Sonic Boom

A sonic boom is a large amplitude sound wave created when the source of the sound is moving faster than the speed of sound. Here is an animation that will help with this understanding. Please see notes below.

Pretend the moving blue sound wave source is a jet airplane moving through the air at a speed greater than the speed of sound. For example, the animation will run this way if the source speed equals 3 and the the wave speed equals 2. Our plane would create sound through its energetic collision with the atmosphere. The plane, though, would out run and pull ahead of this sound, since the plane is traveling faster than sound.

Under these conditions the plane's sound waves from a pattern in which these emitted sound waves constructively interfere to form a loud wave with a large crest and trough amplitude. Here's how to recognize this pattern in the animation:

A swimming duck often forms a wave interference pattern similar to this sonic boom pattern:

In the above picture the duck is moving through the water at a greater speed than the water ripple waves are moving across the pond. A wave pattern similar to a sonic boom is formed on the water. This pattern is highlighted by flashing white lines.