Strange Air Trap

[Clarence Wood]

Hi all,
  a mechanic friend of mine has asked me on several occasions if I could explain a strange type of air trap that is on 80+ autos.  Today he asked again.  Here are the particulars:
  1994 Chevy S10, 4.3L V6.  On the air intake tube, close to the radiator support, there is a small opening on the top of the tube less than an inch square, that leads to a large, molded, plastic buble.  This plastic buble is empty and does not have anything attached.
  My guess is that it is some kind of air dampener.  
  Does any body know why?



  
Clarence Wood
Software&Such...
1982 280zx Turbo
Savannah, Tn.