Ocean Sounds

• Hold an empty seashell up to your ear, and you can hear a noise that sounds very similar to ocean waves crashing on the shore. However, this phenomenon has nothing to do with where the seashell originated. The ocean sounds coming from the interior of seashells are related to the sound of air moving in the inner cavity of the shell.
  
  

Creating the Noise

• When a seashell is free of its inhabitant, it is simply an empty chamber. Because of this, it is able to amplify and distort the sound of air traveling across its surface in a way filled vessels cannot. The sound that comes from the inside of a shell is the sound of air moving across and within the shell. The cavity of the seashell allows the noise to echo and resonate. The movement of air is constant, so the noise coming from the interior of the shell is a continuous whooshing, which is very similar to the sound of the ocean.
  
  

Recreating the Phenomenon

• Seashells are particularly effective in reproducing this noise because of their often twisted shapes and deep interiors. However, this phenomenon is not reserved solely for shells. If you hold the open end of any deep, hollow object (such as a drinking glass or your cupped hand) to your ear, it will produce a similar sound. Different types of objects will produce the noise at different frequencies, depending on the depth and design of the item.