbed by a sound source.
If a tree crashes against the ground, it causes the
molecules around it to vibrate at a rate which is
determined by the specific characteristics of the tree,
and the ground on which it falls.
The molecules nearest the source are rapidly pushed
forward by the fallen tree. As the molecules collide
with adjacent molecules, they are forced backward
then forward again, continually vibrating in place.
Meanwhile, each wave of molecules pushes into the
next, creating a moving wavefront which travels
outward in all directions at the velocity of sound.
The velocity, or combined speed and direction
of the sound, depends on the precise temperature
of the molecules in the air.
As the sound waves travel outward
from the source of the crash,
they form an expanding sphere of energy
which travels through the forest.
The natural energy and momentum
of the waves dissipate at a rate
which is equal to the square of the
increasing distance from the source.
All of this occurs whether or not
there is any particular sound detecting
mechanism in the forest,
including human ears,
to record or process
the acoustic wave information.