Answer: The compression pulse which is produced when the hammer hits the metal bounces backwards and forwards within the metal. Most of the pulse (sound wave) is reflected within the metal rather than transmitted outside the metal into the air because the speed of sound in a metal is much bigger than the speed of sound in air.
Explanation: Brainelist Me
In chapter 2 of the Lightening Thief, Percy sees 3 old ladies knitting a sock and one cuts a string looking in his direction which symbolizes Percy's lifeline is in danger. The ladies know he is a demigod in danger, and the mist keeps him from knowing this. The mist conceals magic. Later as the book goes on strange events lead to a realization that he is a demigod.
