Can you hear
the ocean when you hold a seashell to your ear?
Have you ever tried holding a seashell to your ear
to bring back the beach you just left? It seems like no matter how far
away the beach is, so long as you have that shell, you can put the
seashell up to your ear and hear the roar of the waves rolling on the
shore. The best shells for producing this sound are large spiral conch
Some people suggest that the sound you hear in the
seashell is the echo of your blood rushing through the blood vessels of
your ear. If this were true, then the sound would get louder after
exercising, since your blood flows faster after exercising; however, the
sound is the same before and after exercise.
Others think that the wave sound inside the shell
comes from air flowing through the shell. The air flowing in and out of
the shell creates the sound. The sound is louder when you pull the shell
away from your ear than when it is right up against your head. This
theory does not hold true in a soundproof room. In a soundproof room,
there is still air, but when you hold the shell to your ear, you no
longer hear the ocean.
The most likely explanation for the wave sound is
the background noise from around you. You may not even notice these
background noises any other time, but the shape of the shell causes the
sounds to be amplified (made louder). The shell “collects” the sounds
from your surrounding, so what you hear when you hold the shell up to
your ear are all the background noises bouncing back out of the shell.
You don’t even need the seashell to hear the noise.
You can produce the same ocean sound using an empty cup or even by
cupping your hand over your ear. Go ahead and try it, and vary the
distance at which you place the cup near your ear. The level of the
sound will vary depending on the angle and distance the cup is from your
Noise from outside the shell can also change the
intensity of the sound you hear inside the shell. You can look at the
shell as an amplifying chamber. When sound from outside enters the
shell, it bounces around, creating an audible noise. So, the louder the
environment you are in, the louder the ocean sound will be.