MAIN GOALS of this talk: 1. Let you know/remind you that the IAA has a worldwide reference light scattering laboratory for experimentally studying the angular dependence of the scattering matrices of dust samples of astrophysical interest. 2. Convince the audience of: - Polarization is highly valuable tool for retrieving information on the physical properties of small cosmic dust particles. - How useful laboratory measurements can be for (among some other things) properly interpreting astronomical observations .