🚀 go-pugleaf

I am looking for a way to seal out street noise through my windows:

(1) What are the physical properties which determine sound insulation
    in the audible part of the spectrum.  In particular, how do absorbtion
    and dissipation work.

(2) I suspect that mass of the materials is important in dealing with 
    low frequency  noise.  On this not, will 1.5-2 inch thick water tanks
    in front of my windows be helpful.  Also, is there a good source of
    transparent polyethylene pads (or something like this )

--David Chasman