You are presented with the question "blowing air into a whistle causes a what?" and the following answer choices: 
- rapid blast of heat
 - kinetic energy
 - little beads
 - activation energy
 - sound source
 - wind speed
 - small rattling
 - mechanical

Now knowing that blowing air into a whistle causes air to vibrate inside the whistle and pipe organ Vibrating columns of air inside the pipes are the sound source, choose the best answer.


 

     sound source    