Quick Science Lesson

When I was approximately ten years old, back about 1948, on a cool clear morning, I heard the unmistakable sound of a sledge hammer hitting a steel post driving the post into the ground.  It was emanating from our neighbor’s direction, causing me to look that way.  As I did I noted a repetition of the sound, but our neighbor about ¼ mile away, had the hammer up over his head.  As I watched he once again swung the large hammer and struck the post again.  He then raised the hammer in preparation for the next strike.  Only as the hammer was high in the air did I hear the sound of the previous hit.  I watched this action several more times before coming to the conclusion what I saw was happening faster than what I heard.

Later I learned that the speed of light is approximately 186,282 miles per second.  It is also a fact that the speed of sound is a mere 1/5 mile per second, meaning the speed of light is nearly a million times faster than the speed of sound.

On yet another occasion a question was asked in relationship to a hypothetical phone call.  “If two people are in a room a few feet apart, and one is speaking on a telephone to a third person a long distance away, who hears the sound first, the one in the room, or the one hearing it via the phone?”  As sound via an electrical signal traveling at the speed of light, such as in the phone call, is far faster the person hearing it in that manner would hear the sound prior to the person across the same room.

Lightning splitting the air causes the sound of thunder.  As you see the lightning at the speed of light, but you hear it at the speed of sound, by the time you hear it, it has long since happened depending on the distance it was away from you.  Obviously there is no reason to fear thunder as the possible damage causing lightning is long gone when you hear it.  Lightning distance can be roughly calculated by counting the seconds between seeing the lightning and hearing the thunder.  As the sound travels approximately 5 miles per second, counting the seconds between the lightning and the ensuing thunder will give a rough distance.

You will never hear the bullet that kills you should that unlikely event ever happen.  The speed of the bullet, variable for many reasons, is much faster than the speed of its sound.