Don’t expect the sounds of silence this winter.
Nature is noisy. For those that are willing to brave the cold weather, a sound safari awaits! The drumming of woodpeckers, creaking of trees, rushing of winds and cracking of ice provide a lot of acoustic action this season.
Winter is a slower time for most of us. There is less light, less outdoor time and definitely fewer people. There might even be less noise, though the sounds we hear seem to be so much louder.
The science of sound might suggest an explanation. Sound is a mechanical wave caused by a pressure differential that moves through a liquid, solid or gaseous substance. Each wave is composed of frequencies, some of which can be heard by the human ear and others that can’t. As these sound waves move, they are absorbed or attenuated, reflected or refracted.
Although sound travels relatively fast, it can’t compete with the speed of light. Light moves 900,000 times faster than its sluggish sister, sound.
The speed of sound is variable. Sound travels slowest in gases and fastest in solids. In water, sound moves 3,315 miles per hour. You probably wouldn’t guess it, but one of the fastest conductors of sound is granite, through which sound waves move 13,421 miles per hour!
The speed of sound also depends on temperature and humidity. As the temperature increases, the speed of sound increases. At sea level at 32 degrees, sound is estimated to travel 740 miles per hour. Increase the temperature to 68 degrees and sound moves faster, approximately 767 miles per hour. So, in winter, sound waves move more slowly.
But the velocity of the sound waves is not the only factor that affects what we hear. The environment through which the sounds move is drastically different this time of year. Gone are the leaves that absorb and mute sound. Sound waves travel farther and we hear more without dense foliage to get in the way — as William Shakespeare said, “The empty vessel makes the loudest sound,” and so do empty woods.
In contrast, frozen surfaces don’t absorb sound; they reflect it, allowing sound to travel farther. Once the ground is frozen, sound waves are reflected, and since the atmosphere above the ground is warmer than the surface, sound waves are bounced back toward the ground. Snow reverses the trend, absorbing and muting sound.
Listen is good advice and enjoyable too. Epictetus the Stoic, 2,000 years ago, pointed out that “God gave man two ears but one mouth that he might hear twice as much as he speaks.” This is the perfect time of year to put those ears to good use and appreciate all that they encounter.
Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown.