Why does a gun make noise?
To propel a projectile from a handgun, rifle, or basically any other firearm, a highly explosive material is used. In theory, the more pressure you can put behind a bullet, the faster it will fly. If you have read my explosion write-up, you know that the sound from explosions is caused by the rapid expansion of gases. This rapid expansion is what pushes the bullet ahead, so logic should leade us to believe that there isn’t such a thing as a silent gun Wrong. In theory, if you set of a very very small explosion in a gun barrel that was closed (in other words, in a very strong piece of pipe), you wouldn’t hear the explosion too well. Why? Because the shock wave from the expanding gas never reaches the air outside. Although the pressure inside the barrel might be very high – if the pressure isn’t enough to break the barrel – you don’t hear a thing. The thing is – trying to fire a bullet from a closed pipe is rather useless (we want the bullet to fly, right). Think about a balloon. If you
